A conversion methodology utilizes increasing microprocessor performance characteristics and System Management Mode ("SMM") to provide transparent support of hardware components that include features unsupported by executing application and operating system programs. In one embodiment, a PC system includes code that supports only conventional but unavailable communication interfaces. However, the PC system is equipped with a universal serial bus ("USB") controller. Although the USB controller is unsupported by the executing code by the application and operating system programs, the conversion methodology utilizes system management mode to facilitate transparent support for the USB controller. In SMM, a CPU executes SMM code independently of the operating system(s). The conversion methodology causes entry of SMM upon any I/O operation intended for the supported but unavailable conventional communication interfaces. The SMM code provides data from the USB controller in a format recognizable to the requesting non-supporting software. SMM code supports providing all da t that would otherwise be provided to supporting software.

Personal computer ("PC") systems in general and IBM compatible PC systems in particular have attained widespread use. These PC systems handle information and primarily give independent computing power to a single user (or a relatively small group of users in the case of a PC network). Such PC systems are generally inexpensively priced for purchase by individuals or small businesses and provide computing power to many segments of today's modem society.
A PC system can usually be defined as a desktop, floor-standing, or portable microcomputer that includes a system unit having a central processing unit ("CPU") typically associated with devices such as volatile and non-volatile memory, a display monitor, a keyboard, one or more floppy diskette drives, a hard disk storage device, an optional CD-ROM drive, and an optional printer. A PC system may a include one or a plurality of peripheral devices such as input/output ("I/O") devices coupled to the system processor to perform specialized functions. Examples of I/O devices include keyboard interfaces with keyboard controllers, floppy diskette drive controllers, modems, sound and video devices, specialized communication devices, and even other PC systems. These I/O devices are typically plugged into connectors of computer system I/O interfaces such as serial interfaces and parallel interfaces, for example. Generally, these PC systems use a system board or motherboard to electrically interconnect these devices.
PC systems also typically include basic input/output system ("BIOS") programs to ease programmer/user interaction with the PC system devices. More specifically, BIOS provides a software interface between the system hardware and the operating system/application program. The operating system ("OS") and application program typically access BIOS rather than directly manipulating I/O ports, registers, and control words of the specific system hardware. Well known device drivers and interrupt handlers access BIOS to, for example, facilitate I/O data transfer between peripheral devices and the OS, application program, and data storage elements. BIOS is accessed through an interface of software interrupts and contains a plurality of entry points corresponding respectively to the different interrupts. In operation, BIOS is typically loaded from a BIOS ROM, where it is nonvolatily stored, to main memory from which it is executed. This practice is referred to as "shadowing" or "shadow RAM" and increases the speed at which BIOS executes.
Although the CPU provides the "kernel" of the PC system, I/O communication between an I/O device and the CPU forms a basic feature of PC systems. Many I/O devices include specialized hardware worldling in conjunction with OS specific device drivers and BIOS routines to perform functions such as information transfer between the CPU and external devices, such as modems and printers, coupled to I/O devices.
Referring to FIG. 1, well-known PC system serial and parallel communication system 100 is illustrated as an example of such I/O devices. PC communication system 100 facilitates both serial and data transfer between devices external to the PC system incorporating PC communication system 100. Although, serial interface 106 receives data in parallel, i.e. multiple, simultaneous data streams, from I/O controller 104 via bus 110, serial interface 106 transmits/receives data in a serial data stream, via data link 114, to/from external communication device 118. Serially communicating external communication devices are well-known and include keyboards, modems, mice, and joysticks. Serial interface 106 is often designated as a COM port and, especially in an IBM.TM. compatible PC system, may be an Intel.TM. UART ("Universal Asynchronous Receiver and Transmitter") 8250, 16450, or 16550 chip.
PC communication system 100 also includes a parallel interface that receives data in parallel from I/O controller 104 via bus 112. Unlike serial interface 106, parallel interface 108 also transmits/receives data in parallel to/from external communication device 120 which may be, for example, a printer. Data is generally ultimately transferred between serial interface 106 and a PC system CPU and parallel interface 108 and the PC system CPU via a bus system that includes, for example, ISA ("Industry Standard Architecture") bus 102 which is connected to I/O controller 104.
Referring to FIG. 2, a PC system chassis 202 back plate is illustrated. The backplate illustrates a typical multiplicity of serial connectors 206, 208, 210, parallel connector 204, and video connector 212. Each of the connectors provide communication access to serial interfaces, a parallel interface, and graphics controller, respectively. Each of the different types of connectors generally utilize a unique "pin-out", i.e. pin configuration, and occupy a substantial amount of physical space not only on the PC system chassis 202 backplate but also within PC system chassis 202.
Parallel and serial interfaces are currently very common I/O devices for facilitating communication between PC computer systems and external devices including other PC computer systems. Control and monitoring of the PC system hardware, including the parallel and serial interfaces of FIG. 1, are generally the responsibility of the PC computer system OS which mainly uses device specific driver routines to access PC system hardware. Conventional application programs include specific instructions for, for example, device specific data transfer, device specific control, and obtaining specific device status information. Primarily, these instructions take the form of write data to device address! or read data from device address!. In response, device specific driver routines are utilized to facilitate implementation of these application instructions. Additionally, I/O device logical addresses are typically well-known and specific I/O device drivers generally attempt to access known logical addresses.
FIGS. 3 and 4 illustrate respective conventional parallel interface and serial interface block level interconnect topologies. A brief operational description below of some basic differences between parallel and serial interfaces enhances the reason for using device specific drivers and instructions.
FIG. 3 illustrates parallel interface 108 in more detail. Parallel interface 108 includes a number of registers which are accessed via an OS specific device driver tailored to the requirements of an external device (not shown) connected to parallel connector 302. The parallel interface 108 is assigned a logical base address, such as 378h and 278h, which is utilized by a device driver to access parallel interface 108. (The "h" suffix is used to designate a hexadecimal value). In operation, after receiving data from a printer (not shown) connected to parallel interface 108, a printer driver services the parallel interface 108. Printer driver servicing occurs in response to a parallel interface 108 request for CPU servicing, via bus 112, by instructing interrupt logic 304 to issue a hardware interrupt request. The printer driver responds to the interrupt request, addresses parallel interface 108, and retrieves received data from data register 306. The received data may be subsequently accessed by an application program executing in the PC system incorporating parallel interface 108.
Application programs may also transfer or write information to 8-bit data register 306 using well known commands that request the printer driver to output data to data register 306. By writing to control register 308, application programs may control parallel interface 108 behavior as well as control a connected external device via several well-known control commands. Control register 308 also controls generation of the hardware interrupts. Status register 310, which may generally only be read, reflects a current status of a connected external device. Address decode control 312 decodes address signals transmitted via bus 112 to determine whether a parallel interface 108 is selected by a CPU.
Referring to FIG. 4, serial interface 106 is illustrated in more detail. Serial interface 106 is also assigned a logical base address, such as 03F8h, 02F8h, 03E8h, or 02E8h, which is utilized by a device driver to access serial interface 106. Serial interface 106 transmits exemplary serial data unit 402 and receives exemplary serial data unit 404 using one of a variety of well-known protocols. An application instructs a CPU to transmit specific data to serial interface 106, and a device driver fetches the data to be transmitted and writes the data to transmitter hold register 406 via bus 110. The data is framed with overhead bits into a selected serial data unit protocol by SDU ("serial data unit") logic 408. Transmitter shift register 410 provides individual bits of exemplary serial data unit 402 to a connected external device. The reception of exemplary serial data unit 404 proceeds inversely to the transmission of serial data unit 402 uses receiver shift register 412, SDU logic 408, and receiver buffer register 414. As with parallel interface 108, serial interface 106, transmitter hold register 406, SDU logic 408, transmitter shift register 410, receiver shift register 412, and receiver buffer register 414 all operate in conjunction with baud rate signals provided by interface control baudrate generator 416.
Relatively recently a new standard for external device communication has been instituted which calls for Universal Serial Bus implementation. Universal Serial Bus is a technology standard established through a cooperative effort of Compaq Corp., Digital Equipment Corp., IBM PC Co., Intel Corp., Microsoft Corp., NEC Corp., and Northern Telecom Corp. The USB standard and its hardware and software implementation are well-known. However, many existing applications and operating systems cannot communicate with USB hardware, including USB controllers. As a result, PC systems utilizing USB hardware currently cannot use many existing application programs and operating systems that do not include USB compatible instructions. Therefore, currently in order to utilize application programs and operating systems designed for conventional parallel and serial interfaces or for USB hardware, a PC system must include both parallel and serial interface hardware and USB hardware.

Operating system independent apparatus and method for supporting input/output devices unsupported by executing programs


An composition containing transglutaminase and collagen. The composition can be used to prepare bound food, preferably without the use of allergy-causing casein proteins.

