The present invention provides stock solutions for production of nonlinear-optical materials using a wet coating method. In particular, the invention provides a stock solution containing a nonlinear-optically active organic compound, which is a push-pull π-conjugated compound having a particular chemical structure, having one or more cross-linkable functional groups. In addition, the invention provides a stock solution comprising a nonlinear-optically active organic compound having at least a certain chemical structure and a matrix-forming compound having one or more cross-linkable functional groups. Further, the invention provides a nonlinear-optical material and a nonlinear-optical device, both prepared by using the stock solutions.

1. Field of the Invention
The present invention relates to a nonlinear-optical material and a nonlinear-optical device applicable to fields such as optical communication, optical wiring, optical information processing, sensors, and image processing, and a stock solution for producing the same.
More specifically, the invention relates to a nonlinear-optical device such as an optical switching device, optical modulating device, wavelength-converting device, or phase-shifting devices utilizing second-order nonlinear-optical effects, or a memory device or image-processing device utilizing photorefractive effects; and a nonlinear-optical material applicable to these applications; and a stock solution for manufacturing the same.
2. Description of the Related Art
Most of the functional devices important in optical fields are realized by the use of nonlinear-optical materials, in particular, second-order nonlinear-optical materials. Such devices include wavelength-converting devices, optical modulating devices, and optical switching devices, and these are important in optical fields such as optical communication, optical wiring, optical information processing, sensors, and image processing. Inorganic nonlinear-optical materials, such as lithium niobate, and potassium dihydrogen phosphate, have already been commercialized and are widely used as second-order nonlinear-optical materials, but recently, organic nonlinear-optical materials have been attracting attention due to advantages in their improved nonlinear-optical characteristics, lower material and production cost, higher productivity and the like. Extensive research and development is currently directed to commercialization of these materials in order to replace conventional inorganic materials.
An essential requirement in order to achieve the second-order nonlinear-optical effect is that there be, in principle, no center of symmetry in the system. Second-order nonlinear-optical materials are roughly classified into two systems, the first being a system where an organic compound exhibiting nonlinear-optical activity is crystallized in a crystal structure having no symmetry center (hereinafter, referred to as a "crystalline system"). The second system involves an organic compound exhibiting nonlinear-optical activity (i.e., a nonlinear-optically active organic compound) dispersed in a polymer binder and the symmetry center of the system is eliminated by orientation using a certain means (hereinafter, referred to as a "dispersion system").
Although organic nonlinear-optical materials of the crystalline system are known to exhibit extremely superior nonlinear-optical characteristics, it is almost impossible to control the crystal structure artificially, and thus it is very rare that crystal structures without any symmetry centers are obtained. Even if obtained, it is difficult to produce the large organic crystals required for producing optical devices. In addition, these optical materials often cause various problems, as the organic crystals are very fragile or brittle and are often damaged during production of the devices.
In contrast, organic nonlinear-optical materials of the dispersion system are regarded as more promising, because they have greater potential for commercialization. This is due to the fact that they are provided with favorable characteristics such as good coatability and mechanical strength, attributes that are useful for producing devices with polymer binders.
Dispersion-type organic nonlinear-optical materials must be optically homogeneous and transparent, and thus, the nonlinear-optically active organic compound contained therein should be dispersed in the polymer binder uniformly without aggregation. In addition, as described above, it is necessary to orient the nonlinear-optically active organic compound by using a certain means in order to cause the anisotropy required for the second-order nonlinear-optical effect. It is also necessary order to obtain effective use of the functional devices and to preserve the oriented state consistently in hot or humid environments during production, operation, and storage of the resulting devices.
Accordingly, the nonlinear-optically active organic compounds to be used in dispersion-type organic nonlinear-optical materials must not only have superior nonlinear-optical characteristics, but also a lower tendency toward aggregation and higher compatibility with the polymer binder. The dispersion-type organic nonlinear-optical materials are generally converted to various devices in the form of thin films, and wet coating methods are favorably used for forming the thin films. For this reason, nonlinear-optically active organic compounds used in dispersion-type organic nonlinear-optical materials should be highly soluble in the stock solution solvents. It is also necessary for the polymer binders to have, in addition to qualities such as superior coatability and mechanical strength, a high glass-transition temperature in order to consistently maintain the orientation of the nonlinear-optically active organic compound contained therein.
It is necessary to orient the nonlinear-optically active organic compound as described above for generating the second-order nonlinear-optical activity in dispersion-type organic nonlinear-optical materials, and the electric field-poling method is commonly used as the orientation method. The electric field-poling method is an orientation method of applying an electric field to a nonlinear-optical material and orienting the nonlinear-optically active compound therein in the direction of the applied electric field by the Coulomb force between the dipole moment of the nonlinear-optically active compound and the applied electric field. The orientation of the nonlinear-optically active compound is generally assisted by the activation of molecular motion by heating to a temperature close to the glass-transition temperature during application of the electric field.
It is known that so-called push-pull π-conjugated compounds having an electron-donating group at one end of the π-conjugated chain and an electron-withdrawing group at the other end are effective nonlinear-optically active organic compounds. For example, Disperse Red 1 (generally, abbreviated to DR1) having an N-ethyl-N-(2-hydroxyethyl)amino group as the electron-donating group at the 4 position and a nitro group as the electron-withdrawing group at the 4′ position of the azo benzene structure (π-conjugated chain) is widely known as a typical nonlinear-optically active organic compound. However, given that DR1 does not in essence possess superior nonlinear-optical characteristics and has both a lower compatibility with ordinary polymer binders and a higher tendency to sublimate, DR1 is problematic in that it disappears with the application of heat in the drying and electric-field poling processes, and dialkylamino groups tend to oxidize and deteriorate.
Various nonlinear-optically active organic compounds have been developed hitherto to solve these problems, but compounds satisfying all of the required characteristics at the same time have yet to discovered. In particular, it is quite difficult to provide a compound superior having both nonlinear-optical characteristics and higher binder compatibility. Namely, the nonlinear-optical characteristics of push-pull π-conjugated compounds are known to be improved by generally elongating the π-conjugated chain therein and strengthening the electron-withdrawing capacity of electron-withdrawing group and the electron-donating capacity of electron-donating group. Nonetheless, the improvement in nonlinear-optical characteristics is accompanied by an increase in aggregation between molecules, consequently leading to a decrease in the compatibility of the conjugated compounds with the polymer binder.
For example, it has been disclosed that a compound having the structure shown below exhibited extremely superior nonlinear-optical characteristics, however, it is very difficult to produce a film where the compound is uniformly dispersed in the polymer binder and crystal precipitation is suppressed due to its extremely high tendency to coagulate (see e.g., Chemistry of Materials, 2001, Vol. 13, pp. 3043 to 3050). It has been also disclosed therein that it is necessary to use a halogenated solvent having a low boiling point as the coating solvent, but the use of such a halogenated solvent is not favorable as it negatively affects air quality.

On the other hand, although polymethyl methacrylate (generally abbreviated to PMMA) has been most intensively studied as the polymer binder, the glass-transition temperature of PMMA is lower at about 100° C., and thus the orientation of a dispersion-type organic nonlinear-optical material in the PMMA polymer binder gradually slackens even at room temperature. Nonlinear-optical materials derived therefrom exhibit a marked decrease in nonlinear-optical characteristics over time. Thus, PMMA-based optical materials are not suitable for actual use in functional devices (e.g., Chemical Reviews, 1994, Vol. 94, No. 1, pp. 31 to 75).
In order to solve these problems, binder polymers for replacing PMMA have been intensively studied, leading to polymers having glass-transition temperatures that are higher than that of PMMA. Examples of reported binder polymers include polycarbonate, polyimide, polysulfone, and polycyclic olefin (see e.g., Japanese Patent Application Laid-Open (JP-A) No. 6-202177). Use of these polymer binders having higher glass-transition temperatures is inevitably accompanied with an increase in the heating temperature required for electric-field poling, and this in turn causes oxidation and disappearance by sublimation of the nonlinear-optically active organic compounds such as DR1 during the electric-field poling process. The compatibility between these polymer binders having high glass-transition temperatures and a nonlinear-optically active organic compound such as DR 1 is not always high, and accordingly, addition of the nonlinear-optically active organic compound at a higher concentration for the purpose of improving the nonlinear-optical characteristics causes aggregation or crystallization of the compound. Further, addition of nonlinear-optically active organic compounds even at a lower concentration, still causes aggregation or crystallization by heating or the passage of time.
As a means for solving the problems of the dispersion-type organic nonlinear-optical materials described above, the introduction of a nonlinear-optically active organic compound to the main chain and/or side-chain of a polymer, i.e., conversion of the nonlinear-optically active organic compound to a polymeric compound, is being studied.
For example, a nonlinear-optically active polymeric compound having the following structure where the DR1 structure is bound to the side chain of PMMA has been developed.

