A sunroof apparatus includes a panel, a sunroof unit including a frame portion, and a pair of housings connecting a pair of front ends and a pair of rear ends of side frames in a vehicle width direction, and a sealing member formed in an annular shape, the sealing member attached to the frame portion, the sealing member arranged between the frame portion and a peripheral rim portion of an opening in a vehicle height direction over a whole periphery of the peripheral rim portion. The housings each is formed with an injection space formed in a tapered shape opening so as to include a meeting surface of the side frame, the meeting surface facing the housing, the injection space provided at a connection part between the housing and a part of the side frame, the part disposed above the sealing member. The injection space is filled with a sealant.

A known sunroof apparatus is disclosed in JP2005-162099A (hereinafter referred to as Patent reference 1). The sunroof apparatus disclosed in Patent reference 1 includes a frame-shaped base panel (housing), a sunroof unit, and plural panels. The base panel is mounted on a peripheral rim portion of an opening provided at a roof of a vehicle. The sunroof unit includes, for example, a pair of guide rails attached to the base panel at a lower portion thereof. The plural panels are arranged upward of the base panel and configured to close the opening of the roof.
The sunroof apparatus disclosed in Patent reference 1 generally includes an annular sealing member arranged between the sunroof apparatus and the base panel continuously over the whole periphery of the peripheral rim portion of the opening so as to cover the peripheral rim portion of the opening and all fixation members of the base panel. Accordingly, the sealing member inhibits water outside (water at an outer periphery of the sealing member) from entering inside of the vehicle.
Meanwhile, a sunroof unit may be considered to be mounted directly on a peripheral rim portion of an opening without a base panel. In particular, the sunroof unit is formed in a frame shape so as to be directly mounted on the peripheral rim portion of the opening, the frame shape formed by a pair of side frames mounted on guide rails and a housing connecting distal ends of the side frames with each other in a vehicle width direction.
In this case, in a case where only the annular sealing member is arranged between a set of the side frames and the housing and the sunroof unit over the whole periphery of the peripheral rim portion of the opening, water outside may enter inside through a clearance generated at connection parts provided at the side frames and the housing.
A need thus exists for a sunroof apparatus which is not susceptible to the drawback mentioned above.


A film-forming silicone resin composition, comprising a reaction product obtained by a method comprising the step of heating (A) an alkoxysilyl-functional organopolysiloxane obtained by running an equilibration reaction with components comprising (A1) a polydiorganosiloxane and (A2) an alkylpolysilicate in the presence of (A3) an equilibration polymerization catalyst; (B) colloidal silica, aluminum oxide, antimony oxide, titanium oxide, or zirconium oxide; and (C) water, and a curable film-forming silicone resin composition, comprising above film-forming silicone resin composition and (E) a condensation reaction catalyst.

Prior to this invention, silicone-based aqueous coating agents have included compositions obtained by hydrolyzing methyltrimethoxysilane in an aqueous dispersion of colloidal silica (for example, see U.S. Pat. No. 4,197,230, U.S. Pat. No. 4,223,072, U.S. Pat. No. 4,243,721, U.S. Pat. No. 4,309,319, U.S. Pat. No. 3,976,497). However, the problem with these compositions was their poor storage stability due to the continual hydrolysis of methyltrimethoxysilane over time. In addition, when alcohol was used as the dispersion medium, noxious methanol was generated as a result of the hydrolysis of methyltrimethoxysilane.
Objects of the present invention include providing a film-forming silicone resin composition and a curable film-forming silicone resin composition of superior storage stability which form smooth coating films of superior water repellency on a variety of substrate surfaces.


An illumination optical system comprises plural rod integrators, a combining optical system and a light transmission unit. The rod integrators uniformize light intensity distributions of the light beams. The combining optical system combines the light beams emitted from the rod integrators, so that the light beams are adjacent to each other in cross-sections thereof. The light transmission unit has an entrance plane and an exit plane, divides the light beam combined by the combining optical system into plural light beams on the entrance plane, joins the divided light beams so that a cross-sectional shape of a joined pattern of the light beams on the exit plane is different from a cross-sectional shape of a joined pattern of the light beams on the entrance plane, and transfers each of the light beams from the entrance plane to the exit plane using plural optically coupled light pipes.

1. Field of the Invention
The present invention relates to an illumination optical system, an exposure apparatus, and a method of manufacturing a device.
2. Description of the Related Art
In a lithography process, that is, a process of manufacturing, for example, a semiconductor device or a liquid crystal display device, an exposure apparatus transfers the pattern of an original (reticle or mask) onto a photosensitive substrate (for example, a wafer or glass plate having a resist layer formed on its surface) via a projection optical system. In recent years, as a projection exposure apparatus which transfers a pattern to, for example, a liquid crystal display device, an exposure apparatus which transfers a pattern having a larger area on a mask onto a substrate by full-field exposure is required. To meet this requirement, a step-and-scan type scanning exposure apparatus capable of obtaining a high resolution and transferring a large area has been proposed.
This scanning exposure apparatus transfers a pattern illuminated with a slit light beam onto a substrate by a scanning operation via a projection optical system. Such an apparatus that scans using arcuated light is available. In this type, a projection optical system is present between a first object having a pattern to be transferred, and a second object onto which the pattern is to be transferred, and an exposure process is performed in an arcuated exposure region using only a specific off-axis image point of the projection optical system.
At this time, to illuminate the first object with arcuated light, an illumination optical system described in Japanese Patent Publication No. 4-78002, for example, can be used. This illumination optical system employs a method of guiding a light beam emitted by a light source so that its cross-sectional shape becomes a rectangular shape at a position optically conjugate to that of the first object serving as a surface to be illuminated, and extracting an arcuated illumination distribution using an arcuated opening member from a region illuminated in a rectangular shape. However, the arcuated illumination distribution extraction scheme described in Japanese Patent Publication No. 4-78002 makes it impossible to use light other than the arcuated opening as exposure light. Hence, the light use efficiency is low, and it is difficult to increase the illuminance on the surface to be illuminated of the illumination optical system even when the output of the light source is raised.
Japanese Patent Laid-Open No. 3-171614 to be described next makes an attempt to optically couple a plurality of light pipes to convert the cross-sectional shape of a light beam emitted by a light source into an arcuated shape, thereby improving the light use efficiency. However, these days, to comply with a demand for improvements in throughput and imaging performance in a lithography process, an illumination optical system which more uniformly illuminates the first object plane at a higher illuminance is required. An illumination optical system described in Japanese Patent Laid-Open No. 3-171614 can uniformly illuminate the first object as long as only one light source is used. However, because this illumination optical system uses only one light source, it has a limit in achieving high-illuminance illumination. To achieve high-illuminance illumination using the illumination optical system described in Japanese Patent Laid-Open No. 3-171614, a plurality of light sources can be used. However, in this case, when, for example, the outputs of the light sources vary with time, and a difference in output therefore occurs between the light sources, a variation may occur in the illuminance distribution on the first object serving as a surface to be illuminated, thus making uniform illumination impossible. Also, Japanese Patent Laid-Open No. 3-171614 shows an embodiment in which an illuminance variation is reduced by increasing the dimension of each arcuated light pipe in the direction in which light travels, but it is difficult to manufacture such a long arcuated light pipe. Furthermore, when long light pipes are used, the size of the overall illumination optical system increases.
Japanese Patent Laid-Open No. 2000-164487 describes an illumination optical system which combines light beams, emitted by a plurality of light sources 1a and 1b, using prisms 8a and 8b and uniformizes the light intensity distribution of the combined light beam using a rod integrator 4, as shown in FIG. 16. The use of this illumination optical system makes it possible to uniformly illuminate a first object (a surface to be illuminated) 6 at a high illuminance using a plurality of light sources.
However, when the illumination optical system as described in Japanese Patent Laid-Open No. 2000-164487 is used, light incident on the rod integrator 4 has a nonuniform positional distribution. Hence, to achieve a uniform illuminance distribution on the first object 6 serving as a surface to be illuminated, the dimension of the rod integrator 4 in the direction in which light travels increases. As the rod integrator 4 gets longer, the size of the overall illumination optical system increases. Again, as the rod integrator 4 becomes longer, a larger light loss is generated upon internal absorption of the rod integrator 4 due to manufacturing errors resulting from factors such as the surface accuracy of the rod integrator 4 and the parallelism between its opposed surfaces, thus degrading the light use efficiency of the illumination optical system.

Illumination optical system, exposure apparatus, and method of manufacturing device


A side puller apparatus includes a frame assembly adapted for mounting to a recovery vehicle, the frame assembly having first and second leg members inclined to approximately form an “A” shape and an upper member extending across tops of the leg members, first and second retractable arm assemblies respectively extendable from opposite ends of the upper member, first and second retractable leg assemblies respectively extendable from lower ends of the first and second leg members, and first and second winch assemblies respectively mounted on the first and second leg members, each winch assembly having a cable routed to a respective one of the arm assemblies, so as to be separately routable from the side puller apparatus during recovery operations.

Recovery vehicles, such as tow trucks and wreckers, are frequently called upon to recover vehicles under very difficult conditions. For instance, where the wrecked vehicle has careened off a road embankment, it can be very difficult to safely position the recovery vehicle to allow its regular equipment to pull the wrecked vehicle back to the road surface. This is particularly true for traditional tow trucks equipped with hook and chain or wheel lifts. Even for flatbed wreckers, such recoveries can be difficult or dangerous if road conditions do not permit sufficient space for the wrecker bed to be pointed toward the wrecked vehicle.
To address these problems, it is known to equip tow trucks and other recovery vehicles with side pullers. A side puller is usually mounted proximate to the vehicle frame rearward of the cab, between the cab and the wheel lift or other recovery equipment. The side puller incorporates a winch with a cable that tends out toward one side of the vehicle supported by a frame. The cable can be attached to, and used recover vehicles at angles perpendicular to the vehicle. Although conventional side pullers have proved very useful, and greatly increased the safety and versatility of those recovery vehicles equipped with them, further improvements are possible.