1. Field of the Invention
The present invention relates to an enzyme composition useful for binding food materials, and a process for producing bound food.
2. Discussion of the Background
A variety of methods have been used to bind food materials. One method which is widely used provides a frozen or heat-treated product in many cases. However, the binding strength of the glue used in many of the known processes has not necessarily been satisfactory, and it has been difficult to bind many materials with these glues.
In order to solve this problem, Japanese Laid-Open (Kokai) No. 284,867/1994 discloses a method in which food materials are bound by using a combination of a transglutaminase (hereinafter referred to as "TGase"), which is an enzyme, and caseins (including casein as well as caseinates such as sodium caseinate and calcium caseinate, and a casein partial hydrolyzate).
This method takes advantage of crosslinks between proteins produced by the TGase. In this method, caseins are used as a binder in combination with proteins present in food materials per se to enhance the binding strength. According to this method, a raw bound food, for example, raw restructured steak meat, can be produced without being frozen or heat-treated. In recent years, this method has been widely employed, not only in Japan, but also abroad as a method of producing bound food having a high commercial value.
A technique of producing low-calorie and low-salt bound food by adding TGase and caseins, such as a casein partial hydrolyzate, to animal meat and fish meat has also been investigated.
Methods of binding food materials without using TGase have been reported, and some of them have been put to practical use. For example, a method in which pieces of meat are bound using a combination of (1) a heat-coagulable protein, such as a wheat protein or the like and (2) an alkaline earth metal salt which produces an alkaline solution in water, such as calcium oxide, calcium hydroxide or the like, is disclosed in Japanese Laid-Open (Kokai) No. 268,665/1990. However, the bound food obtained by this method has a bitter taste and an undesirable proteinaceous smell. Accordingly, this method is not acceptable.
Further, it is well-known that myosin is eluted with sodium chloride and pieces of meat can be bound using gel-formability of the eluted myosin. However, since this method requires quite a large amount of sodium chloride, the food has a strong, salty taste. In addition, the salt content is high, which is undesirable for health reasons. Further, heating is required for binding the food. Accordingly, this method can only be used with certain types of food.
For the above-mentioned reasons, a method of binding food materials through the protein crosslinking reaction with TGase is preferable, Above all, the method disclosed in Japanese Laid-open (Kokai) No. 284,867/1994 is considered to be the best technique since bound food which is excellent in taste and flavor is produced.
It is also possible to produce bound food with TGase alone without using caseins, see Japanese 2.sup.nd publication (Koukoku) No. 55,116/1994. However, the use of TGase alone exhibits a binding strength which is inferior as compared to the combined use of TGase and caseins. Therefore, TGase and caseins provide the best results when they are used in combination. Consequently, caseins are considered in the art to be an essential component of an additive for producing bound food.
However, milk proteins cannot be used, in some cases, for producing processed food because of problems such as food allergies and the like. Especially, among milk proteins, caseins are known to cause food allergies. Further, in some foreign countries, the use of ingredients other than proteins derived from the food materials to be bound is legally controlled in accordance with the form of bound food. For example, in the Netherlands when producing processed beef steak meat, proteins derived from cattle meat, cattle bones or cattle skins can be used as a binder, but caseins derived from milk cannot.
Under such circumstances, a technique in which caseins are not used has been also studied. For example, WO 95/08274 discloses a method in which raw meat is bound by using a combination of TGase with an alkali metal phosphate and sodium chloride as a binder. However, in this method, it is indispensable to use, based on the weight of meat, 0.4% (weight %) or less of an alkali metal phosphate and as high as from 1.5 to 4% (weight %) of sodium chloride. Thus, a food product that loses the taste and flavor inherent in meat is produced.
Under these circumstances, a composition for binding food materials by which food materials such as pieces of meat or the like can be bound even in an unheated raw state without using caseins and a process for producing bound food having excellent taste and flavor have been in demand in the field of processed food.

Enzyme preparation for use in the binding of food materials and process for producing bound food


The subject invention pertains to the discovery that the NADH-dependent propanediol oxidoreductase (FucO) can reduce furfural. This allows for a new approach to improve furfural tolerance in bacterial and/or yeast cells used to produce desired products. Thus, novel biocatalysts (bacterial, fungal or yeast cells) exhibiting increased tolerance to furfural and 5-hydroxymethylfurfural (5-HMF) are provided as are methods of making and using such biocatalysts for the production of a desired product.

Carbohydrate components of woody biomass (cellulose and hemicellulose) represent an abundant potential source of sugars for microbial conversion into renewable fuels, plastics, and other chemicals (7, 18, 35). However, cost-effective depolymerization of this complex material to produce fermentable sugar streams remains a major challenge (3, 35). Pretreatment processes such as dilute mineral acids at elevated temperature and pressures open the structure of woody biomass to increase the effectiveness of cellulase enzymes, and hydrolyze the pentose polymers of hemicellulose into monomers. Unwanted side reactions from this pretreatment also produce a mixture of compounds (furans, acetate, soluble products from lignin, and others) that inhibit growth and retard fermentation (1, 18, 31). Most inhibitors can be removed or neutralized by separating the solubilized sugars from the cellulose-enriched fiber using counter-current washing followed by over-liming (25, 26). However, these added process steps would also add cost to renewable products. By developing robust biocatalysts that are resistant to side products from pretreatment it should be possible to design a simpler process (13, 14).
Furfural, the dehydration product of xylose, is of particular importance as a fermentation inhibitor in hemicellulose hydrolysates (1, 31). Furfural concentrations in hemicellulose hydrolysates have been correlated with toxicity (39). The addition of furfural to over-limed hemicellulose hydrolysates has been shown to restore toxicity (25, 26). In model studies with various hydrolysate inhibitors, furfural was unique in potentiating the toxicity of other compounds (39). Furan alcohols (reduced products) are less toxic than the respective aldehydes (38, 39). Several genes encoding oxidoreductases that reduce furfural and 5-hydroxymethylfurfural (5-HMF; dehydration product of hexose sugars) have been implicated in furan tolerance in Saccharomyces cerevisiae (2, 20, 22, 23) and in E. coli (28-30, 37).
Furfural-resistant mutants of ethanologenic Escherichia coli have been isolated and characterized (28, 29, 37). Resistance to low concentrations of furfural was found to result from the silencing of yqhD, an NADPH-dependent, furfural oxidoreductase that is induced by furfural (28, 29, 37). Although there are multiple NADPH-furfural reductases in E. coli and conversion of furfural to the less toxic alcohol would be generally regarded as beneficial, the unusually low Km of YqhD for NADPH appears to compete with biosynthesis for NADPH (29). Metabolic routes for the anaerobic production of NADPH during xylose fermentation are quite limited (12, 16, 34). The metabolism of furfural by YqhD is proposed to inhibit growth and fermentation by depleting the pool of NADPH below that required for essential biosynthetic reactions (28, 29, 37). Sulfate assimilation was identified as a site that is particularly sensitive to NADPH limitation (28). Furan toxicity (furfural and 5-HMF) can be minimized by a variety of approaches that increased the availability of NADPH (FIG. 1) (28-30).
NADH is abundant during fermentation and represents a preferred reductant for furfural conversion to the less toxic alcohol, eliminating any burden on the NADPH pool. Our laboratory previously cloned the E. coli fucO gene (11), an NADH-dependent, L-1,2 propanediol reductase that is induced during fucose catabolism (8, 10).

Over-expression of NADH-dependent oxidoreductase (

UNIVERSITY OF FLORIDA RESEARCH FOUNDATION, INCORPORATED


A polyamic acid comprising at least 10 mol % repeating units represented by the formula [1] or [2]; and a polyimide represented by the formula [3] or [4] which is obtained from the polyamic acid. A polyimide film having high heat resistance and satisfactory in light-transmitting properties and tensile strength is obtained from the polyamic acid.

Polyimide resins are widely used as electronic materials such as protecting materials and insulating materials in liquid crystal display devices and semiconductors for high mechanical strength, heat resistance, insulating property and solvent resistance as their common characteristic properties. Recently, they are expected to also find utility as optical communication materials such as optical waveguide materials.
In recent years, the developments in these fields are remarkable, resulting in a demand for ever-increasing higher characteristics on materials to be used. Described specifically, such materials are expected to be equipped not only with excellent heat resistance and solvent resistance but also with many performances corresponding to their applications.
As a particularly important property, high transparency can be mentioned. As one of methods for realizing this transparency, it has already been reported to obtain a polyimide, which is relatively low in coloration and has high transparency, by obtaining a polyimide precursor through a polycondensation reaction between an alicyclic tetracarboxylic dianhydride and an aromatic diamine and then imidating the precursor (see Patent Documents 1 and 2).
The development of new polyimides having excellent properties is, however, desired under the situation in recent years that there is also an increasing demand for the use of polyimides of high heat resistance, solvent solubility and transparency in the field of electronic materials making use of light.
As a method for realizing this transparency, a wholly-alicyclic polyimide can be expected by obtaining a wholly-alicyclic polyimide precursor through a polycondensation reaction between an alicyclic tetracarboxylic dianhydride and an alicyclic diamine and then imidating the precursor.
However, a polyimide available from 1,2,3,4-cyclobutanetetracarboxylic-1,2:3,4-dianhydride (abbreviated as "CBDA"), a representative compound among conventional alicyclic tetracarboxylic dianhydrides, and an alicyclic diamine was so brittle that it was not usable as films. No film made of a wholly-alicyclic polyimide and having stable strength has been found yet accordingly.
There are certain examples in which bicyclo[2.2.0]hexane-2,3,5,6-tetracarboxylic-2,3:5,6-dianhydride (abbreviated as "BHA"), one of monomers for polyamic acids and polyimides of the invention, was synthesized by the following process.

As shown by Scheme 1, 3-cyclobutene-1,2-dicarboxylic anhydride (abbreviated as "CBA") is synthesized by a photoreaction between acetylene (abbreviated as "AC") and maleic anhydride (abbreviated as "MA"). Subsequently, as shown by Scheme 2, BHA is synthesized by a photoreaction between CBA and MA (see Non-patent Document 1).
It is to be noted that as shown by Scheme 3, CBA can also be synthesized by the process that obtains 3,4-dichlorocyclobutane-1,2-dicarboxylic anhydride (abbreviated as "DCBA") through a photoreaction between 1,2-dichloroethylene (abbreviated as "DCE") and MA and then reacts DCBA with zinc and acetic anhydride (see Non-patent Document 2).
There was, however, no example in which a polyamic acid or polyimide was synthesized using BHA.
Patent Document 1: JP-B 2-24294
Patent Document 2: JP-A 58-208322
Non-patent Document 1: Chemische Berichte, 123, 1869-1879 (1990)
Non-patent Document 2: Synthesis, 4, 574-576 (1999)

Abstract: (In the formulae, R1 and R2 each independently represents hydrogen or C1-10 alkyl; R3 and R4 each independently represents hydrogen, halogeno, C1-10alkyl, or phenyl or the R3 and R4 on adjoining carbon atoms are bonded to each other to form C3-8 cycloalkyl or phenyl; R5 represents a divalent organic group; and n is an integer of 2 or larger.)