The glass-transition temperature of this nonlinear-optically active polymeric compound is about 165° C. and higher than the glass-transition temperature of PMMA (about 100° C.). In contrast to the fact that DR1 can be dispersed in PMMA only at a concentration of up to 30% by mass without crystal precipitation, the nonlinear-optically active polymeric compound, which contains the DR1 structure at a concentration equivalent to 82% by mass, provides a clear film without phase separation. Accordingly, the nonlinear-optically active polymeric compound exhibits higher nonlinear-optical characteristics and higher stability than the dispersion-system compounds where DR1 is dispersed in PMMA.
However, even if polymerization is possible, it is difficult to both polymerize the monomers having a bulky nonlinear-optically active structure and control the degree of polymerization. If the degree of polymerization is not raised sufficiently, the resulting polymers have significantly lower mechanical strength. In addition, insufficient control of the degree of polymerization causes a problem in that it is difficult to produce films having a certain consistent thickness due to fluctuation by production lot of the viscosity of coating solutions (stock solutions). As purification of polymers is generally difficult, residual impurities such as polymerization catalysts may also make it more difficult to apply an effective electric field during electric-field poling. Therefore, introduction of a nonlinear-optically active organic compound into the main chain and/or side-chain of a polymer is hardly the best method.
To solve the problems associated with the aforementioned dispersion-type organic nonlinear-optical materials, a method of preparing a cross-linkable nonlinear-optically active organic compound is being studied. A nonlinear-optically active organic compound such as DR1 is introduced to the cross-linkable functional group in the compound, and the cross-linkable nonlinear-optically active organic compound is coated and dried, after which electric-field poling and curing by cross-linking treatments are conducted simultaneously (hereinafter, referred to as a "curing by cross-linking system"). This method provides a favorable effect of stabilizing the oriented state significantly, as it fixes the oriented state induced by the electric-field poling by cross-linking. In addition, since the raw material, i.e., the cross-linkable nonlinear-optically active organic compound, is a low-molecular weight compound, the problems concerning the polymerization and purification of the aforementioned nonlinear-optically active polymeric compound are reduced.
However, conventional nonlinear-optically active organic compounds are highly aggregative, and thus even if cross-linking and curing of organic compounds having a cross-linkable functional group is conducted, such organic compounds tend to aggregate or crystallize in the drying step prior to curing by cross-linking and clear cured films cannot be obtained. These compounds are also problematic in that a cross-linking reaction causes gelation of the stock solution, or with pot life of the stock solution due to precipitation, leading to deterioration in optical quality and increase in the production cost of the resulting films.

Stock solution for production of nonlinear-optical materials, nonlinear-optical material, and nonlinear-optical device


A fertilizer product comprising an acid-carbonized microporous matrix derived from expanded biomass and a fertilizer reaction product of residual acid from the carbonizing process and at least one added fertilizer precursor. The biomass may include steam exploded wood powder. The expanded biomass may be carbonized with a combination of sulphuric and phosphoric acids, followed by ammoniation to produce ammonium sulphate and mono- or diammonium phosphate. The fertilizer reaction product adsorbs onto the carbon matrix, which results in a slow-release when the material is applied to the soil.

Many techniques have been developed for delivering nutrients to growing plants and for extending or delaying the release of nutrients from a fertilizer. Fertilizer is often applied to the ground as a formulated solid granule or powder, or as a liquid.
There are basically two types of fertilizers, water-soluble fertilizers and "slow-release" fertilizers. While water-soluble fertilizers are generally less expensive than slow-release fertilizers, they have the disadvantage of leaching nutrients very quickly into and through the soil. Slow-release fertilizers are designed to release nutrients to plants or soil over an extended period of time, which is more efficient than multiple applications of water-soluble fertilizers. Therefore, slow-release (also referred to as controlled release or extended release) fertilizers minimize the frequency with which plants must be fertilized, as well as reduce or minimize leaching. The major advantage of slow release fertilizers is the optimal release and absorption of the crop input nutrient by the roots along the period of growth, thus minimizing wastage of the nutrient and delivering better economic value.
Some solid, water-soluble fertilizers can be converted into slow-release fertilizers by employing various coatings. Also, some polymers may bind primary nutrients such as nitrogen in an insoluble form. Polymer coatings such as urea-formaldehyde (UF) condensation products such as polyurethane are widely used as slow-release nitrogen fertilizers for crops, ornamental plants and grasses. Urea-formaldehyde fertilizer materials also can be supplied either as liquids or as solids. Such materials generally contain at least 28% nitrogen, largely in a water-insoluble, slowly available form.
Extended release UF fertilizers may be prepared by reacting urea and formaldehyde at an elevated temperature in an alkaline solution to produce methylol ureas. The methylol ureas then are acidified to polymerize the methylol ureas to methylene ureas, which increase in chain length as the reaction is allowed to continue. These methylene urea polymers normally have limited water solubility, and, thus, release nitrogen throughout an extended period. Such UF fertilizers usually include a mixture of methylene urea polymers generally have a range of molecular weights and are understood to be degraded slowly by microbial action into water-soluble nitrogen. UF fertilizers are usually categorized by the amount and the release characteristics of their water insoluble nitrogen.
Polymer coated slow-release fertilizers suffer from certain disadvantages. The polymer shell may crack or be damaged during transportation and handling, resulting in unrestricted moisture ingress and loss of slow-release ability. The polymer shells are often poorly biodegradable, and build up in the soil after repeated use.
Granular nitrogen-containing fertilizers have been produced commercially by a variety of techniques using water-soluble nitrogen products, such as urea, potassium nitrate, and ammonium phosphate. The practical advantages of handling, blending, and storing such fertilizer granules are known and well documented. The preparation of granular fertilizers using slow-release UF fertilizers also has been described in the prior art.
Nitrogen fertilizer comprising ammonium salts may be produced by absorbing ammonia with an acid. However, uncoated slow-release formulations of such soluble nitrogen fertilizers are not known.

Exploded biomass based slow-release fertilizer


An electro-optical bar code symbol reader initiates reading of a symbol when a target bearing the symbol is detected within a predetermined distance of the reader. The reader is mounted on an operator's arm by being strapped around the operator's wrist. A keyboard and a display are provided on the reader for data entry and display.

1. Field of the Invention
This invention generally relates to electro-optical systems for reading indicia of different light reflectivity such as bar code symbols and, more particularly, to mountable bar code readers.
2. Description of Related Art
Laser scanner systems and components of the type exemplified by U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,460,120; 4,607,156; 4,673,803; 4,736,095; 4,758,717; 4,816,660; 4,808,804; 4,816,661; 4,760,248; 4,871,904; 4,806,742; 4,825,057; 4,835,374; and 4,845,350, as well as U.S. Appln. Ser. No. 08/400,840 filed Mar. 8, 1995--all of said patents and patent applications being owned by the assignee of the instant invention and being incorporated by reference herein--have generally been designed to read indicia having parts of different light reflectivity, e.g., bar code symbols, particularly of the Universal Product Code (UPC) type, at a certain working or reading distance from a hand-held or stationary scanner.
Typically, a light source such as a laser generates a light beam which is optically modified and focused to form a beam spot of a certain size at a working distance relative to a housing and is directed by optical components, including a reflecting mirror, along a light path through an exit port of the housing toward a bar code symbol located in the vicinity of the working distance for reflection from the symbol. A photodetector having a field of view extending across and slightly past the symbol detects light of variable intensity reflected off the symbol and generates electrical signals indicative of the detected light. These electrical signals are decoded into data descriptive of the symbol. A scanning component may be situated in the housing, and is operative to either sweep the beam spot in a scan pattern across the symbol, or to scan the field of view of the photodetector, or simultaneously do both.
The components for the light scanning system, including the light source, optics, photodetector, scanning component and an electrical conductor, are mounted together in a common assembly to constitute a compact, lightweight, scan module. The scan module is mounted in an interchangeable, modular manner in housings of different configurations.
For example, the housing can be hand-held and shaped as a cylinder in a so-called flashlight-type configuration, or shaped as a box, or shaped with a gun-like configuration. The housing can be mounted on the back of an operator's arm (see, for example, U.S. Pat. No. 4,766,299) or on one or more fingers of the operator's hand, typically with the aid of a strap, a clip, or a glove. The housing can be mounted on the operator's arm, typically adjacent or on the wrist. The housing can be mounted in a countertop workstation. The housing can be mounted in a mobile cart, or shopping cart, or, in some cases, even in a stationary installation.
The compact, lightweight nature of the scan module enables myriad other housing configurations to be fashioned. Thus, the scan module can be mounted anywhere on an operator's person, e.g. in a helmet to be worn on the operator's head, in eyeglasses to be worn in front of the operator's eyes, in a shoulder or body harness, etc.