The invention relates to a new antibiotic designated Cyan426-A, to its production by fermentation, to methods for its recovery and concentration from the crude solutions, and to a process for its purification and to semisynthetic ethers of Cyan426-A, Cyan426-A-ethers.

New improved antibiotics are continually in demand, for the treatment of diseases in man. According to the World Health Organization, more than 95% of the Staphylococcus aureus isolates worldwide are now resistant to penicillin and up to 60% are resistant to methicillin (Breithaupt, H. Nat. Biotechnol. 17(12), 1165–9 (1999). Resistance is spreading from hospital-acquired infections to community-acquired pathogens, such as pneumococci and tuberculosis. The structurally related glycopeptides, vancomycin and teicoplanin, are considered the ultimate antibiotics of choice for treatment of methicillin-resistant S. aureus, but alarmingly, the rate of vancomycin-resistant enterococci has been increasing each year (a. Ginzburg, E.; Namias, N.; Brown, M.; Ball, S.; Hameed, S. M.; Cohn, S. M. Int. J. Antimicrob. Agents, 16 (Suppl.), S39–S42 (2000); b. Chopra, I. J.; Hodgson, B. M.; Poste, G. Antimicrob. Agents Chemother., 41, 497–503 (1997)) and there are cases of vancomycin-resistant S. aureus reported in industrial countries (a. Hiramatsu, K.; Hanaki, H.; Curr. Opin. Infect Dis., 11(6), 653–8 (1998); b. Marchese A.; Schito G. C.; Debbia E. A. Journal of Chemotherapy, 12 Suppl 2, 12–4(2000)).
The medical community recognizes that there is an ongoing need for additional antibiotics. The search for new antibiotics which exhibit antibacterial activity against vancomycin-resistant isolates and having structures which are not derivatives of vancomycin are particularly appealing.
Cyan416-A and their ether derivatives are different from the known antibiotics currently used in clinical practice. Some related compounds described in the literature include: Suzuki, S., Hosoe, T., Nazawa, K., Kawai K., Yaguchi, T., Udagawa, S., Antifungal substances against pathogenic fungi, talaroconvolutins, from Talaromyces convolutus, The Journal of Natural Products, 2000, 63 (6), 768; West, R., Van Ness, J., Varming, A., Rassing, B., Biggs, S., Gasper, S., Mackernan, P. A., Piggot, J., ZG-1494a, a novel platelet-activating factor acetyltransferase inhibitor from Penicillium rubrum, The Journal of Antibiotics, 1996, 49 (10), 967. Reported in Japanese Patent Kokai Tokkyo Koho, 2001, JP 2001247574 A2 20010911, Koizumi, F., Hasegawa, K., Ando, K., Ogawa, T., Hara, A., is Antitumor GKK1032 manufacture with Penicillium.
However, all of the above disclosed compounds are distinct from the present invention.


A polysilicon diffusion doping method which employs a deposited dopant-rich oxide layer with a highly uniform distribution of dopant atoms and thickness. Polysilicon layers 1,500 angstroms thick have been doped, achieving average resistance values of 60 ohms and non-uniformity values of 5 percent. Resistance values were measured using the four-point probe method with probe spacings of 0.10 cm. After a polysilicon layer has been formed upon a surface of a silicon wafer, a dopant-rich oxide layer is deposited upon the polysilicon layer at reduced pressure. The dopant-rich oxide layer is deposited, and serves as a source of dopant atoms during the subsequent diffusion process. The dopant-rich oxide layer is a phosphosilicate glass (PSG) including phosphorus pentoxide (P.sub.2 O.sub.5) and phosphorus trioxide (P.sub.2 O.sub.3) and deposited using a PECVD technique. Following deposition of the dopant-rich oxide layer, the silicon wafer is heated to drive dopant atoms from the dopant-rich oxide layer into the underlying polysilicon layer, and to electrically activate the dopant atoms within the polysilicon layer. The presence of electrically active dopant atoms within the polysilicon layer lowers the electrical resistivity of the polysilicon layer. After the heating step, the dopant-rich oxide layer is removed.

1. Field of the Invention
This invention relates to the manufacture of integrated circuits and more particularly to the doping of a layer of polycrystalline silicon.
2. Description of the Relevant Art
Polycrystalline silicon (also called polysilicon, poly-Si, or poly) deposited in thin film form has many important applications in the manufacture of integrated circuits. When doped with impurities, polysilicon exhibits low resistivity. Heavily doped polysilicon films are widely used as gate electrodes and interconnect lines in modern metal oxide semiconductor (MOS) transistors. Polysilicon is used in these applications for a number of reasons. Two important reasons are that polysilicon adheres well to silicon dioxide (oxide) insulating layers, and that polysilicon is able to withstand high temperatures involved in subsequent processing steps (e.g., source-drain implant anneal and thermal oxidation).
Dopant atoms may be introduced into a polysilicon layer during the formation of the polysilicon layer, by diffusion following formation, or by ion implantation. Polysilicon layers are typically not doped during formation due to the inability to closely control the thicknesses and doping uniformities of the layers. Diffusion doping involves the introduction of dopant atoms into an exposed surface of a polysilicon layer from a dopant-bearing ambient at elevated temperatures. During an ion implantation procedure, dopant atoms are ionized, accelerated to a velocity high enough to penetrate the surface of a silicon wafer, focused into a narrow beam, and scanned as a beam across an exposed surface of a polysilicon layer. Dopant ions impacting the surface enter the polysilicon layer and come to rest below the surface. A subsequent heating step is used to activate the dopant atoms within the polysilicon layer. Diffusion doping of a polysilicon layer is faster and cheaper than doping using ion implantation, and is therefore preferred. See, Wolf et al, Silicon Processing for the VLSI Era, Vol. 2, pp. 176-182 (incorporated herein by reference).
Phosphorus is a Group VA element and a common n-type dopant. A typical diffusion doping process used to introduce phosphorus atoms into a polysilicon layer is a batch process carried out in a diffusion furnace. Silicon wafers with polysilicon layers formed thereupon are placed on edge (i.e., vertically) in a wafer boat, and the wafer boat is placed within the diffusion furnace. A source of phosphorus atoms is introduced into the diffusion furnace and the temperature within the diffusion furnace is increased. Due to the closely-spaced arrangement of the silicon wafers in the wafer boat, all areas of the exposed surface are not equally accessible to phosphorus atoms. As a result, the uniformity of the doping of the polysilicon layer varies. It would thus be advantageous to have a polysilicon diffusion doping method which employs a highly uniform source of dopant atoms. Such a polysilicon diffusion doping method would result in highly uniform dopings of polysilicon layers.

Polysilicon diffusion doping method employing a deposited doped oxide layer with a highly uniform thickness


An apparatus for wrapping groups of rolls of products with a sheet of film comprises a station for packaging and moving, with a stepping motion, in a predetermined direction, a succession of groups of products wrapped in a sheet of film, having an open front side defined by two opposite flaps, and means for closing the open side comprising a unit consisting of: two pairs of mobile elements, arranged side by side in said direction, to allow the flaps of film of the two groups of products arranged one after another to be brought together and closed; first movement means for the unit, allowing synchronized movement of the two pairs of elements, respectively, in the same direction as the groups, for one group feed step, bringing together and closing the flaps, and a movement opposite to said direction over a distance equal to the distance previously traveled, simultaneously with a feed step of the groups to be packaged, so as to position the unit at two further and subsequent groups of products to be closed.

The present invention relates to an apparatus for wrapping groups of rolls of products with a sheet of plastic film to form a pack which preferably has a carry handle.
In particular, the present invention is for the production of packs or bundles containing a number of rolls and/or bundles with a rather high closing side.
Said packaging of groups of rolls of paper products, for example toilet or kitchen rolls, is performed using apparatuses designed (see also FIG. 1 which illustrates a known example of a pack):                to automatically wrap sheets 2 of plastic film (such as polyethylene or the like) around the side surfaces of rolls R arranged in an orderly way in one or more rows;        to then close the lower surface P1 of the bundle P by folding the end flaps of the sheet 2 of film over the bottom surfaces of the rolls R contained in the bundle P; and        to seal the folded flaps together;        to feed the partially closed pack, with a stepping motion, so as to fold the film on the front sides P2 and P3 of the pack and        to seal the front sides to form the closed pack.
This method is implemented using known apparatuses comprising:                a station for feeding individual rolls consisting of movement chutes and bars for pushing the rolls towards a        station for collection of the rolls and formation of the group of products (single or multi layered and in several rows) consisting of an elevator which transfers the products received in an orderly way from the feed station to a        packaging station, at a different level to the feed station and the elevator.
The elevator operates by means of a table which receives and transports products, which is horizontal and moves vertically between two end levels: the lower level being at the feed station and the upper level being at a section above for insertion of the products in the packaging station where the film is positioned horizontally so that it is intercepted by the products arriving and wraps around them.
Arranged vertically one after another after the sheet of film there are side folding hoppers and units which feed along the pack which is produced in stages, to obtain the first lower closure of the pack on the surfaces, as indicated above, using sealing bars and, in subsequent steps, also closing of the front of the pack.
It is possible to add to such apparatus, for example for bundles with dimensions such that they contain a large number of rolls, the application of a strip, again made of a plastic film, whose ends are fixed to the two sides of the bundle at one of the two front surfaces and whose length is such that it can be used as a handle for picking up and carrying the bundle.
An alternative for the production of "large" bundles, with sealed closure, preferably with the application of a bundle carry handle (automatically and at a cost lower than before) is illustrated in patent application BO2002A000392 by the Applicant, in which a method for creating a closure (with handle) on the packs is performed using an apparatus comprising two plates, which move vertically in opposite directions to bring together the opposite flaps of the sheet of plastic film at one of the two front surfaces of the bundle. These plates keep the flaps stretched out relative to one another with the possibility of sliding at a tangent to the plates, whilst pusher means neatly push the material of the side surfaces of the sheet located between the flaps into the space between the two flaps, gradually as they are brought together.
The plates are also equipped with sealing means for joining the two flaps once they have been brought together, and means designed to make an opening in the surface at which the two flaps are joined, so as to form a handle where necessary.
Said system therefore allows the bundle to be sealed and closed during the stepping feed of the bundle supporting teeth unit, if necessary forming the carry handle by adding, at the side of the path followed by the teeth, a pair of mobile plates on either side of the path to perform said closing.
However, now the current machines producing "standard" bundles have high productivity in terms of time, with consequent greatly reduced dwell periods for pressing the film, sealing and if necessary creating the handle opening, not sufficient to allow said operation. This is because a strictly predetermined time is required, in which at least the packaging station, therefore the conveyor teeth, must be in the dwell state.
Therefore, said factor would limit the maximum productivity of the machine.

