An apparatus and method for use is described which permits real time monitoring of build-up of particulate contamination in a wafer processing chamber. The apparatus is capable of monitoring particle build up in regions of a processing chamber which are not accessible by traditional optical particle scanners. An accelerometer is fastened to a body in the chamber upon which particulates deposit. The body is subjected to vibrations and produces a vibration signal which is detected by the accelerometer. The signal is processed to form a frequency spectrum of vibration amplitudes. Frequencies in a selected band are directly proportional to the particulate build up on the body. The invention is applied to a wafer annealing tool with a rotatable platform wherein particles deposit on a support body under the wafer. The method and apparatus have been shown to be reliable and accurate as well as cost effective and easily implemented.

(1) Field of the Invention
The invention relates to processes for the manufacture of semiconductor devices and more particularly to a method and apparatus for measuring particulate contamination in an enclosed chamber during wafer processing.
(2) Background of the Invention and Description of Previous Art
A conventional way of detecting particle contamination in a wafer processing chamber is by using an in-situ particle monitor (ISPM) installed in the exhaust line of the chamber. The working principle of most ISPM involves counting the number of particles that pass through a light or laser beam. Such a method is not effective if there is 'blind spot' in the chamber which prevents efficient flow of purge gas to the exhaust line. Particles tend to build up in these 'blind-spots' while the ISPM still detects and reports a low particle count. The build-up of particles in these blind spots may eventually contaminate wafers processed in the chamber. FIG. 1 show the cross-section of a typical annealing chamber 10 having an upper housing 12 containing an array of quartz/halogen lamps 14 in a reflector unit 15 and a lower body 16, isolated from the upper body by a seal 17. The lower body 16 houses a rotatable support ring 18 having an opening with a recess onto which a wafer 20 is placed for processing. In use annealing gases are flowed through the chamber through the gas ports 25. The chamber 10 may also be fitted with a vacuum port (not shown). The support ring 18 is typically formed of silicon carbide and is supported on a fused quartz cylinder 22. In use, the support ring is rotated at a slow speed by a motor (not shown). Particulates, generated by the drive mechanism, in particular by the action of the bearings, build up in the regions 24 between the support ring and the lower body and can, in time, migrate onto the wafer's backside causing contamination thereon. Left in place, these particulates can migrate onto the wafers top side causing yield losses. Yield losses can occur not only in the chamber wherein the particles are initially deposited but, by transfer of the contaminated wafer to subsequent processing tools. Both the subsequent tools and the wafers processed therein can become contaminated. Migration of wafer backside contamination to device areas can occur as a result during subsequent processing or during physical examination of wafer backside. The regions 24 are considered as 'blind spots' because they cannot be observed by conventional optical sensors such as ISPMs. Blind spots occur in most wafer processing chambers.
The annealing chamber shown in FIG. 1 is used here primarily to illustrate regions in a typical processing chamber where particulates accumulate and which are not easily observable in real time using the traditional optical means. Other chamber types which have mechanical devices which operate during processing, in particular wafer rotation mechanisms, may include CVD (chemical vapor deposition) chambers, RIE (reactive ion etching) and plasma etching chambers, ion implant chambers, and PVD (physical vapor deposition) chambers (evaporators). Controlling particle contamination on the backside of a wafer by early detection is important to effective yield management.
Wafer backside contamination can also cause yield problems associated with lithographic depth of focus. If the wafer, more specifically the wafer's exposure field, cannot be maintained in a fully planar position during lithography exposure due to wafer backside contamination, the lithography tool cannot expose the entire wafer uniformly causing wafer to be scrapped. Therefore, it would be advantageous to have a method and apparatus for real-time monitoring of particle contamination in a wafer processing chamber that will take into account the presence of particle build up in 'blind-spots' of the chamber and thereby providing an early signal of the onset of backside contamination problems before expensive yield losses occur.
Hiatt, et. al., U.S. Pat. No. 5,963,315 discloses a method for measuring and monitoring backside contamination on semiconductor wafers while the wafer is still in the processing tool. The wafer is removed from the chuck, which secures it during processing, by a robotic arm. The arm then positions the wafer over a laser-detector arrangement and the exposed backside is scanned for particulate contamination. At completion of the scan, the robotic arm transports the wafer to the next location which may be into another processing chamber or into a load-lock for removal from the processing tool. Aqui, et. al., U.S. Pat. No. U.S. 5,347,138, provide real-time particle monitoring in a processing tool by passing a externally focused laser beam through a shielded plasma to an external detector, using windows in the tool. Moriya, et. al., U.S. Pat. No. 6,115,120, Ashan, et. al., U.S. Pat. No. 5,481,357, Bonin, et. al., U.S. Pat. No. 5,943,130, and Harwell, et. al., U.S. Pat. No. 6,032,544 teach similar procedures wherein external optical beams are focused and pass through flowing gases within a process chambers. Optical sensors then determine particulate intensity by measuring the light scattering caused by the particulates in the beam. Baier, U.S. Patent Application Publication No. 2004/0173310 A1 detects and monitors sidewall flaking in a plasma chamber by measuring the intensity of light scattered by polymer film materials deposited on the wall surface of plasma chamber. Chanayem, U.S. Pat. No. 5,271,264 discloses a method of in-situ particle monitoring in a plasma etching chamber by positioning an ISPM downstream of the chambers vacuum pump.
Koury, et al., U.S. Pat. No. 5,814,733 discloses a method of using an accelerometer for real time monitoring of vibrations in a wafer probe tester produced by various mechanical components such as fans and motors, which cause probe contact errors and otherwise produce inconsistent and erroneous electrical test results.
Although the final objective of the cited prior art is similar, all of the cited methods are limited to detecting particulates in regions of the processing tool which an optical beam/sensor arrangement can observe in real time. None of the optical methods are capable of real time monitoring of particle build up in the so-called 'blind-spot' regions of a processing chamber which cannot be practically fitted with optical detection equipment. It would therefore be desirable to have a non-optical method and apparatus for real-time monitoring of particle contamination buildup in a wafer processing chamber. The method and apparatus taught by the present invention not only accomplishes this goal but is also simpler, cost effective, and easier to implement than the optical methods and is capable of sensing and reporting conditions in blind spot regions.

Real time monitoring of particulate contamination in a wafer processing chamber


A system for implementing a super-user-compatible privilege security policy on a computer operating system is disclosed. The system includes a kernel for enforcing a security policy on processes, based on privileges. The system also includes a privilege model that interfaces with the kernel and implements a framework in which super-user based processes and privilege based processes transparently interface with the kernel. The privilege model includes several privilege sets associated with each process, a privilege awareness property state associated with each process, the property state indicating whether or not a process is privilege aware, and a software module for automatically modifying the privilege sets and the property state, on a per process basis, based on individual process behavior.

The present invention relates to the field of computer operating system security policy implementation. Specifically, embodiments relate to providing a privilege framework in which traditional super-user based processes and traditional privilege based processes can coexist.
The traditional security policy model for Unix-based operating systems has only one mechanism for distinguishing between privileged processes and unprivileged processes. This mechanism is the association of all privileges to a user having a userid of zero, also known as a "super-user." A basic flaw of this model is the all-or-nothing approach. An application which needs a single special privilege, such as a web server binding to a specific reserved port, a program running in the real-time scheduling class, a server to keep the clock synchronized, etc., all need to run or start with a userid of zero, e.g., as "root".
In the traditional super-user model, a user with userid=0 can read and write to all files. In a traditional privilege model, one process may have the ability to read a file, but not to write to the file, for example. The privileges can be split into sub-privileges. In an operating system, one can typically have either super-user (userid=0), as with traditional Unix operating environments, or traditional privileges.
There have been attempts by Unix vendors to combine the models, but to date, the typical model is based on allowing a system administrator to decide whether the system is to use the traditional super-user model (userid=0) or the traditional privileges model or some combination of both.

Method and system for implementing super-user-compatible privileges


A sliding roof system includes a frame, a cover movable into a ventilation position, and a lateral safety screen. When the lateral safety screen is in a covering position, the lateral safety screen extends to lie to a side of and underneath the cover. The lateral safety screen is attached to the frame.

