A novel compound which polymerizes to a thermoset polymer and which pyrols to amorphous carbon, is selected from the group consisting of: ##STR1## where R.sup.1 is --C.tbd.C.phi.. A novel thermoset polymer is made by heating an aromatic acetylenic monomeric precursor with the formula: ##STR2## where R.sup.1 is --C.tbd.C.phi., and where R.sup.2, R.sup.3, and R.sup.4 are independently selected from the group consisting of --H and --C.tbd.C.phi., or a mixture of two or more of these compounds, to a polymerization temperature. A novel process for making amorphous carbon with high char yield and low porosity, comprises pyrolyzing an aromatic acetylenic monomeric precursor/polymer, or a mixture of two or more precursors/polymers to a temperature in excess of 450.degree. C.

1. Field of the Invention
This invention relates to aryl acetylenic monomers and thermoset polymers made from these aryl acetylenic monomers, and to the use of these monomers and polymers as precursors for amorphous carbon.
2. Description of the Related Art
A. Relating to Amorphous Carbon
Amorphous carbon is a high strength, low weight structural material. It is referred to in the literature as glassy carbon, pyrolytic carbon, or simply as carbon. It maintains its mechanical properties at temperatures up to 3000.degree. C., can be formed into shaped structures, and can be included in a wide range of composite materials. These beneficial properties have made amorphous carbon the material of choice for many applications, especially in the aerospace industry where high strength and low weight are critically important.
Amorphous carbon is typically made by pyrolysis of aromatic compounds such as phenolic resins, phthalonitrile resins, etc. Pyrolysis of these compounds into amorphous carbon involves heating the compounds at sufficiently high temperatures (generally above about 450.degree. C.) to break bonds and evolve a variety of gases containing the non-carbon components of these aromatic compounds, such as H.sub.2 O, H.sub.2, NH.sub.3, etc. This results in the formation of a disordered, amorphous network of polycondensed fused aromatic rings with the beneficial properties described above.
Crystalline (i.e. graphitic) inclusions in the amorphous matrix are observed as amorphous carbon is pyrolyzed at temperatures above about 1000.degree. C. This increased ordering of carbon increases the material density, and provides improved structural and electrical properties. Graphitic inclusions improve the stiffness and thermal stability of carbon structures. These improvements in the properties of structures follow increases in the ratio of carbon in crystalline form to carbon in amorphous form in the structure. This ratio in turn follows the length and temperature of the high temperature (>1000.degree. C.) pyrolysis of the structure.
To date, the precursors for and processes for making amorphous carbon have been unsatisfactory to one degree or another. Some precursors are explosive, especially those with ratios of acetylene groups to aryl groups of about 2:1 or higher. Some precursors are made via low yield, multiple step synthetic routes. Moreover, almost all the known precursors result in relatively poor pyrolytic char yield and high porosity, unless carried out under high pressure (>1 atm).
Highly porous materials result from the evolution of large gaseous volumes. In addition to being inherently low yield, highly porous carbon structures have several intrinsic disadvantages, including high gas permeability, poor high temperature stability, poor mechanical properties, and poor chemical inertness. Overcoming these intrinsic disadvantages generally involves some densification of the pyrolytic product.
U.S. Pat. No. 4,284,834 teaches making amorphous carbon with high char yield. However, the complex, multiple step synthesis of the precursor has a very low yield, making this process commercially impractical.
B. Relating to Aromatic Acetylenic Compounds
There are several known compounds with the general formula: ##STR3## where R.sup.1 is --C.tbd.C.phi., and where R.sup.2, R.sup.3, and R.sup.4 are independently selected from the group consisting of --H and --C.tbd.C.phi.. Specifically, the compounds 1,3,5-tris(phenylethynyl)benzene, 1,2,4,5-tetrakis-(phenylethynyl)benzene, and hexa(phenylethynyl)benzene are known. However, to the best of the applicants' knowledge, the prior art has never taught or suggested the use of these compounds as precursors for thermoset polymers or for amorphous carbon.
Furthermore, to the best of the applicants' knowledge, the specific monomers taught and claimed as the monomers of the invention have never been taught or suggested in the prior art.

Aromatic acetylenes as carbon precursors

The United States of America as represented by the Secretary of the Navy


There is provided mechanisms for controlling movement of a propeller shaft on a vessel. A controller includes processing circuitry. The processing circuitry is configured to cause the controller to detect movement of the propeller shaft by determining a signature of a sustained oscillation of the propeller shaft. The processing circuitry is configured to cause the controller to control movement of the propeller shaft according to the determined signature.

Long sea shipping ships relying on electrical propulsion, such as LNG carriers, are characterized by optimized engineering designs that strive to achieve as high an operating efficiency per tonne of fuel, as possible. This design problem encompasses the entire propulsion power generation, transfer, conversion, and delivery, i.e. the entire drive-train of the vessel, terminating ultimately in the end-effector of naval propulsion, the propeller. Traditionally, the philosophy of design of the mechanical part of the drive-train consisting of the shaft, bearings, clutches if present, gearboxes if present, and the propeller has been extensively studied, and is both quite conservative, and considered separately from the design of the electrical part. The propeller especially, with highly non linear hydrodynamics involved in calculation of effects, efficiency, wear-and-tear, and criticality, is often designed from experience. Procedures, design, and build are as a rule grounded in experimental know-how expressed as various design diagrams and curves from scale or true form factor measurements. If cyclic design is present, it is a relatively slow, experiment-driven cycle of prototyping, scaling down, and testing against scale models of vessels and propellers, in testing tanks.
Propellers are designed primarily with respect to two opposed design criteria. The first is propulsion efficiency, i.e. the rate of transfer of energy from the rotational kinetic energy of the propeller assembly, hub, and blades, to the kinetic energy of the entrained water flow. This resultant kinetic energy is what causes the reactive acceleration of the ship and thereby its motion on its course and steering of its heading and course. The other design criterion is avoidance of several critical behaviors, one of which is cavitation. Cavitation is a nonlinear phase-change hydrodynamic phenomenon introducing a wholly new energy flow in the diagram of energy transfer from the rotational kinetic energy to the kinetic energy of the entrained fluid. This parasitic flow is induced by introducing an avenue for the escape of energy as, first, thermal energy of the produced cavitation bubbles, followed by release of mechanical energy of bubble implosion, useless from the point of view of propulsion of the vessel, which is expended on physically eroding the propeller blades.
Consequently, in traditional electrical propulsion shipbuilding of long sea shipping vessels, designers and engineers of the electrical part of the propulsion system are presented with the design envelopes and performance indices of the mechanical part as-is. A variety of parameters of one or more algorithms that steer, control, supervise, and govern the rate of generation, transfer, and conversion of electrical power, are then engineered in order to adapt to, obey, be consistent, and compatible with the presented design envelopes, chief among them those of the end-effector—the propeller.
However, there is still a need for an improved control of the propeller.


An absorbable blood vessel stent (100) has a near end and a far end. A tubular patterned structure is formed between the near end and the far end. The patterned structure comprises a plurality of support bars and connection bars (2, 3). The support bar or the connection bar (2, 3) comprises a straight line section, a U-shaped section, or an S-shaped section, and at least one through groove or through hole (5, 6) is provided on at least one support bar. Because of the special structure of the blood vessel stent (100), the performance of an iron blood vessel stent can be improved, and blood vessel stents made of other absorbable materials can be decomposed more rapidly.