Apparatus for wrapping groups of rolls of products with a sheet of plastic film


A fabrication method for semiconductor devices connecting a multi-crystal semiconductor thin film and a semiconductor region including a high density of an impurity formed in a single crystal semiconductor substrate. After forming a N-type semiconductor region as the emitter by ion implanting, for instance, as into a P-type semiconductor region as the base, a polysilicon thin film 114 is deposited so as to be implanted with As ions and then heat treated. In this case, an amorphous portion of the N-type semiconductor region and an amorphous silicon thin film in contact therewith are transformed by solid phase epitaxial growth so as to form a single crystal semiconductor region, a single-crystalline silicon thin film, and a polysilicon thin film, thus forming a bipolar element having an emitter.

The present invention generally relates to a manufacturing method for semiconductor devices, and more particularly, to a manufacturing method for improving the electrical characteristic in the connection between the polycrystalline semiconductor thin film to be used for bipolar type or field effect type integrated circuit transistors and semiconductor regions including high density impurities formed in the single crystal (monocrystalline) semiconductor substrate.
In the bipolar type or field effect type semiconductor circuit, the usefulness of using polycrystalline semiconductors for creating miniaturized elements is well known. For example, in the field of silicon semiconductor bipolar technology, it has become a common practice to use polycrystalline silicon as a diffusion source for fine wirings (electrodes) or shallow junctions, and particularly, the polysilicon electrode lead-out as a means for forming an emitter region of fine planar dimensions suitable for high speed operation has become an indispensable technology.
As an example of an emitter in which arsenic is diffused from poly-silicon, there is proposed "Self-aligned Double Diffusion polysilicon technology" (K. Kikuchi et al. International Electron device meeting Technical Digest of Papers pp. 420-423, 1986). According to this technique, a shallow emitter of about 50 nanometer junction depth was obtained by subjecting arsenic with a dose amount of 1.times.10.sup.16 /cm.sup.2 implanted into a polysilicon layer of about 300 nanometer thickness to a heat treatment at 900.degree. C. for 30 minutes for thermal diffusion. Furthermore, as shown in FIG. 19, an emitter of about 180 nanometer junction depth was formed by using a similar polysilicon and diffusing arsenic implanted therein under conditions of heat treatment of a comparatively high temperature (1000.degree. C., 20 min.). On the other hand, it is shown in the prior art that since diffusion at a higher temperature and a longer time is required to form a deeper emitter, the semiconductor region, such as a base region having been already formed by the foregoing process, is consequently diffused too deeply, so that it becomes impossible to obtain a transistor structure suitable for high speed operation. More specifically, in the process using thermal diffusion at a comparatively higher temperature (1000.degree. C., 20 min.) for forming an emitter of 180 nanometer depth suitable for high speed operation, since the base region was formed beforehand by ion implanting such as boron, the depth of the base region becomes greater than 400 to 500 nanometer. For example, using a currently commercially available ion implanter, in the case of forming a p-type base region with such a minimum implant acceleration energy (for example, 25 KeV) that is most stable with a little fluctuation, the junction depth of the base becomes about 500 nanometer, and, since the depth of the emitter formed at that time is about 180 nanometer, a transistor of about 320 nanometer base width is formed. A typical collector cut-off frequency f.sub.T of a transistor of 320 nanometer base width is about 5 GHz. In order to manufacture a higher performance transistor of 10 GHz cut-off frequency f.sub.T, it is necessary for the base depth to be 100 to 200 nanometer. In order for this to occur, the target width of the emitter to be formed by the thermal diffusion from polysilicon should be about 300 nanometer or more, and, accordingly, a heat treatment at a very high temperature and for a long time will be required. However, the result of such a treatment is that the base depth becomes considerably deep. Thus, using this method, there is no possibility of realizing a transistor of 100 to 200 nanometer base width.
On the other hand, as an alternative method for forming emitter-base junctions, a method has been proposed of directly implanting ions such as arsenic ions into P-type bases. For example, as shown in FIG. 20, arsenic of 1.times.10.sup.16 /cm.sup.2 was directly ion implanted into polysilicon at an acceleration energy of 50 KeV, and subjected to a heat treatment at 1000.degree. C. The emitter depth after the heat treatment for 60 min. diffusion time (t=60 min.) was about 430 nanometer, the depth after a 20 min. diffusion time (t=20 min.) was about 260 nanometer, while the depth after no heat treatment, that is, immediately after implanting (t=0 min.), was about 100 nanometer. As shown in FIG. 19, although the emitter depth obtained by diffusing arsenic from polysilicon through the heat treatment of 1000.degree. C. and 20 min. was about 180 nanometer, the emitter depth obtained by directly ion implanting arsenic into silicon and subjecting to a heat treating under the same conditions as above, that is, 1000.degree. C. and 20 min., was about 260 nanometer, as shown in FIG. 20, which was 80 nanometer deeper than the emitter depth obtained by diffusing from polysilicon. In this case, since the total amount of the arsenic impurity in silicon becomes larger in the case of direct ion implanting, the emitter resistance can be advantageously reduced. Furthermore, in the case of forming an emitter through the direct ion implanting, with respect to the lead-out method for such as Al electrode, it has become a common practice to directly lead out metallic electrodes from each emitter surface without using electrodes of polycrystalline semiconductors as intermediate layers.
As shown in FIG. 19, an additional problem with the formation of an emitter by diffusion from polysilicon is the existence of a silicon oxide thin film (residual insulation film) naturally formed between a polysilicon layer and a single crystal (monocrystalline) silicon substrate. This natural oxide film grows to a thickness of less than about 2 nanometer when non-single-crystal (non-monocrystalline, for example, polycrystalline or amorphous) semiconductor thin film such as polysilicon or amorphous silicon is deposited. Due to the variation of this thickness, the diffusion depth for the emitter becomes unstable. Furthermore, when this oxidized film becomes thick, the series resistance of the emitter is increased, resulting in deterioration or fluctuation in the transistor characteristic.
This problem makes it more difficult to lead out an electrode of a non-single-crystal material such as polysilicon or amorphous silicon from the deep emitter formed by the ion implantation method as shown in FIG. 20. That is, when polysilicon is deposited on the surface of the silicon containing a high density of surface impurities such as arsenic, the natural oxide film grows thicker than when polysilicon is deposited on the surface of a silicon surface containing a lower density of surface impurities. Thus, the ohmic contact between the highly-doped emitter and the deposited polysilicon is further deteriorated, resulting in a rapid increase in the resistance of the emitter.
Accordingly, the first technical task to be attained is the removal of the instability due to the natural oxide film.
The second technical task of the present invention is to form a comparatively deep or comparatively shallow junction of a predetermined depth through a heat treatment using a comparatively low diffusion temperature or using a comparatively high temperature for a short time. If a homogeneous junction of a predetermined depth for such as an emitter and the like can be formed through a heat treatment using a comparatively low diffusion temperature or using a comparatively high temperature and a short time, a transistor structure of narrow base width having an excellent high speed characteristic can be realized. For example, in order to form an emitter of about 250 nanometer depth according to a method such as the one shown in FIG. 19, a high temperature heat treatment of 1000.degree. C. for about 20 min. is required, resulting in the base region formed simultaneously being diffused too deeply, so that a transistor structure suitable for high speed operation can not be realized.
Furthermore, using the conventional method mentioned above, there is the additional problem that a solid phase epitaxial growth of silicon in the polysilicon film realigns the polysilicon film with the silicon substrate, when the emitter diffusion from polysilicon is performed at 900.degree. C.
This phenomenon is reported in a paper by S. Ozono et. al. entitled "Redistribution of heavily doped Arsenic in Poly-Si Film on Single Silicon Substrate during its Solid Phase Epitaxial Growth", 177th Electrochemical Society Meeting, Abstract No. 378, 1990, pp. 569 to 570.
In instances where influences due to the silicon oxide film, process contamination, etching damage by plasma and the like are small at the boundary (interface) between the polysilicon electrode and the silicon substrate, it is known that, when arsenic in polysilicon is thermally diffused, a solid phase epitaxial growth of silicon aligned to the face orientation of the silicon substrate takes place and a re-crystallized silicon of about 200 nanometer height is formed. By the formation of the re-crystallized silicon, the depth of the emitter diffusion layer becomes shallower than in the case where no epitaxial growth takes place and the current gain of the emitter is reduced. In the case of the formation of a solid phase epitaxial layer, the reliability of the transistor is reduced as the emitter area increases.
Thus, the third technical task to be attained by the present invention is the prevention of the solid phase epitaxial growth upon heat treating the emitter.
In the trial fabrication for NPN transistors for 0.5 .mu.m Bi-CMOS, accompanying the low temperature trend of the CMOS process for accomplishing a high package density, both a diffusion furnace heat treatment at 800.degree. C. to 850.degree. C. or a heat treatment by the Rapid Thermal Annealing (RTA) at 1000.degree. C. to 1100.degree. C. are proposed as heat treatment for the emitter. In the heat treatments at 800.degree. C. to 850.degree. C., because of the existence of a residual insulation film (natural silicon oxide film) between the polysilicon thin film and the silicon single crystal substrate, the arsenic impurities forming the emitter can not be diffused from the polysilicon thin film, and therefore, it is necessary to diffuse arsenic by a heat treatment at a high temperature but for a short time, such as RTA or the like. The NPN transistors made on the trial basis under such conditions realize a high performance of 15 GHz f.sub.r at a collector-emitter breakdown voltage (BV.sub.ceo) of 6 V and an emitter-base breakdown voltage (BV.sub.ebo) of 3 V. The problems with such a process to be solved in the near future are in stabilizing the emitter diffusion since RTA has poor reproducibility and ensuring the emitter-base breakdown voltage is sufficiently larger than the power supply voltage, so as to insure reliability.
The inventors of the present invention proposed a basic idea on which the present invention is based in U.S. patent application Ser. No. 378,671 filed on Jul. 12, 1989, to solve the problems mentioned above. In that application, a method is disclosed for fabricating a semiconductor device which comprises the steps of providing a semiconductor substrate having a single crystalline semiconductor layer of a first conductivity type, forming a first semiconductive region of a second conductivity type in the single crystalline semiconductor layer, forming a dielectric film on the semiconductor substrate either prior to or after the formation of the first semiconductor region, making at least one opening in the dielectric film to expose the first semiconductive region, forming a first non-crystalline semiconductor film on the surface of the first semiconductive region in the opening, forming a second semiconductive region of the first conductivity type into the first semiconductive region by implanting an impurity of the first conductivity type through the first semiconductor film, forming a second non-crystalline semiconductor film on the first semiconductor film and incorporating an impurity of the first conductivity type into the second semiconductor film.