The invention relates to a sliding roof system comprising a frame, a cover that can be moved into a ventilation position, and a lateral safety screen which in a covering position extends underneath the cover.
With known sliding roof systems a cover can expose a roof opening, fully or partially, due to being movably mounted on a guide rail provided on side edges of the roof opening that form part of the frame. Further, a ventilation position can be established by raising a rear end of the cover.
A body part of a vehicle occupant could become pinched as a gap between the cover and the roof decreases in size as the cover moves to a closed position. This could occur for instance if the vehicle occupant puts a hand on an edge of the roof opening in order to get refreshed by a flow of fresh air. In order to prevent this from occurring, pinch protection devices are installed in known sliding roof systems, which identify jammed objects and halt closing movement of the cover. These pinch protection devices traditionally operate with the aid of measuring current in a drive motor of the cover, by measuring rotational speed of an armature, or by switching mats or safety contact strips, for example.
Devices in the form of safety screens are also known, which cover a gap between a wind deflector and the guide rail at a front edge of the roof opening, and which provide a safe pinch protection when the cover is closed starting from a partially or fully open position. These known devices, however, only exhibit a limited effectiveness when the cover is closed starting from the ventilation position. Due to leverage existing in this situation, known pinch protection devices do not always respond as desired.
This is why some sliding roof systems include a safety screen that makes a lateral gap between the cover and roof inaccessible. From DE 34 42 616 A1 there is known a strip-shaped safety screen and from DE 33 08 065 A1 there is known a safety screen shaped like a concertina. Both of these safety screens are firmly coupled with the cover and thus can only be used with sliding/tilting roofs in which the cover moves under a firm roof sheet during retraction, and cannot be used with spoiler roofs in which the cover moves above the firm roof sheet.
It is therefore the objective of the invention to provide a sliding roof system that ensures a pinch protection when the cover is closed starting from the ventilation position, and which can be employed with a spoiler roof.


A read-to-write-back transaction may allow I/O subsystems (or other devices) to perform a write to a portion of a cache block without gaining ownership of the cache block and requiring that it respond to foreign requests for the cache block. In response to an I/O subsystem initiating a read-to-write-back transaction, the device owning the cache block conveys the cache block to the I/O subsystem, and the I/O subsystem may perform partial or entire writes to the cache block. Subsequently, the cache block is written back to a memory subsystem from the I/O subsystem. The system is implemented such that these operations may be viewed logically as an atomic operation with respect to other coherence transactions to the same cache block, and thus the I/O subsystem need not become the owner of the cache line during performance of the read-to-write-back transaction. Accordingly, the design of the I/O subsystem may be simplified while still providing the overall functionality as supported by the read-to-write-back transaction.

1. Field of the Invention
This invention relates to the field of multiprocessor computer systems and, more particularly, to coherency protocols employed within multiprocessor computer systems having shared memory architectures.
2. Description of the Related Art
Multiprocessing computer systems include two or more processors that may be employed to perform computing tasks. A particular computing task may be performed upon one processor while other processors perform unrelated computing tasks. Alternatively, components of a particular computing task may be distributed among multiple processors to decrease the time required to perform the computing task as a whole.
A popular architecture in commercial multiprocessing computer systems is a shared memory architecture in which multiple processors share a common memory. In shared memory multiprocessing systems, a cache hierarchy is typically implemented between the processors and the shared memory. In order to maintain the shared memory model, in which a particular address stores exactly one data value at any given time, shared memory multiprocessing systems employ cache coherency. Generally speaking, an operation is coherent if the effects of the operation upon data stored at a particular memory address are reflected in each copy of the data within the cache hierarchy. For example, when data stored at a particular memory address is updated, the update may be supplied to the caches that are storing copies of the previous data. Alternatively, the copies of the previous data may be invalidated in the caches such that a subsequent access to the particular memory address causes the updated copy to be transferred from main memory.
Shared memory multiprocessing systems generally employ either a snooping cache coherency protocol or a directory based cache coherency protocol. In a system employing a snooping protocol, coherence requests are broadcast to all processors (or cache subsystems) and memory through a totally ordered address network. Each processor "snoops" the requests from other processors and responds accordingly by updating its cache tags and/or providing the data to another processor. For example, when a subsystem having a shared copy of data observes a coherence request for exclusive access to the block, its copy is typically invalidated. Likewise, when a subsystem that currently owns a block of data observes a coherence request to that block, the owning subsystem typically responds by providing the data to the requestor and invalidating its copy, if necessary. By delivering coherence requests in a total order, correct coherence protocol behavior is maintained since all processors and memories observe requests in the same order.
The other standard approach to cache consistency uses a directory-based protocol. In systems that implement a directory-based protocol, both the address network and the data network are typically point-to-point, switched networks. When a processor requests a cache block, the request is sent to a directory which maintains information regarding the processors that have copies of the cache block and their access rights. The directory then forwards the request to those processors which must change their access rights and/or provide data for the request (or if needed, the directory will access the copy of the cache block in memory and provide the data to the requester). Since there is no way of knowing when the request arrives at each processor to which it is sent, all processors that receive the request must typically acknowledge reception by providing data or sending an acknowledge (ACK) message to either the requestor or the directory, depending on the protocol.
Shared memory microprocessing systems often include I/O (input/output) devices or other device types that do not cache data. Because they do not cache data, the interfaces to such devices may be simplified since they need not respond to the various coherence transactions that may be generated, as dictated by the particular coherence protocol. To allow an I/O device to perform a read operation to a cache block, some systems support read stream transactions in which an entire cache block is conveyed from a caching device to the I/O device. Similarly, to allow an I/O device to perform a write operation to a cache block, such systems may further support write stream transactions in which an entire cache block is sent from the I/O device and written within the caching device.
Although a system may allow I/O devices or other non-caching devices to read or write entire cache blocks, such systems typically do not allow an I/O device to obtain a cache block, make partial writes to the blocks and to subsequently write the modified cache block back to memory. Although various performance improvements could be attained, implementation of such functionality could also add significant complexity to the I/O device since the I/O device may be required to respond to foreign coherence transactions while it owns the cache block.

This patent is subject to a terminal disclaimer.

Computer system supporting read-to-write-back transactions for I/O devices


A seating unit includes a seat, a back, a base, and a motion control having a plurality of flexible supports for operably supporting the seat and back on the base. The flexible supports are movable in a generally fore-to-aft direction but stiff in a generally vertical direction, and further the flexible supports have end sections projecting generally outward from said base for operably engaging the seat and/or back, so that when the flexible supports flex in the fore-to-aft direction, they provide for directed movement of the seat and/or the back. In one form, the flexible supports are integrally molded with the center section of the motion control.

The present invention relates to seating units having motion controls, and more particularly relates to a seating unit having mechanically non-complex motion control elements, but which are efficient and effective.
Modern chairs often have backs and seats that move upon recline of a person seated in the chairs. More sophisticated chairs include motion control mechanisms to provide sliding and pivoting motions that move in a particular way relative to the seated user so as to provide an optimally comfortable and adjustable chair motion. However, these mechanisms tend to be sophisticated with rigid pivots and slide elements which can result in complex control mechanisms that have many pieces and that are difficult to assemble. In turn, the chair becomes expensive, and is subject to warranty issues. Further, the complex mechanisms take up space and can become structurally large in size, which is unacceptable for chairs requiring a thin profile or otherwise requiring a clean unobstructed area under their seat. Also, design of these mechanisms is a complex task, with substantial time required to understand and work out competing functional requirements and physical relationships.
Accordingly, a seating unit with motion control mechanism is desired having the aforementioned advantages and solving the aforementioned problems, including having a relatively small, compact mechanism that is flexible and adaptable for different circumstances, and yet that provides a comfortable motion. Also, a motion control mechanism is desired that is easier to incorporate into chair designs without substantial design time, prototyping, and testing.

Seating unit with novel flexible supports


Semiconductor chips may include a substrate; a protective layer on a first surface of the substrate, through electrodes extending through the substrate and the protective layer, and a Peltier structure including first through structures including first conductivity type impurities, and second through structures including second conductivity type impurities, which may extend through the substrate and the protective layer; pads on the protective layer and connected to the through electrodes, respectively, first connection wires connecting respective first ends of the first through structures to respective first ends of the second through structures, and second connection wires connecting respective second ends of the first through structures to respective second ends of one of the second through structures. The first through structures and the second through structures may be alternately connected to each other in series by the first connection wires and the second connection wires.

