A semiconductor wafer processed on both sides simultaneously, the wafer lying in freely movable fashion in a cutout in one of a plurality of carriers that rotate by means of a rolling apparatus, and one thereby being moved on a cycloidal trajectory, the semiconductor wafer being processed in material-removing fashion between two rotating ring-shaped working disks, wherein each working disk comprises a working layer comprising abrasive material, and wherein an alkaline medium comprising no abrasive material is supplied during the processing.

1. Field of the Invention
The invention relates to a method for chemically grinding a semiconductor wafer on both sides. In particular, the invention is directed to a novel processing step for silicon wafers of the next technology generations, primarily having a diameter of 450 mm.
2. Background Art
At present, polished or epitaxially coated silicon wafers having a diameter of 300 mm are used for the most demanding applications in the electronics industry. The silicon wafers having a diameter of 200 mm are gradually being superseded by the 300 mm wafers.
A major reason why the electronics industry demands larger substrates for producing the components in this industry, be they microprocessors or memory chips, resides in the enormous economic advantage that this affords. In the semiconductor industry it has long been customary to focus attention on the available substrate area, or in other words to ask the question of how high is the number of components, that is to say logic chips or memory chips, which can be accommodated on an individual substrate. This is associated with the fact that a large number of processing steps by the component manufacturers are directed to the entire substrate, but also in addition, to individual steps for patterning the substrates, that is to say the production of component structures that subsequently lead to the individual chips. Thus, both groups of processing steps are closely related to the substrate size with regard to the production costs. The substrate size thus considerably influences the production costs per component and is thus of immense economic importance.
However, an increase in the substrate diameter is accompanied by major, in part also totally new, hitherto unknown technical problems.
Ultimately, all the processing steps, whether they be purely mechanical (sawing, grinding, lapping), chemical (etching, cleaning) or else chemical-mechanical in nature (polishing), and also the thermal processes (epitaxial coating, annealing) require thorough reworking, in particular also with regard to the machines and installations used therefor (equipment).
Chemomechanical processing comprises polishing methods in which a material removal is obtained by means of relative movement of semiconductor wafer and polishing pad with the action of force and with the supply of a polishing slurry (for example alkaline silica sol). The prior art describes batch double-side polishing (DSP) and batch and individual wafer single-side polishing (mounting of the semiconductor wafers by means of vacuum, adhesive bonding or adhesion during the polishing processing on one side on a support).
Mechanical processing steps in accordance with the prior art are lapping (simultaneous double-side lapping of a plurality of semiconductor wafers in the "batch"), single-side grinding of individual semiconductor wafers with single-side clamping of the workpieces (usually carried out as sequential single-side grinding of both sides of the wafer, "single-side grinding", SSG; "sequential SSG") or simultaneous double-side grinding of individual semiconductor wafers between two grinding disks (simultaneous "double-disk grinding", DDG).
Methods and apparatuses for the single-side surface grinding of a semiconductor wafer are known for example from U.S. Pat. No. 3,905,162 and also U.S. Pat. No. 5,400,548 or EP-0955126. In this case, a semiconductor wafer is fixedly held on a wafer holder by one of its surfaces, while its opposite surface is processed by means of a grinding disk by wafer holder and grinding disk rotating and being pressed against one another. In this case, the semiconductor wafer is fixed on the wafer holder in such a way that its center substantially corresponds to the rotation center of the wafer holder. Moreover, the grinding disk is positioned in such a way that the rotation center of the semiconductor wafer presses into a working region or the edge region of the grinding disk, the edge region being formed by teeth. The entire surface of the semiconductor wafer can thereby be ground without any movement in the grinding plane.
DDG machines according to the prior art, as are described for example in JP2000-280155A and JP2002-307303A, have two grinding wheels which lie opposite one another and the rotation axes of which are arranged colinearly. During the grinding operation, a workpiece in wafer form which is positioned between the grinding wheels is processed on both sides simultaneously by the two grinding wheels rotating about their axis, while it is held in position by a ring-shaped holding and rotation device and at the same time rotated about its own axis. During the grinding operation, the two grinding wheels are advanced in an axial direction until the desired final thickness of the workpiece has been reached.
The holding and rotation device may, for example, comprise friction wheels which engage on the edge of the workpiece. However, it may also be a device which surrounds the workpiece in ring-shaped fashion and engages in a score, groove or notch which is possibly present at the periphery of the workpiece. A device of this type is generally referred to as a "notch finger". In order to process the entire area of the workpiece, the workpiece is guided relative to the grinding wheels in such a way that the abrasive grinding segments of the grinding wheels describe a circular path which runs constantly over the center of the workpiece.
In this case, the workpiece is not generally in a fixed position, but rather is held axially in position by two apparatuses for hydrostatic bearing, referred to hereinafter as "hydropads", which are fitted on both sides of the workpiece. Apparatuses of this type are described in JP2000-280155A. In accordance with the prior art, those surfaces of the two hydropads which face the workpiece are configured in planar fashion and oriented parallel to one another. Each hydropad comprises a plurality of hydrostatic bearings, between which grooves for discharging the medium used for the hydrostatic bearing (referred to hereinafter as the "hydro-bearing medium") and the grinding coolant are arranged.
For producing particularly planar semiconductor wafers, great importance is ascribed to those processing steps in which the semiconductor wafers are processed largely in a constrained-force-free manner in "free-floating" fashion without force-locking or positively locking clamping ("free-floating processing", FFP). Undulations such as are produced for example by thermal drift or alternating load in MWS are eliminated by FFP particularly rapidly and with little loss of material. FFP processes known in the prior art include lapping, DDG and DSP, inter alia.
DE 103 44 602 A1 discloses a further mechanical FFP processing method, in which a plurality of semiconductor wafers lie in a respective cutout in one of a plurality of carriers that are caused to rotate by means of a ring-shaped outer and a ring-shaped inner drive ring, and are thereby held by a specific geometrical path and processed in material-removing fashion between two rotating working disks coated with bonded abrasive. This method is also called "planetary pad grinding" or simply PPG. The abrasive is composed of a film or "pad" stuck to the working disks of the apparatus used, as disclosed in U.S. Pat. No. 6,007,407, for example.
Hard materials are used as the abrasive, e.g. diamond, silicon carbide (SiC), cubic boron nitride (CBN), silicon nitride (Si3N4), cerium dioxide (CeO2), zirconium dioxide (ZrO2), corundum/aluminum oxide/sapphire (Al2O3) and many other ceramics having grain sizes up to a few tens of micrometers. For the processing of silicon, in particular diamond is preferred, and furthermore also Al2O3, SiC and ZrO2. The diamond is incorporated, as individual grains, or bonded by means of a ceramic, metallic or synthetic resin primary bond to form conglomerates, into the ceramic, metal or synthetic resin matrix of the abrasive bodies.
DE 103 44 602 A1 furthermore discloses a method in which either a multiplicity of abrasive bodies containing bonded abrasive are stuck to the working disks or in which the abrasive is bonded in a layer or a "pad" and pads of this type are stuck to the working disk. There are furthermore fixings of the working layer by means of vacuum, screwing, covering or by means of hook and loop fastening, in electrostatic or magnetic fashion (see e.g. U.S. Pat. No. 6,019,672 A).
Sometimes the working layers are embodied as pads or laminated sheets (U.S. Pat. No. 6,096,107 A, U.S. Pat. No. 6,599,177 B2). Sheets having structured surfaces are also known, comprising elevated regions that come into contact with the workpiece and recessed regions via which cooling lubricant can be supplied and abrasive slurry and spent grain can be discharged. An abrasive tool (abrasive pad) structured in this way is disclosed by U.S. Pat. No. 6,007,407 A, for example. Here the abrasive pad is self-adhesive on the rear side, which permits a simple change of the abrasive tool on the working disk.
Suitable apparatuses for carrying out the processing methods of lapping, DSP and PPG essentially comprise a ring-shaped upper and lower working disks and a rolling apparatus comprising toothed rings arranged on the inner edge and on the outer edge of the ring-shaped working disks. Upper and lower working disks and inner and outer toothed rings are arranged concentrically and have colinear drive axes. The workpieces are introduced into thin guide cages which are toothed on the outside, so-called "carriers", which are moved between the two working disks during processing by means of the rolling apparatus. In the case of PPG, the working disks comprise, as mentioned above, a working layer with fixedly bonded abrasive.
In the case of lapping, use is made of working disks, so-called lapping plates, composed of cast material, generally a steel casting, e.g. ductile gray cast iron. These contain in addition to iron and carbon a multiplicity of nonferrous metals in different concentrations.
In the case of DSP, the working disks are covered with a polishing pad, wherein the polishing pad is composed for example of a thermoplastic or heat-curable polymer. A foamed plate or a felt or fiber substrate which is impregnated with a polymer is also suitable. In the case of lapping and DSP, lapping and polishing agents, respectively, are additionally supplied, but not in the case of PPG. For lapping, oils, alcohols and glycols are known as carrier liquids for the lapping agent (abrasive substance slurry, abrasive substances), also called a "slurry". For DSP, aqueous polishing agents to which silica sol is applied are known, which are preferably alkaline and, if appropriate, contain further additives such as chemical buffer systems, surfactants, complexing agents, alcohols and silanols.
The production of a semiconductor wafer comprises slicing the semiconductor wafer from a crystal followed by a plurality of subsequent material-removing processing steps. These processing steps are necessary in order to obtain the smoothest possible surfaces and parallel sides of the semiconductor wafer, and also to provide the semiconductor wafer with a rounded edge. Appropriate material-removing processing steps usually include edge rounding, lapping or double-side grinding, etching, and polishing of the semiconductor wafer. Processing steps such as double-side grinding and primarily lapping add damage to the wafer surface, this damage necessitating a high amount of material removal in subsequent steps (etching, polishing).
The crystal damage can be reduced by fine grinding of the semiconductor wafer, that is to say by surface grinding using a grinding disk having a fine grain size. Less material removal is then necessary during subsequent etching. Ideally, the intention is to completely dispense with the etching step. Such a reduced etching step is intended to have the effect that impairment of the flatness of the semiconductor wafer that is usually associated with etching is reduced, and less material removal is in turn necessary in the subsequent polishing step. A fine grinding method of this type is described in DE 102 005 012 446 A1.
However, fine grinding also disadvantageously influences the geometry and, in particular, also the nanotopology, which is becoming more and more problematic on account of the constantly increasing requirements made of these two parameters in the course of further miniaturization (Roadmap, Design Rules). The nanotopology is usually expressed as height fluctuation PV ("peak to valley"), relative to square measurement windows having an area of 2 mm×2 mm. Moreover, a conventional fine grinding process by which the wafer situated on a rotating wafer holder and a rotating disk are delivered to one another (advance) cannot readily be employed in view of the forces acting on 450 mm wafers according to the current situation.