In 1977, the first case of Percutaneous Coronary Intervention (PCI) surgery in the world was accomplished in Switzerland. In this surgery, a balloon was employed to dilate the position of the left anterior descending branch stenosis of the patient, successfully. However, the re-stenosis rate of the blood vessel after balloon dilation was very high, over 50%. The main reason was that, after the blood vessel was dilated and the external force was removed, the blood vessel may elastically recoil. In the 1980s, blood vessel stents widely used for coronary artery were invented. There were blood vessel metal stents mainly made of stainless steel, cobalt-chromium alloy or nickel-titanium alloy. After implanted into the human body, the stents may provide durable mechanical support for the blood vessel, thereby preventing the blood vessel from elastically recoiling and reducing the re-stenosis rate of the diseased blood vessel. However, since the stents were permanently implanted into the human body, the stents as foreign substances may cause intimal hyperplasia and quite high re-stenosis rate of the blood vessel. Since 2003, the application of the drug stents reduces the blood vessel re-stenosis rate to about 10%. However, since the drug stents still existed inside the human body permanently, the stents as foreign matter have great differences with vascular tissues in terms of mechanical property, which may cause chronic injury of the blood vessel, cause blood vessel medial atrophy and intimal hyperplasia at the late stage, and may also cause blood vessel re-stenosis finally, thereby limiting the further reduction of the blood vessel re-stenosis rate. As for children, the implantation of blood vessel stents with fixed sizes may hinder the gradual increase of the blood vessel, being unable to meet the requirement on the growth of children.
Both of the above intervention treatment technologies for blood vessel stenosis have defects: for dilating the blood vessel by using balloons, although the short-term effect is good, the re-stenosis rate at the late stage is very high because of elastic recoiling of the blood vessel; for implanting metal stents into the blood vessel, the metal stents including bare stent and drug stent may dilate the narrow blood vessel and provide a durable mechanical support, however, the blood vessel intima may be injured during the dilation of the metal stents, which may induce blood vessel intimal hyperplasia to lead to re-stenosis. The metal stents further have the defects of thrombosis, coagulation complication, flexibility mismatching, and increase of the re-stenosis occurrence rate at late stage if permanently remaining inside the human body.
In order to solve the above problems, in recent years, many people have begun to pay close attention to blood vessel stents that are absorbable by the human body. After a blood vessel stent is implanted into the human body, the ideal situation should be that, at the initial stage, the blood vessel stent provides a sufficient support to the blood vessel, and meanwhile releases drugs to treat the diseased blood vessel, and after the treating function is accomplished, the blood vessel stent is gradually absorbed so as to prevent the re-stenosis. According to different materials, there are two main kinds of absorbable blood vessel stents, one kind is the blood vessel stent made of macromolecular polymer materials, such as polylactic acid; and the other kind is the blood vessel stent made of metal materials, such as magnesium alloy and iron.
Recently, many people have been doing research on making blood vessel stents, for example, a polylactic acid stent, by degradable macromolecular materials, and some research results have started clinical tests. However, compared with the metal materials, the degradable macromolecular materials have obvious defects in terms of mechanical property, and so the application thereof is limited. When compared with the metal materials, the macromolecular polymer materials have low mechanical property and insufficient strength. In order to achieve certain radial support, the wall thickness of the stent must be increased. However, after implantation inside the human body, the stent with a thick wall may hinder the flow of the blood. In addition, the retraction rate of the macromolecular polymer material stents is quite high after dilation by the balloons, and so the expansion ratio of the diameter of the stent after dilated with respect to the diameter of the blood vessel is larger than that of the metal material stents, which may cause greater injury to the blood vessel during the dilation. The X-ray visibility of the macromolecular polymer material stents inside the human body is poor, and so it is difficult to locate and observe the stents during the implantation.
At present, there are mainly two types of metal materials applied to absorbable blood vessel stents: magnesium alloy material and pure iron material. The magnesium alloy material is poor in mechanical property and corrodes quickly. The magnesium alloy material has good bio-compatibility. However, the maximum elongation rate of the magnesium alloy stents is low, which brings great challenge to the structural design of the magnesium alloy stents, and so it is difficult to ensure the good mechanical property of the stents. Furthermore, the corrosion rate of the magnesium alloy stents is too fast, so a complex material manufacture process must be adopted to control the rate by which the magnesium alloy stents are absorbed by the human body. Iron is an essential element for the human body, and simultaneously, pure iron has good bio-compatibility and mechanical property. Compared with the polymer stents or magnesium alloy stents having a same wall thickness, the iron stents may provide a sufficient radial support for the diseased blood vessel at the diseased position. However, the corrosion rate of the pure iron is relatively slow, the iron stents of common structure design may be absorbed by the human body after a long time, during which process the diameter of the blood vessel may be restrained, so it cannot meet the requirement on the gradual increase of the blood vessel for children.
Therefore, how to design a blood vessel stent that can accelerate the absorption process of the human body and simultaneously ensure the mechanical property thereof is an urgent problem to be solved at present.


Firstly, a silicon ingot in which boron and germanium were doped is sliced to prepare a silicon wafer and then the wafer is thermally processed by oxidation to form the thermal oxidation film on the surface layer portion of the wafer. Thereby, the concentration of germanium is enhanced in the vicinity of the interface with the thermal oxidation film of the wafer. Then, the thermal oxidation film is removed from the surface layer portion of the wafer. Further, an epitaxial layer consisting of a silicon single crystal in which a lower concentration of boron than the concentration of boron in the wafer was doped is grown on the shallow surface layer portion of the wafer by an epitaxial growth method. According to the present invention, the doping amount of germanium is reduced and the generation of misfit dislocations is suppressed.

1. Field of the Invention
The present invention relates to a process for producing an epitaxial silicon wafer by growing an epitaxial layer having a low boron concentration on a silicon wafer having a high boron concentration by an epitaxial growth method, and a silicon wafer produced by the process.
2. Prior Art
When an epitaxial layer in which boron was doped at low concentration was grown by an epitaxial growth method on the upper surface layer portion of a silicon wafer with low resistivity (0.003 Ω·cm or less) in which boron was doped at high concentration, misfit dislocations have been conventionally generated caused by the difference between the lattice constant of the silicon wafer and the lattice constant of the epitaxial layer. Since the misfit dislocations are moved on the shallow surface layer portion of the surface of the epitaxial layer during epitaxial growth, dislocations exist in an active zone at which semiconductor devices are prepared. Thus, when dislocations being crystal defects exist in the epitaxial layer, it causes malfunction of semiconductor devices and there is a fear of lowering their yield.
In order to solve the problem, there is disclosed a process for forming an epitaxial structure in which an epitaxial layer is deposited on a silicon substrate to which boron and germanium were doped (for example, refer to the patent literature 1: Japanese Patent Laid-Open Publication No. Sho 61-141700 (Claims 1 to 5, the third line to the eleventh line of an left upper column in page 3 of the specification and the 18th line of the right upper column to the second line of the left lower column in page 3 of the specification)). In the process for forming an epitaxial structure, when the concentration of boron doped on the silicon substrate is referred to as CB and the concentration of germanium doped on the silicon substrate is referred to as CGe, boron and germanium are doped on the silicon substrate so as to satisfy the relational formula of CB=6 CGe. Further, the thickness of the epitaxial layer is set as 5 μm and boron is doped by 0.02% by atom or more (resistivity: 0.015 Ω·cm or less).
In the epitaxial structure thus formed, the greater part of stress and corresponding strain which were caused by lattice incompatibility in an epitaxial wafer which was obtained by depositing an epitaxial layer to which a low concentration of boron was doped on a silicon substrate to which a high concentration of boron was doped are released by doping germanium in the crystal of the silicon substrate. Thereby, the epitaxial wafer does not substantially contain stress and strain is not generated irrespective of the thickness of the epitaxial layer. In other word, the degree of bending of the epitaxial wafer is made irrespective of the thickness of the epitaxial layer by the above-mentioned germanium.
Further, in order to solve the problem, there is also disclosed an epitaxial silicon single crystal wafer in which germanium was doped in the vicinity of the surface of a silicon wafer in which boron was doped in high concentration (for example, refer to the patent literature 2: Japanese Patent Laid-Open Publication No.2003-209059 (Claims 1 to 4 and paragraph [0010])). In the epitaxial silicon single crystal wafer, the concentration of boron in the wafer is 7×1018 atoms/cm3 or more and germanium is doped at a concentration of 1×1020 to 5×1020 atoms/cm3 from the surface of the wafer to a depth of 20 nm or less.
Since the radius of covalent bond of boron is small in comparison with the radius of covalent bond of silicon in the epitaxial silicon single crystal wafer thus composed, the strain which is caused by boron is compensated by supplying tetra-valent germanium which has the larger radius of covalent bond than that of silicon and an atomic valency equal to silicon.
However, in the above-mentioned conventional process for forming an epitaxial structure which was shown in the patent literature 1, when a silicon single crystal is pulled up by the Czochralski method, the segregation coefficient of boron is different from the segregation coefficient of germanium; therefore it is difficult the concentration of boron CB and the concentration of germanium CGe satisfy always the relational formula of CB=6 CGe over the full length of the silicon single crystal which was pulled up.
Further, in the above-mentioned conventional process for forming an epitaxial structure which was shown in the patent literature 1, the doping amount of germanium which is required for doping boron in high concentration is extremely much in order to lower the resistivity of a silicon substrate. For example, when the concentration of boron is 3.6×1019 atoms/cm3 or (resistivity: 0.003 Ω·cm), the weight of germanium required is numerously 1.5 kg when the weight of silicon melt is 35 kg and since germanium is very precious, there is a problem that the production cost of the silicon substrate is increased.
Further, according to the study of the present inventors, when boron is doped in high concentration and germanium is doped in high concentration, there are problems that the probability of dislocating a silicon single crystal at growth of the silicon single crystal is enhanced and the yield of an ingot at production of the silicon single crystal is lowered.
Further, in the above-mentioned epitaxial silicon single crystal wafer which was shown in the patent literature 2, since its process is a single wafer processing that germanium is doped by every wafer, the production time of a wafer is elongated and there was a problem that its production cost was greatly pushed up.
It is the object of the present invention to provide a process for producing an epitaxial silicon wafer which can reduce the doping amount of germanium, can suppress the generation of misfit dislocations and can further shorten the production time of the wafer, and a silicon wafer produced by the process.

Process for producing epitaxial silicon wafer and silicon wafer produced by process thereof


A microelectromechanical system based fluid ejector comprises an ejector nozzle, a chamber that communicates with the ejector nozzle, and a plurality of movable ejection structures associated with the ejector nozzle and arranged to move in the chamber such that a variable volume of fluid is ejected from the associated ejector nozzle. The plurality of movable ejection structures may also be arranged to move in the chamber such that a continuous flow of fluid is ejected from the associated ejector nozzle. A controller may be used to actuate each of the plurality of movable ejection structures independently. The movable ejection structures may comprise a piston, a flexible diaphragm or the like. A plurality of actuators may be provided, with each of the actuators being associated with one of the ejection structures. The actuators may comprise electrostatic, magnetic or thermal actuators, or the like.