Fabrication method for semiconductor devices

Matsushita Electric Industrial Co., Ltd.


An improved Direct Surface Manipulation (DSM) method is disclosed which incorporates a global surface reparametrization scheme for the purposes of extending the DSM method to applications involving multiple surfaces and for reducing the geometric effect of parametric space distortions on the features. This method reparametrizes multiple surface patches with a shared two-dimensional space defined in the object space of the model. The result is a geometrically consistent mesh, called a super-mesh, that serves as a global, uniform parametric space for topologically-disconnected, geometrically-disproportional surface patches. Spherical projection is employed to perform the patch reparametrization. This allows the creation of DSM features on multiple surface patches with improved shape quality.

Design of surface features is a frequent task in a wide variety of industrial CAD applications. In the automotive industry, in particular, surface feature design touches almost all major product development activities. Examples include design of head lamps for vehicle styling, structure reinforcement ribs for inner-panel engineering, spark-plug bosses of a cylinder chamber for engine prototyping, and draw-beads on stamping dies for manufacturing.
While the NURBS (Non-Uniform Rational B-Spline) paradigm allows a CAD user to create surface features by manipulating control points, in reality, however, using the control points as the degrees of freedom has two significant limitations. First, a control point is unable to isolate an arbitrary local or global region of influence and second, the basis function of a control point usually does not match the characteristics of the desired feature. Thus, without more sophisticated alternatives, it is difficult to form and maintain arbitrary user-specified features by employing the basic NURBS paradigm.
This has motivated research on a variety of related topics in an attempt to improve the relationship between the degrees of freedom and the features of the surface. A scheme has been developed for adding a smooth affect distribution to an arbitrary region of a propeller surface. See Interactive Adjustment of Surfaces, International Journal of Mechanical Sciences, 20(1), January 1978 and Simplified Method for the Interactive Adjustment of Surfaces, Computer-Aided Design, 12(6), November 1980 both by J. P. Duncan and G. W. Vicker. A similar technique has been developed for describing functional features such as automobile inner panels. Feature-Based Surface Design and Machining, IEEE CG&A, September 1992 by J. C. Cavendish and S. P. Marin and U.S. Pat. No. 5,119,309. Each is effective for the given application, but neither is well-suited to different surfaces in general.
A more general method was developed by one of the inventors of the present invention. Called Direct Surface Manipulation, or DSM, this method allows the specification of a local or global region of influence to be governed by a single control. See Direct Shape Control of Free-Form Curves and Surfaces with Generalized Basis Functions, Ph.D. Dissertation, by P. J. Stewart, University of Michigan, 1991 incorporated herein by reference.
Once a specific region has been isolated on a base parametric surface patch, selected features within the region can be manipulated by adjusting independent, meaningful parameters, each controlling a specific property of the feature, such as its location, boundary shape, height, and boundary continuities with the base surface. In addition, DSM features are based on and defined within the parametric space of the base surface patch. As a result, they are commutative, meaning that the resulting shape of the surface patch is independent of the order in which individual DSM features are applied. Such a property allows the rapid calculation of surface features, thus facilitating real-time model interaction.
Nevertheless, DSM has two major limitations. The first is its inability to describe features which span multiple surface patches. This is so because DSM features are defined within the parametric space of a single surface patch. In production applications, however, complex models are often described by a large number of surface patches and this limitation imposes a significant restriction on the use of DSM technology. The second limitation is that features described within the parametric space of a surface may be distorted when projected to the object space of a surface. This results from spatial inconsistencies between the two spaces. For instance, an equally spaced rectangular grid in parametric space may become a severely distorted mesh in object space. These distortions are inevitably reflected in the shape of the DSM features mapped onto the surface.
In this context a surface is defined as the geometric shape of at least a portion of a three dimensional CAD object. A surface patch is defined as a surface element with an independent reference frame. By parametric space of a surface, or surface UV domain, we mean the two dimensional parametric domain of a surface patch of parametric representation. A point in this space is given in (u,v) Cartesian coordinates. By object space we mean three dimensional modeling space where all surface patches resides. A point in object space is given in (x,y,z) Cartesian coordinates. By DSM feature space we mean two dimensional space where a DSM feature is defined (originated). A point in this space is given in (u.sub.d,v.sub.d) Cartesian coordinates.
Referring to FIGS. 1 and 2, the prior art DSM method creates an entire geometric feature as a single mathematical entity through the use of basis functions. Basis functions govern the characteristics of the feature and mathematically guarantee the continuities between the feature and base surface patch. Conceptually, the creation of a feature can be summarized in the following steps.
1. Create a basis function in one dimension to represent the characteristic profile of a feature (f(t) in FIG. 1). PA1 2. Translate the one dimensional basis function to a function in two dimensions in a DSM feature space that describes the characteristic shape of the feature (g(u.sub.d,v.sub.d) in FIG. 1). PA1 3. Map DSM feature space (i.e. with function g(u.sub.d,v.sub.d)) to the parametric space of the surface (FIGS. 2 (a) (b)). PA1 4. Specify an offset vector that defines the location of an individual surface point lying within the boundary of the mapped basis function (V in FIG. 2(c)). PA1 5. Offset the remainder of the points within the feature boundary parallel to the offset vector and scaled by the value of the basis function evaluated at the corresponding location (FIG. 2(c)).
The DSM method has also been extended to produce surface features with a fillet region. The so-called double bound DSM feature is formed by applying a basis function to bridge the two boundary curves of the feature, thus forming the fillet region. See for example, U.S. Ser. No. 08/550,151 now U.S. Pat. No. 5,731,816 filed Oct. 30, 1995, by the assignee of the present invention.
Applying the basis function requires the establishment of a one-to-one correspondence between the base surface patch and the feature. Current DSM obtains this relationship by mapping points either from the parametric space of the base surface patch into the DSM feature space or from the feature space into the parametric space, depending on how the surface patch or feature is tessellated. Without losing generality, it is assumed that a surface patch is tessellated based on its (u,v) grid regardless of the existence or shape of DSM features. Under this assumption, evaluation of a point Q always starts from its (u,v) location in the base surface patch's parametric space. Thus, if a DSM feature is involved, the necessary relationship between base surface patch and feature is obtained by mapping Q from the parametric space of the patch into the feature space. This process is illustrated in FIG. 2, where a parametric surface patch point location (u,v) is mapped into the DSM feature space and reparametrized as (u.sub.d,v.sub.d). If the (u.sub.d,v.sub.d) location is within the boundary of a DSM feature, the surface patch point must be modified during the formation of the feature and its final location in object space can be found as follows: EQU Q(u,v)=Q.sub.b (u,v)+g(u.sub.d (u,v),v.sub.d (u,v))V (1)
where Q.sub.b represents the portion of Q obtained from the base surface, g is the two dimension basis function described previously, and V is the corresponding control vector of the DSM feature similar to the one shown in FIG. 2.
With the current DSM approach, which is also referred to as parametric DSM, the DSM feature space is directly superimposed on the parametric space of the base surface patch, as shown in FIG. 2. A major benefit of connecting the two spaces in this manner is that point mapping requires only standard coordinate transformations (rotation and translation), and is thereby computationally efficient. However, there are also negative consequences, the most important being that a DSM feature cannot be analytically defined over multiple surface patches and therefore must reside solely on a single patch. A second limitation is that a feature may not be faithfully formed in object space because there is often a spatial disproportion existing between the parametric space where the basis function is formed and object space that the feature is mapped into. For instance, a uniformly spaced grid in the parametric space may not have uniform spacing, or even be parallel, when mapped to object space. For this reason, the final shape of a feature will almost always exhibit some type of distortion.