Method for chemically grinding a semiconductor wafer on both sides


A room or area designed to facilitate a plurality of users moving while they learn, work, or participate in a simulation. sensor relays aid this process by sending and receiving user information to a central hub, a movement device, one another or any combination of the three, in order to safely benefit the users coordination, exercise, or concentration while multitasking, according to their own user defined set points, a set of default set points, or set points determined by an external observer. This room or area may be further enhanced in applications where a treadmill or moving walkway is present.

Studies related to multitasking have shown that people typically process one task less efficiently when coupled with other tasks (see, e.g., "Cognitive Control in Media Multitaskers" by Ophir and Wagner, Proceedings of the National Academy of Sciences of the United States of America, 2009). Ophir and Wagner found that media related multitasking was distinct from normal multitasking, and caused users switching between activities to perform worse than during normal multitasking. Terms such as cognitive distraction, distracted driving, distracted walking, visual distraction, and manual distraction describe the ways in which people lose focus or the ability to provide a timely response to a situation to which they would otherwise be able to respond, due to an additional task.
Conversely, studies have shown that movement can stimulate the functionality of the brain, (see, e.g., "Exercise and the brain: something to chew on" by Van Praag, National Institute of Health, Trends in Neuroscience, 2009). Van Praag finds that optimal maintenance and brain health may depend on exercise and intake of natural products. Furthermore feedback and assistance while multitasking can be used to stimulate better coordination of movement and any additional tasks. The benefits of movement related to coordination, exercise, and physiotherapy are numerous, including stimulated muscle memory and reflexes due to repetitive movements involving hand-eye coordination, improved health due to weight loss or lowered blood pressure, increased longevity, restoration of function and movement, and the treatment, healing and prevention of injuries or disabilities. Studies show that increasing numbers of people are living sedentary lifestyles (See e.g. "Amount of Time Spent in Sedentary Behaviors in the United States, 2003-2004" by Charles E. Matthews et. al., American Journal of Epidemiology, 2008). In his study, Matthews found evidence that most Americans, both male and female over the ages of 6-11 now spend over 50% of their time in sedentary behaviors. This is at least partially related to the drawbacks of the information age, in which many people learn, create or conduct business, or are entertained all from a stationary position while observing monitors on their televisions and computers.
While inventions exist that allow movement while creating such as the laptop computer, movement while reading or learning such as tablet processors, or movement while being entertained such as virtual reality headsets like the Vuzix wrap 230 eyewear product, none of these devices are designed specifically for use while moving, and none of them are designed to provide feedback to the user or assistance to the user specifically related to that movement. A system method or apparatus specifically designed to allow the user to process, by learning, creating, or being entertained; while moving through coordination, exercise, or physiotherapy; and that aids the user in providing feedback or assistance related to that movement, processing, or any combination thereof; has the potential of being a boon to society.
Furthermore studies have shown that the average human attention span fell from 12 minutes in 1998 to just 5 minutes in 2008 (See e.g. "Stress of Modern Life Cuts Attention Spans to Five Minutes" by Moore, The Telegraph, Nov. 8, 2008) Moore cites a Lloyds TSB Insurance Study which also found that adults over 50 were able to concentrate for younger periods of time than younger people, suggesting that our media heavy and increasingly sedentary lifestyles may be taking its toll on younger generations. If these trends progress they could have potentially devastating effects on the future of our society. Conversely studies have shown that people are capable of longer attention spans when they are doing something they find enjoyable or intrinsically motivating. (See e.g. Dukette, Cornish The Essential 20: Twenty Components of an Excellent Health Care Team. RoseDog Books. 2009) Dukette and Cornish's study shows that attention spans for sustained attention to a freely chosen task range from about 5 minutes in a two-year-old child, to a maximum of 20 minutes in adults. An invention, that ergonomically incorporates the brains processing of external media with movement and exercise, could be revolutionary in a classroom, simulation, or work setting. An area devoted to such movement could be used as an energy efficient training facility, exercise and learning room, or meditation and rehabilitation area.

Method and apparatus for teaching utilizing moving walkways


Novel compositions comprising a high concentration of one or more extended chain homopolymer, copolymer, or block polymer and certain polyphosphoric acids are prepared. Such compositions are optically anisotropic (liquid crystalline), capable of exhibiting excellent cohesive strength, and are especially suited to the production of high molecular weight ordered polymer fibers by dry-jet wet spinning. These liquid crystalline compositions are capable of being drawn through long air gap distances and spun at exceptionally high spin draw ratios. Fibers, films and other articles formed from these liquid crystalline compositions exhibit exceptionally high physical and heat resistant properties.

In general, the class of aromatic heterocyclic extended chain polymers are well known for their outstanding thermal, physical, and chemical properties. Unfortunately, these polymers are essentially non-melting and have proven very difficult to economically process into articles. In order to fashion such polymers into desired articles of commerce, for example fibers, films, fibrids, and the like, it is necessary that they be in solution or dope form. Although such polymers can be dissolved in various acidic solvents, such as sulfuric acid, methanesulfonic acid, chlorosulfonic acid, polyphosphoric acid, and the like, difficulty is often experienced in preparing and using the polymer-acid compositions or dopes because of poor polymer-acid solubility.
Normally, a precipitated or dried particulate form of the polymer is dissolved in a strong acidic solvent by mixing the (isolated) polymer particles at elevated temperatures and/or under high pressures for a period from several hours to several days. If the polymer is insoluble in the particular solvent, other solvents or various solvent mixtures are employed. Usually, heating and cooling cycles are applied and repeated to obtain a useful dope.
The resulting dopes often contain undissolved polymer and must be filtered before further processing into articles.
Although spinning dopes of polybenzobisoxazole, polybenzimidazole and polybenzobisthiazole in sulfuric acid and/or methanesulfonic acid and/or chlorosulfonic acid with polymer concentrations above about 10 percent are known in the art, the intrinsic viscosity of these polymers is for the most part below 5 dL/g and oftentimes less than 3 dL/g. The cohesive strength of such dopes is inherently weak and economically less desirable for use in dry-jet wet spinning. In the case of polybenzobisoxazole, numerous attempts of dry-jet wet spinning an approximately 10% polybenzobisoxazole/methane sulfonic acid-dope into fibers were not successful (E. W. Choe, et al., in Macromolecules 1981, 14, pp 920-924).
In the case of polybenzimidazole, prior art dopes of this polymer lack adequate strength to maintain filament integrity while dropping through the air-gap. In order to overcome this problem U.S. Pat. No. 4,263,245 teaches dissolving a high concentration (up to 30%) of this polymer into suitable solvents such as concentrated sulfuric acid. At such high polymer concentrations lithium chloride is required to prevent the polybenzimidazole from phasing out of solution.
In the case of polybenzobisthiazole, U.S. Pat. No. 4,225,700 teaches the formation of a liquid crystalline composition of this polymer at concentrations near 10% in methane sulfonic acid and chlorosulfonic acid and at about 6% in polyphosphoric acid. Concentrations of polybenzobisthiazole in polyphosphoric acid above about 10% by weight are difficult, if indeed possible to achieve. One difficulty encountered is that the solution of the 2,5-diamino-1,4-benzenedithiol monomer in polyphosphoric acid with the P.sub.2 O.sub.5 content described in U.S. Pat. No. 4,225,700 is very viscous sad dehydrohalogenation is difficult. Also considerable foaming results. Although solutions of precipitated polymer in solvents such as methane sulfonic acid and chlorosulfonic acid can be prepared, high concentrations of polymer are difficult or impossible to achieve. S. R. Allen, et al., in Macromolecules 1981, 14, pp. 1135-1139 describes attempts at spinning polybenzobisthiazole directly from the polymerization medium (polyphosphoric acid) containing 5-6% polymer.
Insofar as polybenzobisthiazole is concerned it is possible to obtain compositions near to 10% of the polymer in polyphosphoric acid with intrinsic viscosity equal to 26 dL/g (J. F. Wolfe, et al., Macromolecules 1981, 14, pp. 915-920). Attempts to increase the intrinsic viscosity of the polymer can only be achieved at a major sacrifice (decrease) in polymer concentration. Liquid crystalline compositions of 10% polybenzobisthiazole in polyphosphoric acid are heretofore unknown in the art. Liquid crystalline compositions of polybenzobisthiazole having intrinsic viscosities greater than about 30.3 dL/g in polyphosphoric acid are heretofore unknown in the art.
In practical terms this means that such polymer-polyphosphoric acid compositions are severely limited in their potential usefulness for the production of highly ordered high molecular weight polymeric articles.
In general, liquid crystalline extended chain polymer compositions (with the exception of polybenzobisthiazole as mentioned above) in polyphosphoric acid are heretofore unknown in the art; and moreover, liquid crystalline extended chain copolymer and block polymer compositions are heretofore unknown in the art.