1. Field of Invention
This present invention relates to micromachined or microelectromechanical system (MEMS) based fluid ejection and ejectors.
2. Description of Related Art
Fluid ejectors have been developed for ink jet recording or printing. Ink jet printing systems offer numerous benefits, including extremely quiet operation when printing, high speed printing, a high degree of freedom in ink selection, and the ability to use low cost plain paper. The so called "drop on demand" drive method, where ink is output only when required for printing, is now the conventional approach. The drop on demand drive method makes it unnecessary to recover ink not needed for printing.
Fluid ejectors for ink jet printing include one or more nozzles which allow the formation and control of small ink droplets to permit high resolution, resulting in the ability to print sharper characters with improved tonal resolution. In particular, drop on demand ink jet print heads are generally used for high resolution printers.
Drop on demand technology generally uses some type of pulse generator to form and eject drops. For example, in one type of print head, a chamber having an ink nozzle may be fitted with a piezoelectric wall that is deformed when a voltage is applied. As a result of the deformation, the fluid is forced out of the nozzle orifice as a drop. The drop then impinges directly on an associated printing surface. Use of such a piezoelectric device as a driver is described in JP B 1990 51734.
Another type of print head uses bubbles formed by heat pulses to force fluid out of the nozzle. The drops are separated from the ink supply when the bubbles form. Use of pressure generated by heating the ink to generate bubbles is described in JP B 1986 59911.
Yet another type of drop-on-demand print head incorporates an electrostatic actuator. This type of print head utilizes electrostatic force to eject the ink. Examples of such electrostatic print heads are disclosed in U.S. Pat. No. 4,520,375 to Kroll and Japanese Laid-Open Patent Publication No. 289351/90. The ink jet head disclosed in the 375 patent uses an electrostatic actuator comprising a diaphragm that constitutes a part of an ink ejection chamber and a base plate disposed outside of the ink ejection chamber opposite to the diaphragm. The ink jet head ejects ink droplets through a nozzle communicating with the ink ejection chamber, by applying a time varying voltage between the diaphragm and the base plate. The diaphragm and the base plate thus act as a capacitor, which causes the diaphragm to be set into mechanical motion and the fluid to exit responsive to the diaphragm's motion. On the other hand, the ink jet head discussed in the Japan 351 distorts its diaphragm by applying a voltage to an electrostatic actuator fixed on the diaphragm. This result in suction of additional ink into an ink ejection chamber. Once the voltage is removed, the diaphragm is restored to its non-distorted condition, ejecting ink from the overfilled ink ejection chamber.
Fluid drop ejectors may be used not only for printing, but also for depositing photoresist and other liquids in the semiconductor and flat panel display industries, for delivering drug and biological samples, for delivering multiple chemicals for chemical reactions, for handling DNA sequences, for delivering drugs and biological materials for interaction studies and assaying, and for depositing thin and narrow layers of plastics for usable as permanent and/or removable gaskets in micro machines.

Systems and methods for microelectromechanical system based fluid ejection


In a scroll fluid machine, a fixed scroll has a fixed wrap, and an orbiting scroll has an orbiting wrap which engages with the fixed wrap to form a compressing chamber between the orbiting and fixed wraps. The orbiting scroll is rotatably mounted around an eccentric axial portion of a driving shaft and revolved by the driving shaft. A gas introduced from the outer circumference of the fixed scroll is compressed in the compressing chamber as it flows towards the center. Parts near the center is heated by a compressed gas. On the other surface of the fixed scroll to the surface having the fixed wrap, a plurality of cooling fins are provided. Air is introduced between the cooling fins to cool the machine. Between the cooling fins, a heat-releasing projection is provided to improve cooling efficiency.

The present invention relates to a scroll fluid machine and especially to a scroll fluid machine such as a scroll compressor or a scroll vacuum pump in which a fixed wrap of a fixed scroll engages with an orbiting wrap of an orbiting scroll mounted around an eccentric axial portion of a driving shaft, the orbiting scroll being eccentrically revolved by the driving shaft so that a gas sucked from the outer circumference of the fixed scroll can be compressed towards the center and discharged.
In a scroll fluid machine, a long-time operation increases temperature of an eccentric axial portion of a driving shaft, and bearings and packing that support the driving shaft to cause the bearings and packing to be damaged.
To prevent such situation, US2004/0241030A1 discloses a scroll fluid machine having a number of cooling fins on the surface of a fixed scroll to increase cooling efficiency.
However, in the scroll fluid machine, the cooling fins are radially provided on the surface of a fixed scroll to limit a cooling area and cooling performance. To increase the cooling area, increased number of the radial cooling fins makes gaps between the cooling fins denser to make cooling wind more unlikely to pass through to decrease cooling efficiency. Particularly, in the radial cooling fins, the gap between the cooling fins becomes narrower towards the center to make it more difficult for cooling wind to pass through towards the center having relatively higher temperature than in the outer circumference.

Scroll fluid machine having a fixed scroll with a heat-releasing projection


Hand-held printing device and systems adapted to receive radio signal information indicative of a position. Hand-held printing device having at least one antenna and a controller adapted to calculate the relative position of the hand-held printing device by comparing received radio signals on the antennae. Methods for using the same.

One feature of a hand-held printer is the random motion printing as compared to a conventional linear-type printer. Most digital printers operate by moving paper under the printing element. This is true for "page printers" which have an active print zone extending across the full width of the paper and true for "serial printers" that also move the print element across the page width in addition to moving the length of the paper by the printing element. This relative movement of paper and print element is a traditional configuration for digital printers. An alternative approach is to fix the position of the paper while the printer element is moved over the paper during printing. An example of this alternative approach is a flat bed plotter where the movement of the print element is controlled by fixed mechanical references along and outside the paper edges. The printer of the present invention is moved manually over the surface of the paper without mechanical linkage and without mechanical control form a fixed reference point. This category of printers is sometimes called a "hand printer" or "random motion printer." One advantage of this type of category is printer is the potential for compact size which makes it attractive for mobile printing operations.
Because of the effect on resulting print quality, a significant factor in printer design is the accuracy of positioning the print element relative to the page during the printing process. To increase accuracy, position sensors are often adopted to "close the loop" and confirm location. Such sensors typically detect rotation of paper feed rolls or lateral travel of the carrier for the print element. Without precise sensing, small errors can accumulate until the print quality is degraded to an unacceptable level. As such, for a random motion printer it is desired to have an improved ability to determine the position of the print element relative to the paper. Prior hand-held printers in the art have utilized one or more optical sensors to detect typographic structure on paper similar to an optical mouse pointing device. However, such designs can require expensive optical elements and may not always produce reliable results. As such, there is a need for new methods of determining position of the print element relative to the paper. Accordingly, improved hand-held printing devices, systems and methods for using the same are desired.

Handheld printing devices and systems adapted to receive radio signal information indicative of a position and methods for using the same


An apparatus for etching a wafer by a single-wafer process comprises a fluid supplying device which feeds an etching fluid on a wafer, and a wafer-chuck for horizontally holding the wafer. The wafer-chuck is equipped with a gas injection device for injecting a gas to the wafer, a first fluid-aspirating device, and a second fluid-aspirating device. The etching fluid supplied on the wafer is spread by a rotation of the wafer. The etching fluid is scattered by a centrifugal force, or flows down over an edge portion of the wafer and is blown-off by the gas injected from the gas injection unit, and is aspirated by the first fluid-aspirating device or the second fluid-aspirating device.