An illustrated embodiment disclosed herein is a method including correlating, by an endpoint, a first frame and a second frame with a plurality of hypotheses, detecting, by the endpoint, for each correlation of the first frame, a first metric and, for each correlation of the second frame, a second metric, identifying, by the endpoint, a first subset of hypotheses based on the first metric and a second subset of hypotheses based on the second metric, identifying, by the endpoint, pairs of hypotheses, each pair including a first hypothesis from the first subset and a second hypothesis from the second subset. The first hypothesis is same or within a predetermined distance of the second hypothesis. The method includes selecting, by the endpoint and from the pairs of hypotheses, a hypothesis based on the second metric and selecting, by the endpoint, a channel for transmission at which the hypothesis is selected.

The following description is provided to assist the understanding of the reader. None of the information provided or references cited is admitted to be prior art.
Doppler Multichannel Spread Spectrum (DMSS) is a new technology that addresses the connectivity needs of the tremendously large Global Asset Tracking and Monitoring Market. DMSS features global indoor penetration and unprecedently low connectivity costs. Existing communication systems (including the cellular approaches of LTE-M and NB-IotT) will not provide the global scale or the required price-points for commercial success.

System and method for detecting a satellite


A grinder pump with a self aligning cutter assembly, the grinder pump having an inlet port, a drive shaft and a cutter assembly, the cutter assembly comprising a rotary cutter and a stationary, annular cutter. The rotary cutter is supported for rotation by the drive shaft, and the annular cutter is supported in the inlet port. The rotary cutter has a pair of primary knife members with knife edges, and the annular cutter is supported in the inlet port, the annular cutter having a central bore in which a plurality of internal cutting edges are formed. The rotary cutter is supported in the central bore so its primary knife members are rotated in operational cutting engagement with the internal cutting edges by the drive shaft. The annular cutter is provided a limited range of radial movement and is positioned within the range of movement by the rotary cutter.

1. Field of Invention
The present invention relates generally to grinder pumps, and more particularly but not by way of limitation, to a grinder pump having a self aligning cutter assembly that produces effective and efficient grinding of influent materials.
2. Discussion
Grinder pumps are known in the art for grinding large solid or semisolid materials in a liquid media to form a slurry which is pumped by the pump. A typical grinder pump has an axial inlet communicating with a pumping chamber, and its motor driven shaft extends through the pumping chamber into the inlet. Mounted on a proximal end of the shaft is a rotary cutting disk having a plurality of peripheral cutting edges. An annular, ring shaped cutting member is supported at the pump inlet, axially aligned with the motor driven shaft. The shaft supports and rotates the rotary cutting disk within the ring shaped annular cutting member to effect the grinding action of the pump. An example of such a pump is disclosed in U.S. Pat. No. 5,016,825 issued to Carpenter.
The configuration of the rotary cutting disk and the ring shaped annular cutting members initially, and over the life of these members, effectively determines the effectiveness and the efficiency of a grinder pump in performing the grinding function. Generally, the closer in spatial juxtaposition that the cutting edges of a grinder pump can be maintained, the better the cutting and shearing of solids that can be achieved. Also, the better the cutting yields, the lower is the amperage draw of the pump motor; the less occurrence of relay reengagements; and the less time required to grind the solids.
Along these lines, fibers and stringy materials are known to cause difficulties for grinder pumps because such materials present relatively small cross sections and are not readily engageable by the cutting surfaces. This is especially true as cutting wear causes greater radial separation of the cutting edges of the rotary and annular cutters. Further, the realities of achieving tight manufacturing tolerances between cutting edges make it very difficult and expensive to achieve close radial separation of the cutting surfaces when the pump is initially manufactured, and maintaining close radial separation during the operational life of the grinder pump is problematic at best.
There is a need for a grinder pump having very close radial separation of the cutting edges of the cutter assembly, both initially and during the operating life of the grinder pump. It would also be desirable to achieve such close radial separation by means that will provide cost effective manufacturing and maintenance over a long operational life.

Grinder pump with self aligning cutter assembly


In one embodiment, a receiver includes: a data path having a first slicer to receive and sample an incoming analog signal and to determine a bit level for the incoming analog signal, the first slicer to provide a bit decision to a consuming logic; an analysis path having a second slicer to receive and sample the incoming analog signal and to determine a second bit level for the incoming analog signal; and a controller coupled to receive an output of the first slicer and an output of the second slicer to determine a bit error rate for the data path based on the first and second slicer outputs. Other embodiments are described and claimed.

As data rates in computing devices increase and power budgets decrease, various design objectives are in opposition. For example, in the design and implementation of high-speed interconnects that are used to communicate data within and to and from integrated circuits and other components of one or more systems, voltage and timing eye margins become tighter. Consequently, resulting interconnects are more sensitive and may suffer data corruption due either to variations in the manufacturing process or variations in operating conditions (temperature gradients, electromagnetic noise, aging, etc.).
For this reason, bit error ratio (BER) measurements are performed during design, development, and testing to ensure an interconnect is fully operational and to eventually tune transmitter/receiver setting in order to guarantee a good error performance. However, online BER measurements (during normal operation of a product) typically are not currently available, particularly in high-speed interconnects as such online techniques require high power consumption, computational complexity, or a loopback path between transmitter and receiver, all of which prevent efficient operation of an interconnect.

Measuring bit error rate during runtime of a receiver circuit


A silicon-controlled rectification device with high efficiency is disclosed, which comprises a P-type region surrounding an N-type region. A first P-type heavily doped area is arranged in the N-type region and connected with a high-voltage terminal. A plurality of second N-type heavily doped areas is arranged in the N-type region. A plurality of second P-type heavily doped areas is closer to the second N-type heavily doped areas than the first N-type heavily doped area and arranged in the P-type region. At least one third N-type heavily doped area is arranged in the P-type region and connected with a low-voltage terminal. Alternatively or in combination, the second N-type heavily doped areas and the second P-type heavily doped areas are respectively arranged in the P-type region and the N-type region.

1. Field of the Invention
The present invention relates to a rectification device, particularly to a silicon-controlled rectification device with high efficiency.
2. Description of the Related Art
Because the IC device sizes have been shrunk to nanometer scale, the consumer electronics, like the laptop and mobile devices, have been designed to be much smaller than ever. Without suitable protection devices, the functions of these electronics could be reset or even damaged under ESD (Electrostatic Discharge) events. ESD devices are used in many integrated circuits to discharge high voltage received by external pins before the high voltage damages internal devices. One type of ESD devices uses an SCR (silicon-controlled rectifier).
FIG. 1 shows such a conventional SCR ESD device, which includes: an N well 10 and a P well 12 located in a P substrate 14, a high density
P+ doped region 16 and a high density N+ doped region 18 located in the N well 10, and a high density P+ doped region 20 and a high density N+ doped region 22 located in the P well 12. In this SCR ESD device, the P+ doped region 16, the N+ doped region 18, the N well 10, and the P well 12 constitute a PNP transistor; the N well 10, the P well 12, and the N+ doped region 22 constitute an NPN transistor. An external pad, PAD, is coupled to the P+ doped region 16 and the N+ doped region 18, and, an external grounding pad, GND, is coupled to the P+ doped region 20 and the N+ doped region 22. Therefore, when the PAD receives a high voltage, the SCR ESD device is triggered to conduct a current to the GND. However, the trigger voltage and the holding voltage of this SCR are fixed. This design does not provide adjustable trigger voltage and holding voltage to satisfy the requirement of ESD protection. In addition, the ESD current of the SCR is not uniformly distributed which results in low ESD efficiency.
To overcome the abovementioned problems, the present invention provides a silicon-controlled rectification device with high efficiency, so as to solve the afore-mentioned problems of the prior art.

Silicon-controlled rectification device with high efficiency


An optical proximity correction method and system are disclosed that allows for the correction of line width deviations caused by nonlinear lithography tools by calculating required chrome on glass line widths for a desired printed line. Line width correction is determined based only on the pitch of the line, defined as the width of the line and the distance to an adjacent line. Correction information is calculated from an aerial simulation and is then organized by pitch to provide a more efficient means of line correction.