System and method for forming geometric features using global reparametrization


A lead calcium tin alloy to which cobalt has been added is described. The alloy is useful in the formation of anodes to be used in electrowinning cells. Electrowinning cells containing the cobalt alloys are particularly suited for electrowinning metals, such as copper, from sulfuric acid electrolytes. The cobalt-containing anodes improve the efficiency of oxygen evolution at the anode during electrowinning and reduce corrosion of the anode.

Lead calcium tin alloys have been used as electrowinning anodes for copper electrowinning for many years. Prengaman et al. in U.S. Pat. No. 4,373,654 developed the first rolled lead calcium tin anode. These anodes have been used in copper electrowinning service since the early 1980's. The anodes utilizing rolled lead calcium tin alloys have a long life. The combination of calcium and tin content along with mechanical working produced a material with high mechanical strength to prevent distortion, warping and short circuits while in service. The combination of tin and calcium reduces the rate of corrosion, promotes the formation of a conductive corrosion layer on the anode surface and improves the stability of the anode leading to improved anode life. Improvements have been made by Prengaman in the attachment of rolled alloy sheets to the copper bus bar in U.S. Pat. No. 6,131,798. In Prengaman et al. U.S. Pat. No. 5,172,850, the copper bus bar is protected from attack by coating it with a layer of electro-deposited lead onto the copper bus bar, thus improving the resistance to acid.
Despite the improvements in life in the copper electrowinning anodes, the anodes are corroded by the oxygen generated in the electrowinning process. Prengaman in "Improved Copper Electrowinning Operations Using Wrought Pb, Ca, Sn Anodes," Cu 99 International Symposium, October 1999, describes the anode corrosion. Oxygen is either evolved as oxygen gas or diffuses through the corrosion product on the surface of the anode to the lead surface where it reacts with the lead alloy to corrode the anode. It is important to produce a complete uniform, compact, thin, adherent and conductive PbO2 corrosion layer on the surface of the anode so that the oxygen can be evolved efficiently.
As the corrosion product becomes thicker, it begins to develop small cracks parallel to the anode surface. These cracks eventually result in the production of non-adherent flakes on the surface of the anode. The corrosion product can then be dislodged from the surface by the bubbles of oxygen generated at the anode surface. If the flakes contact the cathode, they can be reduced to metallic lead and become entrained in the cathode.
The rate of corrosion is related to the electrolyte temperature and current density of the electrowinning cell. The higher the current density and the higher the temperature, the more rapid is the rate of corrosion. In addition to the electrowinning cell conditions, the electrolyte often contains manganese. Manganese can react with the PbO2 corrosion product on the surface of the oxide, making it less stable and adherent and thus more susceptible to shedding. This was described by Prengaman in Cu 87 volume 3 and Electrometallurgy of copper Ed by W. Cooper, G. Loyas, G. Vearte, p. 387.
To reduce the rate of corrosion of the anode, increase the oxygen evolution and reduce the deleterious effects of the manganese, cobalt has been added to copper electrowinning electrolytes. Cobalt addition to electrowinning solutions was first described by O. Hyvarinen, P&D thesis 1971 and more recently by Yu and O'Keefe in J. Electrochem Society 146 (4) 1999, p. 1361, "Evolution of Lead Anode Reactions in Acid Sulfate Electrolytes I. Lead Anodes with Cobalt Additives."
The cobalt depolarizes the oxygen evolution reaction leading to easier oxygen evolution. This results in reduced anode corrosion, improved copper cathode quality and longer anode life. Cobalt ions are absorbed onto the lead corrosion product. Analysis of the corrosion product shows the presence of cobalt.
Cobalt is added to the electrolyte in an amount of generally 50-300 ppm. Jenkins et al., in copper 99 Vol. IV Hydrometallurgy of Copper Electrolyte Copper-Leach, Solvent Extraction and Electrowinning World Operation Data, surveys the operating conditions from 34 copper electrowinning tankhouses. To maintain the cobalt content of the electrolyte, cobalt must be continuously added to make up for the bleed of electrolyte from this system to control the impurities in the electrolyte. The cobalt addition varies from 100-800 g per ton of copper cathode. Loss of cobalt in the bleed is a major cost in operating copper tankhouse.

Alloy and anode for use in the electrowinning of metals


A trench forming assembly for forming a trench of predetermined shaped is disclosed according to the present invention. The assembly includes a pair of elongate frame members for defining a support surface for supporting a trench cover and at least one downwardly extending leg attached to each frame member for anchoring the frame members in a predetermined location. The assembly also includes a form body for shaping a hardenable trench forming composition into the predetermined shape of the trench and having an upper surface, opposed side surfaces and a bottom surface. The trench forming assembly further includes at least one counterbuoyancy member extending between the frame members and having a generally downwardly facing engagement surface for operatively engaging a portion of the upper surface of the buoyant form body between the frame members. The counterbuoyancy member can also have an upper surface, opposite the engagement surface, for operatively engaging the elongate frame members. Accordingly, the combination of the counterbuoyancy member, the pair of elongate frame members and the downwardly extending legs cooperate to substantially counterbalance the buoyant form body against upward flotation forces applied to the form body by a hardenable trench forming composition poured around portions of the buoyant form body.

Drainage and other trenches of various sizes and shapes are desirable for numerous applications. For example, manufacturing facilities typically require drainage systems which include trenches formed in the building floors to collect, remove and/or recycle excess water or other liquids. In addition, numerous outdoor industrial and commercial sites, such as parking lots, require drainage systems, including trenches, to collect and direct rainwater and other liquids to underground storm sewers to prevent flooding and to decrease runoff.
Furthermore, with increasing emphasis being placed on protecting the environment from ecological hazards, a number of relatively stringent environmental regulations have been adopted which restrict the types of materials which can be discharged into drainage systems. In particular, regulations have been enacted which limit the amount of oil and grease which may be discharged into drainage systems. Consequently, drainage systems, such as the drainage systems installed in gasoline stations, chemical transfer stations, oil storage areas and landfills, can include one or more oil water separators to separate solid debris, free oils and other non-soluble chemicals from the waste water.
In the past, the trenches, including oil water separators, which form these drainage systems have generally been formed by initially placing and securing a form of predetermined shape in a ditch which has previously been formed in the ground. A moldable trench forming composition, such as cement, concrete, or the like, is then poured around the form and is allowed to set. Once the concrete has set, the form is removed from the resulting trench.
One common type of form assembly used to define a trench includes a wooden frame and strut structure. The wooden form includes a wooden frame which is covered with wooden sheets or planks to define a generally rectangular elongate trough. The wooden form is generally enclosed along its side and bottom surfaces, but can have an open top. Typically, a number of supporting wooden ribs are installed within the wooden form to increase the strength of the form so that it can withstand the relatively large pressures exerted by moldable trench forming compositions poured about the form.
During installation, the wooden form is placed and secured within a preformed ditch. Concrete is initially poured in lower portions of the preformed ditch up to the bottom surface of the form. Once this initial pour of concrete has set, additional concrete is then poured between the earthen walls of the ditch and the wooden side surfaces of the form. Once this additional concrete has set, the wooden form is disassembled and removed from the trench.
It is normally desirable to finish the trench with an elongate grate covering its open top in order to prevent people from unwittingly stepping in the open trench, to provide a smooth surface for vehicle travel, and/or to prevent relatively large objects from entering the trench and potentially blocking the flow of liquid therethrough. The grate is generally supported by a pair of spaced apart frame members which are set into and extend from the walls of the concrete trench. In order to stabilize the grate and to prevent the grate from rocking when weight, such as from a passing vehicle, is applied thereto, it is important that the frame members are aligned in a common plane during the pouring and setting of the concrete about the wooden form.
Wooden forms are generally formed of lumber having a relatively rough exterior texture. Correspondingly, the inside surface of the resulting trench formed by the wooden form is relatively uneven, thereby reducing the efficiency with which liquid flows through the trench. In addition, the assembly and disassembly of the wooden forms is both costly and labor intensive. The relatively large costs and labor required for assembly and disassembly of the wooden forms is increased in the formation of long trenches, and even further increased in the formation of trenches having a pitched or slanted bottom surface to facilitate drainage.
As an alternative to wooden forms, precast trench assemblies have been developed. Precast trench assemblies generally include preformed metal and/or plastic assemblies designed to be placed in a ditch. Moldable trench forming composition can thereafter be poured about the precast trench assembly. Once the trench forming composition has set, the precast trench assembly is securely bonded to the trench forming composition which stabilizes and supports the trench. Precast trench assemblies, however, are relatively expensive and cannot generally be reused.
In order to overcome at least some of the shortcomings of wooden forms and precast trench assemblies, a trench forming apparatus and associated method which employ an improved removable form to define the shape of the resulting trench are disclosed in several U.S. Patents to Stegall, including U.S. Pat. No. 5,281,051 which issued Jan. 25, 1994, U.S. Pat. No. 5,348,421 which issued Sep. 20, 1994 and U.S. Pat. No. 5,393,171 which issued Feb. 28, 1995; each of which are assigned to ABT, Inc. of Troutman, N.C., the assignee of the present invention. The trench forming apparatus disclosed in the Stegall patents preferably includes longitudinal frame members having a plurality of anchoring legs extending downwardly therefrom. The elongate form body, typically formed of relatively lightweight expanded polystyrene, preferably includes generally upwardly facing surfaces associated with the opposed side walls of the form body for engaging the frame members. In one advantageous embodiment, the opposed side walls of the form body include aligned longitudinal slots which define respective ones of the upwardly facing surfaces for receiving and engaging the frame members. In particular, horizontal portions of the frame members are engaged by the generally upwardly facing surfaces of the opposed side walls so that the frame members are held in alignment during the trench forming operation. In typical practice, one or more wires are wrapped around the outside of the form body and frame members to hold the frame members in engagement with the generally upwardly facing surfaces defined by the opposed side walls of the form.
Preferably, the assembled form and frame members are placed into a preformed ditch by suspending the assembly from its top. A subslab of trench forming composition is initially poured around lower portions of the anchoring legs and is allowed to set. A second pour of trench forming composition is then poured around the form body and is allowed to set. Finally, the form body is removed from the hardened trench forming composition to expose the resulting trench and the properly aligned frame members. According to one advantageous embodiment, the form includes a pair of slots extending a relatively short distance into the form body from its bottom surface in order to facilitate removal of the form. The trench forming assembly can also include wires disposed within the slots such that, once the trench forming composition has set, the wires can be pulled upwardly through the form. The form body is thereby cut into several pieces that can be more easily removed from the resulting trench.
During the trench forming process described above, the moldable trench forming composition will exert an upwardly directed buoyant force on the buoyant form body. Thus, in addition to holding the frame members in alignment during the trench forming process, the engagement of the generally upwardly facing surfaces of the form body with respective horizontal portions of the frame members at least partially counters this buoyant force exerted on the form body by the moldable trench forming composition. In particular, the frame members and, in turn, the form body are held in position relative to the ground due to the secure engagement of the downwardly extending legs within the concrete subslab. Consequently, the engagement of the generally upwardly facing surfaces of the form body with the frame members is also designed to hold the form body substantially against upward movement during the trench forming process.
The upwardly directed buoyant force exerted on the form body during the trench forming process is directly proportional to the volume of the form about which the moldable trench forming composition is poured. Thus, larger form bodies which create correspondingly larger trenches are subjected to greater buoyant forces. However, the surface area of the generally upwardly facing surfaces of the form body which engage respective horizontal portions of the frame members to align the frame members and to counter the buoyant forces is generally limited to the corresponding surface area of the horizontal portions of the frame members.
Consequently, for a trench forming apparatus having frame members which include horizontal portions of a predetermined size for engaging a relatively large form body, the upwardly directed buoyant forces exerted on the relatively large form body may overcome the compensatory forces provided by the engagement of the upwardly facing surfaces of the form body with the frame members and force the form body upwardly from the trench. If the form body is forced upwardly from the trench by the upwardly directed buoyant forces, the form body is typically destroyed and that portion of the trench must generally be reformed in order to properly shape or form the trench.