The inventive concept relates to a semiconductor chip, a stacked semiconductor chip structure, and a semiconductor package, and more particularly, to a semiconductor chip including through electrodes and a stacked semiconductor chip structure and a semiconductor package including the same.
To manufacture electronic devices having small sizes and high performance and being capable of performing multiple functions, semiconductor packages including semiconductor chips are being developed. However, a size of a semiconductor package may increase as a number of semiconductor chips included in the semiconductor package increases. A stacked semiconductor chip structure that includes stacked semiconductor chips including through electrodes and a semiconductor package including the stacked semiconductor chip structure has been researched to reduce a size of a semiconductor package.

Semiconductor chips and semiconductor packages including the same


A frequency synthesizer includes: a fractional-N synthesizer configured to provide, in a locked condition, an output signal with an output frequency based on an input signal with a reference frequency, the fractional-N synthesizer including a charge pump outputting a current to be calibrated; a lock detector coupled to the fractional-N synthesizer to detect the locked condition, the lock detector being configured to send a first signal indicating the detection; a calibration component coupled to the lock detector and the fractional-N synthesizer, the calibration component being configured to provide a second signal to calibrate the current after receiving the first signal, based on a voltage sampled from the fractional-N synthesizer; and a current source array coupled to the calibration component and the fractional N synthesizer, the current source array being configured to calibrate the current based on the second signal.

A frequency synthesizer is an electronic device for providing an output frequency based on an input reference frequency. For example, a fractional-N synthesizer is a frequency synthesizer widely used in many modern devices, including radio receivers, mobile telephones, global positioning systems, etc. The fractional-N synthesizer has advantages over other types of frequency synthesizers, including reduced generation of phase noise and spur levels.
FIG. 1 illustrates a conventional fractional-N synthesizer 100. The fractional-N synthesizer 100 is configured to generate an output signal Sout with a frequency fout based on an input signal Sref with a reference frequency fref generated by a clock source, such as a crystal oscillator (not shown). The output frequency fout is approximately equal to the reference frequency fref multiplied by an adjustable factor D, where the factor D can be an integer or non-integer.
Referring to FIG. 1, the fractional-N synthesizer 100 includes a phase/frequency detector (PFD) 102, a charge pump 104 coupled to the PFD 102, a voltage controlled oscillator (VCO) 106 coupled to the charge pump 104, a loop filter 108 coupled to a node between the charge pump 104 and the VCO 106, and a frequency divider 110 coupled between the VCO 106 and the PFD 102. The frequency divider 110 is configured to provide the adjustable factor D such that the output frequency fout may be adjusted by adjusting the factor D.
The charge pump 104 includes first and second current sources 104-1 and 104-2 coupled in series via a node N. The current sources 104-1 and 104-2 may be metal-oxide-semiconductor (MOS) transistors and provide first and second currents Iup and Idown, respectively. For example, the current source 104-1 may be a PMOS transistor, and the current source 104-2 may be an NMOS transistor.
The charge pump 104 and the loop filter 108 produce a voltage VN at the node N, that is applied to the VCO 106. The VCO 106 generates the output signal Sout with the frequency fout that varies with the voltage VN. For example, the frequency fout of the output signal Sout may increase as the voltage VN increases. The frequency divider 110 receives the output signal Sout with the frequency fout and generates a feedback signal Sfb with a frequency ffb approximately equal to 1/D of the frequency fout.
The PFD 102 receives the input signal Sref with the reference frequency fref and the feedback signal Sfb with the frequency ffb, and compares a phase or frequency difference between the input signal Sref and the feedback signal Sfb. The PFD 102 further provides first and second switch signals Sup and Sdown to turn on the first and second current sources 104-1 and 104-2, respectively, based on the phase or frequency difference.
For example, if the PFD 102 determines that the frequency ffb of the feedback signal Sfb is smaller than the reference frequency fref of the input signal Sref, the PFD 102 may send the first switch signal Sup to turn on the first current source 104-1. Accordingly, the current Iup provided by the first current source 104-1 charges the loop filter 108, such that the voltage VN applied to the VCO 106 increases. As a result, the frequency fout of the output signal Sout and, hence, the frequency ffb of the feedback signal Sfb also increase.
Also, for example, if the PFD 102 determines that the frequency ffb is larger than the reference frequency fref, the PFD 102 may send the second switch signal Sdown to turn on the second current source 104-2. Accordingly, the current Idown provided by the second current source 104-2 discharges the loop filter 108, such that the voltage VN applied to the VCO 106 decreases. As a result, the frequency fout of the output signal Sout and, hence, the frequency ffb of the feedback signal Sfb also decrease.
These operations are repeated until the PFD 102 determines that the frequency ffb is approximately equal to the reference frequency fref, which corresponds to a state in which the fractional-N synthesizer 100 is in a locked condition. In the locked condition, the fractional-N synthesizer 100 generates the output signal Sout with the frequency fout approximately equal to the reference frequency fref multiplied by the factor D.
In the locked condition, the PFD 102 sends the switch signals Sup and Sdown to turn on the first and second current sources 104-1 and 104-2 for substantially the same short period of time. Ideally, the current Iup provided by the current source 104-1 is substantially the same as the current Idown provided by the current source 104-2. Therefore the charge pump 104 outputs a zero net current when the fractional-N synthesizer 100 is in the locked condition. However, in reality, there may be a charge pump current mismatch such that the current Iup may be not equal to the current Idown. For example, a difference between drain-source voltages applied to the PMOS transistor and the NMOS transistor, respectively operating as the first and second current sources 104-1 and 104-2, may cause the current mismatch.
As a result, the charge pump 104 may output a net current I0, which is the difference between the first and second currents Iup and Idown, when the fractional-N synthesizer 100 is in the locked condition. The net current I0 may flow into or out of the charge pump 104 via the node N depending on whether the current Iup is smaller or larger than the current Idown. The current mismatch may degrade performance of the fractional-N synthesizer 100.

Industrial Technology Research Institute


A mounting plate assembly for a notification appliance. For example, a mounting plate is designed with at least one aperture for receiving a plurality of leads, e.g., from a backbox. In turn, these leads can be received by a plurality of contacts that are deployed on the mounting plate. In one embodiment, at least two of these contacts are in physical contact with each other at a juncture, thereby providing a connectivity between these two contacts. However, the physical contact at the juncture is non-resetable, i.e., if a force is applied to the juncture, then the connectivity is severed and the physical contact between the two contacts cannot be easily re-establish even if the force is removed.

Notification appliances are widely used in fire alarm systems, emergency warning systems, facility monitoring systems, and the like. As used herein, the term notification appliance refers to a device which generates an audible alarm (e.g., a horn, a bell, a siren, a buzzer, etc), a visual alarm (e.g., a strobe or a flash), or both. Typically, such notification appliances are attached to an electrical backbox, which in turn is mounted on a wall or ceiling surface (surface mounted or wire mold mounted) or embedded in the wall. Electrical leads or wires extend into the backbox through knock-outs in the rear or sides of the backbox. The audible and/or visual alarm generating elements, e.g., an acoustic transducer and/or an electronic strobe or LED, are usually mounted on the notification appliance, with electric leads leading rearwardly into the backbox. An intermediate mounting or adapter plate is sometimes used to attach the notification appliance to the backbox.
In many deployment scenarios, a plurality of notification appliances is usually daisy-chained together to form a circuit or a loop of notification appliances. In turn, this circuit of notification appliances is in communication with an alarm or control panel that monitors the status of the notification appliances and causes the notification appliances to be triggered during an emergency situation.
As such, each notification appliance may have at least two leads and, at times, up to eight leads that will need to be connected to the circuitry of the notification appliance. Since it is necessary to provide a certain amount of slack in connecting the numerous leads to the circuitry of the notification appliance (e.g., connecting the leads to one or more screws on a terminal block of the notification appliance circuitry), there is often a substantial length of leads that must be careful stowed within the backbox. However, given the gauge of the leads, the bundle of leads are often quite stiff. As such, as the notification appliance is pushed toward the mounting plate during installation in the field, it is possible that one or more leads may disengage from its terminal or one or more leads may create a short. Unfortunately, such errors would not be easily detected until the entire loop of notification appliances is deployed. For example, an installer will perform a continuity test at the panel for the entire loop of notification appliances, where the installer may detect an open condition or a short condition. Although such erroneous condition can be detected, the installer does not have the ability pinpoint exactly the location, i.e., which notification appliance, is causing the error. As such, it is necessary for the field installer to check all the notification appliances in the pertinent loop. This is extremely time consuming and impractical, especially if the loop contains a large number of notification appliances.
Therefore, there is a need for a mounting plate having a configuration that will increase the ease of installation and also allows a continuity test to be performed for a circuit of notification appliances.