1. Technical Field
The present invention relates to optical lithography systems. More particularly, this invention relates to a method and system for correcting line width deviations.
2. Background Art
Since the beginning of the computer era, manufacturers in the field of integrated circuits (IC's) have sought to reduce the geometric size of the devices (e.g., transistors or polygates) present on integrated circuits. The benefits achieved in reducing device dimensions include higher performance and smaller packaging sizes. However, numerous limitations arise as manufacturers attempt to achieve smaller and smaller device sizes. One primary problem manufacturers face is that as smaller devices are sought, the precision required from the tools used to create IC devices increases beyond their capabilities. Given the prohibitive costs involved and potential time lost to wait for the next generation of tools, manufacturers are forced to find techniques and methods that will allow such tools to operate beyond their intended specifications.
One of the first steps in manufacturing integrated circuit chips involves the laying out or designing of the circuits to be packaged on a chip. Most integrated circuits are designed using computer aided design (CAD) layout tools. CAD tools allow chip manufactures to plan the layout of the circuits on a computer where they can be analyzed and stored. Once this step is finished, the designs need to be transferred onto the chip. Unfortunately, present day chip manufacturing tools often lack the capability to create increasingly complicated and compact integrated circuit chips.
The predominate method of creating devices on integrated circuit chips involves the use of masks. In general, masks typically comprise a transparent substrate on which various "circuit" patterns, determined by a CAD system, are disposed. That "circuit" pattern is then transferred onto the surface of a silicon wafer. The transfer of the pattern from the mask to the silicon substrate is accomplished by passing visible, ultraviolet, or even x-ray radiation (e.g., light) through the mask and onto a silicon substrate containing a photoresist material. Because the mask contains a pattern made up of solid lines and clear space, only those areas made up of clear space will allow radiation to pass. This process results in the creation of devices on the silicon substrate. This methodology is referred to as photolithography.
A popular method of creating mask patterns involves the use of chrome and is often referred to as chrome on glass (COG). It is recognized however that the methods and systems described herein are equally applicable to all masks that involve light blocking materials and/or attenuated mask systems. In attenuated mask devices, such as attenuated phase shifters and alternating phase shifters, the chrome or other light blocking material is replaced with an attenuating material that allows a small amount of light (e.g., 6%) to pass through and get phase shifted. The materials may include silicon nitride, carbon, thin chrome with an oxide, thin chrome with the clear areas etched, etc.
Unfortunately, the efficacy of all lithography tools is limited by numerous factors, and is especially limited by the resolution of the lens used to direct the radiation through the mask. When a system is being used within its resolution limits, an aerial image of the circuit will be printed onto the chip as desired (i.e., "on size"). However, when the tool is being used aggressively, that is, past the design limits of the tool, certain images will print with a deviation from their desired size. This is referred to as operating in a nonlinear regime. Thus, under certain circumstances, it is not unusual to have polygates deviate from their desired size by as much as 50 nanometers (nm), which is unacceptably high.
Lens resolution is a function of several factors that make up the "exposure system" and is typically expressed as: ##EQU1## where r is the resolution desired, .lambda. is the exposing wavelength, and Na is the numerical aperture of the lithography tool. For many of today's applications, the lithography tool is being used aggressively, usually past the design limits of the tool, when k.sub.1 is below 0.8. As noted, aggressive use of the tool is driven by the desire to create smaller and smaller devices.
When the tool is being used beyond its design limits, a specific line/space combination or "control grating" may be chosen to print on size and the tool is calibrated accordingly. However, because the tool is operating in a nonlinear manner, the other lines will print with a deviation from their desired size. Thus, without taking some further corrective measure, it is impossible to achieve a complete circuit pattern without significant line deviation.
There have been numerous attempts at solving this problem including those involving proximity corrections. Proximity correction methods work by modifying the dimensions of the chrome lines on the mask to compensate for the error caused by nonlinear operation. Thus, under this technique, it may be necessary to put a chrome line with a width of 0.95 microns on the mask to print a line with a width of 1.0 microns. However, because a given mask may contain millions of lines of varying dimensions, difficulties arise in providing an efficient and accurate method for calculating line modifications.
There exist several vendors who provide various product solutions utilizing proximity correction methods. One such product is FAIM, which requires the running of an aerial image simulation of the entire chip, determining the deviation of each line, and then correcting for each deviation. An aerial image (AI) simulation is a known method of using a computer system to generate predicted printed line deviations based upon various parameters, including the type of lithography tool. The methodology of correcting for each deviation under such systems typically involves adjusting the original chrome-on-glass data by the opposite amount of the aerial image deviation. For instance, if the AI shows an undesired edge movement of +100 nm, then the system would compensate by changing the input shape by -100 nm. Unfortunately, the input shape with the adjustment may have a different deviation than the original shape showed, so this technique would have to undergo an iterative process until the desired AI is achieved. Moreover, there is no guarantee of convergence. The result is that the run time to perform this operation can be prohibitively long.
Another product, PRECIM, requires the printing of a wafer with a predetermined pattern, measuring the pattern, and then running the results through a software package to come up with a set of convolution functions which can then be applied to the design data. Yet another vendor, Trans Vector Technologies, utilizes a rules-based system derived from the lithographic exposure system being used. Their system utilizes the width of the line, the distance to the nearest line, and the width of the nearest line.
In addition, various patents exist that address the same issue. For example, U.S. Pat. No. 5,208,124, entitled "Method of Making a Mask for Proximity Effect Correction in Projection Lithography," issued on May 4, 1993, to Sporon-Fiedler et al. teaches a method of adjusting line sizes on the glass mask based on a series of equations. Unfortunately, these equations are generic to all exposure systems and desired patterns and, therefore, fail to provide accurate line width corrections for all possible cases.
While these and numerous other techniques exist for line proximity correction techniques, none exist that take into account for the particular exposure system and circuit type being designed, and require only information regarding line width and line spacing. Thus, a need exists to provide an accurate and precise proximity correction technique for performing line width corrections during an optical lithography operation. The aforementioned art is herein incorporated by reference.

Optical proximity correction method and system

International Business Machines Corporation


This invention provides a method of contraception which comprises administering to a female of child bearing age for 23-25 consecutive days, a first phase combination of a progestin at a daily dosage of 40-500 .mu.g trimegestone, 250 .mu.g-4 mg dienogest, or 250 .mu.g-4 mg drospirenone, and an estrogen at a daily dosage equivalent in estrogenic activity to 10-20 .mu.g ethinyl estradiol for 9-13 days beginning on day 1 of the menstrual cycle, wherein the same dosage of the progestin and estrogen combination is administered in each of the 9-13 days, and a second phase combination of a progestin at a daily dosage of 40-500 .mu.g trimegestone, 250 .mu.g-4 mg dienogest, or 250 .mu.g-4 mg drospirenone, and an estrogen at a daily dosage equivalent in estrogenic activity to 10-20 .mu.g ethinyl estradiol, for 11-15 days beginning on the day immediately following the last day of administration of the first phase combination, wherein the same dosage of the progestin and estrogen combination is administered in each of the 11-15 days, provided that the daily dosage of second phase progestin is greater than the daily dosage of the first phase progestin and that the daily dosage of the second phase estrogen is greater than or equal to the daily dosage of the first phase estrogen.