Liquid crystalline polymer compositions process, and products


An apparatus and method for connecting servers within a rack-mounted server system. In one embodiment, a plurality of servers are positioned in respective bays of a rack. The bays generally constrain adjacent servers in a generally fixed spacing and in face-to-face alignment. A first server is moved within its bay relative to a second server until a connector on the first server is aligned with a mating connector on the second server. Alignment of the two mating connectors is detected by a position sensor, such as an LED-photodiode pair. A signal from the position sensor causes or at least allows the first and second connectors to be moved toward one another, either using a motor or a hand-actuated mechanism, to provide power and data communication between the servers. Once the connection is established, data is optionally transmitted via the optical sensor.

1. Field of the Invention
The present invention relates to multi-conductor connectors for connecting digital computing devices in a rack system.
2. Description of the Related Art
Large computer systems are often consolidated into centralized data centers having multiple servers assembled in a rack. Rack-mounted systems conserve space and put the servers and infrastructure within easy reach of an administrator. Managing these systems can, therefore, be less problematic and less expensive than separately administering a multitude of scattered smaller servers. Some of the more compact server arrangements currently available include blade servers, such as the IBM eServer BLADECENTER (IBM and BLADECENTER are registered trademarks of International Business Machines Corporation, Armonk, N.Y.). Blade server designs range from ultra-dense, low-voltage servers to high-performance, lower density servers, to proprietary, customized rack solutions.
In many conventional rack-mounted systems, the individual servers are typically configured in a stacked relationship, one above the other. In blade-type configurations, the individual servers are typically configured in a side-by-side relationship. In both configurations, multiple servers are generally positioned in adjacent bays within a rack enclosure. The servers may then be interconnected with cables, such as for scalability. For example, two blade servers, each having eight-processors, may be coupled together in electronic communication to effectively create a sixteen-processor server. Particularly in larger systems, however, it takes a significant amount of time to connect multiple servers. The cables used to manually connect the servers are subject to normal wear and tear, as well as potential breakage if mishandled. The steps and supplies involved in connecting servers in rack systems may represent a significant factor in the overall time, cost, and complexity of server installation and maintenance.
Therefore, there is a need for an improved method and apparatus for coupling servers in rack-mounted systems. It would be desirable for the method and apparatus to allow servers to be connected more efficiently and reliably, with less wear and tear on component parts. Preferably, the method and apparatus would reduce the manual involvement required to connect servers.


A magneto-optical disk comprising a substrate whereon a recording medium is formed, and a depression is formed on the substrate on the inside of the recording medium of the substrate. A center hub is installed on the depression such that the center hub is substantially level with a protective resin layer covering the recording medium. On the center hub, a flying head performs CSS (Contact Start and Stop). This configuration of the disk eliminates the occurrence of dust due to the abrasion and head crash, and achieves stable CSS. A method of manufacturing the magneto-optical disk, wherein the protective resin layer is formed after installing the center hub on the depression. In this method, since a space is not produced between the center hub and the protective resin layer, the stable flying characteristics is obtained. And a magneto-optical disk whereon small physical bumps and pits are formed on the substrate on the inside of the recording medium, which prevents the flying head from sticking to the disk. A method of manufacturing the magneto-optical disk by using a stamper, which permits the disk to be mass produced.