The low-order aberration leading to better visual acuity is calculated from the results of measurement of an eye characteristic by an eye characteristic measuring instrument that can measure up to the high-order aberration, and data on a correction factor is collected, thereby obtaining a result more approximate to the subjective value. According to at least measurement data representing the wave aberration of the eye being examined (S401, S403), an image data creating unit creates optotype retina image data by conducting simulation of the visual acuity of an optotype (S405), considering the correction factor for refraction correction. A correction factor setting unit sets a correction factor to be given to the image data creating unit (S417). A judging unit judges from the correction opotype retina image data corrected by the correction factor whether or not an adequate correction factor is set (S407 to S421). The correction factor setting unit sets a correction factor on the basis of the results of judgment by the judging unit, and changes the correction factor until the judging unit judge that the correction factor is adequate.

Conventionally, as a technology for objectively measuring the refraction data of an eye, correction factors such as S (spherical power), C (astigmatic power), and A (angle of an astigmatic axis) are measured by the use of a refractometer. In recent years, eye-characteristics measurement apparatuses capable of measuring even higher-order aberration have been developed, and therefore, correction factors such as S, C, and A on a line such as a ring having a diameter of 3 mm used by a refractometer can be calculated from lower-order aberration. When such an eye-characteristics measurement apparatus is used, values closer to subjective values than those obtained by a refractometer are obtained especially for sick eyes and eyes on which refractive-power-correction operations have been performed. The following documents, for example, should be referenced.
Japanese Patent Application No. 2001-119145
Japanese Patent Application No. 2001-120002
Japanese Patent Application No. 2001-119086
Japanese Patent Application No. 2000-318534

Correction-factor determination apparatus and method


Disclosed is a method for amplifying a data signal read from a memory device. The method includes sensing an initial voltage difference across a data bus that is coupled to the memory device. Producing an initial voltage difference across a sensed data bus after the sensing detects the initial voltage difference. The initial voltage difference is configured to partially separate a pair of nodes associated with the sensed data bus. The method further includes subsequently isolating the data bus from the sensed data bus to rapidly further separate the pair of nodes associated with the sensed data bus, the rapid separation producing the amplified data signal across the sensed data bus.

1. Field of the Invention
The present invention relates generally to integrated circuits, and more particularly to methods and apparatuses for amplifying signals sensed from selected memory locations.
2. Description of the Related Art
As is well known in the art, random access memory (RAM) devices are generally array structures composed of 2.sup.n by 2.sup.m individual RAM cells which are coupled to wordlines (rows) and complementary bit lines (columns). A typical RAM memory cell may be composed of between 4 and 6 transistors coupled together to form a data storage device. An individual RAM memory cell may be selected when an X-decoder is used to select rows and a Y-decoder is used to select columns. Typically, data is written into an individual RAM cell when the proper address is selected and a WRITE ENABLE circuitry allows digital data in the form of a differential voltage signal to be input into a selected memory cell location. As is well known in the art, once a specific memory cell is addressed within a RAM device and a READ ENABLE circuitry is active, a very small voltage amplitude representing the addressed digital data is sensed. However, to produce a readable voltage amplitude representing useful digital data, a sense amplifier is typically implemented to amplify the sensed signal.
FIG. 1 shows a conventional RAM block diagram used for outputting digital data stored within a RAM core 100. By way of example, when RAM core 100 includes 1,000 rows by 1,000 columns, RAM core 100 may be classified as a one megabit (1 MB) RAM storage device. In typical architectures, computers access RAM core 100 through an address input bus 110 that may be coupled to a conventional X-DECODER 102 and a conventional Y-DECODER 104. In general, X-DECODER 102 is used for addressing a selected row (wordlines) within RAM core 100, and Y DECODER 104 is used for addressing a selected column (bitlines) within RAM core 100. By way of example, X and Y decoders are generally implemented for reducing memory array aspect ratios by folding (i.e., dividing) long addressable memory columns into several shorter memory columns. Once folded into several columns, the X and Y decoders are capable of reading or writing the addressed data by appropriately performing a suitable multiplexing function.
Once a row and column is selected from RAM core 100, either a write or a read operation may be performed on the selected RAM memory cell. In order to perform a write operation, a write control circuit 107 is enabled which allows digital data to be input into a selected RAM memory cell via an input data bus 101. Generally, this digital data is in the form of a voltage waveform that represents either a logical "1" or a logical "0". Input buffer 109 amplifies a input signal 103 that is supplied by RAM input bus 111. In this manner, the selected transistors in RAM core 100 may be driven to an appropriate state.
In a like manner, once the row and column is selected in RAM core 100, a read operation may be performed which produces a voltage representing the addressed digital data on a data bus 112. At this point, the addressed digital data may be as low as about 50 milli-volts (mV). As described above, to appropriately read the addressed digital data, suitable amplification is typically performed in a sense amplifier 106. Once the sensed data signal is amplified to full rail voltage level (i.e., about 3.3 volts or about 5 volts) in sense amplifier 106, the voltage amplified data is passed out as amplified data output 114 to an output buffer 108. At output buffer 108, the voltage amplified data 115 is current amplified to provide an appropriate level of current drive once the read data is passed to a RAM output bus 116.
There are a variety of well known conventional sense amplifiers 106, however, most conventional sense amplifiers 106 are not well optimized for performing fast read operations once data is sensed on data bus 112. In addition, conventional sense amplifiers are generally somewhat sluggish in recovering after the successful read operation has been performed. As is well known in the art, in order to perform a successful read/write operation, the nodes of a sensed data bus (i.e., SD and /SD) must be pulled apart somewhere between Vss (i.e., 0 volts) and V.sub.CC (i.e., 3.3 or 5 volts). That is, to accurately define a "1-bit" or a "0-bit", the sensed data (SD) node must be, for example, pulled towards V.sub.CC, and the sensed data (/SD) node must be, for example, pulled towards V.sub.SS. Unfortunately, most conventional sense amplifiers suffer in that SD and /SD are pulled apart too slow for speed sensitive applications.
Once SD and /SD are adequately pulled apart to complete a successful read operations, the sensed data nodes SD and /SD must be switched back to their original state (i.e., a ready to read state). That is, the nodes of the sensed data bus must be equalized (i.e., pulled back together) to their original voltage levels. Consequently, the next operation may not be performed until the nodes of the sensed data bus are equalized. It is therefore important to realize that most conventional sense amplifiers lack the ability to quickly amplify sensed data by rapidly pulling SD and /SD apart as well as the ability to rapidly restore the sensed data bus to its "ready" state.
In view of the foregoing, there is a needed for methods and apparatuses for rapidly amplifying sensed data signals read from memory locations. In addition, there is a need for methods and apparatuses for rapidly recovering a sense amplifier to a "ready to read" state after a previous operation is complete.

Voltage sense amplifier and methods for implementing the same


A low pressure CVD system comprising an inner tube having an upper end and a lower end opened, and made of a silicon carbide material, an outer tube including a circumferential wall surrounding an outer periphery of the inner tube with a predetermined spacing, an upper wall closing an upper end of the circumferential wall and a flange provided at a lower portion thereof, the outer tube having a lower end opened, a base portion for supporting the inner tube and the outer tube at the lower ends thereof, and for providing hermetic sealing between the lower end of the outer tube and the base portion, the base portion having a central portion formed with an opening, a lid provided for opening and shutting the opening in the base portion, and a furnace wall surrounding the circumferential wall and the upper wall of the outer tube, the furnace wall having a heater arranged on an inner side thereof wherein the outer tube is made of a silicon carbide material, and padding of a silicon carbide material is formed at a corner of a joined portion between the circumferential wall and the flange of the outer tube.