1. Field of the Invention
The invention relates to an apparatus for etching a wafer while horizontally holding a single wafer and rotating the wafer.
2. Description of Related Art
Generally, a manufacturing process of semiconductor wafers comprises: slicing a wafer from a single crystal ingot; facing and mechanically grinding (lapping) the wafer; etching the wafer; mirror polishing (polishing) the wafer; and cleaning the wafer. Through such steps, wafers having highly flat surfaces are manufactured. During the manufacturing process, a wafer is subjected to various mechanical workings such as cutting a block from the ingot, grinding the outside cylindrical surface of the block, slicing the wafer from the block, and lapping the wafer. As a result, the upper side of the wafer includes a damaged-layer as a work-affected layer. During the manufacturing process of semiconductor devices, the damaged layer of the wafer induces crystal defects such as slip dislocations to occur, and thereby deteriorating the mechanical strength of the wafer and causing adverse effects on the electrical property of the wafer. Therefore the damaged layer needs to be removed completely. In order to remove the damaged layer from the wafer, the wafer is subjected to etching treatment. Currently, immersion etching and etching by a single-wafer process are applied as the etching treatment.
Since the above-described etching by a single-wafer process is capable of controlling the surface roughness of a large-sized wafer, and the texture-size of the wafer, it is regarded as an optimal method for etching a wafer and has been subjected to examination. The etching by a single-wafer process is a method for etching a wafer by dropping an etching fluid on the upper surface of a flattened single wafer, horizontally rotating (spinning) the wafer so as to spread the dropped etching fluid over the whole area of the upper surface of the wafer, and etching the wafer. The etching fluid supplied to the upper surface of the wafer is applied with centrifugal force caused by rotation of the wafer in the horizontal plane, and the etching fluid is spread all over the wafer surface from a portion to which the etching fluid is supplied to the edge of the wafer. Therefore, the upper surface and the edge of the wafer are etched simultaneously. Most of the etching fluid supplied to the wafer is scattered from the wafer by centrifugal force and is recovered in a cup or the like provided in the etching apparatus. However, a certain amount of the etching fluid passes round the wafer edge to the undersurface of the wafer, and etches the edge portion and undersurface of the wafer.
In order to avoid the etching of the edge portion and undersurface of the wafer, Patent Document 1 (Japanese Unexamined Patent Application, First Publication No. H11-289002: see claims 1, 2, paragraphs [0010], [0018], [0019] and [0021]) discloses a single-wafer processing apparatus. In that apparatus, a center axis of a rotation base is connected to a rotation driver; a positioning portion for mounting a wafer on a predetermined position is provided at the peripheral portion of the rotation base; a support member for supporting the circumference of the wafer is disposed between the positioning portions at the periphery of the rotation base; and a treatment nozzle for supplying the etching fluid is disposed at the position above the rotation base. In such a single-wafer processing apparatus, the relative height X of the positioning portion and the support base compared with the undersurface of the wafer making contact with the rotation base is within a range of 0<X<(A+0.5), where A mm is the thickness of the peripheral portion of the wafer. In addition, in the above-described processing apparatus, a block for a gas supply is disposed around the central axis beneath the rotation base, and gas supply unit is disposed penetrating the interior of the rotation base. The gas from the block is supplied through the gas supply unit.
In such configurations of a single-wafer processing apparatus, by controlling the projecting height of the positioning portion and support member so as to satisfy the above-described range of relative height, it is possible to suppress the generation of turbulence and rebound of the etching fluid. In addition, by supplying a gas from the supply unit disposed at the block, it is possible to increase the atmospheric pressure in the space between the rotation base and the undersurface of the wafer, thereby preventing the etching fluid from passing round to the undersurface of the wafer.
In the conventional single-wafer type processing apparatus exemplified by the above-described apparatus of Patent Document 1, by supplying the gas to the space below the wafer, the etching fluid is prevented from passing round to the undersurface of the wafer. However, there is a possibility that the etching fluid stays for a long duration at the peripheral portion of the wafer causing undesirable etching of the edge portion subjected to the staying etching fluid. In such a case, the chamfered shape of the periphery of the wafer is deformed by the etching, and the edge of the wafer is etched heterogeneously.
In addition, in the conventional single-wafer type processing apparatus described in the above-described Patent Document 1, there is a possibility that the gas supplied to the space below the wafer scatters the etching fluid. The scattered etching fluid may be rebound by the inner wall of the apparatus and adhere again to the upper surface of the wafer.
The object of the present invention is to provide an apparatus for etching a wafer by a single-wafer process and a method for etching a wafer by a single-wafer process that prevent etching fluid from passing round towards the undersurface of the wafer as well as preventing re-adhesion of the etching fluid to the upper surface of the wafer and further preventing the localized deformation of the edge portion of the wafer.

Apparatus for etching wafer by single-wafer process and single wafer type method for etching wafer


Different embodiments of a one-time-programmable antifuse cell included. In one embodiment, a circuit is provided that includes an antifuse element, a high voltage device, and a sense circuit. The antifuse element has a voltage supply terminal to be at a sense voltage during sensing/reading and a higher programming voltage during programming. The sense circuit is configured to enable programming the antifuse element during programming and to sense the state of the antifuse element during sensing. The high voltage device is coupled between the antifuse element and the sense circuit to couple the antifuse element to the sense circuit during programming and sensing and to protectively shield the sense circuit from the higher programming voltage during programming.

One time programmable ("OTP") cells are used in integrated circuit ("IC") devices for a variety of applications including OTP memory applications. They may be used as a single memory cell, or in arrays of memory cells to provide unique die/chip IDs and to set operating parameters such as clock multipliers and voltage levels for devices such as microprocessors. They may also be used to configure, customize, and repair a chip after testing (e.g., to repair a processor chip's cache memory array). OTP cells are typically implemented using charge storage, fuse, or antifuse approaches. Charge storage approaches have typically involved defining a bit value based on charge stored on an insulated metal oxide semiconductor ("MOS") type gate structure. Such charge storage approaches, however, are not practicable with current and future deep sub-micron technologies that feature very thin gate oxide because of the high gate leakage current that prevents a long retention time of the information.
On the other hand, fuse and antifuse solutions are more reliable with such technologies. A fuse (or anti-fuse) link can be used to indicate a logic level (e.g., a High or Low level) depending on whether or not it is "blown" or left in its normal state. The natural state of a fuse is closed, but when it is blown (or burned), its resistance is increased to an open state (relative to its normal, closed state). In contrast, an antifuse is blown closed, with its natural state being an open circuit (relative to its normal, open state). A fuse or antifuse can thus be used to establish a logic level whose value depends upon whether it is blown or left in its normal state. Unfortunately, materials such as polysilicon and metals (used for fuses) and amorphous silicon (used for antifuses) require excessive voltages and currents (e.g., potentials exceeding 10 volts at currents greater than 10 Amps) for reliable programming. This is problematic because it means that large, robust transistor circuits are needed in each cell for reliable fuse/anti-fuse programming that does not do damage to surrounding, more sensitive circuitry. Another drawback is that the blowing of such fuse/antifuse structures is unreliable because it is not cumulative; if a device does not blow correctly the first time, it generally cannot be further blown by applying the programming current again. As a result, a certain redundancy is required to compensate for the portion of fuses/antifuses that don't blow correctly at the first try. A further drawback is that the difference of resistance between such blown and non-blown fuse/antifuse structures can be quite small (typically less than an order of magnitude), which makes it difficult to design a sensing scheme that operates reliably through process and temperature variations.
As silicon manufacturing technologies scale, the thickness of the oxide layer isolating the gate of MOS transistors scale. As a result, it has become feasible to break down this oxide by applying a sufficiently high voltage (e.g., 3 V or higher) across the oxide layer. Accordingly, oxide layers are now being used to implement antifuse elements. They are naturally open but when broken down, become closed. (For examples of oxide layers used as antifuse elements, see U.S. Pat. No. 6,686,791 to Zheng et al. and U.S. Pat. No. 6,515,344 to Wollesen.) Unfortunately, even though the required voltage to break down the gate oxide has diminished (e.g., reduced from 10 V to 3V), it still presents a danger to the fragile transistors of the circuit surrounding the oxide element being programmed. This means that the surrounding transistors should be sufficiently protected from the high programming voltages. Accordingly, disclosed herein are improved circuits for implementing antifuse cells and cell arrays using oxide (or other dielectric materials) as antifuse elements.


A pharmaceutical composition for inhibiting production or secretion of amyloid .beta. protein, which comprises a compound of the formula (I): ##STR1## wherein ring A is an optionally substituted benzene ring, R represents OR.sup.1, ##STR2## or SR.sup.1, wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and each is selected from a hydrogen atom, an optionally substituted hydrocarbon group or R.sup.2 and R.sup.3, taken together with the adjacent nitrogen atom, form an optionally substituted nitrogen-containing heterocyclic group, and Y is an optionally substituted alkyl group, or a pharmaceutically acceptable salt thereof, if necessary, with a pharmaceutically acceptable excipient, carrier or diluent.