This application claims the benefit of U.S. Provisional application Ser. No. 60/022,681, filed Jul. 26, 1996.
The vast majority of oral contraceptives consist of a combination of a progestin and estrogen that are administered concurrently for 21 days followed either by a 7 day pill free interval or by the administration of a placebo for 7 days in each 28 day cycle. The most important aspects of a successful oral contraceptive product are effective contraception, good cycle control (absence of spotting and breakthrough bleeding and occurrence of withdrawal bleeding), and minimal side effects. Combination oral contraceptives have traditionally acted by suppression of gonadotropins. In addition, it appears that the progestin component is primarily responsible for contraceptive efficacy through inhibition of ovulation, and other peripheral effects which include changes in the cervical mucus (which increase the difficulty of sperm entry into the uterus) and the endometrium (which reduce the likelihood of implantation). The estrogenic component intensifies the anovulatory effect of the progestin, and is also important for maintaining cycle control.
Since the introduction of oral contraceptives (OCs) over a quarter-century ago, research has been directed toward developing preparations that minimize the potential for side effects while maintaining efficacy and normal menstrual patterns. The first-generation OCs contained more progestin and estrogen than was necessary to prevent conception. Adverse hemostatic and metabolic changes, clinical problems, and side effects were associated with these high-dose preparations. In 1978, the World Health Organization (WHO) recommended that the focus of OC research should be the development of products containing the lowest possible dose levels of estrogen and progestin.
The first reductions in steroid content in a combination pill were focused on estrogen because it, rather than progestin, was thought to be related to the most serious side effects. Reduction in progestin content followed, as evidence mounted that lowering progestin intake might lower the risk of cardiovascular complications such as stroke and ischemic heart disease. Kay C R, Am J Obstet Gynecol 142:762 (1982)!. However, this evidence was not as clear as that implicating estrogen in thromboembolic disorders. Inman W H W, Br Med J 2:203 (1970); Stolley P D, Am J Epidemiol 102:197 (1975)!. The need for a balance between estrogens and progestins to minimize adverse effects on carbohydrate metabolism and on lipid and lipoprotein levels was also recognized. Bradley D D, N Engl J Med 299:17 (1978); Wynn V, Lancet 1:1045 (1979)!. Researchers then found that the synergistic action between progestin and estrogen in a balanced ratio successfully inhibited ovulation at low levels of both components.
Research into low-dose progestins was advanced significantly by the development of norgestrel (Ng) and levonorgestrel (LNg). Levonorgestrel is the biologically active moiety of racemic norgestrel. It is strongly progestational, has no inherent estrogenic activity, is antiestrogenic, and possesses good biologic activity. The contraceptive effects of levonorgestrel are manifested throughout the hypothalamic-pituitary-gonadal-target organ axis.
Ethinyl estradiol (EE) is the estrogen most frequently used in combination OCs. In attempts to fulfill the WHO objective, the dosage of EE in marketed OC formulations has been steadily reduced from that found in earlier OCs. Thromboembolic mortality decreased when the amount of synthetic estrogen in OC formulations was reduced from 100 .mu.g to 50 .mu.g. Subsequently, a significant reduction in fatal myocardial infarctions was reported for women using OCs with 30 .mu.g of EE rather than 50 .mu.g of EE. Meade T W, Br Med J 280:1157 (1980)!.
In keeping with the goal of reducing the total steroidal dosage, while maintaining contraceptive efficacy, good cycle control, and minimizing side effects, numerous regimens have been developed in which the progestin/estrogen combination is administered either as a fixed dosage combination (monophasic) or as biphasic or triphasic regimens in which the dosage of the combination is varied either once or twice throughout the menstrual cycle. In these regimens, the progestin/estrogen combination is typically administered for 21 days followed by either a 7-day pill free period or the administration of a non-contraceptive placebo (or iron supplement) for 7 days. In these regimens, 3-ketodesogestrel (3-KDSG), desogestrel (DSG), levonorgestrel (LNg), gestodene (GTD), norgestrel (NG), and norethindrone (NE) are typically used as the progestin while ethinyl estradiol (EE); 17 .beta.-estradiol, and mestranol are typically the estrogenic components. Other progestins less frequently used include drospirenone (DRSP) and dienogest (DGST).
An oral contraceptive product containing a combination of 3 mg DGST and 30 .mu.g EE for 21-day administration per cycle is marketed in Germany.
Several examples of attempts at reducing the total steroidal dosage are provided below.
Spona (PCT Publication WO 95/17194) discloses contraceptive regimens which consist of the administration of a combinaton of a progestin (50-75 .mu.g GTD, 75-125 .mu.g LNg, 60-150 .mu.g DSG, 60-150 .mu.g 3-KDSG, 100-300 .mu.g DRSP, 100-200 .mu.g cyproterone acetate, 200-300 .mu.g norgestimate, or >350-750 .mu.g norethisterone) and an estrogen (15-20 .mu.g EE or 2-6 mg 17.beta.-estradiol) for 23-24 days per cycle.
Lachnit-Fixson (U.S. Pat. No. 3,969,502) discloses biphasic progestin/estrogen combination regimens in which a combination of 50-125 .mu.g LNg and 25-35 .mu.g EE are administered for 10-12 days in the first phase and 100-350 .mu.g LNg and 30-50 .mu.g EE are administered for 10-12 days in the second phase. Placebo is administered for 5-7 days following the administration of the contraceptive steroid regimen.
Oettel (EP 628,312 A1) discloses combination contraceptive combinations containing the combination of three components: a biogenic estrogen (estradiol, estrone, or estriol), a synthetic estrogen (EE or mestranol), and a progestin (LNg, desogestrel, progesterone, norethisterone acetate, DGST, chlormadinone acetate, gestodene, or cyproterone acetate). In one embodiment, the combination is administered for 21 days followed by the administration of placebo (or pill free) or an estrogen on days 22-28 of the cycle.
Oettel (EP 696,454 A2) discloses a three phase contraceptive regimen in which the first phase consists of the administration for 3-4 days of a composition containing at least one biogenic estrogen; the second phase consists of the administration for 20-22 days of at least one biogenic estrogen and at least one progestin (progesterone, DGST, desogestrel, 3-KDSG, GTD, LNg, norgestimate, norethisterone, norethisterone acetate, dehydrogestrone, chloromadinone acetate, cyproterone acetate, medroxyprogesterone acetate, or megestrol acetate); and the third phase consists of the administration for 3-4 days of a composition containing at least biogenic one estrogen.
Lachnit (PCT Publication WO 95/26730) discloses bridged regimens consisting of the administration of a combination of a progestin/estrogen combination (50-125 .mu.g LNg and 10-40 .mu.g EE) for the first 23-24 days of the menstrual cycle followed by the administration of an estrogen (2-40 .mu.g EE) for 4-10 days for a total administration of at least 28 days per cycle. The use of 100-300 .mu.g drospirenone and 10-40 .mu.g EE as the 23-24 day progestin/estrogen combination is disclosed. Lachnit also discloses a triphasic plus bridging regimen (4-9 days, 4-9 days, 9-13 days, and 28 days for the three phases and estrogen phase, respectively) in which a combination of 50 .mu.g LNg and 20 .mu.g EE are administered in the first phase, a combination of 75 .mu.g LNg and 25 .mu.g EE are administered in the second phase, a combination of 100 .mu.g LNg and 20 .mu.g EE are administered in the third phase, and 10 .mu.g EE is administered in the estrogen phase. Other progestins disclosed include GTD, DSG, 3-KDSG, DRSP, cyproterone acetate, norgestimate, and norethisterone.
Upton (EP Patent Specification 253,607 B1) teaches the use of low dose progestin/estrogen combinations for combined hormone replacement therapy and contraception in climacteric women. Climacteric women are defined in Upton as pre-menopausal women around 40 years of age whose hormone levels are waning. The climacteric woman still ovulates (albeit may have irregular ovulation), but she still experiences many of the symptoms of the hypoestrogenic menopausal woman, such as insomnia, hot flushes, and irritability. Upton teaches the administration of a 23-26 day monophasic regimen of progestin/estrogen followed by a pill free or placebo interval of 2-5 days; with 24 days of progestin/estrogen administration followed by a 4-day pill free or placebo administration being preferred. Upton teaches the use of a progestin selected from 25-100 .mu.g LNg, 10-70 .mu.g GTD, 25-100 .mu.g DSG, 25-100 .mu.g 3-KDSG, and 85-350 .mu.g NE used in combination with an estrogen selected from 500-2000 .mu.g 17.beta.-estradiol, 8-30 .mu.g EE, and 15-60 .mu.g mestranol. Based on relative potencies, Upton teaches that a dose of 75 .mu.g LNg is equivalent to 35 .mu.g of GTD, 75 .mu.g of 3-KDSG or DSG, and 250 .mu.g NE and that a dose of 1000 .mu.g of 17 .beta.-estradiol is equivalent to a dose of 15 .mu.g EE and 30 .mu.g mestranol. Upton also teaches that NG may be substituted for LNg, but at twice the dose.
Sartoretto (Clinica e Terapeutica 3: 399 (1974)) discloses a monophasic contraceptive regimen consisting of the administration of a combination 100 .mu.g LNg and 20 .mu.g EE for 21 days.
Lachnit-Fixson (U.S. Pat. No. 3,957,982) discloses triphasic 21-day progestin/estrogen regimens in which a combination of 40-90 .mu.g LNg and 20-50 .mu.g EE is administered for 4-6 days in the first phase, 50-125 .mu.g LNg and 30-50 .mu.g EE is administered for 4-6 days in the second phase, and 100-250 .mu.g LNg and 25-50 .mu.g EE is administered for 9-11 days in the third phase. It is preferred that the first, second, and third phases are 6, 5, and 10 days, respectively.
Bennick (U.S. Pat. No. 5,418,228) discloses triphasic regimens which consist of the administration of a combination progestin/estrogen in a 6-8 day phase, a second 6-8 day phase, and a third 6-8 day phase, with it being preferred that the three contraceptive steroid phases be 7 days each. Bennick discloses that the first contraceptive steroid phase consists of a progestin at a daily dosage equivalent to 75-150 .mu.g DSG and an estrogen at a daily dosage equivalent to 20-25 .mu.g EE; the second contraceptive steroid phase consists of a progestin at a daily dosage equivalent to 75-125 .mu.g DSG and an estrogen at a daily dosage equivalent to 20 .mu.g EE; and the third contraceptive steroid phase consists of a progestin at a daily dosage equivalent to 75-100 .mu.g DSG and an estrogen at a daily dosage equivalent to 20 .mu.g EE. Placebo is administered for 7 days following the 21-day contraceptive steroid period. Bennick discloses that the progestin may be 3-KDSG, DSG, LNg, or GTD.
Bergink (U.S. Pat. No. 5,262,408) discloses a 24 day triphasic combination regimen in which the first 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 100 .mu.g DSG and an estrogen at a daily dosage equivalent to 25 .mu.g EE, the second 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 125 .mu.g DSG and an estrogen at a daily dosage equivalent to 20 .mu.g EE, and the third 7-9 day phase consists of the administration of a progestin at a daily dosage equivalent to 50 .mu.g DSG and an estrogen at a daily dosage equivalent to 20 .mu.g EE. It is preferred that the three phases be 8 days each. Following the 24 day contraceptive steroid administration, a placebo may be administered for 4 days, the 4 day interval may be pill free, or a progestin at a dosage equivalent to 25-35 .mu.g DSG may be administered.
Boissonneault (U.S. Pat. No. 4,962,098) discloses triphasic progestin/estrogen combinations in which the amount of the estrogenic component is increased stepwise over the three phases. Contraceptive steroid combinations are taken for 4-7 days during the first phase (5 days being preferred); for 5-8 days during the second phase (7 days preferred); and for 7-12 days during the third phase (9 days being preferred). Following the administration of 21-days of the contraceptive steroid combination, placebo is taken for 7 days. For all three phases, 0.5-1.5 mg of norethindrone acetate is used in the progestin, with 1 mg being preferred. 10-30 .mu.g EE is used in the first phase, 20-40 .mu.g in the second, and 30-50 .mu.g in the third phase.
Pasquale (U.S. Pat. No. 4,921,843) discloses combination progestin/estrogen contraceptive regimens which contain 0.5 to 1 mg of progestin and an estrogen having a dose equivalent to 10-40 .mu.g of EE. NE, LNg, D-17 .beta.-acetoxy-13 .beta.-ethyl-17 .alpha.-ethinyl-gon-4-en-3-one oxime, and 19-nor-17-hydroxy progesterone ester are disclosed as progestins, with NE being preferred. Specifically disclosed regimens include a uniphasic regimen (2 days of placebo, 5 days of 20 .mu.g EE, and 21 days of a combination of 500 .mu.g NE and 35 .mu.g EE); a uniphasic regimen (2 days of placebo, 5 days of 40 .mu.g EE, and 21 days of a combination of 500 .mu.g NE and 35 .mu.g EE); and a triphasic regimen (2 days of placebo; 5 days of 20-40 .mu.g EE; 7 days of a combination of 500 .mu.g NE and 35 .mu.g EE; 7 days of a combination of 750 .mu.g NE and 35 .mu.g EE; and 7 days of a combination of 1 mg NE and 35 .mu.g EE).
Pasquale (U.S. Pat. No. 4,628,051) discloses triphasic progestin/estrogen combination regimens in which contraceptive steroid is administered for 21 days. Contraceptive steroid combinations are taken for 5-8 days during the first phase (7 days being preferred); for 7-11 days during the second phase (7 days preferred); and for 3-7 days during the third phase (7 days being preferred). In all three phases, an estrogen at a daily dosage equivalent to 20-50 .mu.g EE is administered in combination with a progestin having a daily dosage equivalent to 65-750 .mu.g NE in the first phase, 0.25-1.0 mg NE in the second phase, and 0.35-2.0 mg NE in the third phase. A specific triphasic regimen discloses the administration of 35 .mu.g EE in each of the three 7-day phases in combination with 0.5 mg, 0.75 mg, and 1.0 mg in the first, second, and third phases, respectively. A second specific triphasic regimen discloses the administration of 35 .mu.g EE in each of the three 7-day phases in combination with 50 .mu.g, 75 .mu.g, and 100 .mu.g in the first, second, and third phases, respectively. A third specific triphasic regimen discloses the administration of 35 .mu.g EE in each of the three 7-day phases in combination with 25 .mu.g, 35 .mu.g, and 50 .mu.g in the first, second, and third phases, respectively.
Lachnit-Fixson (U.S. Pat. No. 4,621,079) discloses triphasic 21-day progestin/estrogen combination regimens in which a combination of 40-70 .mu.g GTD and 20-35 .mu.g EE is administered for 4-6 days in the first phase; 50-100 .mu.g GTD and 30-50 .mu.g EE is administered for 4-6 days in the second phase; and 80-120 .mu.g GTD and 20-50 .mu.g EE is administered for 9-11 days in the third phase. Placebo is administered for 7 days following the 21-day contraceptive steroid regimen.
Pasquale (U.S. Pat. No. 4,530,839) discloses triphasic 21-day progestin/estrogen combination regimens in which a dose of 20-50 .mu.g EE is administered in all three phases in combination with a contraceptively effective daily dose of progestin in the first phase, 1.5-2 times that dose of progestin in the second phase, and 2-2.5 times the first phase dose of progestin in the third phase. Each of the three phases is 7 days long. A specific regimen discloses 20-50 .mu.g EE in combination with 500 .mu.g LNg, 750 .mu.g LNg, and 1 mg LNg during each of the three 7-day phases, respectively.
Edgren (U.S. Pat. No. 4,390,531) discloses triphasic 21-day progestin/estrogen combination regimens in which a dose of 20-40 .mu.g EE (or another estrogen in an equivalent dosage) is administered in all three phases in combination with 0.3-0.8 mg NE (or another progestin in an equivalent dosage) for 5-8 days in the first phase, twice the dose of NE for 7-11 days in the second phase, and the dose of NE being the same as in the first phase for 3-7 days in the third phase. It is preferred that each of the three phases is 7 days. Placebo is administered for 6-8 days following administration of the contraceptive steroid combination. A specific regimen discloses a first phase of 7 days of 0.5 mg NE in combination with 35 .mu.g EE, a second 7 day phase of 1.0 mg NE in combination with 35 .mu.g EE, and a third 7 day phase of 0.5 mg NE in combination with 35 .mu.g EE.
Moore (DE 4313926 A1) discloses bridged triphasic regimens consisting of the administration of a combination of 10-50 .mu.g LNg and 5-20 .mu.g EE from days 1-7 of the menstrual cycle; of 50-75 .mu.g LNg and 5-20 .mu.g EE from days 8-14 of the menstrual cycle; of 75-125 .mu.g LNg and 5-20 .mu.g EE from days 15-21 of the menstrual cycle; and 5-20 .mu.g EE from days 22-28 of the menstrual cycle.
Erlich (German Patent DE 4,104,385 C1 and U.S. Pat. No. 5,280,023) discloses sequential contraceptive regimens consisting of the administration of an estrogen which effects a disturbance of follicle stimulation, followed by the administration of a combination of a progestin/estrogen in a dose at least adequate to inhibit ovulation. The regimen is administered for a total of 28 days per cycle. It is preferred that the estrogen is administered for 5-14 days per cycle and the progestin/estrogen combination is administered for 23-14 days per cycle, so that the total administration is for 28 days per cycle. Specific regimens include (a) 4 mg estradiol for 7 days followed by 21 days of the combination of 1 mg norethisterone acetate and 4 mg estradiol; (b) 2 mg estradiol valerate for 7 days followed by 21 days of the combination of 2 mg chlormadinone acetate and 4 mg estradiol valerate; and (c) 20 .mu.g EE followed by 18 days of the combination of 150 .mu.g LNg and 20 .mu.g EE. Regimen (c) in Erlich provides a total steroidal load of 2.7 mg of LNg and 560 .mu.g EE per 28 day cycle.