1. Field of the Invention
The present invention relates to a low pressure CVD (chemical vapor deposition) system which is used to form a film of e.g. silicon nitride on semiconductor wafers.
2. Description of the Related Art
As such a low pressure CVD system, there has been used a system as shown in FIG. 6 (see JP-A-93166741 corresponding to U.S. Pat. No. 5,316,472). In the low pressure CVD system shown, a dual tube 13 is constituted by an outer tube 11 and an inner tube 12. A base portion 14 is arranged under the outer tube 11 and the inner tube 12 to support the tubes 11 and 12. The base portion 14 is provided with a gas feed pipe 15 leading to a space in the inner tube 12, and an exhaust pipe 16 leading to a space between the inner tube 12 and the outer tube 11.
The base portion 14 has a lower surface formed with an opening, and a lid 17 which is vertically moved by a lift 18 is arranged to open and shut the opening. The lid 17 has a wafer boat 20 placed thereon through a pedestal 19, and the wafer boat 20 supports numbers of semiconductor wafers W. When the lid 17 is raised by the lift 18 the wafer boat 20 and the wafers W placed on the lid 17 through the pedestal 19 are loaded into the dual tube 13 and the lid 17 seals the opening of the base portion 14. When the lid 17 is lowered by the lift 18, the opening of the base portion 14 is opened, and the wafer boat 20 and the wafers W which have been placed on the lid 17 through the pedestal 19 are unloaded. A cylindrical furnace 21 with a heater is arranged along an outer periphery of the dual tube 13.
In the conventional low pressure CVD system, quartz glass has been used as the material for the outer tube 11. The reason is that it is easy to obtain high-purity quartz glass, and that use of quartz glass is preferable to prevent contamination of the semiconductor wafers W. Since quartz glass has sufficient heat-resistance and a significantly low thermal expansion coefficient for the outer tube of a low pressure CVD system, no fracture due to thermal stress has not occurred even if a temperature difference is created between a portion of the outer tube which is arranged in the furnace 21 and a portion of the outer tube arranged below the furnace 21. Because quartz glass has low thermal conductivity the temperature of a lower end of the outer tube is hardly raised, and it is easy to provide hermetic sealing.
When the conventional low pressure CVD system is used to deposit a film on the semiconductor wafers W by CVD technique, CVD films are deposited on an inner surface of the outer tube 11 and on the inner tube 12 as well. Since the CVD films on the outer tube and the inner tube peel off easily to produce particles having created a problem in that the semiconductor wafers W are contaminated. As a result, it has been necessary to frequently carry out operations wherein the outer tube 11 and the inner tube 12 are cleaned to remove the CVD films deposited on the tubes.


The invention provides a wet vacuum accessory for a domestic vacuum cleaner that separates liquid droplets from the suction airstream before the airstream is drawn into the vacuum cleaner intake hose. A suction intake passage is formed between a pair of baffles, which discharges the airstream into a reservoir that is isolated from the airflow outlet of the accessory body by the baffles. The reservoir is provided with a relatively large cross sectional area, which reduces the suction airstream velocity sufficiently to allow liquid entrained in the airstream to fall into the reservoir before the airstream is drawn out of the accessory into the vacuum cleaner intake hose. In the preferred embodiment a hollow handle of the accessory is provided for connection to the vacuum cleaner intake hose.

The domestic vacuum cleaner is the most common power cleaning tool used in households today. A conventional domestic vacuum cleaner provides a motor driven impeller which creates a suction airstream and draws or blows the airstream through a dirt collector such as an air permeable filter bag or a canister. Dirt and dust pass through the collector and are removed from the airstream, which then escapes into the environment. A typical domestic vacuum cleaner cannot vacuum a liquid, because liquid droplets entrained in the airflow would travel through and damage or destroy the impeller assembly and/or the collector.
Canister vacuum cleaners are available which are adapted to vacuum a liquid, often called "wet-vacuums", which provide a reservoir beneath the impeller assembly into which liquid entrained in the suction airstream is released. In such wet vacuum cleaners the impeller assembly and its associated electrical connections must be kept well away from both the high velocity airstream discharged from the suction intake and liquid collected in the reservoir, to ensure that the impeller assembly is completely isolated from any liquid. Except for these differences, wet vacuums tend to have all of the same components as a conventional canister vacuum cleaner and are to a large degree redundant in this respect.
Hand-held wet vacuums are also available, but they tend to be weak and ineffective because the battery-powered motors that they use are capable of generating only a very low pressure suction airstream, and they often utilize elaborate systems of baffles in order to maintain sufficient operating pressure while isolating the impeller from the suction intake and the reservoir to ensure that no water is drawn through the impeller assembly.
The present invention overcomes these disadvantages by providing a wet vacuum accessory for a domestic vacuum cleaner that separates liquid droplets from the suction airstream before the airstream is drawn into the vacuum cleaner intake hose. The invention provides a suction air intake passage defined between a pair of baffles, which discharges the suction airstream into a reservoir that is isolated from the airflow outlet from the body of the accessory by the baffles themselves. The reservoir is provided with a relatively large cross sectional area, which reduces the suction airstream velocity sufficiently to allow liquid entrained in the airstream to fall into the reservoir before the air is drawn out of the accessory body into the vacuum cleaner intake hose. In the preferred embodiment both the suction passage and the airflow outlet are located at the front end of the accessory, separated by the baffles that define the suction intake passage, and a hollow handle of the accessory is used as an extension to connect the vacuum cleaner intake hose to the airflow outlet.
The present invention thus provides an accessory for a vacuum cleaner for cleaning liquid, comprising means for creating a higher suction airstream velocity region comprising a suction intake passage having a suction inlet and a suction outlet, defined between a pair of baffles, a lower suction airstream velocity region contained within a body of the accessory comprising a reservoir in communication with the suction outlet, and an airflow outlet for attachment to a suction intake of the vacuum cleaner, for drawing the suction airstream out of the body of the accessory, whereby the airflow outlet is isolated from the suction outlet by the baffles such that the suction airstream must pass through the reservoir before egressing from the airflow outlet.

Wet vacuum accessory for a vacuum center


The present disclosure provides a method and an apparatus for processing concurrent transactions, and a non-transitory computer readable storage medium. The method includes: determining whether a two-dimensional digraph for a set of concurrent transactions has a cyclic structure, wherein the set of concurrent transactions comprises a transaction to be committed and at least one committed transaction, the two-dimensional digraph comprises a plurality of nodes corresponding respectively to the transactions in the set, and directed edges between the nodes of the two-dimensional digraph indicate a serializability relation among the transactions in the set; aborting the transaction to be committed if it is determined that the two-dimensional digraph has the cyclic structure; and committing the transaction to be committed if it is determined that the two-dimensional digraph does not have the cyclic structure. Embodiments of the present disclosure can improve the performance of a concurrent system.

In concurrency control systems such as database and transactional memory, scheduling is performed in unit of transaction. In design of a real concurrency control system, transactions may be added with more strict correctness conditions. These correctness conditions are generally referred to as semantics in programming languages. Semantics that is the most intuitive to humans is serializability, and Concurrency control algorithms aim to forming a transaction scheduling table with serializability.
The existing concurrency control algorithms are mainly classified as (1) Pessimistic Concurrency Control algorithm and (2) Optimistic Concurrency Control algorithm. The Pessimistic Concurrency Control algorithm generally adopts a concurrency control mechanism based on a lock protocol. If an operation performed by a user requests a lock, any other user cannot perform an operation colliding with the lock until the lock is released by the owner of the lock. The pessimistic concurrency control algorithm causes a large number of transactions to be aborted, so its concurrency performance is poor. The Optimistic Concurrency Control algorithm, when each transaction is executed, initially optimistically assumes that data that is accessed has not modified by any other concurrent transaction. Then, after the execution of the transaction is completed, the algorithm checks whether each transaction meets this assumption. Thus, the optimistic concurrency control algorithm does not require locking of data. A system that employs the optimistic concurrency control algorithm has a better concurrency performance than that employs the pessimistic control algorithms.
In conventional optimistic concurrency control algorithms, in order to independently check the serializability of each transaction, additional constraints need to be added, which makes the resultant semantics more constrained than the serializability semantics. As a result, some transactions that could have been committed are aborted, weakening the concurrency performance of the system.

Method and apparatus for processing concurrent transactions, and storage medium

Wuxi Research Institute of Applied Technologies Tsinghua University


A slider for a slide fastener, comprising: a slider body including an upper wing having a cutout; a board shaped cap resiliently received in the cutout and having a claw stopper hole; a claw stopper pivotally mounted in the cap and projecting through the upper wing and into the claw stopper hole; and a resilient claw stopper support mounted on a back surface of the cap and resiliently contacting the claw stopper.