Trench forming assembly having a counterbuoyancy member and associated method


Techniques are described for implementing automated control systems that repeatedly perform automated modifications to control system actuator components' ongoing operations to improve functionality for target battery systems, such as to reduce power dissipation while performing other battery power use activities to maximize battery life. Controlling a battery's usage may include using a DC-to-DC amplifier, and the repeated automated modifications may include modifying the state of the DC-to-DC amplifier actuator to adjust a level of resistance and/or an amount of time during which power is supplied. The repeated automated modifications may be performed to repeatedly reduce the distance between the current battery performance and an idealized version of the battery performance (e.g., a version with no power dissipation).

Attempts have been made to implement automated control systems for various types of physical systems having inputs or other control elements that the control system can manipulate in an attempt to provide desired output or other behavior of the physical systems—one example of such automated control is to manage operations of a battery that is discharging electrical power to support a load and/or is charging using electrical power from a source, while uncertainty exists about an internal temperature and/or chemical state of the battery, and potentially with ongoing changes in load, source and/or internal state of the battery. Such automated control systems have used various types of architectures and underlying computing technologies to attempt to implement such functionality.
However, various difficulties exist with existing automated control systems for battery systems, including with respect to managing uncertainty in a current state of a system being controlled and in how different types of inputs will affect operation of the automated control systems.

This patent is subject to a terminal disclaimer.

Controlling ongoing battery system usage while repeatedly reducing power dissipation


A dentifrice composition of the invention can be applied to teeth and/or gums by any conventional A dentifrice composition comprises (a) calcium carbonate having properties of particle size and angularity effective to provide mild abrasivity to dental enamel; (b) red iron oxide of low abrasivity in an effective amount on which to impart red color to the composition; and (c) a herbal component comprising at least one botanical or extract thereof, in a total herbal component amount effective to promote oral health.

Dentifrices such as tooth powders and toothpastes containing herbal ingredients are known. An example of such a dentifrice is Red Tooth Powder, manufactured by Dabur India Ltd, and is reported to contain, inter alia, clove oil, black pepper, blend of mint oils, long pepper, ginger, camphor, tomar seed and terminalia chebula.
Other oral care compositions that contain antibacterial seed or pulp extract from the citrus or grape families are known. These compositions may contain additional components such as red iron oxide as a tooth cleaning cum color modifying substances, and calcium carbonate as an abrasive polishing agents.
Red color can be imparted to dentifrices by red ocher, a mineral rich in red iron oxide (anhydrous iron (III) oxide or hematite). However, red ocher is harshly abrasive to tooth enamel.
There remains a need for herbal dentifrice compositions having a pronounced red color, which can be associated in the minds of consumers with certain oral health benefits, but which exhibits a mild abrasivity to teeth and gums.


A method, system, and information handling system provides better system power consumption of a redundant power system having a plurality of power supply units (PSUs) by taking into consideration each PSU's sleep power consumption during selection of one or more PSUs to place into a “hot spare” sleep mode. For each PSU, power efficiency data at different load ratings are measured and stored. During the PSU selection, a calculation of system power consumption is conducted on each of several configurations where a different PSU is hypothetically disabled. Each calculation takes into consideration both the sleep power consumption of a disabled PSU and power efficiency data of an enabled PSU. Selection of one or more PSUs to disable is determined according to the configuration yielding the lower or lowest system input power consumption based on the results of the calculations.

1. Technical Field
The present disclosure generally relates to a redundant power system used to supply power to an information handling system, and more particularly to a system and method for reducing power consumption when selectively putting one or more individual power supply units (PSUs) of a redundant power system to sleep.
2. Description of the Related Art
As the value and use of information continue to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
An information handling system (IHS), such as a computer server or a blade server system, often utilizes a redundant power system to achieve uninterrupted and reliable supply of power. With a redundant power system (RPS), there are at least two power supply units (PSUs) working in concert to collectively provide uninterrupted power to an IHS. Occasionally, for an RPS having two PSUs, there are circumstances under which one PSU supplies power to the IHS while the other PSU is put into the "hot spare" state. The "hot spare" state refers to a state where the PSU is disabled from actively supplying power by being put into a sleep mode, while remaining in readiness to supply power without any startup delay when required. Thus, in an RPS having two PSUs, if one PSU is detected as failed, the other PSU maintained in the "hot spare" state can pick up where the failed PSU left off by supplying power without any delay, thereby enabling the IHS to receive uninterrupted power.
In the conventional approach to a PSU shutoff situation, the PSU having the lower or lowest power efficiency is automatically selected to be shut off. The conventional approach, however, overlooks the fact that when a PSU is disabled by being put into the "hot spare" state, the disabled PSU still consumes power in order to be held in readiness to supply power. As a result, selecting the one PSU to disable by using the conventional approach at times results in system power consumption higher than what would have resulted if the other PSU was selected for disabling.
Accordingly, aspects of the disclosure recognize that, in order to truly minimize the overall power consumption of the RPS in a PSU-shutoff situation, there is a need for a different approach than the aforementioned conventional approach of automatically selecting the PSU with the lower power efficiency to disable.

Reducing power consumption of a redundant power system utilizing sleep power consumption considerations for power supply units within the redundant power system


A system for monitoring for gas and oil flow venting from a surface using time intervals, size and velocity, and using a processor with a data storage containing a bubble flow classification chart and bubble flow categories. The data storage receives at least one: video feed, drilling parameter data feed, seismic profile data feed, logging while drilling data feed, measurement while drilling data feed, sonar data feed, and hydrographic data feed to verify a determined bubble flow category and bubble flow classification as a baseline bubble flow classification and provides an alarm when a bubble flow emergency is ascertained due to a change in bubble flow classification without an anticipated change or changes outside predefined acceptable limits within the video feed, drilling parameter data feed, seismic profile data feed, logging while drilling data feed, sonar data feed, hydrographic data feed, or measurement while drilling data feed.