1. Field of the Invention
The present invention relates to a composition, particularly a pharmaceutical composition, for inhibiting production or secretion of an amyloid .beta. protein. The composition is effective in treating degenerative brain disorders such as senile dementia, Alzheimer's disease, Down's syndrome, etc., amyloid angiopathy, brain disorders caused by amyloid .beta. protein in cerebrovascular diseases, etc.
2. Description of Related Art
Alzheimer's disease is a neurodegenerative disease characterized by senile plaque and neurofibrillar tangles as well as degeneration and loss of neurons. The senile plaques, which are most characteristic of the disease, are deposits composed of amyloid .beta. protein (hereinafter sometimes abbreviated as A.beta.) derived from .beta.-amyloid precursor protein (hereinafter sometimes abbreviated as .beta.APP) as a major component (Biochem. Biophys. Res. Commun., 122, 1131 (1984)), apolipoprotein E (Brain Res., 541, 163 (1991)) and heparan sulfate proteoglycan (Am. J. Pathol., 133, 456 (1988)), etc.
A.beta. of 40 or 42 amino acids exhibits toxicity to neurons (Science, 250, 279 (1990)), and induces neurofibrillar changes (Proc. Natl. Acad. Sci., 90, 7789 (1993)). In patients with familial Alzheimer's disease, mutations on the .beta.APP gene are observed (Lancet, 337, 978 (1991); Nature, 349, 704 (1991); Science, 254, 97 (1991); Nature, 354, 844 (1991)). Cells containing such mutated gene produce and secrete an increased amount of A.beta. (Nature, 360, 672 (1992); Science, 259, 514 (1993); Science, 264, 1336 (1994)).
Patients with Down's syndrome showing cerebral changes pathologically similar to those of Alzheimer's disease (Proc. Natl. Acad. Sci., 82, 4245 (1985)) have trisomy 21 (i.e., three chromosome 21s containing the .beta.APP gene) and promoted expression of the .beta.APP gene and .beta.APP protein in the brain (Science, 235, 880 (1987); N. Eng. J. Med., 320, 1446 (1989)).
Based on these findings, the participation of the abnormal production or secretion of A.beta. in the onset of Alzheimer's disease is considered to be highly important.
It is believed that .beta.APP is metabolized with proteases called .alpha.- and .beta.-secretases through two pathways (Science, 248, 492 (1990); Science, 248, 1122 (1990); Science, 255, 726 (1992); Science, 255, 728 (1992); Nature, 357, 500 (1992)). When .beta.APP is metabolized with a-secretase, .beta.APP is cleaved at position 16 of A.beta., A.beta. is not produced, and the N-terminal fragment of .beta.APP is released out of the cells as secreted .beta.APP, which acts as a neurotrophic factor (Neuron, 10, 243-254 (1993)). On the other hand, when .beta.APP is cleaved with .beta.-secretase, a C-terminal fragment of .beta.APP containing A.beta.is produced. However, it is unclear where the C-terminal fragment or A.beta. is produced in the cells and how A.beta. is secreted out of the cells. In addition, although candidate enzymes for .alpha.- and .beta.-secretases have been reported (J. Biol. Chem., 268, 16699 (1993); Biochemistry, 33, 192 (1994)), they have not identified.
It has been reported that some compounds, phorbol esters (Proc. Natl. Acad. Sci., 89, 3055 (1992)) and M1 muscarinic receptor agonist, carbacol (Science, 258, 302 (1992)) increase the secreted .beta.APP and inhibit A.beta. production or secretion in in vitro various cells. However, these compounds are unsatisfactory in terms of efficacy, safety, etc.

Composition for inhibiting production or secretion of amyloid .beta. protein to treat Down's syndrome


A closure device for a lower opening of a coke drum pressure vessel is quick acting. The opening has an annular flange. An annular movable support encircles the pressure vessel above the flange. A stationary support secures to the flange below the movable support. A number of coil springs are evenly spaced around the stationary support between the stationary support and the movable support. Hydraulic cylinders between the movable and stationary support move the movable support axially relative to the stationary support. A head will abut the flange. Hooks mounted to the movable support will engage the head and pull the head tightly upward into engagement with the flange when the retracting cylinders are released. Pivotal cylinders will pivot the hooks between engaged and disengaged positions. The bias of the springs is independently adjustable.

1. Field of the Invention
This invention relates in general to closing devices for pressure vessels and in particular to a closure head for a coke drum utilizing springs which can be adjusted.
2. Description of the Prior Art
In a coke manufacturing process, high temperature petroleum products are placed inside a large pressure vessel. The pressure vessel may be as much as 80 feet high, with a nozzle or discharge opening on its bottom. A head, which is a large, flat plate up to six or seven feet in diameter, secures across the opening of the nozzle. The plate bolts to a flange on the pressure vessel by a large number of bolts.
Subsequently, the high temperature petroleum products will be quenched and cooled with water, forming coke. After cooling, the head is removed and a chute positioned below the nozzle. High pressure water jets will be used to break up the coke, which flows out the opening of the nozzle.
The process of removing and reinstalling the head is time consuming and messy. A carriage moves under the head to engage the lower side and provide support during the removal and installation process. Workers must physically unscrew all of the bolts, which can number 60 or so. There have been various proposals in the past to improve head closures, however generally these proposals are complex.

Adjustable springs for pressure vessel closure


The claimed invention meets these and other objects by providing a method of preparing a metal salt of a dialkyl ester of 5-sulfoisophthalic acid. Broadly speaking, the method provides for the contacting of a dialkyl ester of 5-sulfoisophthalic acid with a metal cation in a buffered reaction mixture to form the metal salt of the dialkyl ester. The reaction mixture is buffered, at least in part, by the acetate of the metal cation. The method according to invention also encompasses various methods of preparing the dialkyl ester of 5-sulfoisophthalic acid.

The present invention pertains to the field of polymer chemistry and specialty chemicals. In particular, the present invention pertains to the field of specialized chemicals that are often associated with dyeing nylon fibers, among other uses. More specifically, the invention pertains to metal salts of a dialkyl ester of 5-sulfoisophthalic acid and methods of preparing them.
The term "nylon" generally encompasses a family of synthetic polymers first developed by DuPont in the 1930's. Since then nylon and nylon fibers have found use in products as diverse as carpet fibers, clothing, sutures, parachutes, and footwear, among other uses.
Nylon fibers, especially those used for carpet fiber, are often classified as to type, depending on the fiber's receptivity to acid dyes and basic or cationic dyes. Cationic dyeable nylon fibers generally exhibit inherent stain resistant properties as compared to other nylon types but traditionally suffered from poorer lightfastness, especially in light shades. This resulted in the under-utilization of cationic dyeable nylon as a carpet fiber.
As expected, considerable time, energy, and resources were devoted to finding new and improved methods to improve the dye absorbing characteristics of cationic dyeable nylon. Over the years, several methods were developed in which very specialized chemicals were added to the basic nylon dyeing process to impart improved cationic dye-ability to the polymer. Metal salts of dialkyl esters of 5-sulfoisophthalic acid are one family of such chemicals. The sodium salt of dimethyl-5-sulfoisophthalic acid (aka: DMSSIPA) is a well known. A few other metal salts are known (such as the lithium salt) and can be used as polymer additives. Research into these salts continues to further refine their polymer modifying characteristics and explore additional uses.
The term "drowning" as used herein means the addition of one liquid component to another liquid component. In other words, the term means pouring a solution or intermediate slurry into a second liquid. As used herein, the term usually refers to the addition of an intermediate solution containing a dialkyl ester of 5-sulfoisophthalic acid to a buffered aqueous solution.
The preparation of any salt of a dialkyl ester of 5-sulfoisophthalic acid typically contains a step in which the dialkyl ester is contacted with a metal cation to form the metal salt.
The contacting step is often accomplished by drowning a solution containing a dialkyl ester of HSIPA into a neutralizing solution buffered by a base such as NaOH, Na2CO3, NaHCO3, or Na2SO4 to form the salt product. A further alternative is to add the HSIPA to a single solution containing an alcohol and a base.
The resulting product, the metal salt of a dialkyl ester of 5-sulfoisophthalic acid, is then separated, usually by some filtration method, purified and packaged.
There are several problems associated with these traditional methods of forming metal salts of dialkyl esters of HSIPA. Use of sulfate bases to buffer the drowning step is undesirable because sulfate precipitates on nylon filaments, which leads to filament breakage, decreased product throughput, and inferior product.
In addition, a hazardous byproduct (methyl hydrogen sulfate) is formed in substantial amounts in some processes that utilize high levels of sulfate. Extra equipment and record keeping is required to appropriately handle this hazardous byproduct, which increases production costs.
Similarly, problems exist in those traditional processes that utilize carbonates to buffer the system. The dialkyl ester of HSIPA reacts with the carbonate to produce CO2 gas (a process known as "degassing"), which then generates foam in the product slurry, which in turn complicates materials handling and increases costs. The CO2 may also be subject to regulatory reporting/control, which increases costs.
Accordingly, there is a need for a new method of producing metal salts of the dialkyl ester of HSIPA that avoids the problems associated with current production methods. In particular, there is a need for a manufacturing process that reduces the use of sulfates to reduce or substantially eliminate sulfate related filament breakage. There is also a need for a manufacturing process that reduces the formation of methyl hydrogen sulfate and the regulatory issues associated with it. There is a need for a manufacturing process that reduces or substantially eliminates the costs and problems associated with carbonate based degassing. Finally, there is a need for a method that can serve as a platform to make multiple metal salts of dialkyl esters of 5-sulfoisophthalic acid.
In addition, there is a need for new metal salts of dialkyl esters of 5-sulfoisophthalic acid to expand the portfolio of salts that are available to polymer chemists.
If one looks at the general needs discussed above, it becomes apparent that a common factor related to each is the manner in which the reaction system is buffered. Metal sulfates as the source of metal cations do not provide the necessary buffering and adds undesirable sulfates which can lead to inferior product. Carbonate based buffers lead to degassing, which complicates manufacture. Thus, although there is a general need for a new manufacturing process, a more precise recitation of the industry's need would be: there is a need for a new buffering system for use in making metal salts of dialkyl esters of 5-sulfoisophthalic acid.
The process according to the invention provides a new buffering system and provides a high quality product in a manufacturing process that is efficient from both an engineering and economic perspective. The invention also serves as a platform technology that can be used to make multiple metal salts of dialkyl esters of 5-sulfoisophthalic acid, including several novel salts. Additional benefits of the invention are discussed at the end of the detailed description so that they can be understood in their technical context.