1. Field of the Invention
The present invention relates to a slider for slide fasteners used to join seat lining or seat covers for seats such as vehicle seats.
2. Description of the Related Art
Conventionally, sliders for slide fasteners which are to be used to join seat covers have had an inclined mountain shaped stopper claw formed in the end of the upper wing opposite to the end which goes in the closing direction. This is to say that the slider has a stopper claw which sets itself in between the fastener elements at the back opening of the fastener (Japanese Utility Model Laid-Open Publication No. Sho 51-81104).
A further kind of slider for items such as cushion covers and bed quilt covers is also well known (Japanese Utility Model Laid-Open Publication No. Hei 50-31127). Here, the outer surface of the upper wing of the slider body is flat, and there are stepped portions made in both of the outside walls of the upper wing. A pull tab then fits into these stepped portions and these stepped portions restrict the degree to which this pull tab can pivot to less than 90 degrees.
With slide fasteners for items such as vehicle head rests a slider is bulky and would get in the way so the slider is removed from the fastener chain by some means once the fastener chain has been closed. For example, the fastener chain would have a separable end assembly at one end but would not have a stopper at its other end. In this way the slider could be removed from the end of the fastener chain without a stopper once the fastener chain had been closed. A stopper such as a clip could then clinch the end of the fastener chain (Japanese Utility Model Laid-Open Publication No. Hei 3-3272).
In the example described above in the first mentioned publication, the slider described is a single body with a claw stopper formed in the upper wing of its slider body in order to provide a reverse stop function. This means that once the slider has been slid in the closing direction it cannot be slid again in the opposite direction, i.e. it cannot be moved in the opening direction. Also, as this slider is not an automatically stopping slider with reverse stopping function, it is impossible for it to be re-used.
In the example described above in the second mentioned publication, the slider described is not an automatically stopping slider and can slide freely. This means that it could easily be opened accidentally and would therefore no longer serve the purpose for which it was originally intended. Also, if the slider gets turned over sideways it is easy for the pull tab to also fall over onto its side. It would then be easy for somebody to injure his foot when he accidentally steps on the slider.
In the example described in the third publication, there is a box-shaped separable end stop assembly at one end of the fastener chain while the other end of the chain is clinched with a stopper such as a clip. The problem here is that when the slide fastener is used to seal sheets or covers, the fastener chain cannot be opened when it is time to wash the sheet or cover because of the clip so the which limits the reusability of the sheet or cover.


Provided is a semiconductor apparatus in which a plurality of semiconductor chips stacked in a vertical direction. Each of the semiconductor chips comprises: a bank area comprising a plurality of banks configured to store data; and a peripheral area including a pad area in which a plurality of pads configured to receive signals for controlling the bank area and a plurality of TSV for electrically connecting the plurality of pads, respectively.

1. Technical Field
Various embodiments relate to a semiconductor apparatus, and more particularly, to a semiconductor apparatus including a plurality of semiconductor chips stacked therein.
2. Related Art
As semiconductor products are highly integrated, a structure including a plurality of semiconductor chips stacked three-dimensionally therein, that is, a stack package has been proposed.
The plurality of semiconductor chips included in the stack package may be electrically connected using a interconnecting member such as a wire which connects between each chip and a package board. The stack package may decrease a fabricating cost, have various performances and be mass-produced. However, with the increase in the number of stacked semiconductor chips, an interconnection space for electrical connection in the stack package is reduced and a height of the stack package increase.
As an example of a stack package considering such a disadvantage, a structure using a through-silicon via (TSV) has been proposed.
The TSVs are formed in each of the semiconductor chips. The TSVs are formed to penetrate the each of the semiconductor chips. The one or more semiconductor chips are physically and electrically stacked and coupled through a connection between TSVs.
Referring to FIG. 1, the first semiconductor chip of the conventional stack package includes a bank unit 110, a TSV insertion unit 120, a pad unit 130, and a TSV control unit 140. The bank unit 110 includes a plurality of banks BANK0 to BANK7 for storing data. The TSV insertion unit 120 includes a plurality of TSVs. For stacking the chips, a TSV of a first semiconductor chip (not shown) is physically and electrically coupled to that of a second semiconductor chip (not shown). The pad unit 130 includes a plurality of power pads 131, a plurality of signal pads 132, and a plurality of probe pad 133 which are alternately arranged. The TSV control unit 140 is configured to control the TSV formed through the TSV insertion unit 120.
As known well, a selected TSV of the first semiconductor chip has to be electrically connected with a selected pad of the pad unit 130 which are formed in the first semiconductor chip. Since the TSV insertion unit 120 is arranged between the bank unit 110 and the pad unit 130 to occupy a predetermined area, the size of the semiconductor chip inevitably increases. Further, it needs a plurality of interconnection lines for connecting between the TSVs and the pads.

Semiconductor chip, semiconductor apparatus having the same and method of arranging the same


A scroll-type machine is disclosed which is particularly well suited for use as a compressor in refrigeration and air conditioning systems and incorporates a unique arrangement for modulating the capacity thereof. In one group of embodiments the capacity of the scroll-type machine is modulated by relative axial movement between the scroll members so as to form a leakage path across the wrap tips and opposed end plates. In another group of embodiments, modulation is achieved by reducing the orbital radius of one of the scroll members to thereby form a leakage path across the flank surfaces of the wraps. Both types of scroll separation may be accomplished in a time pulsed manner to thereby enable a full range of modulation with the duration of the loading and unloading periods being selected to maximize the efficiency of the overall system. A motor control arrangement is also disclosed which may be used with either of the modulation methods mentioned above to increase the efficiency of the motor during periods of reduced load. Additionally, either of the modulation arrangements mentioned above may be combined with a delayed suction form of capacity modulation with or without the motor control feature to thereby achieve better operating efficiency under certain conditions.

The present invention is related to capacity modulation of compressors and more particularly to capacity modulation of scroll-type compressors.
Capacity modulation is often a desirable feature to incorporate in air conditioning and refrigeration compressors in order to better accommodate the wide range of loading to which the systems may be subjected. Many different approaches have been utilized for providing this capacity modulation feature ranging from controlling of the suction inlet to bypassing discharge gas back to the suction inlet. With scroll-type compressors, capacity modulation has often been accomplished via a delayed suction approach which comprises providing ports at various positions which, when opened, allow the compression chambers formed between the intermeshing scroll wraps to communicate with the suction gas supply thereby delaying the point at which compression of the suction gas begins. This method of capacity modulation actually reduces the compression ratio of the compressor. While such systems are effective at reducing the capacity of the compressor, they are only able to provide a predetermined amount of compressor unloading, the amount of unloading being dependent upon the positioning of the unloading ports along the wraps. While it is possible to provide multiple step unloading by incorporating a plurality of such ports at different locations, this approach becomes costly and requires additional space to accommodate the separate controls for opening and closing each set of ports.
The present invention, however, overcomes these deficiencies in that it enables virtually a continuous range of unloading from 100 percent or full capacity down to virtually zero capacity utilizing only a single set of controls. Further, the system of the present invention enables the operating efficiency of the compressor and/or refrigeration system to be maximized for any degree of compressor unloading desired.
In the present invention, compressor unloading is accomplished by cyclically effecting axial or radial separation of the two scroll members for predetermined periods of time during the operating cycle of the compressor. More specifically, the present invention provides an arrangement wherein one scroll member is moved axially or radially toward and away from the other scroll member in a pulsed fashion to cyclically provide a leakage path across the tips or flanks of the wraps from higher pressure compression pockets defined by the intermeshing scroll wraps to lower pressure pockets and ultimately back to suction. By controlling the relative time between sealing and unsealing of the scroll wrap tips or flanks, virtually any degree of compressor unloading can be achieved with a single control system. Further, by sensing various conditions within the refrigeration system, the duration of compressor loading and unloading for each cycle can be selected for a given capacity such that overall system efficiency is maximized. For example, if it is desired to operate the compressor at 50 percent capacity, this can be accomplished by operating the compressor alternately in a loaded condition for five seconds and unloaded for five seconds or loaded for seven seconds and unloaded for seven seconds, one or the other of which may provide greater efficiency for the specific operating conditions being encountered.
The various embodiments of the present invention described below provide a wide variety of arrangements by which one scroll member may be axially or radially reciprocated with respect to the other to accommodate a full range of compressor unloading. The ability to provide a full range of capacity modulation with a single control system as well as the ability to select the duration of loaded and unloaded operation cooperate to provide an extremely efficient system at a relatively low cost.
Additionally, in order to even further improve system efficiency in some applications, it may be desirable to combine a delayed suction type of capacity modulation with the pulsed unloading approach mentioned above. For example, when operating conditions are such that system pressures just downstream of the discharge valve are at a level below the full load design level, the compression ratio of the compressor will result in pressure of the compressed fluid as it is discharged from the compression chamber being too high, a condition known as over-compression. The most efficient way to reduce capacity under these conditions is to reduce the compression ratio of the compressor and hence the pressure of the compressed fluid exiting the compression chamber such that it is equal to or only slightly above the system pressure just downstream of the discharge valve thus eliminating the lost work due to over-compression. However, if a further reduction in capacity is indicated by system condition once the over-compression condition has been eliminated, the use of a pulsed type of capacity modulation will be more efficient as it will avoid creation of a condition known as under-compression, that being a situation where the pressure of the compressed fluid as it leaves the compression chamber being below that of the system just downstream of the discharge valve. Thus, the present invention also includes a system in which both pulsed and delayed suction capacity modulation approaches are combined which result in even greater efficiencies for systems likely to encounter such operating conditions than could be achieved by either of the two capacity modulation approaches alone.
Additionally, the present invention may also incorporate a motor control module which will operate to control various operating parameters thereof to enhance its operating efficiency during periods when the motor load is reduced due to unloading of the compressor.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims taken in conjunction with the accompanying drawings.