In recent years, research and development into a magneto-optical memory element has been much more carried out than research and development into a read only optical memory element, such as a so-called compact disk, and the magneto-optical memory element now comes into practice. The magneto-optical memory element has a high capacity and whereon information can be recorded, reproduced and erased. Lately, a study of the recording system has been made to realize higher speed and higher density recording, and especially a recording method called overwriting has been focused. In the overwriting, recorded information can be rewritten directly without erasing, thereby permitting time required for recording to be shortened.
The following will explain the overwriting together with a conventional recording system.
In recording, first a perpendicular magnetized film that is a recording medium is initialized by applying a strong external magnetic field or the like so as to produce a uniform magnetization direction. To make the explanation easy, it is assumed in this example that the direction of magnetization is set in a predetermined direction, e.g. upwards in a direction crossing the film surface at a right angle. Next, a laser beam having a high output level is irradiated on a portion wherein information to be recorded so as to raise the temperature thereon to or exceed the Curie temperature or the vicinity of the magnetic compensation temperature of the recording medium. This method allows the coercive force on the recording portion to be substantially zero, so that the magnetization direction of the recording portion can be switched downwards by applying a magnetic field whose direction is downwards in a direction crossing the film surface at a right angle. When the irradiation of the laser beam is stopped, the temperature of the recording portion return to room temperature, which permits the switched magnetization direction to be fixed and information to be recorded thermomagnetically.
In reproduction, a laser beam having such a low level of output that it does not switch the magnetization direction due to the temperature rise is irradiated on the recording medium, and information is detected optically by the use of an effect that the direction of rotation of a polarization plane varies according to the magnetization direction.
There are two information rewriting systems for writing new information in portions storing other information. (1) A system in which a recording medium is initialized through erasing operation so that a uniform magnetization direction of the recording medium is produced again, and new information is then recorded thereon. (2) The overwriting system in which information is directly rewritten without erasing by improving a recording medium or an external magnetic field generating device.
In the system of (1), an erase head needs to be provided separately, or recording can be performed only after erasing if only one magnetic head is used. However, providing the erase head causes a manufacturing cost rise and the device to be larger in size. In the mean time, if a single magnetic head is employed like many conventional devices, the same time taken for recording is required for erasing, so a long time is needed for rewriting.
If improving the external magnetic field generating device relating to the ore writing system of (2) is adopted, i.e. the direction of an external magnetic field is switched from downwards to upwards or vice versa according to information to be recorded while keeping the laser beam to have a high output level, the recording medium does not need to be changed much from the conventional one, and therefore it seems to be the most effective way.
To achieve a high-density recording, if the direction of an external magnetization is switched at a very high frequency rate, for example about 10 MHz, a coil and a coil core of the external magnetic field generating device need to be miniaturized to a sufficient level. This causes the intensity of the generated magnetic field to be lowered and the magnetic field generating area to be smaller. Therefore, the magnetic head and the recording medium need to get closer each other sufficiently, i.e. specifically the head-to-medium separation ranges from several micrometers to some tens of micrometers. If a stationary type magnetic head is employed, it is difficult to achieve the above-mentioned small clearance between the magnetic head and the recording medium as the surface of the recording medium is vibrated, i.e. bumps and pits exist in a circumferential direction.
To counteract this, as shown in FIGS. 7(a)(b), a flying head 26 of a slider type which is capable of sliding over a magneto-optical disk may be used as an external magnetic field generating device. In order to make the flying head 26 fly above the magneto-optical disk surface, the flying head 26 comprises a slider section 26a provided with a magnetic field generating member 26b and is pressed towards the magneto-optical disk surface while being supported by a suspension 27. The magnetic field generating member 26b is composed of a coil and a coil core (not shown specifically), and the suspension 27 is made, for example, of a plate spring. The flying head 26 maintains a constant flying height by making a flying force exerted upwards due to the air flow between the slider section 26a and the magneto-optical disk caused by the spinning disk balance a depressing force exerted downwards by the suspension 27. The flying type magnetic head thus described is adopted in conventional hard disk system, and the flying height in the system is generally submicron order. In the mean time, in case the recording medium is a magneto-optical disk, dust tends to stick on the disk surface more frequently as the magneto-optical disk is transportable, and troubles such as a crash may occur when the head gets close to the disk excessively. Therefore, a flying height of 5 .mu.m to 15 .mu.m which is higher than a flying height in the hard disk system is needed for the magneto-optical disks.
In magneto-optical recording using the flying head 26, the flying head 26 maintains a constant flying height while a magneto-optical disk rotates at a constant speed, however it needs to be supported by some means when the disk starts/stops rotating and is in a static state. For supporting the disk, two methods are listed. (I) Improving the supporting mechanism of the flying head 26 so as to prevent the head from making contact with the magneto-optical disk when the disk is in a static state. (II) Making the flying head 26 slide over or come into contact with the magneto-optical disk when the disk starts/stops rotating and is in a static state.
There is a problem in method (I) that the supporting mechanism becomes extremely complicated. Method (II) called CSS (Contact Start and Stop) method is a common use method in the field of hard disk. In the CSS method, the ability of a magneto-optical disk surface to endure slides is a very important factor. In a conventional hard disk system, a lubricating layer having the excellent ability to endure slides is formed on a recording medium. The lubricating layer is formed by applying, for example fluorocarbon lubricating oil which is a liquid lubricant (usually perfluoropolyether) or PTFE (polytetrafluoroethylene) which is a solid lubricant onto the recording medium.
Additionally, in the CSS method, it is necessary to prevent data from being lost by head crash when the recording medium starts or stops spinning, i.e. when the flying head slides over the recording medium. In the hard disk system, therefore, a flying head is generally allowed to perform contacting and sliding action in an area for CSS which is located inside of the recording area of the disk. With a recording and reproducing device using a magneto-optical disk, it may also be preferable to allow a flying head to perform a sliding action in an area other than the recording area of the disk.
As shown in FIGS. 10(a)(b), a conventionally suggested magneto-optical disk comprises a transparent substrate 21, a recording medium layer 22, a protective resin layer 23, and a center hub 24.
Polycarbonate which can be mass-produced by the injection molding is widely used as the transparent substrate 21. The transparent substrate 21 is provided with guide tracks and guide address grooves 21a whereon track and address information is recorded so as to guide an optical beam used for recording and reproducing information to a given position. In the injection molding, the guide tracks and the guide address grooves 21a are formed by the use of a stamper installed in a metallic mold (not shown) when the transparent substrate 21 is formed. At this time, a stamper presser groove 21b is secondarily formed by a member for fixing the stamper in the metallic mold, so called a stamper presser.
The recording medium layer 22 is formed such that it covers the guide tracks and the guide address grooves 21a, and has multilayer structure (however, shown as a single layer in the figure), for example, a first transparent dielectric film, a thin film made of an alloy of rare earth elements and transition metals that is a magneto-optical recording medium, a second transparent dielectric film, a reflecting film are laminated in that order onto the transparent substrate 21.
The protective resin layer 23 protects the recording medium layer 22 from scratches, dust and oxidization. For materials as the protective resin layer 23, an ultraviolet hardening resin is widely used. The ultraviolet hardening resin has excellent waterproof properties and environment resistance, and the advantages of handling and processing time. The protective resin layer 23 is usually formed by the spin coating method. For example, first the ultraviolet hardening resin is applied to the recording medium layer 22 by spin coating, wherein the resin is dropped onto the outer edge of the stamper presser groove 21b so as to cover the recording medium layer 22. Next, ultraviolet light is irradiated on the resin to harden it.
The center hub 24 is a means for loading a magneto-optical disk into a rotating spindle of a recording and reproducing device. Since the guide tracks/guide address grooves are not coaxial with a center hole 21c of the transparent substrate 21 generally, the center hub 24 absorbs this during the loading. The center hub 24 has a guide hole 24a which is used for loading the disk into the rotating spindle 25 (see FIG. 11(b)) of the recording and reproducing device. Regarding the material for the center hub 24, stainless steel, for example, SUS430 is used because the center hub 24 is often installed into the rotating spindle 25 magnetically.
For the shape of the center hub 24, the one with an outward flange 24b formed on the upper edge thereof shown in FIG. 10(b) is widely used. The outward flange 24b is mounted on one side of the transparent substrate 21, i.e. on the side whereon the recording medium layer 22 is formed, by an adhesive agent, such as epoxy adhesive agent, silicone adhesive agent, ultraviolet hardening resin and double-sided adhesive tape.
FIGS. 11(a)(b) shows the recording and reproducing device for recording and reproducing information on the magneto-optical disk using the CSS method.
The magneto-optical disk of FIGS. 10(a)(b) is magnetically secured to the rotating spindle 25, and a flying head 26 is disposed above the magneto-optical disk.
In the mean time, an optical head 29 having an optical system unit is disposed below the magneto-optical disk. Since the optical head 29 needs to move with the flying head 26 in a radial direction of the magneto-optical disk, a supporting base 28 is connected to the optical head 29. An objective lens 29a of the optical head 29 is located opposite the undersurface of a magnetic field generating member 26b of the flying head 26.
Based on the above arrangement, the following provisionally deduces a range where the flying head 26 is allowed to perform sliding action in the CSS method.
If a 3.5-in. (86-mm) diameter substrate which is most demanded as a consumer product is employed as the transparent substrate 21, the recording area where the guide tracks and the guide address grooves 21a are formed occupies the area between the radii of about 22 mm and 40 mm of the substrate. In order to ensure the magneto-optical recording characteristics in this recording area, it is preferable to for the recording medium layer 22 in the range of radius r.sub.1 ' (FIG. 10(a))=20.5 mm to radius r.sub.2 '=41.5 mm.
The size of a slider 26a of the flying head 26 is determined according to the flying characteristics and the like, and a sliding surface of the slider 26a with respect to the magneto-optical disk needs to be ensured to be about 4 mm in a radial direction and about 5 mm in a circumferential direction of the magneto-optical disk.
If the above sizes are taken into consideration, it is difficult to allow the flying head 26 to slide outside of the recording area of the magneto-optical disk, and therefore the sliding area (CSS area) needs to be located on the inside of the recording area. In order to prevent losing data in the recording medium, it is preferable not to provide the CSS area outside of a radius of 20 mm if the recording area is not formed inside of radius r.sub.1 ', i.e. a radius of 20.5 mm.
Next, disallowing for the outer side face of the rotating spindle 25 making contact with the inner edge of the optical head 29, the innermost permissible CSS area is determined.
The outer diameter of the rotating spindle 25 is determined according to a motor torque and the area of a cramping zone, and it is about 21 mm (10.5 mm in radius) here. In the mean time, the optical head 29 is provided with an actuator (not shown) for actuating an objective lens 29a to execute stable servo of a light beam, and is covered with a housing for protecting optical parts from dust or the like. Therefore, the distance between the center of the beam and the inner edge of the optical head 29 is about 8.5 mm at least. According to the above-mentioned dimensions, to prevent the rotating spindle 25 from making contact with the optical head 29, the central point of the optical beam (i.e. the position of the magnetic field generating means 26b) should not be inside of a 19-mm radius of the substrate.
Therefore, the magnetic field generating member 26b is positioned in the range of a 19 mm radius to a 20 mm radius of the substrate, and thus the area where the flying head 26 executes CSS is restricted to a very limited range.
Further, as aforesaid, the stamper presser groove 21b on the transparent substrate 21 is just secondarily formed by transferring the stamper presser member for securing the stamper to the metallic mold onto the transparent substrate 21. Therefore, the stamper presser groove 21b can not be formed much inside. If the stamper presser groove 21b is formed innermost permissible position, its outer edge is located about 15 mm radius position of the substrate (the width of the stamper presser groove 21b is about 1 mm).
If the adhesive strength and the flatness of the center hub 24 to the transparent substrate 21 are taken into account, the center hub 24 needs a certain area for adhesion, and therefore the hub 24 needs to have, for example, a diameter of about 28 mm. As described above, the CSS area is also restricted by the position of the stamper presser groove 21b and the adhesive area of the center hub 24.
Therefore, the area where CSS action can be executed is only a small range of 15 mm to 20 mm in radius. As a result, the shape of the flying head 26 including the magnetic field generating men, her 26b is restricted, and the degree of freedom of the flying characteristics decreases.
The protective resin layer 23 for protecting the recording medium layer 22 is formed in the shape of a concentric circle from the outer edge of the stamper presser groove 21b. Since the flying head has a flying force due to the air flow between the flying head 26 and the surface of the protective resin layer 23, it is necessary to have the protective resin layer 23 on the portions of the recording medium layer 22, which faces the surface of the slider 26a of the flying head 26 during CSS action. In this case, if the slider 26a deviates from its regular position and a part of the slider 26a enters an inner portion of the substrate which is not covered with the protective resin layer 23, a turbulent air flow is caused, and thereby the flying characteristics are adversely affected.
Even if the slider 26a does not enter the inner portion, turbulence from the air flow may happen as the edge of the slider 26a is very close to the edge of the protective resin layer 23 as shown in FIGS. 11(a)(b), and therefore this is not an ideal state.
The protective resin layer 23 is developed to obtain environmental resistance such as waterproof properties and moisture resistance as its duty is protecting a thin film made of an alloy of rare earth elements and transition metals which is a very easily oxidizable film. However, it fails to obtain the ability to sufficiently endure slides and wear resistance against CSS action, so some problems may arise, i.e. the slider 26a sticks to the protective resin layer 23 and dust is raised due to the abrasion. A protective resin having the ability to endure slides, wear resistance and environmental resistance has being developed. In the mean time, it is confirmed that fluorine contained polymers having the excellent ability to endure slides and wear resistance can not obtain sufficient environmental resistance.
There is an idea of forming a fluorine contained polymer resin onto the protective resin layer 23, however this causes increases in the number of parts and in cost. Additionally, the affinity between two kinds of resin is insufficient, so this is not an effective method.
Further, some magneto-optical disks which can be used with a flying head are manufactured with small physical bumps and pits (hereinafter referred to as texture) on a surface thereof facing the flying head 26 so as to prevent the disk surface from sticking to the surface of the flying head 26. As shown in FIGS. 8(a)(b), the texture is given by pressing a texture tape 31 having small bumps and pits on its surface onto a magneto-optical disk 30 by the use of a tape presser roller 32 while feeding the tape 31 in the direction of arrow C and rotating the disk 30. In this case, the direction of rotation of the disk 30 is substantially parallel with the feeding direction of the tape 31, and therefore the texture is uniformly given to the surface of the disk 30 facing the flying head 26 in the direction shown by the alternate long and two short dashes line of FIG. 9.
However, in order to manufacture the magneto-optical disk 30 with the texture, the tape 31 needs to be pressed onto the disk 30 one by one, causing an increase in cost. Thus, this is not suitable for mass manufacturing. In manufacturing, unnecessary stress may be given onto the disk 30 and dust may stick on the surface, and therefore the quality of the disk 30 may be lowered.

Magneto-optical disk and method of manufacturing the same


A method for HLA typing by amplification of a sample followed by sequence-specific oligonucleotide hybridization with a labelled oligonucleotide probe provides for both positive and negative controls. Control sequences representing known allelic polymorphisms at the locus in question are subjected to the labelled probe along with the sample. This method reduces errors and improves the chance of obtaining a successful tissue match, as is vital in the case of tissue transplants, particularly bone marrow transplants. Probes and PCR primers useful in HLA-DR typing are also provided.