Metal salts of a dialkyl ester of 5-sulfoisophthalic acid and method of preparing same


An apparatus and method for improving turbo code performance in a communication system are provided. In the apparatus, a bit inserter inserts a predetermined number of bits into a transmission information bit stream, if the effective coding rate of a transmission packet is a predetermined coding rate. A turbo encoder turbo-encodes a bit stream received from the bit inserter and outputting code symbols. A rate matcher matches the code symbols to a predetermined size.

1. Field of the Invention
The present invention relates generally to a packet communication apparatus and method in a mobile communication system, and in particular, to an apparatus and method for improving turbo code performance.
2. Description of the Related Art
Mobile communication systems are evolving toward high-speed, high-quality wireless data packet communication systems that can provide data service and multimedia service beyond voice-oriented service. The 3rd Generation Partnership Project (3GPP) and 3GPP2 standardization of High Speed Downlink Packet Access (HSDPA) and 1xEvolution in Data and Voice (1xEV-DV) are major examples of efforts expended to find a solution to high-speed, high-quality wireless data packet transmission service at or above 2 Mbps in 3G mobile communication systems.
Obstacles to high-speed, high-quality data service in wireless communications are caused mainly by the wireless channel environment. The wireless channel environment frequently changes due to fading-caused power change, shadowing, Doppler effects arising from the terminal's mobility and frequency mobile velocity changes, and interference from other users and multipath signals. Therefore, the provisioning of high-speed wireless data packet service requires advanced technology that increases adaptability to the channel changes in addition to existing technologies used for 2G or 3G mobile communication systems. While fast power control increases the adaptability to channel changes in the legacy systems, the 3GPP and 3GPP2, which are working on the standardization of a high-speed packet transmission system, commonly address Adaptive Modulation and Coding (AMC) and Hybrid Automatic Repeat Request (HARQ) schemes.
In AMC, a modulation scheme and a coding rate for a channel encoder are selected adaptively according to channel environment. Typically, a Mobile Station (MS) measures the Signal-to-Noise Ratio (SNR) of the downlink and feeds back the SNR measurement to a Base Station (BS). The BS then estimates the downlink channel condition based on the feedback information and selects an appropriate modulation scheme and coding rate according to the estimation.
HARQ is a retransmission technique for, when an initially transmitted packet has errors, retransmitting the packet. HARQ schemes are categorized into Chase Combining (CC), Full Incremental Redundancy (FIR), and Partial Incremental Redundancy (PIR). CC simply retransmits the same initial transmission packet, while FIR retransmits a packet with only redundancy bits generated from a channel encoder, instead of the same initial transmission packet. In PIR, a retransmission packet has information bits and new redundancy bits.
While the AMC and HARQ schemes are mutually independent in increasing adaptability to the changes in the uplink and downlink, their combination can improve system performance considerably. That is, a transmitter selects a modulation scheme and a coding rate suitable for the downlink channel condition by AMC and transmits a data packet using the modulation scheme and coding rate. When a receiver fails to decode the transmitted data packet, it requests a retransmission of the data packet. The BS then retransmits a predetermined data packet according to a predetermined HARQ scheme.
At present, 3 G communication systems (e.g. 1xEV-DV and HSDPA) and 4 G communication systems (e.g. Broadband Wireless Access (BWA)) employ a turbo encoder for transmission and reception of high-speed packet data.
FIG. 1 illustrates the structure of a typical turbo encoder.
Referring to FIG. 1, the turbo encoder includes a first constituent encoder 101 for encoding an input information bit stream xk, an internal interleaver 100 for interleaving the input information bit stream xk, and a second constituent encoder 102 for encoding an interleaved information bit stream x′k received from the interleaver 100. The turbo encoder is additionally provided with an output line via which the input information bit stream xk passes without encoding. The first and second constituent encoders 101 and 102 can be Recursive Systematic Convolutional (RSC) encoders or Non-Recursive Systematic Convolutional (NSC) encoders. The configuration of these constituent encoders can be changed according to coding rate (R), constraint length (k) and generator polynomial. The interleaver 100 permutes the sequence of the input information bit stream, thus decreasing the correlation between bits in the information bit stream. Elements denoted with D in the constituent encoders represent delay blocks.
FIG. 2 is a block diagram of a transmitter in a communication system using HARQ.
Referring to FIG. 2, this communication system supports both AMC and HARQ schemes, and the transmitter includes a Cyclic Redundancy Check (CRC) adder 201, a turbo encoder 203, and an HARQ processor 205.
In operation, the CRC adder 201 calculates a CRC code for an input information bit stream of a predetermined size and adds the CRC code to the end of the information bit stream. The turbo encoder 203 encodes the information bit stream received from the CRC adder 201 at a predetermined coding rate. The HARQ processor 205 is a block for supporting AMC and HARQ. It generates a packet at a corresponding coding rate by rate-matching the coded bit stream received from the turbo encoder 203 through repetition or puncturing. This packet is transmitted through an antenna, after interleaving, modulation, spreading, and Radio Frequency (RF) processing.
The HARQ processor 205 includes a puncturer (not shown) for matching the number of the coded bits received from the turbo encoder 203 to that of bits transmittable on a physical channel. The puncturer matches the size of the channel-coded bit stream to the size requirement for the physical channel, irrespective of AMC and HARQ. Accordingly, the coding rate of the packet generated from the transmitter illustrated in FIG. 2 varies and it is called an "effective coding rate".
FIG. 3 is a graph illustrating BS power requirements with respect to effective coding rates, for a Block Error Rate (BLER) of about 10% in an HSDPA communication system. Here, horizontal line index is lor/loc wherein for is BS total power spectral density and loc is white Gaussian noise density.
Referring to FIG. 3, with respect to the origin, the innermost curve denotes an effective coding rate of 0.75 (7/9−), the middle curve denotes an effective coding rate of 0.80 (7/9+), and the outermost curve denotes an effective coding rate of 0.77 (7/9). In general, as the number of punctured bits increases, the effective coding rate and the BLER increase. In other words, required BS power increases. However, the graph illustrated in FIG. 3 reveals unexpected results. In a comparison between the effective coding rates, 0.8 and 0.77, a general expectation is that more transmit power is required for the effective coding rate 0.8 at the same BLER. However, in fact, more transmit power is required for the effective coding rate 0.77. This result is attributed to the nature of the turbo encoder.
FIGS. 4A and 4B illustrate performance degradation caused by an identical periodicity between the turbo encoder and the puncturer.
When the turbo encoder illustrated in FIG. 1 has a coding rate of 1/3, the constituent encoders (convolutional encoders) have an output period of 7. The output period is determined by the constraint length k and 2k−1=7 when k is 3. That is, a first parity sequence (the output of the first constituent encoder) and a second parity sequence (the output of the second constituent encoder) in the turbo encoder are periodic binary sequences which are correlated every seven bits.
As illustrated in FIGS. 4A and 4B, if the puncturer of the HARQ processor 205 has a puncturing period of 7, puncturing takes place at the same bit positions and the remaining bits reside at the same bit positions. In this way, when bits output from a constituent encoder are grouped by sevens and bits are punctured at the same bit positions, turbo code performance is decreased. As illustrated in FIG. 3, this phenomenon appears for a particular effective coding rate. Accordingly, there exists a need for adjusting a puncturing period for a particular effective coding rate causing the degradation of turbo code performance.

Apparatus and method for improving turbo code performance in a communication system


In an electric parking brake system including a tension control unit that controls the friction member pushing force in a brake by controlling the tension of a cable, the target tension is set to a larger value when a vehicle is maintained at a standstill on a downhill slope than when the vehicle is maintained at a standstill on an uphill slope.

1. Field of the Invention
The invention relates generally to an electric parking brake system and a method for controlling the electric parking brake system, and, more specifically, to a control over a force with which a pushing mechanism pushes a friction member against a friction face in the electric parking brake system.
2. Description of the Related Art
Japanese Patent Application Publication No. JP-2003-327099 (JP-A-2003-327099) describes a technology related to an electric parking brake system. According to the technology, when a parking brake is applied while a vehicle is standstill on a slope, the target value of the tension of a cable is set to a larger value when the absolute value of the inclination angle of the vehicle is large than when the absolute value of the inclination angle of the vehicle is small. In addition, when the vehicle is standstill on a downhill slope and the shift position is in Drive, the target value of the tension of the cable is set to a value larger than the target value that is determined based on the absolute value of the inclination angle of the vehicle. When the vehicle is standstill on an uphill slope and the shift position is in Reverse, the target value of the tension of the cable is set to a value larger than the target value that is determined based on the absolute value of the inclination angle of the vehicle.

This patent is subject to a terminal disclaimer.

Electric parking brake system and method for controlling the electric parking brake system


The invention includes a method for selective deposition of semiconductor material. A substrate is placed within a reaction chamber. The substrate comprises a first surface and a second surface. The first and second surfaces are exposed to a semiconductor material precursor under conditions in which growth of semiconductor material from the precursor comprises a lag phase prior to a growth phase, and under which it takes longer for the growth phase to initiate on the second surface than on the first surface. The exposure of the first and second surfaces is conducted for a time sufficient for the growth phase to occur on the first surface, but not long enough for the growth phase to occur on the second surface.