Mounting plate for a notification appliance


Diffusion of dopants within the gate of the transistor and/or the source/drain regions can be inhibited by the ion co-implantation of impurities in addition to the ion implantation of the n-type or p-type dopants. Implanting a combination of nitrogen and carbon for p-type devices in addition to the p-type dopants and implanting a combination of nitrogen and fluorine for n-type devices in addition to the n-type dopants, significantly reduces the diffusion of the n-type and p-type dopants. The co-implantation of the additional impurities may be performed before patterning of the polysilicon layer to yield the gate conductors. The impurities may be implanted first, followed by the n-type or p-type dopants. Additional implantation of the impurities may be performed after the patterning of the polysilicon layer in order to reduce dopant diffusion in the source and drain regions. The ion implantation of the gate conductors and source/drain regions may performed at the same time following the patterning of the polysilicon layer.

1. Field of the Invention
This invention relates to the field of semiconductor processing and, more particularly, to a transistor and method of making same with reduced dopant diffusion.
2. Description of Relevant Art
Fabrication of a metal-oxide-semiconductor ("MOS") transistor is well-known. Fabrication typically begins by introducing n-type or p-type impurities into a single-crystal silicon substrate. The active regions of the substrate (where the transistors will be formed) are then isolated from each other using isolation structures. In modern fabrication technologies, the isolation structures may comprise shallow trenches in the substrate filled with a dielectric such as oxide which acts as an insulator. Isolation structures may alternatively comprise, for example, locally oxidized silicon ("LOCOS") structures. A gate dielectric is then formed by oxidizing the silicon substrate. Oxidation is generally performed in a thermal oxidation furnace or, alternatively, in a rapid-thermal-anneal ("RTA") apparatus. A gate conductor is then patterned using a photolithography/etch process from a layer of polycrystalline silicon ("polysilicon") deposited upon the gate dielectric. The photolithography process allows selective removal of a photoresist film deposited entirely across the polysilicon. The portion of the photoresist film that is exposed can, according to one embodiment, be polymerized, and that which is not exposed removed during the "develop" stage of the lithography process. The regions that are non-polymerized form a mask for a subsequent etch during which portions of the polysilicon layer that are not masked by the photoresist pattern are removed. After the etch process, the patterned photoresist layer is stripped away.
The polysilicon is typically rendered conductive with the introduction of ions from an implanter or a diffusion furnace. Subsequently, source and drain regions are doped with a high-dose n-type or p-type dopant. If the source and drain regions are doped n-type, the transistor is referred to as NMOS, and if the source and drain regions are doped p-type, the transistor is referred to as PMOS. A channel region between the source and the drain is protected from the implant species by the pre-existing gate conductor. When an appropriate bias is applied to the gate of an enhancement-mode transistor, a conductive channel between the source and drain is induced and the transistor turns on.
As transistor geometries shrink below 1 micron, the limitations of conventional transistor processing become more and more apparent. As the thickness of the gate oxide decreases below 100 angstroms, devices become more susceptible to diffusion of impurities contained within the gate structure across the gate oxide and into the active area of the transistor. This problem is especially acute for gate structures into which boron is implanted. In addition, it is believed that many loosely formed bonds exist at the interface between the gate oxide and the polysilicon gate structure in conventionally formed transistors. The presence of these loosely formed bonds is believed to contribute to undesirable transistor characteristics such as susceptibility to voltage breakdown. Still further, as devices become smaller and more densely packed upon a semiconductor substrate surface, it becomes increasingly important to minimize the leakage current of each individual transistor. It is believed that leakage current can be created by a scattering effect that occurs as electrons traverse the channel between a device's source region and drain region. As the number of transistor devices within a single integrated circuit increases, leakage current can become significant enough to raise the temperature of the semiconductor substrate thereby slowing the device and, eventually, raising the temperature above the operational limit of the device. In addition, the presence of impurities in the channel of the device may cause a significant change in the threshold voltage. If the change brings the threshold outside the specification limits, the device is considered non-functional.
Therefore, it would be highly desirable to fabricate MOS transistors in a manner that reduced or eliminated diffusion from the gate transistor structure to the underlying active region of the transistor, improved the bond structure of the polysilicon-gate oxide interface, increased the source/drain drive current without a corresponding increase in leakage current, and prevented a significant change in the threshold voltage.

Reduction of dopant diffusion by the co-implantation of impurities into the transistor gate conductor


A method for manufacturing a display device using light emitting diode chips contemplates manufacturing a plurality of light emitting diode (LED) chips using a porous template; forming a plurality of first electrodes on a substrate; attaching the LED chips to pixel sites on the first electrodes using fluidic self assembly (FSA); and forming a plurality of second electrodes on a top surface of the LED chips.

1. Field of the Invention
The present invention relates to a method of manufacturing a display device, and more particularly, to a method of simplifying the manufacture of display devices using light emitting diode (LED) chips while reducing the costs of manufacture.
2. Description of the Related Art
Light emitting diodes (LEDs) are devices which transform electric energy into light. LEDs are used in illumination, as backlighting units in liquid crystal displays (a LCD), and in display devices projecting variable visual images to viewers, as for example, in a video display device such as a monitor.
Display devices using LED chips are constructed with numerous LED chips arranged in a predetermined form on an electrode of a substrate; the chips form a visible image formed with light from predetermined colors such as red (R), green (G), and blue (B) which are emitted from the LED chips. In these display devices the LED chips have a structure in which an impurity-doped compound semiconductor layer is stacked. In the prior art, one method for the manufacture of LED chips grows a compound semiconductor layer on an electrode of a substrate by using metal organic chemical vapor deposition (MOCVD). In this method however, manufacturing costs are high, yield is low, and high process temperatures are required.

Method of manufacturing display device using LED chips formed in a porous template


A first embodiment of a radially disposed thrust bearing assembly for rotary cone rock bits consists of a first non-rotating radially disposed steel thrust bearing disc and an adjacent, carbide thrust bearing disc. One of the thrust bearing discs is pressed into a disc retention socket formed in the end of a spindle bearing extending from the end of a main axially aligned bearing cantilevered from a leg of the bit and the other thrust bearing disc is pressed into a disc retention socket formed in the rotary cone. An edge of the carbide disc is formed with large valleys and peaks, the robust undulations resist cracking when the carbide thrust bearing disc is pressed into its respective socket. Unique air passages and channels are formed in the main and spindle bearings to direct cooling air to the thrust bearing discs. A second embodiment of a radially disposed thrust bearing assembly for rotary cone rock bits consists of a pair of preferably carbide thrust buttons, each of which has a central bore and a plurality of channels on its back face. The channels and central bore communicate with an air passage through the bit so as to provide a flow of cooling fluid such as air to the back of each thrust button. The invention further includes thrust bearing systems in which both of the thrust buttons comprise hard metal or sintered material.