The major histocompatibility complex of humans (denoted HLA--human leukocyte antigen) is a cluster of genes occupying a region located on the sixth chromosome. The polymorphic proteins encoded by the HLA region have been designated HLA-A,--B,-C,-DR,-DQ, and -DP. HLA-A, -B, and -C consist of a single polymorphic chain. HLA-DR, -DQ, and -DP proteins contain two polymorphic chains, designated alpha and beta. These D-region proteins are encoded by loci designated DRA, DRB1, DRB3, DRB4, DQA1, DQB1, DPA1, and DPB1.
The products encoded by the polymorphic HLA loci are most commonly typed by serological methods. Such typing is used in paternity determinations, transplant and transfusion histocompatibility testing, blood component therapy, anthropological studies and in disease association correlation to diagnose diseases or predict susceptibility to diseases. The major drawbacks to such HLA typing, particularly of the Class II loci, are the complexity of the sera and the lack of widespread availability of standard sera necessary to conduct the tests. In addition, since serological typing is based on reactions of sera with the HLA gene products, it is not useful for HLA typing for HLA-deficient individuals in whom HLA products are reduced or absent.
Serological or cellular HLA typing techniques require the presence of detectable levels of HLA proteins on the surface of lymphocytes. In some cases (e.g., HLA-deficient SCID or cellular depletion due to chemotherapy), the levels of the HLA proteins or number of available cells are inadequate to achieve reliable HLA typing. Another limitation of traditional typing methods is the inability to resolve all functionally important HLA alleles. These circumstances have prompted the development of methods for analysis of HLA polymorphism at the genetic level, as described in Bidwell, J., 1988, Immunology Today 9:18-23, and Angelini et al., 1986, Proc. Natl. Acad. Sci. USA, 83:4489-4493.
Non-serological HLA typing methods have been proposed to overcome drawbacks with serological typing. One such method involves the use of DNA restriction fragment length polymorphism (RFLP) as a basis for HLA typing. See Erlich U.S. Pat. No. 4,582,788, issued April 15, 1986. Polymorphism detected by this method is located in both coding and noncoding sequences of the genome. Therefore, RFLP often does not directly measure functional polymorphism, but relies upon linkage disequilibrium between polymorphism in non-coding regions and the coding region. RFLP analysis has been used for typing an HLA-deficient: severe combined immunodeficiency (SCID) patient, but its utility as a routine method is limited by laborious procedures, inadequate resolution of alleles, and difficulty in interpreting data for certain combinations of alleles.
Some RFLP and similar typing methods utilize labelled oligonucleotides to identify specific HLA and DNA sequences. In particular, the use of oligonucleotide probes have been found advantageous in HLA-DR typing in identifying variant genes encoding products which are not detectable serologically. See Angelini et al., above, Scharf et al., Science, Vol. 233, No. 4768, pp. 1076-1078, Cox et al., Am. J. Hum. Gen., 43:954-963, 1988, Tiercy et al., Proc. Natl. Acad. Sci. USA, Vol. 85, pp. 198-202, 1988, and Tiercy et al., Hum. Immunol. 24, pp. 1-14 (1989). Sequence-specific oligonucleotide probe hybridization (SSOPH) can discriminate single base pair mismatches, which is equivalent to detecting a single amino acid polymorphism in HLA proteins.
The polymerase chain reaction (PCR) process, as described in Mullis U.S. Pat. No. 4,683,202, issued Jul. 28, 1987, allows the amplification of genomic DNA and has given rise to more convenient HLA typing procedures. HLA-DQ alpha and HLA-DP alpha and beta genes have been amplified, and then sequenced or hybridized with oligonucleotide probes. See Saiki et al., Nature, Vol. 324, pp. 163-166, 1986, Bugawan et al., J. Immunol., Vol. 141, No. 12, pp. 4024-4030, 1988, and Gyllensten et al., Proc. Natl. Acad. Sci. USA, Vol. 85, pp. 7652-7656, 1988. However, these methods have limited reliability due to the tendency of the probes to bind with greater or lesser specificity depending on the reaction conditions employed. The present invention addresses the latter problem and provides certain specific probes and primers useful in HLA-DR typing.
The invention further concerns the use of HLA typing methods for tissue matching, especially for purposes of tissue transplantation. Bone marrow transplants, in particular, are the treatment of choice for certain immunodeficiency syndromes and hematological disorders. The success of bone marrow transplantation is influenced by the degree of HLA compatibility between recipient and donor. However, aberrant HLA expression sometimes makes it difficult, if not impossible, to determine the patient's HLA type by standard serological and cellular techniques.
Successful bone marrow transplantation depends on the degree of HLA matching between donor/recipient pairs. This results from the physiological role of human lymphocyte antigens in self-restriction of cellular interactions during and immune response. See Schwartz, Ann. Rev. Immunol. 3:27-261, 1985. If polymorphic residues in the HLA proteins are mismatched, the immune system may recognize the cells bearing the mismatched HLA as foreign. The consequences of such mismatching include graft-versus-host disease (GVHD), graft rejection, and failure to reconstitute a competent immune system. See Hows, Bone Marrow Transplantation, 1:259-264. These problems are minimized by selection of HLA-matched siblings as donors. Unfortunately, this option is available for only about 30-40% of patients who could benefit from a bone marrow transplant. In the remaining patients (60-70%), HLA typing with high resolving power is necessary for selection of an optimally matched, unrelated donor.
More than 40 variant HLA-DR beta alleles have been identified among the population, and more are being identified on an ongoing basis. It has been suggested that, within the population, HLAs may exist as numerous combinations of a group of polymorphic sequences, rather than a limited number of discrete alleles. The present invention provides a comprehensive process for HLA typing which overcomes many problems associated with serological typing methods, for example, the requirement for HLA-expression, viable cells, and limitations in resolving certain alleles. The invention further provides a method of tissue matching which has provided superior results in the context of bone marrow transplantation.

The Blood Center Research Foundation, Inc.


A housing includes a 3-D composite structure. The structure includes a flex foil. An antenna trace is provided on a first surface of the flex foil. A shield, which may be a sheet, is positioned on the antenna trace. A resin is molded to the first surface, the shield and the antenna trace. The resultant structure allows for a thin-walled design that can communicate efficiently via wireless signals.

1. Field of the Invention
The present invention relates to field of antennas, more particularly to the field of antennas suitable for use with portable electronic devices.
2. Description of Related Art
The portable electronic device (PED) has increasingly been used to communicate in a wireless manner. One major issue with PEDs is the desire to keep the device small enough to make it easy to carry. Another major issue with PEDs is a desire for an efficient wireless communication system that does not cause the PEDs' battery to drain prematurely. Unfortunately, sometimes these goals are at odds with each other. For example, reducing the size of an antenna in the portable device will tend to decrease the space necessary to package antenna but will also tend to decrease the efficiency and/or effectiveness of the antenna system. Solutions that could help in both areas would be appreciated by users and designers of PEDs.


A surgical instrument includes an outer shaft defining a passageway. An inner shaft is disposed within the passageway and defines a lumen. An expandable structure has a first end coupled to a second end of the outer shaft and a second end coupled to a second end of the inner shaft. The expandable member defines a chamber. A delivery shaft includes a first end positioned within the passageway and a second end positioned within the chamber. The delivery shaft defines a channel configured to deliver a coolant out of an opening in the second end of the delivery shaft and into the chamber to move the expandable structure from an unexpanded configuration to an expanded configuration. A variable exhaust valve is in communication with the passageway and is configured to regulate pressure within the chamber. Systems and methods are disclosed.

Spinal disorders such as degenerative disc disease, disc herniation, osteoporosis, spondylolisthesis, stenosis, scoliosis and other curvature abnormalities, kyphosis, tumor, and fracture may result from factors including trauma, disease and degenerative conditions caused by injury and aging. Spinal disorders typically result in symptoms including pain, nerve damage, and partial or complete loss of mobility.
In an effort to more effectively and directly treat vertebral compression fractures, minimally invasive techniques such as vertebroplasty and, subsequently, kyphoplasty, have been developed. Vertebroplasty involves creating a cavity in a fractured, weakened, or diseased vertebral body. A flowable reinforcing material, usually polymethylmethacrylate (PMMA—commonly known as bone cement), is injected into the cavity. Shortly after injection, the liquid filling material hardens or polymerizes, desirably supporting the vertebral body internally, alleviating pain and preventing further collapse of the injected vertebral body. However, creating the cavity in the fractured, weakened, or diseased vertebral body may involve pain, if untreated.
Traditional cryogenic systems, such as, for example, cryoablation systems can provide denervation capabilities, but the procedures can take a considerable amount of time to perform. Another problem with currently available cryoablation devices is that they are not cost effective. Further, the health care practitioner may have difficulty positioning the tip of the device in the optimal location to get an optimal and consistent clinical result. This may also result in unwanted necrosis of adjacent tissue, which can lead to clinical adverse events including subsequent repair of the necrotic tissue. This disclosure describes an improvement over these prior art technologies.

Cryogenic kyphoplasty instrument and methods of use


An apparatus comprising an encoded pressure signal propagating in a fluid flowing in a conduit. An optical fiber measurement element has a reflector on one end and is disposed around at least a portion of the conduit. A light source injects a second optical signal and a third optical signal propagating in first and second optical fibers, respectively. A delay section is disposed in the second optical fiber. The second optical signal and the third optical signal are directed into the optical fiber measurement element and are reflected back from the reflective end such that at least a portion of the reflected second and third optical signals propagate through the second and first optical fibers respectively to an optical detector. The optical detector senses an interference between the reflected optical signals and outputs a first signal related thereto.

The present disclosure relates generally to the field of telemetry systems for transmitting information through a flowing fluid. More particularly, the disclosure relates to the field of signal detection in such a system.
Sensors may be positioned at the lower end of a well drilling string which, while drilling is in progress, continuously or intermittently monitor predetermined drilling parameters and formation data and transmit the information to a surface detector by some form of telemetry. Such techniques are termed "measurement while drilling" or MWD. MWD may result in a major savings in drilling time and improve the quality of the well compared, for example, to conventional logging techniques. The MWD system may employ a system of telemetry in which the data acquired by the sensors is transmitted to a receiver located on the surface. Fluid signal telemetry is one of the most widely used telemetry systems for MWD applications.
Fluid signal telemetry creates pressure signals in the drilling fluid that is circulated under pressure through the drill string during drilling operations. The information that is acquired by the downhole sensors is transmitted by suitably timing the formation of pressure signals in the fluid stream. The pressure signals are commonly detected by a pressure transducer tapped into a high pressure flow line at the surface. Access to, and penetration of, the high pressure flow line may be restricted due to operational and/or safety issues.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims.