There are numerous applications in which it is desired to selectively deposit semiconductor material onto a semiconductor surface relative to other surfaces. For instance, it can be desired to epitaxially form one or both of silicon and germanium on a semiconductor surface. A prior art method of epitaxially forming semiconductor material over a semiconductor surface is described with reference to FIGS. 1-3.
FIG. 1 shows a semiconductor wafer fragment 10 at a preliminary processing stage. Fragment 10 comprises a semiconductor substrate 12. Substrate 12 can comprise, consist essentially of, or consist of monocrystalline silicon. The silicon can be appropriately doped with one or more conductivity-enhancing dopants. For instance, the silicon can be lightly background doped with p-type dopant, and can comprise various conductively-doped diffusion regions (not shown) formed therein. To aid in interpretation of the claims that follow, the terms "semiconductive substrate" and "semiconductor substrate" are defined to mean any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials thereon), and semiconductive material layers (either alone or in assemblies comprising other materials). The term "substrate" refers to any supporting structure, including, but not limited to, the semiconductive substrates described above. The term "semiconductor material" refers to a material comprising one or more of the semiconductive elements, such as, for example, a material comprising one or both of silicon and germanium.
An electrically insulative material 14 is formed over substrate 12. Material 14 can comprise, consist essentially of, or consist of silicon and one or both of oxygen and nitrogen. For instance, material 14 can comprise silicon dioxide, silicon nitride, and/or silicon oxynitride. In the illustrated example, substrate 12 has an upper surface 13, and material 14 is formed directly against (i.e., in physical contact with) the upper surface 13. Material 14 is patterned to have a gap 16 extending therethrough to the upper surface 13 of substrate 12. Material 14 has exposed surfaces 15.
Referring to FIG. 2, a semiconductor material 18 is formed within gap 16 and also over the surfaces 15 of insulative material 14. Material 16 will typically comprise, consist essentially of, or consist of one or both of silicon and germanium. If material 16 comprises, consists essentially of, or consists of silicon, such material can be formed utilizing dichlorosilane, H2 and HCI. The dichlorosilane provides a silicon source. The H2 participates in the silicon deposition, and also can remove undesired oxides forming over the growing silicon. The HCI etches material 18 before the material can form a uniform layer over insulative material 14. Specifically, the material 18 nucleates over insulative material 14 to form small islands on surface 15, as shown. The HCI continuously etches material 18 from the small islands, and accordingly removes material 18 from the islands before the islands can merge to form a continuous layer. The HCI is also thought to remove material 18 which is growing over surface 13 (the shown material 18 within gap 16), but such removal is too slow to prevent the layer of material 18 from forming within gap 16. Accordingly, the HCI effectively creates a selective deposition of material 18 over the surface 13 of semiconductor material 12 relative to the surfaces 15 of insulative material 14. The HCI can be replaced with Cl2 in some aspects of the prior art.
FIG. 3 shows construction 10 at the conclusion of the epitaxial growth, and shows that the semiconductor material 18 has been selectively formed over surface 13 of semiconductor substrate 12 relative to surfaces 15 of insulative material 14.
A problem with the processing of FIGS. 1-3 is that the utilization of HCI significantly slows the rate of deposition of semiconductor material 18 relative to a rate which would occur in the absence of the HCI. Accordingly, it is desired to develop deposition processes which can selectively form a semiconductor material over an exposed semiconductor substrate surface relative to exposed surfaces of non-semiconductor materials, and which have a higher rate than the processing sequence of FIGS. 1-3.
The processing sequence of FIGS. 1-3 is an exemplary prior art process. Other processes have been developed which are modifications of the process described with reference to FIGS. 1-3. For instance, in one modification a semiconductor precursor (such as, for example, dichlorosilane) is provided in combination with H2 to form semiconductor material 18 over a surface of a semiconductor substrate and over surfaces of insulative materials. After the growth of the semiconductor material, HCI is provided to selectively remove the semiconductor material from over the insulative materials surfaces while leaving a layer of the semiconductor material over the semiconductor substrate surface. In some aspects, the cycling of deposition of semiconductor material, etching of semiconductor material from over insulative material surfaces, deposition of the material, etching of the material, etc., is repeated multiple times to form a semiconductor material to a desired thickness over a semiconductor substrate surface. A particular prior art methodology flows disilane for about 10 seconds, then Cl2 for about 10 seconds, then H2 for about 10 seconds, and repeats the process multiple times to form a semiconductor layer to a desired thickness over a semiconductor substrate surface.
FIGS. 4 and 5 illustrate another exemplary prior art application for selective formation of epitaxially-grown semiconductor material over a semiconductor substrate. Referring initially to FIG. 4, a wafer fragment 20 comprises a substrate 22. Substrate 22 can comprise the same construction as described previously relative to substrate 12 of FIG. 1, and accordingly can comprise monocrystalline silicon lightly-background doped with p-type dopant. Substrate 22 comprises an upper surface 23.
An isolation region 24 extends within substrate 22. Isolation region 24 can comprise, for example, a shallow trench isolation region, and accordingly can comprise silicon dioxide. Isolation region 24 comprises an upper surface 25.
A transistor gate 26 is formed over surface 23 of substrate 22. Transistor gate 26 comprises an insulative material 28, a conductive material 30, and an insulative cap 32. Insulative material 28 can comprise, for example, silicon dioxide, and can be referred to as pad oxide. Conductive material 30 can comprise, for example, one or more of metal, metal compounds and conductively-doped semiconductor material (such as, for example, conductively-doped silicon). Insulative cap 32 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. For instance, insulative cap 32 can comprise, consist essentially of, or consist of silicon dioxide, silicon nitride, or silicon oxynitride. Insulative cap 32 comprises an upper exposed surface 33.
An anisotropically-etched sidewall spacer 34 is along a sidewall of transistor gate 26. Spacer 34 can comprise, consist essentially of, or consist of silicon together with one or both of oxygen and nitrogen. Accordingly, spacer 34 can comprise, or consist essentially of, or consist of one or more of silicon dioxide, silicon nitride and silicon oxynitride. Spacer 34 has an exposed surface 35.
A conductively-doped diffusion region 36 extends within substrate 22 beside transistor gate 26. The conductively-doped diffusion region 36 and transistor gate 26 can be together incorporated into a transistor device.
Referring to FIG. 5, a semiconductor material 38 is formed over surface 23 of semiconductor substrate 22 selectively relative to surfaces 25 and 33 of insulative materials 24 and 32, respectively. Semiconductor material 38 can comprise, consist essentially of, or consist of one or both of silicon and germanium, and can be formed utilizing processing analogous to that described previously with reference to FIGS. 1-3. Accordingly, the semiconductor material can be formed by deposition from a semiconductor precursor in combination with an etch which removes the deposited material from over surfaces 25 and 33 while leaving the material over surface 23. An undesired consequence of the etch is that such rounds an outer corner of deposited material 38, as can be seen at a location 40 in the diagram of FIG. 5. The rounded outer corner can be referred to as a faceted corner, and can increase degradation of a transistor device component (with a common effect being p-channel degradation), and can also adversely affect an implant profile if a dopant is implanted either into or through semiconductor material 38. For instance, conductively-doped diffusion region 36 would sometimes be formed by an implant subsequent to formation of material 38 rather than being present prior to deposition of semiconductor material 38. The rounded faceted corner 40 could then adversely affect formation of the diffusion region 36.
The semiconductor material 38 of FIG. 5 can ultimately be conductively doped, and can be incorporated into, for example, an elevated source/drain region associated with a transistor device comprising gate 26.
Numerous problems are encountered during the processing described above with reference to FIGS. 1-5. Such problems include the faceted corner 40 and slow growth rate discussed previously. Another problem is that the deposition rate and quality can be sensitive to the amount of etchant (such as, for example, HCI) utilized during the deposition/etch processing, which can make it problematic to control wafer throughput and quality in a fabrication process. For instance, it is sometimes found that increasing HCI flow by 10% will decrease the growth rate of a deposited semiconductor material by about 20%. It would be desirable to develop deposition methods which alleviate, and preferably eliminate, some or all of the above-discussed problems.


An idler roll bearing assembly, made by a method, includes a shaft having a non-grooved outer surface. A shell extends about the shaft and is rotatable relative to the shaft. A rolling bearing is secured to the shaft. A roll head is secured to the rolling bearing. The roll head includes a portion preventing axial displacement of the rolling bearing. The shell is supported for the relative rotation by the roll head. A retaining sleeve is located on the shaft to prevent axial displacement of the rolling bearing. The sleeve has an interior surface in engagement with the non-grooved outer surface of the shaft. An inner diameter of the sleeve and an outer diameter of the shaft are sized such that the sleeve is secured onto the shaft by frictional interference fit and the sleeve is maintained at a position on the shaft by the frictional interference.