A labeling device including a release liner and a label where the release liner is imprinted with variable information prior to being equipped with the usual release material, i.e., silicone coating.

This invention relates to a labeling device and method and, more particularly to a labeling device in which there is action-inducing, instructional printing on the release liner normally associated with a pressure sensitive adhesive-equipped label.
Historically, release liners have not been imprinted because they are thrown away. When a person desiring to use a label pulls the label from the carrier sheet, there is nothing useful normally remaining in the carrier sheet, i.e., the release liner which is made up of an inexpensive paper stock coated with a release material such as a silicone. Occasionally, manufacturers of labels have printed logos on the liner--before coating--but this is not instructional, as for conveying information to be acted upon.
Now, however, I have found a novel use of release liners and in a first advantageous embodiment, the release liner (imprinted before coating) serves as a security device.
As an illustration, some fairly sizeable "big ticket" items such as television sets have their selling price labels switched--so that the person involved can purchase a $2,000 set for $500. This stems from the fact that the label (provided by the manufacturer as part of a business form) carries a bar code or similar indicia which is scanned at the check-out point and the price charged according to the retail store's computer output for that particular bar code. Retail stores have been using removable labels for scanning because of the difficulty at check-out of handling large bulky items so as to subject the labels on the cartons to scanning.
Now, by duplicating the bar code from the label on the release liner, a scanning check may be made to see whether the bar codes on both label and liner (in this particular embodiment) are the same. If not, an attempted fraud is detected.
In general, the use (by imprinting) of an item which previously was thrown away, has many advantageous applications. The release liner itself can be used as an additional copy. It can serve as an inventory control. And outside the realm of point of sale induced actions, it can perform other functions--for example, it can carry instructions. An example is where the purchaser is buying a lawn mower and the label has a warning about use--and the release liner has an instruction where to place the warning label. Thus, in broad terms, the release liner provides information causing the reader to act, i.e., providing action-inducing instructional printing.
In the simplest use, the printing on the liner stack can be a bar code and this can vary from label to label. The same variable information can be printed on the labels themselves, as when the labels are being employed for different wares. In the case where the wares are identical and provided in substantial quantity, the entire roll or stack can carry the same variable information, i.e., the variable information is cyclically changed after one or more positions on the liner have been printed.
Other objects and advantages of the invention will be seen in the details of the ensuing specification.


A method for manufacturing an electronic device includes forming a first source layer including a trench, forming a first sacrificial layer in the trench, forming a first structure over the first source layer, wherein the first structure includes first material layers and second material layers which are alternately stacked over the each other, forming first openings passing through the first structure and extending to the first sacrificial layer, forming first channel layers in the first openings, forming a slit passing through the first structure and extending to the first sacrificial layer, forming a second opening by removing the first sacrificial layer through the slit, and forming a second source layer in the second opening, wherein the second source layer is coupled to the first channel layers.

Field of Invention
Various exemplary embodiments relate generally to an electronic device and a method for manufacturing the same, and more particularly, to an electronic device including a data storage unit having a three-dimensional structure and a method for manufacturing the same.
Description of Related Art
All types of electronic devices include data storage units although these data storage units may have different functions and configurations. Performance improvement of electronic devices is continuously evolving. Accordingly, data storage units having a high performance and high capacity in addition to performance improvement are in demand. To achieve such requirements, proposals for electronic devices including high performance, high-capacity data storage units have been made.
The number of electronic devices requiring data storage units which retain data even though power is turned off, is increasing. Recently, data storage units having high storage capacity and high read and write speeds, in addition to retaining data, have been required. Therefore, technical development is being actively conducted to meet these requirements.

Electronic device and method for manufacturing the same


A monitoring system and method monitor changes in clearance distances between a sensor and a rotating component of a machine. Imbalance and/or wear in the machine is identified based on the changes in the clearance distances. The system and method optionally both measure the clearance distances and a rotating speed of the rotating component of the machine with the same sensor. In order to identify imbalance in the machine, a spectral energy of the machine can be calculated based on the changes in the clearance distances, and the imbalance in the machine can be identified based on the spectral energy. The system and method can determine a trigger speed of the machine that is associated with the wear in the machine based on the changes in the clearance distance. A remaining useful life of the machine can be estimated based on changes in the trigger speed.

Machines having rotating components can wear down over time due to prolonged use, even if the machines are maintained and/or periodically repaired. Some machines are not monitored for wear during use, but only are examined for wear between periods of use. For example, turbochargers in some vehicles, such as locomotives, may not have instrumentation to monitor vibration, temperatures of bearings, or rotor response during operation of the turbocharger. Excessive wear of bearings can lead to rotor instability, high displacement and eventual rubs, which can result in failure of the turbocharger. High imbalance caused by foreign object damage (FOD) or excessive deposition on the turbine blades can also lead to high shaft motion, bearing wear and eventual failure due to rotating contact with stationary parts.
Some machines include external accelerometers and/or use direct measurement of bearing temperatures to monitor bearing health. But, these devices add to the cost and complexity of the machines. Other machines can be inspected at specified megawatt intervals, but this can involve the tear down of the machine, which reduces the time that the machine can be used.