Apparatus and method for detecting pressure signals


Electrochemical methods, preferably the Kolbe coupling reaction, are utilized to create intramolecularly bridged peptides, segments or peptide isosteres which are conformationally restricted and preferably, biologically active. Preferably, the peptide analogues contain methylene groups bridging particular amino acid side chains. Analogues of a variety of peptide hormones, including insulin, insulin-like growth factors, somatostatin, melanocyte stimulating hormone, and the like are prepared by the above methods. Such peptides are useful as agonists or antagonists for treatment of diseases associated with deficiency of the hormone or dysregulation of hormone activity, as well as for mechanistic studies to understand the interactions between peptide hormones and cells.

1. Field of the Invention
The invention in the field of peptide chemistry and medicine relates to novel conformationally restricted biologically active peptides and isosteres, methods for producing such peptides based on oxidative or reductive electrochemical coupling reactions, and methods of using such peptides as hormone agonists or antagonists in treating disease.
2. Description of the Background Art
A. Chemical Stabilization of Peptides
New methods for restricting the secondary structure of peptides and proteins are highly desirable for (1) basic structure-function studies, (2) the elucidation of mechanisms, and (3) the rational design of therapeutically useful conformationally-restricted (or "locked") pharmacophores.
These applications are exemplified by an analogue of eel calcitonin, [Asu.sup.1,7 ]-eel calcitonin, in which .alpha.-aminosuberic acid (Asu) replaces the cysteine residues at positions 1 and 7 (Morikawa, T. et al., Experientia 32:1104-1106 (1976)). This analogue had significant biological activity, leading the authors to conclude that the disulfide bond in calcitonin is not essential for biological activity as long as the specific conformation of the peptide is maintained by an intramolecular bridge.
The purely chemical approaches for restricting secondary structure often requires extensive multistep synthetic work (Olson, G. L., J. Am. Chem. Soc. 112:323 (1990)). An alternative approach involves installing covalent bridges in peptides. However, due to the sensitivity of the peptide backbone and side chains, this method necessitates careful protection/deprotection strategies. For example, this problem occurs in the preparation of polymethylene analogues of [Arg.sup.8 ]vasopressin in which .alpha.-aminosuberic acid (Asu) replaces the cysteine residues at positions 1 and 7 and in which the N-terminal amino group is removed (S. Hase et al., Experientia 25:1239-1240 (1969); S. Hase et al., J. Amer. Chem. Soc. 94:3590 (1972)), yielding deamino-dicarba-Arg.sup.8 -vasopressin.
Covalent linkages can, in selected instances, be established using other chemical methods, for example, by lactam formation between carboxylic acid and amine side chains (J. S. Taylor, Acc. Chem. Res. 23:338 (1990)), or by incorporation of pairs of Cys residues which form a disulfide bridge. However, these approaches suffer from disadvantages which the present invention has been designed to overcome in the creation of new cross-linked peptides.
B. Promotion of Peptide Secondary Structures
A number of approaches have attempted to induce .alpha.-helical secondary structures by the introduction of covalent bridges (Taylor, supra). Most of these procedures require an extensive synthetic effort as they involve constructing several intermediates typically, and require orthogonal protection strategies. The potential of intramolecular bridging in peptide design has become evident from recent studies on lactam-bridged amphiphilic structures (Taylor, supra).
For example, after synthesizing a protected peptide linked to an oxime polystyrene-resin through a glutamyl gamma-carboxyl side chain, an internal nucleophilic cleavage step generates the lactam ring and simultaneously frees the protected peptide. The utility of the lactam-bridging approach is exemplified by a 21-residue peptide prepared from three lactam-bridged units in series which exhibits unusually high .alpha.-helicity. This method is, however, cumbersome, and only allows covalent bridging on the hydrophilic side of an amphiphilic structure.
Another method, involving the metallation of an [i,i+4]-bishistidyl or [i,i+4]-histidyl-cysteinyl peptide, raises the .alpha.-helicity of the unmetallated sequence from about 54% to about 90% in 5 mM sodium borate buffer, pH 6.7 at 4.degree. C. (M. R. Ghadiri et al., JACS 112:9633 (1990); S. Marqusee et al., Proc. Natl. Acad. Sci. USA 84:8898 (1987)). The use of toxic or heavy metals (e.g., Cu.sup.+2, Ru.sup.+2, Cd.sup.+2) to induce helicity however makes the method less likely to find application in the design of clinically useful peptides.
C. Electrochemical Methods in Organic Chemistry
Electrochemical methods have a long history in organic chemistry and have recently found preparative application in the field of peptide synthesis (S. Coyle et al., J. Chem. Soc., Chem. Commun. 980 (1976)), largely limited to the installation or cleavage of protecting groups.
Using electrochemical methods, it is possible to convert selectively compounds with functional groups which differ in half-wave potential by approximately 200 mV (M. Baizer, ed., Organic Electrochemistry, 2nd ed., Dekker, New York (1983)). Chemical methods are not readily capable of the precision and extent of variability of redox potential that is essential for this selectivity.
Electrochemical methods generate reactive intermediates in concentration gradients which are highest near the surface of the electrode, whereas solution methods produce low steady-state levels of the intermediate species in the bulk medium (Baizer, supra). The high concentration of reactive intermediate at the electrode results in greater yields of coupling versus reaction with solvent or electrolyte (L. Eberson et al., In: M. Baizer, supra, p. 889; J. H. P. Utley et al., J. Chem. Soc., Perkin Trans. 2:395 (1978)).
One of the classic methods of organic electrochemistry is the Kolbe synthesis (Eberson et al., supra). In this reaction, the anodic oxidation of carboxylic acids produces hydrocarbon coupling products with the loss of carbon dioxide, often with excellent efficiencies. The reaction proceeds under acidic conditions to give free radical intermediates, which react to form either coupling products R--R, EQU 2 RCO.sub.2 H.fwdarw.2 R..fwdarw.R--R
proton transfer, or disproportionation, while under basic conditions the anodic process generates carbenium ion intermediates, which yields nucleophilic addition products (H. -J. Schafer, Top. Cur. Chem., 152:91 (1990)).
By its nature, an electrochemical process involves molecules interacting at an electrode interface at which heterogeneous electron transfer takes place. After becoming loosely associated or perhaps adsorbed on the surface and being exposed to a sufficiently oxidizing or reducing potential, the most reactive functional group present in the molecule will form a reactive intermediate, such as a radical cation, radical anion, or free radical. Proton transfer may then follow, affecting the net charge of the reactive intermediate.
If a second reactive moiety is available at an appropriate distance and located on the same sterically accessible face of the molecule, coupling of the reactive intermediates will lead to bond formation. In the Kolbe method, two carbon free radicals join to form a new macrocyclic ring containing a carbon-carbon single bond. As long as the current density at the electrode is maintained at a sufficiently high level, the probability of forming two reactive intermediates in the same molecule within the lifetime of the first intermediate is reasonably high (Baizer, supra).
D. Electrochemical Reactions of Amino Acids and Peptides
Few precedents exist for the electrochemical transformation of protected amino acids and peptides under typical conditions common to other kinds of molecules (Schafer, supra). Suberic acid derivatives, from which dicarba analogues of cystine-containing peptides have been obtained chemically (for example, oxytocin, calcitonin and somatostatin) have been prepared by Kolbe electrolysis of protected D-Glu and L-Glu (R. F. Nutt et al., J. Org. Chem. 45:3078 (1980)). There, the electrochemical reaction was performed on amino acids, not on a peptide. Electrochemical reactions of amino acids and peptides have been carried out at platinum, lead or glassy carbon electrodes, in solvents routinely used for organic electrochemistry such as methanol, acetonitrile, tetrahydrofuran, and N,N-dimethylformamide (Baizer, supra).
Classical studies by Takayama of the oxidation of simple amino acids in aqueous acid solutions, revealed that anodic electrolysis yields aldehydes resulting from loss of the carboxylic acid and primary e-amino groups. At alkaline pH, oxidation of amino acids yields nitriles as well as aldehydes, depending on the electrode used (Baizer, supra). These side reactions may have prevented the more widespread use of electrochemical reactions in peptide chemistry.
E. Peptide Hormones and Growth Factors
Peptide hormones are central to the regulation of metabolism, differentiation, proliferation, and growth. The relationship between peptide structure and activity remains best understood from studies of synthetic analogues designed to model biologically functional regions of the peptide. Direct structure-function correlation is rare due to difficulty in preparing crystals of intermediate-sized peptides of quality adequate for X-ray study.
There is a long-standing need in the art for a better understanding of how the conformational structure of a peptide modulates its regulatory role, in order to improve the prospect of treating or ameliorating diseases associated with defects or dysregulation of proteins such as growth factors and peptide hormones. A wide range of diseases, including cancer, osteoporosis, diabetes, and other metabolic defects, await the development of rationally designed agonists and antagonists to native polypeptide hormones. As chemical and electrochemical manipulation of peptide structure becomes a more precise science, the likelihood improves for major strides in the prevention and management of a multitude of diseases related to metabolism, cell development and differentiation.
1. Insulin and Insulin-Like Growth Factors
The development and application of insulin for the treatment of diabetes mellitus, the first example of a peptide pharmaceutical, is one of the great medical achievements of the twentieth century. Insulin is a 6 kDa peptide hormone made up of two chains, A and B, linked by a pair of disulfide bonds, and is derived biosynthetically from proinsulin which consists of A and B chains coupled by a third segment, designated C.
Glucose regulation, which is tightly correlated with normal development, is known to be associated also with other insulin-like peptide hormones (P. D. Gluckman, Oxford Rev. Reprod. Biol. 8:1 (1986)). Specific polypeptide hormone growth factors, like insulin, are now known to be critical in development (S. Heyner et al., In: Growth Factors in Mammalian Development, I. Y. Rosenblum et al. (eds), CRC Press, Boca Raton, Fla., 1989, pp. 91-112). The insulin-like growth factors, IGF-I (A. Ullrich et al., EMBO J. 5:2503 (1986)) and IGF-II (E. Rinderknecht et al., FEBS Lett. 89:282 (1978))), have extensive sequence homology with proinsulin. Computer modelling purports a similarity in the tertiary structures of IGFs and insulin (T. L. Blundell et al., Nature 287:781 (1980); T. L. Blundell et al., Feder. Proc. 42:2592 (1983)). X-ray crystal data are not yet available for IGF-I or IGF-II. All of these peptides have overlapping functions with differing activities at each other's receptor.
Insulin has also been found to play a central role in growth regulation as well (D. S. Straus, Endocrinol. Rev. 15:356 (1984)). Receptors which bind insulin and IGFs have been detected in early mammalian embryos. Both deficits and excesses of insulin have been correlated with birth defects (D. E. Hill, In: The Diabetic Pregnancy: A Perinatal Perspective, R. Merkatz et al., (eds) Grune & Stratton, New York, 1979, pp. 155-156). Nanomolar concentrations of insulin and IGF-I induce myoblast differentiation in chick embryos (C. Schmidt et al., FEBS Lett. 116:117 (1983)). Insulin also enhances neuronal proliferation (Garofalo, R. et al., Molec. Cell. Biol. 8:1638 (1988)). IGF-I and insulin are both able to stimulate RNA and protein synthesis (U. Widmer et al., Acta Endocrinol. 108:237 (1985)). Abnormally high levels of insulin or proinsulin have been found to cause abnormal growth, teratogenic effects, and death in chick embryos, possibly by interaction at the IGF receptor (F. DePablo et al., Diabetologia 28:308 (1985)).
2. Melanocyte Stimulating Hormone
Melanocyte stimulating hormone (MSH) is produced in the pituitary, and controls skin melanin dispersion (T. K. Sawyer et al., Am. Zool. 23:529 (1983); E. Schroder et al., In: The Peptides: Synthesis, Occurrence, and Action of Biologically Active Polypeptides, vol. 2, Academic Press, New York, pp. 165ff (1966)). The alpha, beta, and gamma forms of MSH are derived from the precursor proopiomelanocortin, which is also the source of adrenocorticotrophic hormone (ACTH) and the opioid peptide .beta.-endorphin. MSH is thought to play a role in fetal growth and development (Sawyer et al., supra). For example, MSH has been detected in human and other mammalian fetal pituitary tissue (A. J. Kastin et al., Acta Endocrinol. 58:6 (1968)), and postulated to be central to the timing of human birth (R. E. Silman et al., Nature 260:716 (1976)). Fetal MSH is also important for prenatal growth (G. J. Boer et al., Applications of Behavioral Pharmacology in Toxicology, Zbinden et al. (eds), Raven Press, New York, p. 251, 1983). Removal of the fetal rat pituitary prevents the normal growth spurt between days 19 and 21, which can only be restored by exogenous administration of MSH. In addition, treatment with antibodies to MSH stunts the growth during this same interval. The importance of restricted conformation to function in MSH, as has been shown for other cyclic lactam analogues (see below), makes it a good system in which to apply the approaches of the present invention. To date, effective MSH receptor agonists and antagonists have depended on the use of D-amino acids, as in [Nle.sup.4,D-Phe.sup.7 ]-.alpha.-MSH (Schroder et al., supra; W. M. Westler et al., J. Amer. Chem. Soc. 110:6256 (1988)).
3. Cholecystokinins
The C-terminal peptide of cholecystokinin, known as CCK-8 (residues 26-33), is a hormonal regulator of pancreatic secretion and gallbladder contraction, as well as a neuropeptide (Charpentier, B. et al., Proc. Natl. Acad. Sci. USA 85:19681972 (1988)). Cyclization of the CCK-8 analogue, Boc-[2-aminohexanoic acid]CCK-(27-33), has been carried out using a fragment condensation method (Charpentier, B. et al., J. Med. Chem. 30:962-968 (1987)) in conventional chemical peptide synthesis. Two cyclic compounds having an internal amide bond between the side chain amino group of D-Lys-29 and either the .beta.-carboxyl group of a D-Asp-26 residue or the .alpha.-carboxyl group of a D-Glu-26 residue were shown to have high affinity and selectivity for guinea pig brain CCK receptors.