A belt of a conveyor is conventionally supported between its ends by a plurality of carriers. Each carrier typically includes a frame extending transversely to the conveyor belt and journals generally three idler rolls in an end-facing-end relationship. Generally, the intermediate idler roll is disposed in a horizontal position while the outer two idler rolls are disposed at an upwardly inclined angled relationship to a horizontal plane to give the conveyor belt a trough-like shape for the purpose of keeping a load centered on the conveyor belt.
The idler rolls typically have bearing assemblies, which are interposed between a rotating roller shell and a stationary shaft. The bearing assemblies commonly include ball bearings as the rolling elements. However, it is also known for the bearing assemblies to have tapered roller bearings as the rolling elements because the tapered roller bearings can provide twice the minimum life of ordinary ball bearings. However, tapered roller bearing elements require precise axial clearance settings. It is known to secure bearing assemblies, and particularly tapered roller bearings assemblies, with threaded assemblies and/or snap rings with compensating washers to account for manufacturing variations.
Also, it is generally known to press various bearing assemblies onto various shafts. This is a rather simple and low-cost approach. The long shaft lengths of idler rolls, however, have made press fitting roller bearing assemblies directly onto a shaft impractical because of the precise axial clearance seating required versus shaft flexibility and compressibility. As such, there is an increased problem with obtaining and maintaining axial positioning of bearing assemblies.
It is further known to machine-cut rectangular grooves into shafts for application of retaining rings to secure idler roll assemblies in proper location. As such, it is to be appreciated that several processing steps are needed. Reference is hereby made to U.S. Pat. Nos. 6,287,014 and 6,385,849, which each shown the use of ring grooves cut in shafts for retaining bearing assemblies of idler rolls.
Accordingly, there is a need for an idler bearing assembly having a different structure and thus having a different manufacturing process.

Idler roll ball bearing assembly and method of making


An embodiment of the disclosure includes a method of dicing a semiconductor structure. A device layer on a semiconductor substrate is provided. The device layer has a first chip region and a second chip region. A scribe line region is between the first chip region and the second chip region. A protective layer is formed over the device layer thereby over the semiconductor substrate. The protective layer on the scribe line region is laser sawn to form a notch. The notch extends into the semiconductor substrate and the protective layer is formed to cover a portion of the notch. A mechanically sawing is performed through the portion of the protective layer and the substrate to separate the first chip region and the second chip region.

In a typical integrated circuit formation process, semiconductor wafers, each including a plurality of identical semiconductor chips (also referred to as dies), are manufactured first. After manufacturing, the semiconductor wafers are sawed to separate the semiconductor chips, so that each of the semiconductor chips may be packaged individually.
However, the conventional wafer dicing processes have a number of shortcomings. For example, the upper metal layers on the semiconductor substrate may crack during the process enabling contaminants or moisture to penetrate through the die. Therefore, the failure rate of the overall assembly could increase.
Accordingly, there is a need for an improved method to saw the semiconductor wafer into individual dies with robust electrical performance.

Methods of dicing a semiconductor structure

Taiwan Semiconductor Manufacturing Company, Ltd.


A method of creating and using a software application module includes coding, by a developer, a software application module for extending a functionality of a main software application. The software application module is adapted to interface with the main software application using an application programming interface (API). The method further includes compiling the software application module to produce an executable software application module, determining if the developer is authorized to use the API, and embedding a watermark in the executable software application module if it is determined that the developer is authorized to use the API. The method still further includes executing the main software application, reading the watermark from a executable software application module, verifying if the watermark is correct, and executing the software application module if the watermark is verified as correct.

Technologies exist for determining whether a particular software application is licensed during startup of that software application. However, it is much more difficult to detect whether an application programming interface (API) used during development of a software application module used to extend the functionality of a main software application is properly licensed. A need exists for applying a license check on a particular API for developers using that API to develop code to extend the functionality of a computer application associated with that API.

Method of and system for watermarking application modules


A communication device such as a Voice over Internet Protocol (VoIP) gateway multiplexes data intended for multiple voice connections within a single IP packet. If it is known in advance that packets for multiple connections between a given Originating Exchange (OEX) and Terminating Exchange (TEX) will travel between the Originating Gateway and Terminating Gateway, voice samples are multiplexed into the same VoIP packet. This “cell multiplexing” is accomplished by adding a cell header field to each cell payload portion. The cell header field indicates at least a connection identifier, so that the terminating gateway can route the payload to the correct TEX trunk. The scheme permits greatly improved efficiency in the carrying of VoIP traffic, especially where efficient voice coders are used.

This invention relates generally to digital telephone networks, and in particular to techniques for transporting voice information over packet networks such as Internet Protocol (IP) networks.
The Internet and other packet switched networks are increasingly used as a transmission medium for voice telephone calls. Internet telephony software and services now provide low cost, or even free, telephone calls anywhere in the world. With simple equipment at the subscriber end, a virtual connection can be established between two callers through a system of interconnected packet based networks that may include the Internet, intranets or other digital networks. These systems are thus emerging as a viable alternative to legacy circuit switch networks.
In order to facilitate communication over the internet, various industry and international standard bodies have established different functional requirements and rules that govern the transmission of data packets that carry voice information. Implementation of these common rules, known as "protocols," is necessary to allow equipment provided by different manufacturers to interoperate.
One typical device within a packet network is called a gateway. Gateways allow dissimilar computer networks that might use different protocols to connect with one another. A gateway provides, in effect, an interface that translates data between the different communication protocols that may be used. One type of gateway is an Internet Protocol (IP) telephony gateway. A typical IP telephony gateway can handle multiple simultaneous telephone calls originating from standard telephone connections within the Public Switched Telephone Network (PSTN) and route them over the internet using the Internet Protocol (IP).
In a typical Voice Over Internet Protocol (VoIP) connection, a caller located at an "originating" point places a telephone call to a terminating point using a standard telephone or computer modem. The call is then routed first to an originating internet telephony gateway, typically through an exchange which is local to the originating point. The originating gateway then establishes one or more IP connections, or "sessions" with a remote "terminating" gateway that services the telephone equipment at the terminating end of the call. The terminating gateway then completes the circuit by connecting to the destination telephone via a local circuit switched connection. The connections are duplexed, i.e., signals flow both from the originating point to the terminating point, and from the terminating point to the originating point.
In order to communicate voice audio signals over a digital network, the gateways modify the audio signals received from and transmitted to the parties' telephones. These audio signals are typically encoded using Pulse Code Modulation (PCM) according to various voice coding standards. At the originating end, equipment is used to sample and encode an analog voice signal. The encoded bits are then arranged into packets for transmission over the IP network that provides the virtual connection. At the terminating end, the terminating gateway disassembles the packets, decodes the sample bits, and converts them back to an analog voice signal once again.
One transport protocol often used for carrying VoIP packets between gateways is the Internet Engineering Task Force (IETF) Real-Time Transport Protocol (RTP), as defined in Request For Comment (RFC) on 1889. RFC 1889 has now been placed into the International Telecommunication Union (ITU) standard H225.0.
While the IP telephony infrastructure has become somewhat popular, users have come to expect to have to tolerate occasional delays and sometimes inferior quality of service. There are a number of factors contributing to this. In a VoIP connection that uses the RTP transport protocol, each end typically encodes the voice samples with a scheme such as used by G.711, G.723 or G.729 type codecs. These codecs are known to be quite efficient. For example, the G.729 codecs can often result in voice payloads of 10 bytes or less, per IP packet, per connection (assuming a 10 millisecond (ms) sampling period).
However, standard VoIP/UDP/RTP packet formats require several headers. These include a 20 byte IP header, an 8 byte User Datagram Protocol (UDP) header, and an 12 byte RTP header. Thus, the typical VoIP packet using the most efficient codecs may have 40 bytes of overhead but only 10 bytes of payload!
It is known that certain transport networks, such as Asynchronous Transfer Mode (ATM) networks, provide subcell multiplexing. In particular, some ATM switches support a so-called ATM Adaptation Layer 2 (AAL2) mode that allows multiple voice channels to be carried over a single ATM virtual circuit. AAL2 requires an additional byte of overhead for each ATM cell and additional 3 bytes of overhead for each voice packet. AAL2 is designed to efficiently handle real-time traffic such as voice. However, conventional wisdom is that other data traffic payloads implemented over AAL2 are sometimes inefficient.
There is a "common part" of AAL2 (AAL2-CP) which has been proposed to adapt the capabilities of ATM to the traffic requirements of low and variable bit rate applications. AAL2-CP thus suggests multiplexing several low bandwidth AAL2 connections into a single ATM virtual channel connection.
Some have proposed a scheme known as Compressed Real Time Transport Protocol (CRTP) which allows the compression of headers within a single VoIP packet. This scheme uses a CRTP header with length of 4 bytes for each payload. Special purpose state update headers permit the end-to-end connections to be properly maintained.
However, this approach requires routers to support PPP or any other data link layer protocols to handle the CRTP packets. This can pose a difficulty when VoIP traffic is to be carried over public networks such as the Internet, and where the configuration of intervening routers cannot be known in advance.

Voice over internet protocol (VOIP) subcell multiplexing