System and method of determining bearing health in a rotating machine


A variable displacement compressor which has a suction chamber, a discharge chamber, and a crank chamber. The displacement of the compressor is controlled by supplying refrigerant to the crank chamber from the discharge chamber via a pressurizing passage and releasing the gas into the suction chamber via a pressure releasing passage. An increase in the pressure in the crank chamber decreases the displacement, and a decrease in the pressure in the crank chamber increases the displacement. A displacement controlling structure of the compressor includes an electromagnetic valve which alters the size of an area of the pressurizing passage. A computer controls the electromagnetic valve in accordance with commands to alter the displacement. The computer enlarges the opened area of the pressurizing passage by controlling the electromagnetic valve in response to commands to reduce the displacement.

1. Field of the Invention
The present invention relates to clutchless variable displacement compressors. More particularly, the present invention pertains to controlling the displacement of a compressor by supplying the pressure in a discharge pressure zone to a pressure control chamber through a pressurizing passage while releasing the pressure in the control chamber into a suction pressure zone through a pressure releasing passage.
2. Description of the Related Art
Compressors are typically provided in vehicles to air-condition passenger compartments. Compressors capable of varying their displacement are preferred since they accurately control the temperature inside the passenger compartment and thus allow the environment in the compartment to be maintained at a comfortable level. Such a compressor, that is, a variable displacement compressor, typically has a tiltable swash plate, which is mounted on a shaft. The inclination of the swash plate is controlled based on the difference between the pressure in a crank chamber and the suction pressure. The rotating movement of the swash plate is converted to reciprocating linear movement of pistons.
U.S. Pat. No. 5,173,032, which corresponds to Japanese Unexamined Patent Publication No. 3-37378, describes a piston type compressor that does not employ an electromagnetic clutch. Generally, an electromagnetic clutch connects the compressor's drive shaft to an external drive source for transmission of driving power and disconnects the shaft from the drive source to stop transmission of the power. However, the external drive source and the drive shaft are directly connected to each other in the described compressor.
The elimination of the clutch and direct connection of the drive source with the drive shaft solves the problems of shocks, which would occur when connecting and disconnecting the clutch. By employing such compressors in vehicles, it is possible to provide further comfort to the driver and the passengers when driving the vehicle. Elimination of the clutch reduces the weight of the cooling apparatus and the costs of the compressor.
A typical clutchless compressor is operated even when cooling is unnecessary. When cooling is unnecessary, the displacement of the compressor should be minimized and formation of frost on the evaporator should be prevented. Circulation of refrigerant gas between an external refrigerating circuit and the compressor is stopped when cooling becomes unnecessary or when there is a possibility of formation of frost. The afore-mentioned U.S. Patent describes an electromagnetic valve that blocks the flow of gas from the external circuit to a suction chamber of the compressor and thus stops the circulation of gas between the external circuit and the compressor.
In this prior compressor, the pressure in the suction chamber decreases when the flow of gas from the external circuit to the suction chamber is stopped. This results in a displacement control valve, which detects the pressure in the suction chamber, being completely opened and thus permitting the gas in a discharge chamber to flow into the crank chamber and raise the pressure therein. The gas in the crank chamber is then supplied to the suction chamber. A circulating passage is thus defined extending between cylinder bores, the discharge chamber, the crank chamber, the suction chamber, and the cylinder bores.
The pressure decrease in the suction chamber also lowers the pressure in the cylinder bores. Thus, the difference between the pressure in the crank chamber and the pressure in the cylinder bores becomes large. This minimizes the inclination of the swash plate, which reciprocates the pistons, and results in the displacement becoming minimum. In this state, the drive torque required to operate the compressor becomes minimum and power loss, which occurs when cooling is unnecessary, is minimized.
By closing the electromagnetic valve, the flow of gas from the external refrigerating circuit to the suction chamber is brought to a stop. The electromagnetic valve is attached to an inlet of the compressor, from which refrigerant is introduced. Therefore, since the electromagnetic valve is used together with the control valve, the structure of the compressor is complicated. This results in high costs.

Displacement controlling structure for clutchless variable displacement compressor

Kabushiki Kaisha Toyoda Jidoshokki Seisakusho


A heat and fire resistant planar unitary shield formed of heat and flame resistant fibers and voluminous bulking fibers. The shield material has a heat and flame resistant zone with a majority of the heat and flame resistant fibers, and a voluminous bulking zone with a majority of the voluminous bulking fibers. The fibers are distributed through the shield material in an manner that the heat and flame resistant fibers collect closest to the outer surface of the shield with the heat and flame resistant zone, and the voluminous bulking fibers collect closest to the outer surface of the shield material with the voluminous bulking zone.

The present invention generally relates to materials for use in shielding from heat and/or flame, and in particular, heat and/or flame shielding material that can be used in applications such as hood liners for automobiles, engine compartment liners, bedding construction, upholstery, wall padding, and the like.
Numerous industries require materials which not only deliver heat and flame resistant properties, but can also provide volume, opacity, moldability, and other properties in a cost effective single substrate. Often times these barrier properties are best accomplished by using specialty materials which generate a high level of performance, but also introduce significant cost to the substrate. Especially in a voluminous substrate (high z direction thickness) even the introduction of a small percent of these materials into the shield material can introduce a significant level of cost to the overall substrate. For this reason composites having specialty surface layers are often used to provide these barrier properties. An example of a composite having specialty surface layers would be a skin laminated to a voluminous lower cost material. While this method effectively reduces the cost of the high cost raw material, there are disadvantages to this method such as additional processing steps and the potential delamination of the skin layer.
The present invention provides an alternative to the prior art by using a unitary heat shield material with different zones to provide the various desired properties of the material

This patent is subject to a terminal disclaimer.


A pad refurbisher that provides in situ, real-time conditioning and/or cleaning of a polishing surface on a polishing pad used in chemical-mechanical polishing of a semiconductor wafer and other microelectronic substrates. The pad refurbisher has a body adapted for attachment to a wafer carrier of a chemical-mechanical polishing machine, and a refurbishing element connected to the body. The body has a distal face positioned proximate to a perimeter portion of the wafer carrier and facing generally toward the polishing surface of the polishing pad. The body travels with the wafer carrier as the wafer carrier moves over the polishing pad. The refurbishing element is connected to the distal face of the body so that the refurbishing element can operatively engage the polishing surface substantially adjacent to the perimeter of the wafer carrier. The refurbishing element is a pad conditioning device and/or a pad cleaning device that conditions and/or cleans the polishing surface of the pad to remove waste particles from the polishing surface of the polishing pad and place the pad in a desired polishing condition. In operation, the refurbishing element travels with the wafer carrier and is selectively engaged with the polishing surface while the wafer carrier presses the wafer against the polishing surface to selectively condition and/or clean generally only the deteriorated areas on the pad.

Chemical-mechanical polishing ("CMP") processes remove material from the surface of a wafer in the production of ultra-high density integrated circuits. In a typical CMP process, a wafer is pressed against a polishing pad in the presence of a slurry under controlled chemical, pressure, velocity, and temperature conditions. The slurry solution generally contains small, abrasive particles that abrade the surface of the wafer, and chemicals that etch and/or oxidize the surface of the wafer. The polishing pad is generally a planar pad made from a relatively soft, porous material such as blown polyurethane. Thus, when the pad and/or the wafer moves with respect to the other, material is removed from the surface of the wafer by the abrasive particles (mechanical removal) and by the chemicals in the slurry (chemical removal).
FIG. 1 schematically illustrates a conventional CMP machine 10 with a platen 20, a wafer carrier 30, a polishing pad 40, and a slurry 44 on the polishing pad. An under-pad 25 is typically attached to the upper surface 22 of platen 20, and the polishing pad 40 is positioned on the under-pad 25. A drive assembly 26 rotates the platen 20 as indicated by arrow A, or in another existing CMP machine the drive assembly 26 reciprocates the platen 20 back and forth as indicated by arrow B. The motion of the platen 20 is imparted to the pad 40 through the under-pad 25 because the polishing pad 40 frictionally engages the under-pad 25. The wafer carrier 30 has a lower surface 32 to which a wafer 12 may be attached, or the wafer 12 may be attached to a resilient pad 34 positioned between the wafer 12 and the lower surface 32. The wafer carrier 30 may be a weighted, free-floating wafer carrier, or an actuator assembly 36 may be attached to the wafer carrier 30 to impart axial and rotational motion, as indicated by arrows C and D, respectively.
In the operation of the conventional planarizer 10, the wafer 12 is positioned face-downward against the polishing pad 40, and then the platen 20 and the wafer carrier 30 move relative to one another. As the face of the wafer 12 moves across the planarizing surface 42 of the polishing pad 40, the polishing pad 40 and the slurry 44 remove material from the wafer 12.
In the competitive semiconductor industry, it is desirable to maximize the throughput of the finished wafers and minimize the number of defective or impaired devices on each wafer. The throughput of CMP processes is a function of several factors, one of which is the rate at which the thickness of the wafer decreases as it is being planarized (the "polishing rate"). Because the polishing period per wafer decreases with increasing polishing rates, it is desirable to maximize the polishing rate within controlled limits to increase the number of finished wafers that are produced in a given period of time.
One problem with CMP processing is that the throughput may drop because the condition of the polishing surface on the pad deteriorates while polishing a wafer. The deterioration of the polishing pad surface is caused by waste particles from the wafer, pad, and slurry that accumulate on the polishing surface of the polishing pad. Since the accumulations of waste particles alter the condition of the polishing surface on the polishing pad, the polishing rate tends to drift over time. For example, after polishing a single wafer for only 4 minutes with a Rodel IC-1000 polishing pad and a Rodel ILD-1300 slurry (both of which are manufactured by Rodel Corp. of Arizona), the polishing rate drops and reduces the throughput for semiconductor wafers. Many semiconductor manufacturers accordingly recondition the pad after each wafer, but unless the reconditioning process is performed in situ and in real-time, then the reconditioning of the pad also causes down-time that reduces throughput. Thus, the waste particles on the polishing surface reduce the throughput of the CMP process.
CMP processes must also consistently and accurately produce a uniform, planar surface on the wafer because it is important to accurately focus the image of circuit patterns on the surface of the wafer. As the density of integrated circuits increases, it is often necessary to accurately focus the critical dimensions of the circuit pattern to better than a tolerance of approximately 0.1 .mu.m. Focusing the circuit patterns to such small tolerances, however, is very difficult when the distance between the emission source and the surface of the wafer varies because the surface of the wafer is not uniformly planar. In fact, several devices may be defective on a wafer with a non-uniformnly planar surface. Thus, CMP processes must create a highly uniform, planar surface.
Another problem with CMP processing is that the accumulations of waste particles reduce the uniformity of the polished surface because they do not accumulate uniformly across the polishing surface of the pad. The polishing rate accordingly varies from one region on the pad to another resulting in a nonuniform polished surface on the wafer. Therefore, in light of the problems associated with accumulations of waste particles on polishing pads, it is necessary to periodically clean and condition the polishing surface to remove such accumulations and bring the polishing pad back to a desired condition.
Polishing surfaces on polishing pads are typically cleaned by brushing the pad with a brush, or by flushing the pad with a fluid. To perform the brushing and flushing processes, the wafer is generally removed from the pad while the brush or fluid engages the polishing surface of the polishing pad. One problem with the brushing and flushing processes, therefore, is that a significant amount of down-time is necessary to merely clean the polishing pad. Thus, it would be desirable to develop a pad cleaner that effectively cleans the pad in situ and in real-time.
Polishing surfaces of polishing pads are typically conditioned with a diamond embedded plate mounted to a separate device that moves the plate across the polishing pad to abrade the surface of the pad. Some pad conditioners remove a portion of the upper layer of the deteriorated polishing surface to form a new, clean polishing surface. One problem with conventional pad conditioners is that they condition the pad substantially uniformly across the polishing surface. Since the wafers only polish on a well-defined area of the pad (usually a concentric band spaced radially away from both the center of the pad and the perimeter of the pad), the pad conditioning needs to be performed proportionate to the pad surface wear. Moreover, it is desirable to condition a pad in situ and in real-time to avoid costly down-time associated with conditioning processes that stop the polishing of the wafer. Thus, it would be desirable to develop a device for selectively conditioning areas on the pad that require conditioning in situ and in real-time.