This patent is subject to a terminal disclaimer.


The object of the present invention is to provide a band blade automatic working device with a marking unit which can automatically perform a marking operation for indicating a position for forming a notch and improve a measurement accuracy thereof and an operation efficiency thereof, wherein a structure thereof and an operation thereof are simple. In order to achieve the object, a band blade bending device according to the present invention, for bending and cutting a band blade comprises a marking unit for marking a blade edge thereof so as to be visually recognized from a side of a sharpened surface of the blade edge, and a computer for supplying a driving signal for driving the marking unit based on a data for deciding a position of a concave portion which should be formed at a back of the band blade. Furthermore, the band blade bending device comprises a carrying roller for carrying longitudinally the band blade by way of repeating a carry and a stop, and a band blade bending unit for bending and cutting the band blade. Moreover, it includes a computer for driving and controlling successively the marking unit and the band blade bending unit. The marking unit marks the blade edge of the band blade so as to be visually recognized from sides of both sharpened surfaces of the blade edge. In addition, the marking unit is an imprinter having a rubbery elastic body on a tip thereof for imprinting by way of exuding an ink on a surface of the rubbery elastic body, or an ink jet printer.

1. Field of the Invention
The present invention relates to a band blade automatic working device for automatically performing predetermined bending and cutting works a Thomson blade for pressingly cutting a paper, a plastic sheet and leather or the like and a straight shape band blade such as pressing horizontal rule for folding a paper box or the like.
2. Description of the Prior Art
As a band blade automatic working device, a technique for bending the band blade at a desirable radius of curvature and bending angle, and cutting the band blade in a predetermined measure by a computer control has already been used in practice.
Thus, the worked band blade is embedded in a groove formed on a substrate to make a sheet of pushing cutter die. The groove has a structure to be pierced from an upper surface of the substrate to a bottom surface thereof. In case of forming the grooves on the substrate successively, the substrate is separated. As a means for avoiding it, in order to prevent the grooves from being continuous, the substrate has conventionally been appropriately provided with discontinuous portions of the groove, and at each position corresponding to the discontinuous portions, a back portion 51 of a band blade 50 is provided with a concave portion or a bridge 16 as shown in FIG. 5. However, in working the bridge 16, a series of manual operations are performed as below: visually recognizing the discontinuous portions of the substrate, marking the band blade 50, forming the bridge 16 based on marks, thereby having a defect wherein the operation efficiency is low.
Moreover, the band blade 50 is provided with a notch or a connection 17 formed on a blade edge 52 thereof except the blade edge 52 and a portion adjacent to the blade edge 52 corresponding to the bridge 16. In case that, as soon as completing a step for pressingly cutting a development view of a paper container, a corrugated fibreboard container or the like, punched useful portions and unnecessary portions, i.e., portions adjacent to the punched useful portions are separated, it is difficult to treat them and the steps thereafter is more complicated. Therefore, the connection 17 has an arrangement wherein the connecting part is formed in order to carry a connected sheet as one body until reaching a missing leaf step. Then, the connection 17 is usually formed by a grinding work. A size of the connection 17 is different according to each punched paper thickness. For example, a connecting work has a width of about 1 mm, a depth of about 1 mm and more than 4 connections are usually arranged on a pair of punching dies. The connection 17 is formed in a final step wherein the bridge 16 cannot be visually recognized after embedding the band blade 50 in the groove of the substrate. As a result, working the connection 17 is performed at the blade edge or the portion adjacent to the blade edge, thereby causing an inconvenience to overlap the bridge 16. However, the portions forming the connection 17 requires not to overlap the bridge 16 so as to maintain a strength of the band blade 50. Therefore, in working the connection 17, the substrate where the worked band blade is embedded is marked so as to indicate the "connecting" position, whereby a blade edge has conventionally been formed by a grinding work based on marks.
As mentioned above, the operation for forming the bridge 16 and the connection 17 is still performed visually with the result that there are defects wherein the measuring accuracy is low and the operation efficiency is bad.

Band blade bending and cutting device with marking unit


A paper doll in which a trunk portion is hollow and disposed with its axial line directed in a longitudinal direction. Right and left shoulder joint members each formed in an approximately U-shape are rotatably coupled with the trunk portion by a first metal coupling passing through the trunk portion and the intermediate wall portions of the shoulder joint members. The base end portion of each of hollow upper arm members is held between a pair of side wall portions of the shoulder joint member and the upper arm members are rotatably coupled with the shoulder joint members by a second metal coupling passing through the side wall portions and the upper arm members, and femoral members each formed to be hollow are rotatably abutted against the trunk portion through the portions where the femoral members are abutted against sides of the trunk portion by a third metal coupling.

There are ordinarily found dolls that are made by movably coupling various parts such as a head, a trunk, both right and left arms, both legs, and the like with each other. Among these dolls, there are also widely known paper dolls which can be three-dimensionally made by one's own work by cutting out a thick paper sheet, and folding and bonding the cut-out paper sheets.
In many of these paper dolls, the arms and legs of the dolls can be bent in the joint portions of the shoulders, elbows, crotches, knees, and the like thereof to realize motion near to human motion. In this type of the dolls, however, since the motion of the joint portions is ordinarily very mechanical and stiff, it is difficult for the dolls to express the flexible motion of the joints similar to the human motion. Accordingly, even if it is admitted that the motion of the dolls cannot help being restricted because they are made of the paper sheet, the motion of them is greatly different from the human motion in many cases.
In contrast, in paper doll kits having a plurality of movable joint portions as described above, there is a tendency that the arrangement of the joint portions are made complex, which often makes it difficult to form a doll in its entirety.    Patent document 1: Japanese Unexamined Utility Model Application Publication No. 59-73993    Patent document 2: Japanese Unexamined Utility Model Application Publication No. 59-76294    Patent document 3: Japanese Utility Model Gazette No. 3068314


A method for forming deep trench or via airgaps in a semiconductor substrate is disclosed comprising the steps of patterning a hole in the substrate, partly fill said hole with a sacrificial material (e.g. poly-Si), depositing spacers on the sidewalls of the unfilled part of the hole (e.g. TEOS) to narrow the opening, removing through said narrowed opening the remaining part of the sacrificial material (e.g. by isotropic etching) and finally sealing the opening of the airgap by depositing a conformal layer (TEOS) above the spacers. The method of forming an airgap is demonstrated successfully for use as deep trench isolation structures in BiCMOS devices.