Conformationally restricted biologically active peptides, methods for their production and uses thereof


The embodiments of the disclosure provide a radio resource control (RRC) connection recovery method and apparatus and a terminal. The method includes that: a terminal receives a paging message triggered by a first node or a second node and determines whether downlink data of a master node (MN) side arrives or downlink data of a secondary node (SN) side arrives based on first information included in the paging message; and the terminal sends an RRC connection recovery message to a third node, the RRC connection recovery message including second information and the second information being configured for the third node to determine whether the third node is an MN or an SN to correspondingly execute a key and a SRB recovery process on the MN side or a key and a SRB recovery process on the SN side.

a terminal may access a network through two links based on a Dual Connectivity (DC) architecture. A DC network may include a master node (MN) and a secondary node (SN). On the other hand, for reducing air interface signaling, rapidly recovering a wireless connection and rapidly recovering a data service, a new RRC state, i.e., an RRC_INACTIVE state, is defined in a 5th Generation (5G) network environment. This state is different from an RRC_IDLE state and an RRC_ACTIVE state. A terminal is needed to execute an RRC connection recovery process to enter the RRC ACTIVE state from the RRC_INACTIVE state.
In a Multi-Radio Access Type (RAT) DC (MR-DC) mode, due to existence of bearers configured by two nodes, RRC connection recovery in a DC mode is not supported. For MR-DC, an MN and an SN may adopt different RATs. Due to coverage discontinuity, a terminal may reside on the RAT that the SN adopts. In such case, how to recover an RRC connection is a problem to be solved.

Method and apparatus for recovering RRC connection, and terminal

GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD.


A semiconductor device includes a gate structure on a channel region of a semiconductor substrate adjacent to a source/drain region therein and a surface insulation layer directly on the source/drain region of the substrate adjacent to the gate structure. The device further includes a spacer on a sidewall of the gate structure adjacent to the source/drain region. A portion of the surface insulation layer adjacent the gate structure is sandwiched between the substrate and the spacer. An interface between the surface insulation layer and the source/drain region includes a plurality of interfacial states. Portions of the source/drain region immediately adjacent the interface define a carrier accumulation layer having a greater carrier concentration than other portions thereof. The carrier accumulation layer extends along the interface under the spacer. Related methods are also discussed.

A conventional MOS transistor may include a gate pattern formed on a semiconductor substrate, a channel region defined below the gate pattern, and source/drain regions formed in the semiconductor substrate on both sides of the channel region. Generally, the source/drain regions may include a lightly doped drain (LDD) structure for example, to reduce and/or suppress hot carrier effects. More specifically, by lowering the impurity concentration of the source/drain regions adjacent to a channel region, the electric field concentration may be reduced, which may suppress hot carrier effects.
A method for forming a conventional MOS transistor will now be described with reference to FIG. 1. As illustrated in FIG. 1, a gate pattern 5 is formed on a semiconductor substrate 1. The gate pattern 5 includes a gate oxide layer 2, a gate electrode 3, and a capping pattern 4, which may be sequentially stacked. The substrate 1 below the gate pattern 5 is defined as a channel region. Using the gate pattern 5 as a mask, impurities may be implanted at a relatively low dose to form a lightly doped layer 6.
A gate spacer 7 may be formed on opposing sidewalls of the gate pattern 5. Using the gate pattern 5 and the gate spacer 7 as a mask, impurities may be implanted at a relatively high dose to form a heavily doped layer 8. Since the lightly doped layer 6 may have a shallower junction than the heavily doped doping layer 8, the source/drain region 9 formed at both sides of the channel region may have a lightly-doped drain (LDD) structure, including the lightly and heavily doped layers 6 and 8.
In recent years, there has been demand for semiconductor devices with increasingly high operating speeds. As such, MOS transistors with increased on-current have been provided. However, MOS transistors including the above LDD structure may suffer from decreased on-current, due to the relatively high resistance of the lightly doped layer 6.
Many efforts have been made to increase on-current in MOS transistors. For example, the lightly doped layer 6 may be doped to have an impurity concentration similar to that of the heavily doped layer 8. However, as the impurity concentration of the lightly doped layer 6 increases, the junction depth of the lightly doped layer 6 may increase, due to diffusion of the impurities. Thus, short channel effects may become severe enough to degrade characteristics of the MOS transistor.

Semiconductor device including carrier accumulation layers


A semiconductor device and a manufacturing method thereof which is suited for forming both a transistor for a memory cell and a transistor for a high voltage circuit part on one semiconductor substrate, and moreover, has little deterioration of an electric characteristic in the structure that a sidewall insulating film in a shared contact plug part is removed is provided. An active layer is formed by performing an additional impurity injection on a part where a sidewall insulating film is removed in a forming portion of a shared contact plug. An insulating film is laminated in a high voltage circuit part and a sidewall insulating film of wide width is formed. According to this, a forming width of a sidewall insulating film can be made small in a MOS transistor for a memory cell part, and a forming width of a sidewall insulating film can be made large in a MOS transistor for a high voltage circuit part. Thereupon, in the high voltage circuit part, a source/drain active layer can be formed in the position more distant from a gate electrode.