Polishing pad refurbisher for in situ, real-time conditioning and cleaning of a polishing pad used in chemical-mechanical polishing of microelectronic substrates


A lamp unit is provided having polymer electrical conductors adhered to a non-conductive substrate in which adjacent conductors present a gap therebetween for securing a light radiating device within the gap the conductors of one embodiment having raised abutments formed in the conductors at the gap for capture of a light radiating device therebetween, such as an LED in said gap to hold the light device between the abutments to secure the light device in the lamp and power the light device.

A wide variety of signal lights serving many different purposes are found in road vehicles, in railway signals and in street traffic signals. In each of these situations, a light source, such as a vehicle lamp or railway signal lamp or traffic light lamp, must be electrically connected to a power source via some type of electrical connection. Because the large number of electrical connections may be included in a single signal lamp, a small savings in cost per electrical connection can translate into a significant savings for the overall vehicle cost. Costs also result as each light source having an electrical connection requiring assembly and installation into the vehicle signal lamp or other signal lamp which then must be assembled into the vehicle or signal apparatus and connected to a power source. Each of these steps adds time, complexity and expense to the manufacturing process. As such, a reduction in the number of parts and steps needed to accomplish assembly and connection of a signal lamp causes a direct impact on lowering the manufacturing time and costs.
Reducing light device electrical connection costs is not easy due to a number of constraints that confront the light device electrical connection field. Throughout the design and manufacturing process quality is an important consideration. The light device electrical connection must be sufficiently robust that the electrical connection performance is not degraded by mishandling during manufacture, shipment and assembly processes. Depending on the application, electrical connections must function reliably under severe operational conditions such as severe shock and vibration, a wide range of temperature, and exposure to water, oil and dirt.
Additional constraints are specific to the vehicle light device field. The engine compartment and surrounding space increasingly has been filled by various other components putting space at a premium. A wire harnesses tends to be bulky and difficult to manipulate within tight spaces. This is a significant disadvantage when the wire harness is to be used in the increasingly limited space of modern vehicles. Therefore vehicles present an enhanced design problem in the areas of sufficient space and in installing the wire harness into the designed space.
These design and manufacturing problems can contribute to reduced reliability of light device electrical connections. Where the space of installation of the wiring harness is cramped, assembling the wire harness into the vehicle can result in poor engagement of the wire harness plugs. When subjected to normal shock and vibration, the plugs can then become disengaged. While locking tabs on plugs may be used to prevent disengagement, this adds additional material and additional steps to the manufacturing process resulting in plug components being even more expensive. Further, the difficult manipulation of the wire harness in a cramped area may subject the internal wires to stresses resulting in breakage of the wires or a loss of connection between the wires and the plugs.
The difficult manipulation of the wire harness in a cramped space can increase the potential for creation of an electrical short. The wire harness will frequently be in contact with other surfaces once installed in a vehicle. As the vehicle is shocked and vibrates, the wire harness will rub against the other surfaces, fraying the insulating material. A breach of this insulation presents a substantial risk of electricity arcing from the exposed wire to other parts of the vehicle. Of course, a more robust insulation results in a bulkier wire harness, presenting increased manufacturing and design costs.
Recently, vehicle lamps, railway signal lamps and traffic signal lamp have begun to employ light emitting diodes LED as a light device to replace the incandescent light bulbs. This application of LEDs has allowed the use of several LEDs on a circuit board to replace a single light bulb with multiple LED's and multiple light bulb with a number of LED's The advantage provided is that if one of the several LEDs ceases to operate, the other LEDs contained in the vehicle lamp will continue to illuminate and the signal or warning purpose of the lamp will continue to be served. This use of multiple LED's, while reducing the costs associated with incandescent lights presents another set of costs associated with the installation of multiple LEDs onto a circuit board.
It is desirable, therefore, to provide a light device electrical connection for a signal lamp that is inexpensive and simple to manufacture. It also is desirable that the light electrical connection be easily installed into a vehicle or signal instrument such as a railway signal or a traffic signal. It would be desirable that the light device electrical connection provide reliable operation in a wide range of environmental conditions including shock, vibration, and in the presence of oil, dirt and water, and in temperature extremes. The light device electrical connection also should be easily configured to fit within space confines of a variety of vehicle designs while minimizing the risk of electrical shorts.

Vehicle lamp with polymer conductors and mounting structures


A self-encapsulated power conductor component with improved heat transfer has a chip bearing at least one power transistor having at least one interdigitated electrode, provided with an air bridge, and a sink provided with at least one metal islet in relief. The air bridge is reinforced and the chip is brazed in reverse to the islet of the sink by its air bridge. Other islets brazed to the metallizations on the rim of the chip reinforce the mechanical fixing. The access to the electrodes is obtained by via holes and the second face of the substrate may receive non-integrable components. The device can be applied to power transistors and integrated circuits, notably on GaAs.

1. Field of the Invention
The present invention relates to a semiconductor device including at least one interdigitated transistor, the chip of which is mounted on the reverse side, i.e. by its active face, to a base used as a heat sink. The mounting can be done in such a way that the chip is self-encapsulated.
2. Description of the Prior Art
It is known that, in a semiconductor device, the active part is on a first face of a chip and that it has a thickness of the order of 1 to 10 micrometers while the substrate has a thickness of the order of 300 to 500 micrometers. However, during operation, heat is produced by the active part and has to cross the entire substrate to be discharged by the second face of the substrate, by means of a heat sink.
The problem exists for semiconductors on silicon substrates which, however, have fairly good qualities of heat conduction capacity, but it is aggravated for semiconductors on substrates made of III-V materials such as GaAs, which is a very poor conductor of heat, and it becomes a very irksome problem in the case of power semiconductors which dissipate a lot of heat.
The currently used approaches are difficult and costly to implement. Among many possibilities, we might cite:
the thinning of the substrate, by its rear face, to reduce the length of the heat transfer. However, this method embrittles the chip, especially if the circuit is a large-sized one; PA1 the implanting of a heat drain in the substrate, as shown in FIG. 1. If we consider a semiconductor reduced to an active layer 1 supported by a substrate 2, it is possible to etch a cavity in the substrate 2, up to the vicinity of the hottest region of the active layer 1, and to fill this cavity with a metal, which makes it a heat drain 3, in contact with a sink 4. But this technique is a delicate one. PA1 if the base 4 is itself a heat insulator, for example an alumina wafer in a hybrid circuit, it can be converted, in a manner similar to that described above, by being overlaid with metal regions 5 which improve the heat transfer coefficient, as shown in FIG. 1.
A further disadvantage of the different approaches is that they have a sequence of junctions between materials that are poor conductors of heat and materials that are good conductors of heat. This does not make for an optimum arrangement.
The invention proposes to dissipate the heat released during operation by means of a direct contact between the active layer of the semiconductor device and a heat sink, by brazing the chip "backwards" or in reverse to the sink.
However, in order to avoid short-circuiting the metallizations of the different electrodes of the semiconductor device, for example the source, gate and drain of a field-effect transistor, the electrodes of a same type, for example the source, which are at a same potential, are connected to one another by metal bridges, called "air" bridges, reinforced by an extra thickness in order to give them sufficient mechanical resistance. The invention can therefore be applied to an electronic circuit that includes at least one power transistor, which is itself interdigitated, including at least two fingers of a same electrode to enable a metal bridge to be set up between them.