The semiconductor industry is continuously reducing the dimensions of devices. In Back End Of Line (BEOL) processing, there is an interest in reducing dimensions of conductive layers as well as in the separation of the different conductive structures from each other. Isolation of these structures therefore becomes extremely important, and low-k materials are used to replace conventional dielectric insulating materials. The trend is to move on to the incorporation of air, namely, so-called "air regions" or "airgaps", as an isolation material for conductive structures.
Examples of airgaps incorporated in BEOL structures include those based on the removal of a sacrificial material through a porous capping layer. The sacrificial material is evaporated through the porous capping layer and sealed afterwards by deposition of an extra layer. Examples of these methods are described in U.S. Pat. No. 6,165,890 and U.S. Pat. No. 6,287,979.
In Front End Of Line (FEOL) processing, isolation of the active device areas is one of the critical issues when dimensions are reduced. The device isolation methodology has been changed or modified several times with the aim of enhancing density or device functionality. Many of the methods had certain process limitations and were not very scalable. The introduction of "trench isolation technology" has been accepted quickly by industry as the primary isolation technique for advanced device and circuit designs (see, e.g., U.S. Pat. No. 4,104,086).
For bipolar or BiCMOS technologies, device isolation is of particular importance, because the collector nodes, which are buried in the substrate, carry active signals. This is in contrast to MOS transistors, where the wells do not carry active signals. The collectors are isolated from the substrate by collector-substrate pn junctions. This junction has a box-like shape with a bottom surface determined by the transistor area and a lateral surface determined by both the transistor perimeter and the n-type region depth. It introduces a parasitic junction capacitance at the collector terminal. The value of the parasitic junction capacitance is given by the sum of a perimeter term, associated with the lateral junction, and an area term, associated with the bottom junction.
Deep trench isolation structures are employed in conventional systems, and are commonly used in advanced bipolar technologies in order to reduce the total device area and the collector to substrate parasitic capacitance. The introduction of a deep trench filled with an insulator adjacent to the bipolar transistor replaces the lateral junction with a silicon-insulator-silicon capacitor, and it can be used to reduce the value of the perimeter component of the capacitance. As the transistor dimensions are scaled down, the total value of the capacitance is also effectively reduced, because the percent weight of the perimeter component increases.
The reduction of the collector-substrate capacitance allows further optimization of the high-speed or low-power performance of bipolar transistors. In common-emitter stages designed in a low-power bipolar technology, the collector-substrate capacitance is a significant contributor to the total switching delay. A low collector-substrate capacitance value helps to produce state-of-the-art power-delay products. Other applications that can benefit from the introduction of deep trench isolation include, for example, high voltage applications that achieve high breakdown voltage. Deep trench isolation can also be employed to isolate high voltage regions from low voltage regions in applications where good latch-up immunity or low substrate noise is desired.
In a full BiCMOS technology, the deep trench has to be etched, refilled, and planarized with a CMOS compatible process module. This fact imposes constraints on the selection of the process steps and on the location of the module in the complete process flow. The trench isolation technology is based on four key process elements: trench formation; trench lining; trench filling; and trench planarization. In particular, the choice of the filling material is very important, as it determines the value of the actual capacitance of the collector substrate perimeter component. LOW-κ materials are desired, with silicon dioxide being the most straightforward candidate. Although a complete oxide filling is preferred, because of its good isolation properties and low dielectric constant, this scheme is not easy to implement for several reasons. Namely, it is difficult to obtain a complete fill of the deep trench without leaving any voids, and also because a completely oxide-filled deep trench would generate localized stresses and defects during and after processing.
For these reasons, a state-of-the-art deep trench module often consists of a combined oxide/polysilicon filling. The polysilicon material makes it easier to fill the trench properly and thermal stress is reduced because the thermal expansion coefficient of polysilicon and the silicon substrate match much better. However, the isolation qualities are less (i.e., the κ-value of polysilicon is roughly a factor of 3 higher than that of oxide). For that reason, it is beneficial to increase the oxide/polysilicon ratio as much as possible, as this will reduce the final collector to substrate perimeter capacitance. One of the ways to accomplish this in a modern CMOS technology with a shallow trench isolation scheme is by the introduction of the deep trench isolation prior to the shallow trench isolation. In this way, the thickness of the oxide liner in the deep trench can be well balanced with respect to possible stress generation, thereby obtaining a low perimeter capacitance value without affecting the CMOS shallow trench isolation module itself.
Alternatively, as described by Washio et al. (IEEE Transactions on Electronic devices, Vol. 48, 2001), double deep trenches can be used, at the expense of increased device area.

Formation of deep trench airgaps and related applications

Interuniversitair Microelektronica Centrum (IMEC) vzw


An integrated circuit on a semiconductor substrate has logic gates comprising FDSOI-type transistors made on said substrate, including at least one first transistor comprising a gate with a first work function, and including a transistor comprising a second work function, a memory including memory cells, each memory cell comprising FDSOI type transistors, including at least one third nMOS transistor with a gate presenting a third work function, the third transistor comprising a buried insulating layer and a ground plane at least one fourth pMOS transistor with a gate presenting said third work function, the fourth transistor comprising a buried insulating layer and a ground plane, the ground planes of the third and fourth transistors being made in a same well separating these ground planes from said substrate.