1. Field of the Invention
This invention relates to thrust bearings for rotary cone rock bits that utilize fluid such as air to cool and clean the bit as it works in a borehole.
More specifically, this invention relates to a thrust bearing radially disposed between a roller cone and a journal and a means to secure and cool the thrust bearing therebetween. Still more particularly, the present invention comprises a thrust bearing made of very hard, temper resistant material, in which the non-wearing bearing is supported in the cone and channels are provided along the back of each thrust bearing for the purpose of allowing cooling air to contact each bearing.
2. Background
Rotary drill bits are generally well known in the art. These bits typically include three cone-shaped members adapted to connect to the lower end of a drill string. The bit includes three individual arms that extend downward from the bit body at an angle with respect to the bit axis. The lower end of each arm is shaped to form a spindle or bearing pin. A cone cutter is mounted on each spindle and adapted to rotate thereon. As the drill string rotates, the cones roll on the borehole bottom and rotate on about their respective spindles, thereby disintegrating the formation to advance the borehole. Individual bearing systems allow rotation of the cone cutter and serve to maintain the cone cutter on the spindle. These bearing systems have traditionally comprised roller bearings, ball bearings or friction bearings, or some combination of these.
In addition to providing bearings to facilitate rotation of the cone cutter, the interface between each spindle and its cone cutter typically includes a device for transmitting thrust (axial) forces from the cone cutter to the spindle and thence to the bit. These "thrust bearings" for rotary drill bits can generally be grouped into two different types. In one type the bearing system is sealed and the bearings are supplied with a lubricant. This bearing construction is most practical in oil drilling, where the axial feed forces are moderate. The frictional work and the development of heat in the bearings are small and the temperature in the bearings can be held at a low level. Thus, it is not necessary to supply air or other cooling fluid to the bearing. The other type of bearing is not sealed, and includes an internal channel or passage through which cooling air is supplied to the bearing. This type of bearing is commonly used in mining operations, where the load on the bearings is substantial. Because of the large load, the frictional forces on the bearing generate extreme heat and wear and it is necessary to provide a flow of air across the bearing to cool it, or an advanced material that has low friction characteristics and high temper resistance. The prior art includes several patents that disclose various wear-resistant means for transmitting the thrust load from each cone cutter to its respective spindle via a journal bearing surface and means for cooling the frictional interface.
For example, it is within the state of the art to provide a bearing surface, which comprises a hardmetal surface deposited on radially disposed areas of the journal. The deposited hardmetal material is subsequently machined to provide a smooth bearing surface between the journal and the rotary cone thrust button. This technique has the disadvantage that, when hardmetal material is metallurgically deposited within the cone or on the radially disposed bearing surfaces of the journal, the heat generated causes stress risers in the substrate that can result in cracks, especially in rotating cones. In addition, it is difficult, costly and time-consuming to machine the surface of these rough, hardmetal deposits to form the smooth bearing surfaces essential to the proper operation and longevity of the rock bit. These materials have poor thermal shock capabilities and limited resistance to the softening effects of high temperature.
Another type of thrust bearing comprises a pair of "thrust buttons" that are manufactured separately from the cone and spindle and then inserted into opposing recesses in the cone and spindle respectively. U.S. Pat. No. 4,194,794 to Kling discloses such a system, in which thrust buttons 22 and 25 are provided to transmit thrust loads from the cone cutter to the bit. Concentrating the load in a small area in this manner results in the generation of large amounts of heat as the frictionally engaged faces of thrust buttons 22 and 25 are forced to rotate with respect to each other. In addition, even small amounts of axial misalignment lead to severe stress concentrations at the edges of the buttons with this combination of materials because the hard, non-wearing members in the leg do not accommodate the misalignment. Kling further discloses an air cooling system that includes the placement of air ducts in each leg. The ducts are positioned so that they provide a flow of air at a point on the periphery of the spindle thrust button. The presence of dual roller bearings tends to reduce the cross-sectional spindle area available for air flow and thrust bearings.
Another variation on the double thrust button concept is disclosed in U.S. Pat. No. 4,098,358 to Klima. Klima discloses a spindle thrust button having a central opening and channels on its wear face that communicate with an air duct in the leg. The cone thrust button also has channels on its wear face. These channels communicate with the central opening and channels on the face of the spindle thrust button as the two buttons rotate relative to each other. While the placement of the cooling air channels on the wear faces of the thrust button would appear to allow more efficient removal of heat from the wear faces, this configuration actually produces a marked adverse effect. Namely, as a given portion of one wear face rotates over the other wear face, it is heated by friction with the other face. When the same portion then rotates over one of the cooling channels in the other wear face, it is subject to an abrupt reduction in temperature, which is then followed by another heat-generating contact, etc. This type of temperature fluctuation results in thermal fatigue that is very detrimental to high strength tool steels and hardmetal weld deposits. The surfaces of tool steel buttons, for example, develop fine heat checking cracks, which in turn eventually propagate until the button ultimately fails.
Still another disadvantage associated with the thrust buttons of the prior art arises out of the nature of the interference fit between each thrust button and the socket in which it is received. Specifically, while it is desirable to provide wide, robust teeth or knurls for engaging the hoop, it is also desirable to provide some clearance into which material deformed from the hoop can flow. As the amount of clearance area increases, the portion of the periphery of the thrust disc that is available for the teeth decreases. As the teeth are forced closer together, each tooth tends to get sharper. In addition, if it is desired to provide any flow of cooling fluid to the periphery of a thrust disc, the addition of passageways for the cooling fluid tends to further compromise the space available for the teeth and therefore tends to result in sharper, and therefore weaker, teeth.
Another common problem with the systems of the prior art lies in the relative positions of the wearing and non-wearing thrust bearing components. Specifically, if the non-wearing thrust bearing is placed on the spindle, the wearing member cannot compensate for misalignment of the friction bearing surfaces. Misalignment will occur after wear accumulates on the radial bearing and thrust bearing systems, with the result that the surfaces will no longer be parallel and a stress concentration will develop on the load side of the bearing.
Hence, it is desired to provide a thrust bearing system that adequately cools the thrust bearings without causing thermal fatigue, and compensates for slight misalignments of the cone cutter. It is further desired to provide a thrust bearing system for use in a rolling cone cutter that is relatively simple and inexpensive to manufacture and assemble, and that is durable under normal operating conditions. It is further desired to provide a thrust button configuration that allows for peripheral cooling of the thrust button and allows clearance into which deformed hoop material can flow, while still providing a plurality of wide, robust teeth, or knurls around the periphery of the disc.

Thrust disc bearings for rotary cone air bits


In a pulling apparatus operated according to the multi-pulling method or CCZ method, granular silicon material is first fed to a feed pipe from a feeder so as to form stagnation of the granular silicon material in the feed pipe. The feeding of the granular silicon material from the feeder to the feed pipe is repeatedly commenced and stopped so as to maintain the stagnation of the granular silicon material. The feed rate of the granular silicon material from the feeder to the feed pipe is increased with time until the feed of the silicon material is completed. This prevents abrasion of a coating or lining provided on the inner surface of the feeder and also prevents damage of the feeder. In a pulling apparatus operated according to the Czochralski method, after causing granular silicon material to stagnate in the feed pipe, the crucible is lowered or the feed pipe is raised, while the stagnation of the granular silicon material is maintained, so as to form an unmolten layer of the granular silicon material on the molten or solidified surface of the silicon melt. The unmolten layer is then melted, and the granular silicon material is fed onto the unmolten layer through the feed pipe while the stagnation of the granular silicon material in the feed pipe is maintained. Accordingly, silicon material can be recharged without damaging the crucible, so that productivity and manufacturing yield of silicon monocrystals can be improved.