A need exists for a system for monitoring for gas and oil flow venting from a surface and to provide an early indication of subterranean formation problems by analyzing bubble size, time interval, and velocity for bubbles or globules venting from a surface.
A further need exists for a system for monitoring for gas and oil flow venting from a surface utilizing a video feed and a bubble flow classification chart to create a bubble flow classification for the surface and then additionally to verify the bubble flow classification results using data feed in real time, 24 hours a day, 7 days a week, from a plurality of data feeds including but not limited to at least one of: video feeds, seismic profile data feeds, measurement while drilling data feeds, logging while drilling data feeds, drilling parameter data feeds, sonar data feeds, and hydrographic data feeds, and further to monitor bubble flow and classify additional bubble flow over time to verify that the baseline bubble flow classification of bubble flow is valid or another classification of bubble flow needs to become the new baseline bubble flow classification.
A need exists for a system for monitoring for gas and oil flow venting from a surface during marine drilling, development, or production operations.
A need exists for a system for monitoring for gas and oil flow venting from a surface that can create immediate alarms regarding potentially dangerous situations and transmit those remote alarms to client devices, such as through a network.
The present embodiments meet these needs.
The present embodiments are detailed below with reference to the listed Figures.

System for monitoring a surface for gas and oil flow


Optical apparatus incorporating a lighting source capable of providing a substantial equal irradiance at each point of an image plane for use in backlighting transparencies during their reproduction and recordation. There is also disclosed and claimed apparatus using the lighting source to produce for the first time high quality electronic images in an analogue format of medical imagery originally or subsequently produced in a tangible form such as X-ray, CT, or MR images. There is further disclosed an integrated system providing apparatus for converting, storing, and retrieving images originally produced in tangible or intangible form that are subsequently converted to an analogue electronic format and stored in analogue format on an optical disc in an optical disc library. The system includes the apparatus for converting the tangible images into high quality electronic images and for converting digital images produced during CT or MR imaging or the like into a common analogue medium.

The present invention relates to apparatus for producing substantially equal irradiance at each point of a pre-selected area; to apparatus for converting visual data contained in transparencies or other visual media into electronic media; and to a system for integrating records contained in various media into a single useable media.
The modern medical practitioner has been blessed with a variety of new equipment capable of producing medical information in a variety of media. For example, computed tomography (CT) and magnetic resonance imaging (MRI) technologies produce information about the human body in a digital form that may later be displayed on a monitor or produced in a tangible form such as a negative for the treating physician to observe and to evaluate. With ultrasound imaging technology, the practitioner is able to view either a single snap shot taken at an instant in time or a movie produced from a series of such snap shots. With traditional X-ray equipment, the practitioner is provided with a view of the human body in the form of a negative, which can be observed and evaluated when the X-ray is displayed on a radiologist's lightbox. These are but some of the examples of the presently available devices that produce visual images for the medical practitioner to view and evaluate. Angiography, positron emission tomography (PET) scanning, and mammography are other examples.
While these devices produce vital medical imagery, they do so in a variety of different media. As noted above, the traditional X-ray is produced on a photographic negative. Most often, CT and MRI imagery are produced and stored as electronic media, although negative transparencies are also often produced from the electronic data. Images produced by ultrasound may be printed onto paper or may be captured in the form of a movie on videotape.
This broad variety of image storage media creates several problems. First, storage problems are presented for the institution where the information is gathered. Second, with the new imaging technologies, large numbers of images are created whereas in the past, perhaps only two or three X-rays would need to be accounted for by the record storage system. Third, the transfer of information in the form of the original images among medical personnel is hindered. Fourth, societal costs of the ill patient are increased. Examples of each of these problems may be readily given. Thus, X-ray negatives consume a considerable amount of often limited, expensive hospital floor space for storage of this form of tangible medical imagery. Other tangible imagery similarly use up large volumes of storage space. At large hospitals where thousands of these images are produced in short periods of time, filing of the images in the storage area so they can be found again may itself be a problem. Additionally, since other hard or paper copies of electronically produced imagery such as CT, ultrasound or the like are produced for viewing, the large numbers of images produced by these technologies exacerbates the storage problem.
Data transfer problems are increasing due to the ever-increasing specialization in the medical field. Medical records are being transferred from location to location both within and without a medical facility, with greater frequency.
Examples of data transfer problems include time delays inherent in the movement of tangible information from one location to another. Obviously these delays themselves slow communication between medical personnel. They also ma be additionally wasteful of time because they may keep busy a physician waiting for the information. The delays also may create a danger for a patient in need of rapid evaluation by an expert not present where the information is produced. Tangible media do not present the only communication problem, however. Information stored in electronic formats also presents problems because, presently, each manufacturer of CT, MRI, or other such imaging apparatus utilizes different electronic formats to acquire and store the data. Thus, even the data produced by these disparate techniques can present difficulties in providing a single storage system for electronically gathered technology; and because of that difficulty, utilization of the data after its acquisition can be difficult at any place other than the originating location.
Unnecessary, perhaps excessive, costs arise directly from the present system of medical record storage. For example, a patient may be retained in a hospital until a consulting physician, who may be an expert in a particular field, examines the particular medical imagery involved. Where the image media is an X-ray negative, the patient may be retained needlessly overnight while the X-ray is shipped to the consulting physician in a neighboring hospital, city or state or completely across the country. Not only may there be increased costs associated with retaining the patient in the hospital, but there are costs associated with the transfer of the important medical data in its tangible form such as postage expenses, handling costs, and reproduction costs if the medical images is copied and the copy sent rather than the original. Finally, a danger always exists that a vitally important medical image may be lost or misplaced during such shipments or storage.
Attempts have been made to deal with these problems. Thus, there exists apparatus capable of storing imagery produced in a digital format. Such systems do not well incorporate imagery that is produced in a non-electronic format in the first instance, such as X-rays, however. This stems from the fact that electronic reproductions of X-rays and the like have not been of a high enough quality for the evaluating physician to rely upon them. This inability to qualitatively reproduce the X-rays stems from an inability of present light sources to provide the proper backlighting to record the image on the transparency. The backlighting must, to provide a faithful, high quality reproduction, substantially equally irradiate each point of the transparency so that the data contained therein can be duly recorded. When too much light passes through one point relative to another, the information of the first point may be over emphasized and the information of the second point may be de-emphasized or lost entirely in the glare of the light passing through first point. Where the points form part of an X-ray, critical data important to a proper evaluation may be lost. Treating physicians are reluctant to rely on images for evaluation purposes when the image may have lost valuable or critical information in its reproduction from the original. Thus, equal irradiance is critical to high quality recording of X-rays, but not possible with present devices.
The above referred to systems rely upon digital transmission and replication of an image on a computer monitor, which is slow, however. Analogue transmission of the image would be faster; the technology in the medical area has shown a decisive digital trend, however, due, no doubt to the initial production of the electronic images in a digital format. Furthermore, because of its slowness, the digital systems provide little archiving capability to a medical institution. Because of these limitations, the digital systems presently available also provide limited education or training functions. This itself is critical in that many of the digital technologies are of a recent vintage and older practitioners are in need of training in the proper use of the data made available by digital imaging. Additionally, present day systems cannot provide true color displays of the data, which can aid in proper evaluation procedures, nor do they provide full motion. That is, with ultrasound and the like, motion studies are possible but since the present digital systems can take up to ninety seconds to transmit a single image from storage to a workstation, motion studies are essentially impossible to do.
This type of digital system is very expensive also, with costs often over one million dollars because of all of the necessary digital processing equipment. Analogue systems are quite inexpensive by comparison. Additional costs include the paper copies often produced of the digital images.
Another problem with the current image storage system is that there exists no single location where all of a patients records are stored. That is, X-rays may be in one location, an MR image may be in another, and the doctor's notes in still another. Gathering all of the records together is a tedious, time consuming task that could be improved if all of the images were stored in one location such as an electronic library. Storage of all records in a common medium including physician's notes, would completely eliminate this problem.
Thus, it has not been possible to design a single system capable of handling all medical imagery produced by the various apparatus now available. It would be desirable, therefore, to be able to convert tangible medical images originally in negative or positive views to an analogue electronic format and combined with digitally produced images such as that produced by CT, PET, MRI and the like devices in a common analogue format in a high density storage library such as that provided by optical disc technology at a reduced cost.

Apparatus for recording, storing and electronically accessing images


System and method for performing MRI-guided cryosurgery are provided. The system includes: (a) an MRI magnet for accommodating a patient, the MRI magnet having at least one opening for enabling access of a surgeon to the patient, the MRI magnet including at least one channel extending therethrough for receiving a line member of a surgical device; (b) a surgical device, including: (i) an operating member for operating the patient; (ii) a control member for controlling the operating member, the control member being positioned externally to the MRI room; (iii) a line member having a first end connectable to the operating member and a second end connectable to said control member, wherein at least a portion of the line member is received within the channel of the MRI magnet. Preferably, the line member includes an underground portion extending through an underground channel. The MRI magnet may include an interface member for connecting the operating member thereto. Preferably, the operating member is a cryogenic probe including a Joule-Thomson heat exchanger, the line member is a gas tube, and the control member includes a gas container for providing high pressure gas to the cryogenic probe via the gas tube. Preferably, the control member includes a microprocessor for controlling the operation of said surgical device.