In most advanced integrated circuits, the embedded memory blocks amount to more than half of the total surface area of the circuit. In the future, it is expected that the memory blocks will exceed more than 70% of the total surface area of the circuit. The surface area of the memory cell therefore plays a vital role in the race towards miniaturization. For many years, the gain in integration density has been obtained by reducing the different dimensions of the transistors (the front end), the contacts (the middle end) and the metals (the back end), enabling the integration of ever-increasing numbers of memory cells on a given surface area of substrate.
The reduction of certain dimensions in the transistors has led to the appearance of parasitic physical effects which become non-negligible (in terms of variation of dopants, short channel effects, etc.) and affect miniaturization. Novel materials have therefore appeared along with novel transistor architectures in order to compensate for these parasitic effects.
However, the use of novel materials and/or novel architectures generally leads to difficulties of manufacture and/or problems of reliability of the integrated circuit. Similarly, the use of a novel type of transistor entails problems in terms of portability and compatibility of the already existing circuits as well as the circuit techniques used to improve performance.
Integrated circuits made with SOI technology have a certain number of advantages. Such circuits generally show lower static and dynamic electricity consumption for equivalent performance, owing to better electrostatic control of the channel by the gate. Because there is a non-doped channel, the dispersions of the electrical characteristics are also smaller. Such circuits generally result in lower parasitic capacitances, thus improving switching speed. Furthermore, the latch-up or parasitic triggering phenomenon encountered by CMOS transistors in bulk technology can be avoided to the benefit of operating robustness, owing to the presence of the insulating oxide layer. Such circuits therefore prove to be particularly suited to SoC type applications. It is generally noted that SOI integrated circuits are less sensitive to the effects of ionizing radiation and hence prove to be more reliable in applications where such radiation can give rise to operational problems, especially in space applications. SOI integrated circuits can especially include SRAM random-access memories or logic gates. The making of SOI integrated circuits also remains relatively similar to that of bulk technology.
Reducing the static consumption of logic gates while at the same time increasing their switchover speed has been the subject of much research. Certain integrated circuits being developed integrate both low-consumption logic gates and high-switching-speed logic gates. To generate both these types of logic gates on a same integrated circuit, fast-access logic gates or low-consumption logic gates are chosen from libraries of logic gates. In bulk technology, the threshold voltage level of transistors of a same type is modulated by differentiating their channel doping level. However, in FDSOI (Fully Depleted Silicon-On-Insulator) technology, the doping of the channel is almost zero. Thus, the channel doping level in the transistors cannot show major variations without losing the associated advantages, and this fact makes it impossible to differentiate the threshold voltages by bringing this doping into play. The threshold voltages in non-doped channel FDSOI technology are thus essentially determined by the work function of the gate. For nMOS transistors, a work function slightly below the midgap, known as an N-type work function, is generally desired to obtain threshold voltages between 0.2 and 0.5V. Symmetrically, for pMOS transistors, a work function slightly above the midgap, called a P-type work function, is generally desired to obtain threshold voltages between −0.2 and −0.5V.
In order to have distinct threshold voltages for different FDSOI technology transistors, there are also known ways of using a biased ground plane placed between an insulating thin-oxide layer and the silicon substrate. By playing on the doping of the ground planes and on their biasing, it is possible to define a range of threshold voltages for the different transistors. We could thus have low-voltage-threshold or LVT transistors, high-voltage-threshold or HVT transistors and medium or standard-voltage-threshold or SVT transistors.
For certain functions of the circuit, it is possible to combine transistors of a same type, for example LVT or HVT transistors, in a same region. However, certain functions of the circuit require the contiguous joining of different types of transistors with ground planes having different biases. The designing of such functions of the circuit proves to be relatively difficult because additional designing constraints have to be taken into account. FIGS. 1a to 1c provide an example of pairs of nMOS and pMOS transistors of different types, namely HVT, SVT and LVT types respectively.
FIG. 1a shows an example of a pair of HVT-type transistors, namely an nMOS transistor 1nH and a pMOS transistor 1pH. The transistors 1nH and 1pH are made with SOI technology. The transistors 1nH and 1pH are made on a layer of silicon substrate 101H. The transistors 1nH and 1pH comprise respective buried insulating layers, 103nH and 103pH, separated from the substrate layer 101H by means of respective ground planes 102nH and 102pH and wells 112nH and 112pH. The insulating layers 103nH and 103pH are surmounted by an active silicon layer. The active silicon layer of the transistor 1nH comprises a source, a channel 104nH and a drain. The active silicon layer of the transistor 1pH comprises a source, a channel 104pH and a drain. The ground planes 102nH and 102pH enable the electrostatic control of the transistor to be improved by limiting the penetration of the electrical fields generated by the drain and the source beneath the channel 104nH and 104pH. The reduction of the lateral electrostatic coupling reduces short-channel effects and limits the drain-induced depletion effect through DIBL. The channels 104nH and 104pH are lined respectively with gate oxide layers 105nH and 105pH. The gate oxides 105nH and 105pH are surmounted by respective gate stacks comprising metal layers 108nH and 108pH and polysilicon layers 111nh and 111ph. The stacks are demarcated laterally by spacers 110nH and 110pH. Insulation trenches 106H, 107H and 109H are placed around the transistors 1nH and 1pH.
To obtain HVT type transistors, the ground plane 102nH has P-type doping and is biased to ground, and the ground plane 102pH has an N-type doping and is biased to Vdd, and thin BOX insulating layers 103nH and 103pH, (with a typical thickness of 10 to 50 nm) are used. The ground plane 102nH could also be biased to a voltage ranging from Gnds (Gnds being a voltage below ground voltage Gnd) and Vdd/2. The ground plane 102pH could also be biased to a voltage ranging from Vdd/2 (Vdd being a high-level voltage) to VddH (VddH>Vdd). The wells 112nH and 112pH have respective P-type and N-type dopings. The ground planes 102nH and 102pH are biased by means of wells 112nH and 112pH respectively.
FIG. 1b shows an example of a pair of SVT-type transistors, namely an nMOS transistor 1nS and a pMOS transistor 1pS. The transistors 1nS and 1pS have substantially the same structure as the transistors 1nH and 1pH: they are made on a silicon substrate layer 101S comprising respective buried insulating layers 103nS and 103pS separated from the substrate layer 101S by means of the respective ground planes 102nS and 102pS and wells 112nS and 112pS. The insulating layers 103nS and 103pS are surmounted by an active silicon layer. The active silicon layer of the transistor 1nS has a source, a channel 104nS and a drain. The active silicon layer of the transistor 1pS has a source, a channel 104pS and a drain. The channels 104nS and 104pS are lined respectively by gate oxide layers 105nS and 105pS. The gate oxide layers 105nS and 105pS are surmounted by respective gate stacks comprising metal layers 108nS and 108pS and polysilicon layers 111nS and 111pS. The stacks are demarcated laterally by spacers 110nS and 110pS. Insulating trenches 106S, 107S and 109S are placed around the transistors 1nS and 1pS.
To obtain SVT type transistors, the ground plane 102nS has an N-type doping and is biased to ground and the ground plane 102pS has P-type doping and is biased to Vdd, and thin insulating BOX layers 103nS and 103pS are used. The ground plane 102nS could also be biased to a voltage ranging from Gnds (with Gnds<Gnd) and Vdd/2. The ground plane 102pS could also be biased to a voltage of Vdd/2 to VddH. The wells 112nS and 112pS have respective P-type and N-type dopings. The biasing of the ground planes 102nS and 102pS is done by means of the wells 112nS and 112pS respectively.
FIG. 1c shows an example of a pair of LVT-type transistors comprising an nMOS transistor 1nL and a pMOS transistor 1pL. The transistors 1nL and 1pL have substantially the same structure as the transistors 1nH and 1pH: they are made on a silicon substrate layer 101L comprising respective buried insulating layers 103nL and 103pL separated from the substrate layer 101H by means of respective ground planes 102nL and 102pL and wells 112nL and 112pL. The insulating layers 103nL and 103pL are surmounted by an active silicon layer. The active silicon layer of the transistor 1nL has a source, a channel 104nL and a drain. The active silicon layer of the transistor 1pL has a source, a channel 104pL and a drain. The channels 104nL and 104pL are lined respectively with gate oxide layers 105nL and 105pL. The gate oxides 105nL and 105pL are surmounted by respective gate stacks comprising metal layers 108nL and 108pL and polysilicon layers 111nL and 111pL. The stacks are demarcated laterally by spacers 110nL and 110pL. Insulating trenches 106L, 107L and 109L are placed around the transistors 1nL and 1pL.
To obtain LVT type transistors, the ground plane 102nL has an N-type doping and is biased to Vdd and the ground plane 102pL has P-type doping and is biased to ground, and thin insulating BOX layers 103nL and 103pL are used. The ground plane 102nH could also be biased to a voltage of Vdd/2 to VddH. The ground plane 102pH could also be biased to a voltage of Gnds to Vdd/2. The wells 112nL and 112pL have respective N-type and P-type dopings. The ground planes 102nL and 102pL are biased by means of the wells 112nL and 112pL respectively.
It is also possible to integrate different gate materials for these transistors to modify the threshold voltages of the different transistors. To this end, it is possible to use different types of doping in the polysilicon layers, make different types of polysilicon layers or use different materials in the metal layers so as to obtain gates with distinct work functions.
These technical solutions provide for a specialization of the transistors in the logic gates and the memory cells of the integrated circuit. The characteristics of the integrated circuits designed may thus be more specifically defined.
The process of implanting dopants in the structure leads to undesirable variations in concentration at the edge of the implantations, inducing undesirable doping of the channel of the transistors. At the scale of the integrated circuits used, these variations take the form of effects known as WPE (well proximity effects) that are not negligible and affect the reliability and efficiency of manufacture of such circuits. The use of different gate materials also has non-negligible consequences on the complexity of the manufacturing process and its efficiency, especially as the integrated circuit has high density.

SOI integrated circuit comprising adjacent cells of different types

Commissariat à l'énergie atomique et aux énergies alternatives


A device has a body defining a space for the passage of a fluid, as well as a detector of a hydraulic or chemical-physical property of the fluid in the space. The detector is connected to a control unit by means of a wireless communication system that includes a data transmission circuit, connected to the detector, and a data receiving circuit, interfaced to the control unit. The wireless communication system includes a radio-frequency passive electric circuit without independent power supply.

1. Field of the Invention
The present invention refers to a device comprising a body defining a space containing or allowing the passage of a fluid, said body being associated to detecting means of at least a hydraulic or chemical-physical property of the fluid present in said space, the detecting means being operatively associated to a control system of the device.
2. Description of the Related Art
Some hydraulic devices, such as for instance some types of electric valves, integrate a flow meter designed to measure the flow rate of a fluid under control or to be treated by said device. Conversely, other hydraulic devices integrate detectors of one or more chemical-physical properties of a fluid, for instance some decalcifying devices for household appliances, which are associated to detecting means for water hardness. An application field exemplifying the problems underlying the present invention comprises mixing valves, and in particular those used for drink vending machines.
Some drinks, such as for instance non-alcoholic drinks, consist of a mixture of at least two liquid ingredients, usually a concentrated syrup and water, the latter suitably diluting the syrup. In some drink vending machines, the so-called post-mix type, syrup and water are mixed directly by the consumer, or by an operator, on the spot where the vending machine is installed. A post-mix vendor therefore comprises a device mixing the two components straight before they are supplied to the consumer. Said mixing device typically comprises at least two electric valves, for water and syrup respectively, installed so as to operate together and generally integrated into one module shaped as a mixing valve.
Some mixing valves used in the aforesaid field envisage the detection of hydraulic or chemical-physical properties of the water-syrup mixture. In particular, some applications envisage the use of flow meters for syrup and water, so as to measure the instantaneous flow rate of the fluid ingredients and to adjust the mixing ratio consequently by acting onto the mixing valve. In other applications the mixing operation is based on the measurement of the percentage of sugar, usually known as "Brix", present in a final mixture comprising known ratios of water and syrup. In further systems, conversely, the mixing operation is regulated on the basis of the measurement of electric conductivity (see for instance U.S. Pat. No. 6,387,424) or refractive index (see for instance U.S. Pat. No. 6,374,845) referred to the mixture of water and syrup.
The integration into the mixing valve of means required to detect said quantities involves the presence of electric connections and contacts between said sensors and the control system supervising the operation of the valve. The presence of cables, beyond making the installation of the device quite complex and having given overall dimensions, limits the positioning of the detecting means within the valve. The electric contacts between the detecting means and the corresponding supply and/or signal cables then undergoes wear and tear in time, typically due to oxidation, considering that said devices often operate in moist environments; that is why high requirements of electric insulation are to be met. The presence of connections and contacts eventually involves the risk of unintentional dispersions of electric currents that can be dangerous, above all if we consider that said detecting means have to be put in contact with the liquid to be measured (for instance sensors of conductivity, refractive index, and so on). The presence of electric contacts further makes the separation and/or removal of components of the device quite difficult, for instance to washing and/or maintenance purposes.
The same applies also to the integration into a mixing valve as described before of a flow or flow rate sensor, aiming at enabling the measurement of the amount of one or more of the liquid ingredients used.

Device comprising detecting means for hydraulic or chemical-physical properties of a fluid