1. Field of the Invention
The present invention relates to a method of feeding silicon material at the time of manufacture of a silicon monocrystal using the Czochralski method as well as to a feed pipe used in the method . Further, the present invention relates to a method of manufacturing a silicon monocrystal using the Czochralski method.
2. Description of the Related Art
A multi-pulling method has been known as a method of reducing costs associated with manufacture of a silicon monocrystal using the Czochralski method (see "SEMICONDUCTOR SILICON CRYSTAL TECHNOLOGY," Fumio SHIMURA, pp. 178-179, 1989).
According to the multi-pulling method, after a silicon-monocrystal having a dopant concentration within a predetermined range has been pulled, silicon material is recharged into a crucible in a volume corresponding to the reduction in volume of the silicon material in the crucible. After the thus-recharged silicon material has been melt, the pulling of a silicon monocrystal is repeated. This method leads to an improved manufacturing yield. Further, the above-described method makes it possible to produce a plurality of silicon monocrystals from a quartz crucible capable of being usually used only once according to the common Czochralski method. Consequently, the cost of the crucible is decreased, thereby resulting in a decrease in manufacturing costs of the silicon monocrystal.
In addition to the multi-pulling method, there is a continuous Czochralski method (a CCZ method). According to this method, during the course of manufacture of a silicon monocrystal, a silicon monocrystal is pulled while silicon material is supplied to the silicon melt within the crucible which has been reduced in volume as a result of pulling of the silicon monocrystal. This method makes it possible to pull a silicon monocrystal while the quantity of silicon melt is maintained. Therefore, the concentration of oxygen in a silicon monocrystal and the resistivity of the silicon monocrystal, both of which depend on the quantity of silicon melt, can be made constant. Further, the method permits pulling of a long silicon monocrystal, which in turn makes it possible to considerably improve a manufacturing yield of the silicon monocrystal and to reduce manufacturing costs of the silicon monocrystal.
The previously-described multi-pulling method and CCZ method require recharge of silicon material to the crucible containing silicon melt after a silicon monocrystal has been pulled or while the silicon monocrystal is being pulled.
As silicon material recharging methods, there are a method of recharging granular silicon material and a method of recharging silicon material in the form of a rod or block, as shown in FIG. 1. In the method shown in FIG. 1, a large amount of silicon material 55 in the form of a rod or block is recharged into a crucible 51 containing residual silicon melt 52 at one time after a silicon monocrystal 53 has been pulled from the silicon melt 52.
The weight of silicon material to be recharged is approximately 80 kg in case of pulling a 200 mm diameter crystal and approximately 200 kg in case of pulling a 300 mm diameter crystal, and as the period of time required to recharge such a silicon material is shorter, the time required to manufacture a silicon monocrystal can be reduced, whereby the productivity of a silicon monocrystal can be improved. For this reason, a larger recharge rate of silicon material is desirable. If silicon material is recharged to the silicon melt while it is in the form of a rod or block, the recharge rate will become larger. However, intensive heating becomes necessary to melt a large quantity of silicon material recharged in a short period of time. A quartz crucible is apt to become damaged by the intensive heating. Consequently, dislocations may generate easily during the course of growth of a monocrystal. In the case where granular silicon materials are recharged to a silicon melt, the recharge rate can be increased; however, intensive heating becomes necessary, thereby causing the same problems as previously described.
Another method as shown in FIG. 2 is also known (see Japanese Patent Application Laid-Open (kokai) No. 62-260791). In the method shown in FIG. 2, the surface of silicon melt 62 remaining in a crucible 61 after a silicon monocrystal has been pulled is solidified, and silicon material 64 is deposited on the thus-solidified surface 63 of the silicon melt 62 through a feed pipe 60.
According to this method, silicon material is melted after having been deposited on the solidified surface of silicon melt. Therefore, in the case where a particularly large amount of silicon material is recharged, or the case where silicon material is supplied in such a highly-dense granular form, intensive heating becomes necessary to melt the silicon material. As a result, as in the previously described conventional method, the quartz crucible becomes apt to be damaged, thereby resulting in dislocations being apt to occur during the course of growth of a monocrystal.
The inventors of the present invention have previously proposed a method of feeding granular silicon material to silicon melt (Japanese Patent Application Laid-Open (kokai) No. 6-286246). In this method, granular silicon material is fed to silicon melt through a feed pipe from a feeder. Granular silicon material is first caused to stagnate in the feed pipe. At this time, the granular silicon material discharged from the tip end of the feed pipe is deposited on the silicon melt. Subsequently, the tip end of the feed pipe is brought into contact with the thus-deposited granular silicon material, whereby the granular silicon is fed to the silicon melt while the stagnation of the granular silicon material in the feed pipe is maintained.
According to this method, a high speed at which the granular silicon material falls on the silicon melt from the feeder through the feed pipe can be changed to a slow speed at which the granular silicon material stagnated in the feed pipe is discharged to the silicon melt from the tip end of the feed pipe, without changing a feed rate of the granular silicon material to the silicon melt. Consequently, scattering of the granular silicon material and splashing of the silicon melt can be prevented.
In this method, it is important to maintain the granular silicon material stagnated in the feed pipe. It is possible to maintain the granular silicon material stagnated in the feed pipe by increasing the feed rate of the granular silicon material from the feeder to the feed pipe to be maintained so as to become equal to or higher than the discharge rate of the granular silicon material from the feed pipe to the silicon melt.
However, the discharge rate of the granular silicon material from the feed pipe to the silicon melt varies according to the state of an internal wall of the feed pipe, the structure and diameter of the tip end of the feed pipe, a distribution of particle size of the granular silicon material, and the state of the surface of the granular silicon material. However, the discharge rate of the granular silicon material may significantly change as a result of sudden collapse of the silicon material stagnated on the silicon melt, and, in this event, it is difficult to match the feed rate of the granular silicon material from the feeder to the feed pipe to this discharge rate in a superiorly responsive manner. Therefore, there is a risk of the granular silicon material stagnated in the feed pipe momentarily disappearing as a result of flowing into the silicon melt. To prevent such a risk, the maximum discharge rate of the granular silicon material from the feed pipe to the silicon melt is previously estimated, and the granular silicon material is fed from the feeder to the feed pipe at a rate equal to or higher than the maximum discharge rate.
In the case where the feeder is made of common metal such as SUS (stainless steel), in order to prevent the metal from being mixed into the silicon melt as a result of the granular silicon material from coming into direct contact with the metal, the internal surface of the feeder is coated or lined with material such as fluororesin that is hardly contaminated by heavy metal. However, the coating or lining is susceptible to abrasion if the feed rate of the granular silicon material from the feeder to the feed pipe is large.
In the case where a feeder formed from quartz or silicon is used, there arise no problems even if the granular silicon material comes into direct contact with the feeder. The internal surface of the feeder is covered with neither a coating nor a lining, and therefore the foregoing problem will not arise. However, the feeder made of quartz or silicon is relatively fragile. For this reason, if the feed rate of the granular silicon material from the feeder to the feed pipe is high, vibrations of the feeder must be increased, thereby resulting in fracture of the feeder.
In view of the previously-described problems, a feed rate of the granular silicon material from the feeder to the feed pipe is desired to be as low as possible.

Method for feeding granular silicon material, feed pipe used in the method, and method of manufacturing a silicon monocrystal


An electrode for use in actuating MEMS elements. The electrode declines in height along its length from a first end thereof to second end thereof. In use, the first end of the electrode is disposed proximal to an axis of rotation or axis of bending of an overlying MEMS element. In one embodiment, the decline in height of the electrode along its length is linear such that the electrode has a wedge-shaped profile. In another embodiment, the height of the electrode declines in discrete steps such that the electrode has a stepped profile.

The present invention pertains to micro-electromechanical systems (MEMS) devices. More particularly, the present invention relates to improvements in electrodes for use in MEMS devices.
MEMS devices have been used in a variety of optical applications. The prior art is replete with examples of MEMS-based optical modulators, add-drop filters, attenuators and routers.
Each optical MEMS device typically incorporates a xe2x80x9cmirrorxe2x80x9d that is capable of altering the path of a received optical signal or simply attenuating the signal""s intensity. The mirror, which is usually realized as a movable beam or plate, is configured to use either optical interference principles or simple reflection to provide the above-stated capabilities. In optical MEMS devices that rely on simple reflection, the movable beam typically comprises polysilicon or silicon that is coated with metal to provide a reflective surface. The movable beam is usually configured for movement via one of the two arrangements that are described below.
In a first arrangement 100 depicted in FIG. 1A (top view) and FIG. 1B (side view), movable, electrically conductive beam 102 is cantilevered over a cavity 104. Flat planar electrode 106 is disposed within cavity 104 beneath movable beam 102. In a second arrangement 200 depicted in FIG. 2A (top view) and FIG. 2B (side view), movable, electrically conductive beam 202 is suspended by supports 208A and 208B over cavity 204. Flat planar electrodes 206A and 206B are disposed in cavity 204 beneath movable beam 202.
As a potential difference is developed across movable beam 102 and electrode 106 of first arrangement 100, an electrostatic force is generated. The force bends movable beam 102 toward electrode 106. Similarly, as a potential difference is developed across movable beam 202 and either one of electrodes 206A or 206B, an electrostatic force is generated that draws the movable beam towards the actuated electrode. Supports 208A and 208B twist to allow movable beam 202 to move in such fashion. As beam 102 and beam 202 move, the path followed by an optical signal that is reflected therefrom is altered.
Both arrangement 100 and arrangement 200 suffer from a significant shortcoming. In particular, the actuation voltage necessary to achieve the required amount of mirror rotation (for sufficiently altering the path of an optical signal) is large (i.e., about 150 volts for a typical design). There is a need, therefore, to reduce the actuation voltage requirements of electrostatically-driven, MEMS-based, movable mirrors.
Some embodiments of the present invention provide an electrode that is capable of reducing the actuation voltage of MEMS-based mirrors.
An electrode in accordance with the present teachings declines in height along its length from a first end thereof to second end thereof. In one embodiment, the decline in height of the electrode along its length is regular or linear such that the electrode has a wedge-shaped profile. In another embodiment, the height of the electrode declines in discrete steps such that the electrode has a stepped profile.
In use, the electrode is disposed beneath a MEMS mirror (e.g., a beam, etc.). The first end of the electrode is disposed proximal to an axis of rotation or axis of bending of the mirror. Due to the geometry of the present electrode, the gap between the MEMS mirror and the surface of the electrode can be smaller than the gap between a MEMS mirror and the flat-planar electrodes in the prior art. Consequently, in such embodiments, the voltage requirement for a MEMS mirror that is actuated by the present electrode is reduced relative to voltage requirement for a MEMS mirror that is actuated by electrodes of the prior art.