1. Field of the Invention
The present invention relates to a semiconductor device which includes MOS (Metal Oxide Semiconductor) transistors, wirings etc. and a manufacturing method thereof.
2. Description of the Background Art
Conventionally, a semiconductor device which includes MOS transistors, wirings etc. is manufactured by performing an impurity injection in a semiconductor substrate and forming an insulating film and a conductive film on a surface of the semiconductor substrate.
Information of conventional art documents which relates to the invention of the present application is described below.
Japanese Patent Application Laid-Open No. 2000-353803
Japanese Patent Application Laid-Open No. 2002-231821
K. Imai et al., xe2x80x9cCMOS device optimization for system-on-a-chip applicationsxe2x80x9d, (U.S.A.). IEDM, 2000. p. 455-458
H. Watanabe et al., xe2x80x9cNovel 0.44 xcexcm2 Ti-Salicide STI Cell Technology for high-Density NOR Flash Memories and Performance Embedded Applicationxe2x80x9d, (U.S.A.). IEDM, 1998. p. 975-976
It is general that an active layer which becomes a source/drain region of a MOS transistor is composed of an extension region and a region whose impurity concentration is higher than that of the extension region. The high impurity concentration region is formed by forming a sidewall insulating film on a side of a gate electrode after forming the extension region and performing an impurity injection with the gate electrode and the sidewall insulating film as a mask. Thus, a position where the high impurity concentration region is formed is determined by a forming width of the sidewall insulating film in a channel direction of the transistor.
Generally, with regard to a MOS transistor which is used for a memory cell in a SRAM (Static Random Access Memory) etc., the high impurity concentration region is widely formed so that it is distributed close to the gate electrode. It is performed by reason of reducing a resistance value in the source/drain region. Therefore, the forming width of the sidewall insulating film is arranged to be a small value.
In the meantime, with regard to a MOS transistor which is used for a high voltage circuit part, the high impurity concentration region is formed distant from the gate electrode as compared with a case of the MOS transistor for the memory cell. It is because, with regard to the high voltage circuit part, it is desirable that the high impurity concentration region is distant from the gate electrode to prevent a phenomenon, that is so-called GIDL (Gate Induced Drain Leakage) generation (a phenomenon that when a high voltage is applied to a gate, atoms which are stably existent in a drain region separates into holes and electrons, and thus a leakage current flows between a drain and a substrate). Therefore, the forming width of the sidewall insulating film is arranged to be a large value.
In the meantime, there is a case that both the MOS transistor for the memory cell and the MOS transistor for the high voltage circuit part are formed on one semiconductor substrate. In this case, it is general that both types of the MOS transistors are formed in the same step without adding the number of steps, and the forming widths of the sidewall insulating films are determined to be identical. In other words, the forming width of the sidewall insulating film is arranged to be a value fitting to either of the MOS transistors. Generally, in order to give priority to preventing a drain voltage breakdown in the high voltage circuit part, the forming width of the sidewall insulating film is determined to suit to the MOS transistor for the high voltage circuit part.
However, essentially as described above, it is desirable to make small the forming width of the sidewall insulating film in the MOS transistor for the memory cell and make large the forming width of the sidewall insulating film in the MOS transistor for the high voltage circuit part.
Moreover, there is a case that the active layer such as the source/drain region etc. which is formed by performing the impurity injection into the semiconductor substrate and the wiring which is formed near the active layer on the semiconductor substrate are short-circuited by a shared contact plug. In that time, as described in FIG. 23 of the patent document No. 2000-353803, there is a case that the sidewall insulating film formed on a side of the wiring is removed.
When the sidewall insulating film is removed as described above, a problem arises as described below. In other words, under the sidewall insulating film, the active layer has a low impurity concentration caused by a low injection rate of the impurity, and thus a value of a contact resistance between that part of the active layer and the shared contact plug is liable to become high. Moreover, a part of the semiconductor substrate which is under the sidewall insulating film is liable to be damaged caused by an etching when the sidewall insulating film is removed, therefore, a PN junction between the active layer and the semiconductor substrate is not definitely formed, and a junction leakage current often increases.
It is an object of the present invention to provide a semiconductor device and a manufacturing method thereof which is suited for forming both a transistor for a memory cell and a transistor for a high voltage circuit part on one semiconductor substrate, and moreover, has little deterioration of an electrical characteristic in the structure that a sidewall insulating film in a shared contact plug part is removed.
According to the first aspect of the present invention, a manufacturing method of a semiconductor device includes the following steps (a) to (f).
(a) A conductive film is formed on a semiconductor substrate.
(b) The conductive film is patterned by a photolithography technique and an etching technique.
(c) A first active layer is formed by performing an impurity injection in proximity of the patterned conductive film in a surface of the semiconductor substrate.
(d) An interlayer insulating film is formed on a surface of the semiconductor substrate.
(e) A contact hole in which both the first active layer and the conductive film are exposed is formed in the interlayer insulating film by a photolithography technique and an etching technique.
(f) A second active layer is formed by performing an impurity injection on a surface of the semiconductor substrate which is exposed in the contact hole.
The contact hole in which both the first active layer and the conductive film are exposed is formed, and the second active layer is formed on the surface of the semiconductor substrate which is exposed in the contact hole. By reason of forming the second active layer, when a conductive substance is filled in the contact hole and a shared contact plug which conducts to both the first active layer and the conductive film is formed, a contact resistance between the shared contact plug and the first active layer can be reduced than ever.
According to the second aspect of the present invention,
a semiconductor device includes a semiconductor substrate, a first transistor and a second transistor.
The first transistor includes a first gate electrode which is formed on the semiconductor substrate, a first sidewall insulating film which is formed on a side of the first gate electrode on the semiconductor substrate and first source/drain active layers which are formed in the semiconductor substrate.
The second transistor includes a second gate electrode which is formed on the semiconductor substrate, a second sidewall insulating film which is formed on a side of the second gate electrode on the semiconductor substrate and second source/drain active layers which are formed in the semiconductor substrate.
Layers of an insulating film which composes the second sidewall insulating film are more in number than layers of an insulating film which composes the first sidewall insulating film, and accordingly, a width of the second sidewall insulating film in a channel direction of the second transistor is larger than a width of the first sidewall insulating film in a channel direction of the first transistor.
By reason that the width of the second sidewall insulating film is larger than the width of the first sidewall insulating film, in the second transistor, the source/drain active layer can be formed in the position more distant from the gate electrode as compared with the first transistor. Thus, while using the second transistor for a high voltage circuit part and the first transistor for a memory cell, a semiconductor device which is suited for forming both the transistor for the memory cell and the transistor for the high voltage circuit part on one semiconductor substrate can be obtained.
These and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.

Semiconductor device and manufacturing method thereof


An air bag device includes an air bag, a cover concealing the air bag and including a side wall formed with a groove, and a base plate supporting the air bag and including a peripheral wall that faces the inner periphery of the side wall of the cover and is formed with a slit corresponding to the groove of the cover. A belt is disposed along the outer periphery of the side wall of the cover, and includes a holder cooperating with the peripheral wall of the base plate to hold the side wall of the cover. The belt further includes engagements that are engaged with the groove of the side wall of the cover and the slit of the peripheral wall of the base plate and include each an engaging portion engaged with the inner periphery the peripheral wall of the base plate.

The present invention relates to air bag devices having an air bag and a cover disposed thereon.
Air bag devices are known conventionally, which are arranged, for example, at a boss of a steering wheel of a motor vehicle to absorb impact on a driver upon collision. The air bag device comprises an inflator for jetting out gas, an air bag arranged in fold, a cover disposed on the air bag, and a base plate having the inflator, the air bag, and the cover mounted thereon. The air bag device is constructed such that when detecting collision of the motor vehicle, i.e. its sudden deceleration over a predetermined value, the inflator jets out gas instantaneously to distend the air bag. Its pressure serves to break the cover along a predetermined tear line for door-like extension, from which the air bag protrudes to develop in front of the driver.
The cover includes a covering portion for covering the folded air bag and a mounting portion that protrudes downwardly from the covering portion, having substantially a box-like form with an opening on the lower side. Likewise, the base plate includes a base portion having the inflator and the air bag mounted thereon and a support portion that protrudes downwardly from the base portion, having substantially a box-like form with an opening on the lower side. With the mounting portion engaged with the outer periphery of the support portion, the mounting portion, the support portion, etc. are fixed to each other by a number of rivets, obtaining the cover fixed to the base plate.
However, the structure using a number of rivets for fixing the cover is difficult to reduce a manufacturing cost due to the increased number of component parts and complicated assembling process.
JP-A 6-298031 proposes another structure for fixing the cover, wherein the mounting portion of the cover and the support portion of the base plate are formed cylindrically. With the mounting portion engaged with the outer periphery of the support portion, a fastening band is tightly wound on the outer periphery of the mounting portion, obtaining the mounting portion held between the support portion and the band.
However, the structure using the fastening band is difficult to control the fastening strength due to the need of applying an appropriate fastening force for assembling the cover to the base plate. Further, due to the fact that no means are provided to position the fastening band, sure fixing of the cover needs to fasten the band in holding it in an accurate position, resulting in complicated fastening work. Furthermore, the use of the fastening band is not available except the cover and the base plate having a rounded section such as a circle, resulting in limited form of the cover and the base plate.
JP-A 6-144139 proposes still another structure for fixing the cover, wherein with a pair of substantially C-shaped plates disposed on the outer periphery of the mounting portion of the cover engaged with the support portion of the base plate, the support portion, the mounting portion, and the plates are integrally mounted by a number of rivets. Each plate is formed with claws at the lower end, which are engaged with the support portion of the base plate and the mounting portion of the cover for positioning.
However, the structure using the claws has a problem that the claws, arranged for positioning, cannot support the mounting portion against the distending pressure of the air bag, requiring a number of rivets for fixing the air bag, resulting in a difficult reduction in a manufacturing cost due to the increased number of component parts and complicated assembling process.
As described above, the structure using the fastening band needs not only to apply an appropriate fastening force for assembling the cover to the base plate, but to fasten the band in holding it in an accurate position, resulting in complicated fastening work and limited form of the cover and the base plate. On the other hand, the structure using the claws has a problem that the claws, arranged for positioning, cannot support the mounting portion against the distending pressure of the air bag, requiring a number of rivets for fixing the air bag, resulting in a difficult reduction in a manufacturing cost due to the increased number of component parts and complicated assembling process.
It is, therefore, an object of the present invention to provide air bag devices that enable easy and secure fixing of the cover to the base plate.