The present invention relates to system and method for MRI (Magnetic Resonance Imaging)-monitored and guided cryosurgery. More particularly, the present invention relates to system and method which enable a surgeon to safely and conveniently perform a relatively complicated cryosurgery procedure under the influence of an open MRI magnet, and to obtain accurate and artifacts-free imaging results, thereby enabling effective guidance of the cryosurgery procedure.
MRI-monitored and guided surgical procedures are currently performed by using an "open MRI" apparatus, wherein the MRI magnet includes apertures so as to enable access of a surgeon to the patient.
However, the surgical process within such MRI environment is susceptible to the strong magnetic field of the MRI magnet (about 0.5-2 Tesla). Therefore, the range of surgical tools which may be used within he MRI room is substantially limited.
Various attempts have been made to provide surgical methods and devices which are unsusceptible to the magnetic field of the MRI magnet o as to enable a surgeon to perform substantially complicated surgical procedures within the MRI room.
Most of such attempts are directed toward the development of surgical tools made of compatible materials which are not influenced by the magnetic field of the MRI magnet and which enable to minimize the creation of artifacts interfering with the imaging results.
However, the prior art fails to provide method and device for carrying out an effective MRI-guided cryosurgery procedure.
Currently, cryosurgery procedures are performed by using a liquid nitrogen. The application of such liquid nitrogen to MRI guided cryosurgery requires the positioning of liquid nitrogen containers and appropriate control system within the MRI room, thereby exposing such cryosurgery system to the strong influence of the MRI magnet.
The extent to which such liquid nitrogen cryosurgery system can be kept away from the MRI magnet is substantially limited, since the tubes which supply liquid nitrogen from the containers to the operating tip tend to freeze and rigidify, thereby substantially limiting the manipulation of the operating tip by the surgeon. Therefore, MRI-guided cryosurgery procedures which apply liquified gas such as liquid nitrogen are substantially limited and almost impossible.
There is thus a widely recognized need for, and it would be highly advantageous to have, system and method for MRI-guided cryosurgery which enable a surgeon to safely and conveniently perform an MRI procedure.
There is further a recognized need for such system and method which enable a surgeon to perform a substantially complicated cryosurgery procedure which is unsusceptible to the influence of an MRI magnet, and which enable to obtain accurate and artifacts-free imaging results.

System and method for MRI-guided cryosurgery


Provision is made of a differential amplifier arrangement with a current source (S1), two controllable paths (T1, T2), which are in each case coupled by one terminal to the current source (S1) and the control terminals of which form the input of the differential amplifier arrangement. Via a respective cascode circuit (K1, K2), a load (L1, L2) is respectively connected to the first and second controllable paths (T1, T2). At least one tap (A1) between one of the loads and one of the cascode circuits forms an output of the differential amplifier arrangement. Provision is made of a comparison means (D1) having two inputs, which is designed for outputting a control signal dependent on a comparison. A first input is coupled to the first tap (A1) and the second input is designed for feeding a reference signal. Furthermore, the differential amplifier arrangement contains a regulable current source (G1), the control input of which is connected to the output of the comparison means and the current output of which is connected to the second terminal (P1) of at least the first controllable path (T1).

In receiving devices, a low-noise amplifier is usually situated such that it is connected directly downstream of the receiving antenna. Its task is to amplify an input signal received by the antenna. In this case, the amplifier is intended to have only a low inherent noise in order thus to have a good signal/noise ratio. In addition to the requirement for a low noise figure, a switchable gain is likewise desirable. This switchable gain is called "gain step". This prevents amplification of input signals with very high levels which overdrive the downstream signal-processing switching elements and thus cause signal distortions. In the case of such switchable gains, however, the accuracy that can be achieved is problematic since most circuit concepts have a different operating point depending on the gain. Changing the operating point in a manner dependent on the switchable gain reduces the accuracy of the "gain step".
A further requirement is a so-called dual band combination. In this case, the receiver device is designed for the reception and the processing of signals which lie in two different frequency bands. Generally, the two frequency bands lie in the spectrum in a range which cannot be covered by a normal low-noise amplifier. In particular, CMOS amplifiers have the required impedance for matching in only a very narrow frequency range, so that the two frequency bands are not covered with just one CMOS amplifier. It is therefore expedient to provide a respective amplifier for each frequency band and to combine them in a suitable manner within the signal processing chain.
However, such combination is always associated with additional parasitic signals that influence the performance of the receiver. On the other hand, by contrast, combining the two frequency bands at a suitable location makes it possible to save chip area and thus to reduce the costs.
A further problem is improving the signal/noise ratio in low-noise amplifiers. The latter usually use field-effect transistors as input transistors IN and INX. One example of a known amplifier can be seen in FIG. 7. A similar differential amplifier is described in Tietze/Schenk "Halbleiter-Schaltungstechnik", ["Semiconductor circuitry"], 12th Edition, Springer Verlag 2002, in Chapter 4.1.3. In order to improve the ratio at the input transistors, it is necessary to maximize the bias current flowing through the transistors. However, the use of normal nonreactive load resistors instead of the coils L1 and L2 illustrated in the example leads to a higher voltage drop across the load resistors in the case of a large DC current. As a result, the voltage range available for the transistors IN and INX is reduced and the voltage swing of the output signal OUT is reduced. It is therefore additionally necessary to increase the supply voltage, which, however, leads to additional power losses.
For this reason, an inductive load having a low quality factor is very often used instead of nonreactive load resistors. However, such an on-chip inductance requires a very large area on the chip and thus enlarges the receiver unit in a disadvantageous manner.

Differential amplifier arrangement with current regulating circuit and method for operating a differential amplifier arrangement


A semiconductor device having a pad structure for preventing a stress of a silicon nitride film. The semiconductor device includes a semiconductor substrate, a lower structure formed on the semiconductor substrate, a first insulation film formed on the lower structure, a first metal layer coupled to the lower structure through a first metal contact in the first insulation film, a second metal layer formed on the first metal layer, and a plurality of dummy gates having a concentric square structure formed at the lower portion of the pad region on the second metal layer.

1. Field of the Invention
The present invention relates to a semiconductor device and, more particularly, to a pad structure for relieving a stress applied to a barrier insulation film of a semiconductor device.
2. Discussion of Related Art
In general, all semiconductor memory devices manufactured by using silicon wafers have a pad structure. The pad structure opens a part of a passivation layer on an upper metal layer such as a second metal layer, thereby exposing the upper metal layer. The pad structure is operated as a connection means installed between the inside and outside of the semiconductor device, for supplying a voltage to the semiconductor device and inputting or outputting a data to/from the semiconductor device according to a wire bonding process. The pad structure is one of the major factors that must be considered in manufacturing of the semiconductor device. In the case that the pad structure of the semiconductor device is not reliable, the semiconductor device is not usable.
The pad structure must satisfy the following conditions. First, the pad structure must be formed to minimize a pad stress. The pad stress seriously reduces the adhesive strength of the wire bonding and causes pad lifting. Second, the pad structure must be foamed to maximize a wire bonding strength. Third, the pad structure must be formed to minimize a pad capacitance. If the pad capacitance exists, the semiconductor device may be deteriorated due to the data inputted/outputted through the pad at a speed of a few ns (nano second), and the wire bonding may be separated. The disadvantages of the conventional pad structure will now be explained in detail with reference to FIG. 1.
FIG. 1 is a cross-sectional diagram illustrating a pad structure of a conventional semiconductor device in a back-end process of a NAND flash memory device. FIG. 2 is a partial layout diagram illustrating the conventional semiconductor device having the pad structure of FIG. 1. FIG. 3 is a state diagram illustrating state variations of a silicon nitride film by influences of a thermal stress in the pad structure of the conventional semiconductor device.
Referring to FIG. 1, the pad structure in the back-end process of the NAND flash memory device has a sequentially-stacked structure of a semiconductor substrate 102, a field oxide film 104, a silicon nitride film 106 for a self aligned contact, a first interlayer insulation film 108, a first metal layer 110, a trench stop silicon nitride film 112, an insulation film 114 for a trench, a second metal contact stop silicon nitride film 116, a second interlayer insulation film 118 and a second metal layer 120. Three layers, namely, the silicon nitride film 106 for the self aligned contact, the trench stop silicon nitride film 112 and the second metal contact stop silicon nitride film 116 are silicon nitride films. The silicon nitride films 106, 112 and 116 are used as barrier layers in an etching process by using a select ratio of an oxide to a nitride. As shown in FIG. 2, in the pad structure, the silicon nitride films 106, 112 and 116 are coupled over the outside of a pad region PR formed by partially exposing the second metal layer 120 as well as the inside of the pad region PR, to cover the whole chip.
On the other hand, the silicon nitride film has different thermal properties from those of the upper and lower layers. That is, as compared with a layer including an oxide or polysilicon oxide, the silicon nitride film shows a very high thermal stress. For example, a thermal stress constant of the oxide film SiO2 is 2˜4×109 dyne/cm2, and a thermal stress constant of the silicon nitride film Si3N4 is 9˜10×109 dyne/cm2. Therefore, the thermal stress constant of Si3N4 is larger than that of SiO2 by about 2.5 to 4.5 times.
As depicted in FIG. 3, such thermal stress differences cause lifting between the lower layers 104, 108 and 114 including oxides and the upper layers 106, 112 and 116 including nitrides. In the case that Si3N4 is coupled to a first metal contact, a second metal contact and a first metal layer, if Si3N4 is lifted due to a high stress, the first metal contact, the second metal contact or the first metal layer may be opened. That is, when the silicon nitride film is excessively exposed to the thermal stress, the silicon nitride film is lifted, and thus reliability of the device is seriously 15 reduced. Especially, the structural portion of the pad influenced by the thermal properties of the silicon nitride film in the NAND flash memory device is the adjacent portion between the trench stop silicon nitride film 112 and the second metal contact stop silicon nitride film 116. Accordingly, the stress for the silicon nitride film in that portion must be relieved in the back-end process of the NAND flash memory device, and countermeasures therefore must be provided.

Semiconductor device having pad structure for preventing and buffering stress of silicon nitride film