Article comprising wedge-shaped electrodes


A method of operating a fabric treatment appliance comprises a steam generation step and a steam generator cleaning step. In the steam generator cleaning step, a chamber of the steam generator can be flushed by introducing a volume of liquid into the chamber greater than the internal volume. The steam generator cleaning step can also involve thermally shocking scale formed within the chamber.

1. Field of the Invention
The invention relates to removal of scale and sludge in a steam generator of a fabric treatment appliance.
2. Description of the Related Art
Some fabric treatment appliances, such as a washing machine, a clothes dryer, and a fabric refreshing or revitalizing machine, utilize steam generators for various reasons. The steam from the steam generator can be used to, for example, heat water, heat a load of fabric items and any water absorbed by the fabric items, dewrinkle fabric items, remove odors from fabric items, etc.
A common problem associated with steam generators involves the formation of scale and sludge within the steam generation chamber. Water from a household water supply typically contains dissolved substances, such as calcium and magnesium, which lead to the formation of scale and sludge in the steam generation chamber when the water is heated. Scale and sludge are, respectively, hard and soft deposits; the hard scale tends to deposit on the inner walls of the steam generation chamber, and residue water in the steam generation chamber carries the soft sludge. Formation of scale and sludge can detrimentally affect heat transfer and fluid flow and can lead to premature failure of the heater.

Removal of scale and sludge in a steam generator of a fabric treatment appliance


The invention provides novel cross-linkable, photoactive silane derivatives and mixtures with 3-aryl-acrylic acid esters and amides. The present invention also provides orienting layers for liquid crystals, and non-structured and structured optical elements and multi-layer systems based on the silane mixtures and derivatives.

The orienting layer is of particular significance in (electro-optical) liquid crystal devices. It serves the purpose of guaranteeing a uniform and disturbance-free alignment of the molecular axes.
Uniaxially rubbed polymer orienting layers, such as e.g. polyimide, are usually used for the orientation of liquid crystal molecules in liquid crystal indicators (LCD's). The direction of rubbing provides the orienting direction in this procedure. However, some serious disadvantages are associated with the rubbing and these can severely influence the optical quality of liquid crystal indicators. Thus, by rubbing, dust is produced which can lead to optical failure in the display. At the same time, the polymer layer becomes electrostatically charged, which, for example, in the case of Thin Film Transistor (TFT)-TN LCD's can lead to the destruction of the thin layer transistors which lie below. For these reasons the yield of optically faultless displays in LCD production has hitherto not been optimal.
A further disadvantage of rubbing is that it is not possible to produce in a simple manner structured orienting layers, since the direction of orientation can not be varied locally by rubbing. Accordingly, mainly uniformly directed layers of large area can be produced by rubbing. Structured orienting layers are, however, of great interest in many areas of display technology and integrated optics. For example, the viewing angle dependence of Twisted Nematic (TN) LCD's can be improved with them.
Orienting layers in which the orienting direction can be produced by irradiation with polarized light have been known for some time. Thereby, the problems inherent in rubbing can be avoided. In addition, there exists the possibility of producing a different orienting direction in a regional manner and thus to structure the orienting layer.
One possibility for the structured orienting of liquid crystals utilises the isomerizing capability of certain dye molecules in order to photochemically induce a preferred direction by irradiation with polarized light of suitable wavelength. This is achieved, for example, by admixing a dye with an orienting polymer and then irradiating with polarized light. Such a guest/host system is described, for example, in U.S. Pat. No. 4,974,941. In this system azobenzenes are incorporated in polyimide orienting layers and subsequently irradiated with polarized light. Liquid crystals, which are in contact with the surface of a thus-irradiated layer, are orientated correspondingly to this preferred direction. This orienting procedure is reversible, i.e. by repeated irradiation of the layer with light of a second polarization direction the already inscribed direction of orientation is again reversed. Since this re-orientation procedure can arbitrarily be repeated frequently, orienting layers on this basis are less suitable for use in LCD's.
A further possibility for the production of a high resolution orienting pattern in liquid crystal layers is described in Jpn. J. Appl. Phys. Vol. 31 (1992), 2155. In this procedure the dimerization of polymer-bonded photoreactive cinnamic acid groups induced by irradiation with linear polarized light is used for the structured orienting of liquid crystals. In contrast to the above-described reversible orienting procedure, an anisotropic polymer network is produced in the photo-structurable orienting layers described in Jpn. J. Appl. Phys. Vol. 31 (1992), 2155. These photo-orientable polymer networks are primarily usable where structured or non-structured liquid crystal orienting layers are required. Apart from use in LCD's, such orienting layers can also be used, for example, for the production of so-called hybrid layers as are exemplified in European Patent Applications EP-A-0 611 981, EP-A-0 689 084, EP-A-0 689 065 and EP-A-0 753 785. Optical elements such as, for example, non-absorptive color filters, linear and circular polarizers, optical delay layers, etc. can be realised using these hybrid layers of photo-structured orienting polymers and cross-linkable lower molecular liquid crystals.
Cinnamic acid polymers, which are suitable in principle for the production of such anisotropic cross-linked, photo-structured orienting layers for liquid crystals, are described in EP-A-611,786. These cross-linkable cinnamic acid derivatives are basically linked via the carboxyl function of the cinnamic acid (phenylacrylic acid) and a spacer to the main chain of the polymer. In these polymers the dimerizable acrylic ester group of the cinnamic acid is always aligned "inwards" to the spacer or polymer backbone, while the aromatic residue is always oriented "outwards" from the polymer backbone.
It has now been found that this type of cinnamic acid alignment in known photopolymers is by no means optimal. Concurrent photochemical reactions disturb the orienting capacity. The known cinnamic acid polymers have an inadequate photochemical long-term stability. For example, a lengthy UV light irradiation of a pre-produced orienting layer leads to the destruction of the originally present orientation. Multiple irradiations, in which an already present orienting layer having a predetermined inscribed pattern is irradiated once more in order to orientate the still non-irradiated regions in another direction, can only be carried out when the previously irradiated sites are covered by a mask. On the other hand, the already oriented regions of the layer can lose their structure wholly or in part by photochemical side-reactions.
A further disadvantage of the previously used cinnamic acid polymers is that no tilt angle occurs in the case of orienting surfaces produced from these materials by a simple irradiation with polarized light. In particular, for use in LCD's the orienting layer must produce a tilt angle in addition to the orienting direction.
In the case of the aforementioned uniaxially rubbed polymer orienting layers this tilt angle is already produced by the rubbing procedure on the polymer surface. When a liquid crystal is brought into contact with such a surface, then the liquid crystal molecules lie not parallel, but inclined to the surface, with the tilt angle thus being conferred to the liquid crystal. The size of the tilt angle is thus determined not only by rubbing parameters such as, for example, feed velocity and contact pressure, but also by the chemical structure of the polymer. A tilt angle between 1.degree. and 15.degree. is required for the production of liquid crystal indicators depending on type. The largest tilt angles are required especially for Supertwisted Nematic (STN) LCD's in order to avoid the occurrence of so-called fingerprint textures. In TN and TFT-TN LCD's the direction of rotation and the direction of tilt is defined by the tilt angle, whereby "reverse twist" and "reverse tilt" phenomena are prevented. While reverse twist in the unswitched state gives rise to fields having a false sense of direction, which is noticeable optically in a speckled appearance of the indicator, reverse tilt is noticeable optically to a very disturbing extent primarily upon switching the LCD's by tilting the liquid crystal in different directions. Reverse twist can be prevented by doping the liquid crystal mixture with a chiral dopant having a suitable direction of rotation. However, in order to suppress reverse tilt there has hitherto been no alternative possibility to the use of orienting layers having a tilt angle.
Cinnamic acid esters which are not, as described above, bonded to a polymer backbone, but which are linked via the spacer with a trialkoxysilane group have recently been reported in Liq. Cryst. 20, 171 (1996). In this case, the trialkoxysilane group serves to anchor the cinnamic acid unit to the substrate as a carrier, for example to glass. The spacer, which links the trialkoxysilane group with the cinnamic acid ester, is thereby always situated in the 2-position (ortho-position) of the cinnamic acid ester. For the production of the orienting layer, the trialkoxysilanes are firstly applied from a solution to the glass carrier. Thereafter, the orientation is effected by irradiation with linear polarized light of 259 nm wavelength. The capacity of the thus-prepared layer to orient liquid crystals is ascribed to a reversible Z/E isomerization. On the other hand, when the cinnamic acid molecules are irradiated at 330 nm, they become cross-linked. Thereby, the orientation capacity is lost in proportion to the degree of cross-linkage.
The orienting layers produced in this manner have the same disadvantages which the cinnamic acid polymers described above have. Also, they have an insufficient photochemical and thermal stability, since the Z/E isomerization is reversible and therefore leads to problems of re-orientation in the case of multiple irradiation. Moreover, they do not also have the capability of inducing a tilt angle.

Photoactive silane derivatives for liquid crystals


The device for implementing the method comprises a receptacle (3) whose internal profile has the shape of an asymmetric cone (3d) inside which is arranged a blade (5b) of an agitator (5) to agitate with a slow motion the bath of refrigerating liquid contained in the receptacle (3), an orifice (3i) being provided at the bottom of the cone (3d) and communicating with a pipe (3j) wherein is rotationally driven an Archimedean screw (6b) of an extractor device (6) to evacuate continuously the solid particles.

1. Field of the Invention
The present invention relates to a method and device for the production of solid particles from a liquid and the separation of solid particles contained in a bath of refrigerating liquid. The method of producing and separating solid particles is intended for example for obtaining balls of ice for surface cleaning by projection of the particles, or for constituting solid products from aqueous mixture. Finally, the method of production and separation is provided for obtaining solid particles from liquids of which the latent heat of solidification is less than that of pure water.
2. History of the Related Art
French Patent 2 630 668 discloses a method and a device for producing balls of ice for surface treatments. The method consists in dispersing by gravity a spectrum of droplets of water in a column of cold gas, so that the droplets of water pass through said column of cold gas by gravity and cool, solidifyig superficially before dropping in a bath of refrigerating liquid where they are solidified entirely in the form of balls of ice. The device for carrying out the method comprises an exchange column supplied with cold gas and droplets of water which are regularly distributed via an injector to create a spectrum of droplets. The device also comprises a receptacle secured to the exchange column comprising a spray pipe for feeding the refrigerating liquid, a cone for receiving the balls of ice and an orifice for evacuating the balls of ice at the bottom of the cone.
The receptacle has a cylindro-conical form in which a refrigerating liquid such as liquid nitrogen is introduced with a view to completely solidifyig the droplets of water which pass therethough.
A phenomenon of heating will be noted, when the partially solidified droplets of water reach, at the end of their free fall, the surface of the refrigerating liquid, said phenomenon due to the evaporation of the liquid nitrogen. The phenomenon of heating retains each ball of ice in lift until it has attained the temperature of the gaseous nitrogen coming from the change of phase of the liquid nitrogen.
It will be noted that it is only after complete solidification of the ball of ice that it starts its descent by gravity to the bottom of the cylindro-conical receptacle the phenomenon of heating also provokes a high rate of occupation of the surface of the bath of liquid nitrogen, risking constituting either out-of-calibre balls or agglomerates which are highly detrimental to the manufacture of the balls of ice and to the extraction thereof at the Archimedean screw.
A second phenomenon which is detrimental in the manufacture of the balls of ice is noted, which is induced by the slight difference in density between the ice at -196.degree. and that of the liquid nitrogen, viz. respectively about 0.850 and 0.8068. The slight difference in density influences the dynamics of descent by gravity of the balls of ice, hence a strong tendency to constitute agglomerates at the surface of the bath of liquid nitrogen.
DE-A-2 805 676 discloses a method and a device for producing solid balls comprising a supply of cold gas, an agitator with blade, a receptacle and an Archimedean screw belonging to an extraction device. In this device, the movement of the liquid in the bottom of the receptacle is not directed downwardly, this resulting in risks of turbulences and choking.

Method and device for producing and separating solid particles


A seal ring has an annular body which is constituted so that a disc section extended to a radially inward direction is overlapped with one end of a cylindrical section, and a sensor member for detecting rotation of an inner ring is provided to an outer periphery of the cylindrical section, and an outer case for covering the sensor member is provided by insert-forming. The outer case contracts after it is formed and is press-contact with the cylindrical section so that a gap is hardly generated.

1. Field of the Invention
The present invention relates to a seal ring which is incorporated in, for example, a rolling bearing and relates to a sealing apparatus so-called a pack seal.
The present invention, more particularly, relates to a seal ring into which a rotation detecting sensor is incorporated, a sealing apparatus into which a rotation detecting apparatus composed of the above sensor and a pulsar ring whose rotation is detected by the sensor, and a bearing apparatus having them.
2. Description of the Related Art
Both a magnetic sensor and a pulsar ring provided with N poles and S poles alternatively in a peripheral direction are incorporated as a rotation detecting device into, for example, a bearing apparatus for an axle of an automobile, and they are used for detecting a wheel speed when anti-locking brake control is made.
The present inventors suggest a structure that such a rotation detecting device is integral with a sealing apparatus called as a pack seal.
The seal pack of this suggestion has an outer diameter side seal ring fixed to an inner periphery of an outer ring of a rolling bearing, and an inner diameter side seal ring fixed to an outer periphery of an inner ring.
The magnetic sensor is attached to an inner diameter side of the outer diameter side seal ring. The pulsar ring is attached to an outer diameter side of the inner diameter side seal ring so as to face the magnetic sensor in a radial direction.
In this case, the magnetic sensor is attached to an inner periphery of an annular body of the outer diameter side seal ring by a mold using a resin material. The resin material is formed integrally with or bonded to the annular body of the outer diameter side seal ring so as to become a outer case which covers a periphery of the sensor.
Such a structure is provided because the annular body of the outer diameter side seal ring is press-fitted into an inner peripheral surface of an outer ring or the like so that the outer diameter side seal ring is attached firmly to the outer ring.
However, in the case of the structure that the magnetic sensor is attached to the inner periphery of the annular body of the outer diameter side seal ring by the mold, since a difference in coefficient of linear expansion between the annular body of the outer diameter side seal ring and the outer case is large, after the outer case is formed, it contracts. As a result, a gap is easily generated on a boundary surface between the inner periphery of the annular body of the outer diameter side seal ring and the outer case.
When such a gap is generated, water which splashes on the seal ring from the outside easily penetrates from the gap into the bearing, and this might cause deterioration of the bearing performance such that lubricant inside the bearing is deteriorated.
Therefore, a main object of the present invention is to provide a seal ring in which a gap is hardly generated on a boundary surface between an annular body of the seal ring and an outer case so that high sealing performance is provided.
Other objects, characteristics and advantages of the present invention will become clear from the following description.
A seal ring according to the present invention is attached to an inner peripheral surface of a fixed outside member, and forms a sealing section on an outer peripheral surface of an inside member to be inserted through the outside member inwardly and rotatably. The seal ring has an annular body with a substantially cylindrical shape, and a sensor member is provided to an outer peripheral side of the annular body, and a resin-made outer case, which is fitted into said outside member in states that the outer case covers the sensor member and has a predetermined interference for the outside member, is provided by insert-forming.
In the case of the present invention, since the outer case formed on the outer periphery of the annular body is formed integrally or bonded to the outer periphery of the annular body in states that its contraction towards an radially inward direction and the outer case press-contacts therewith, a gap is hardly generated on a boundary surface between the annular body and the outer case. Therefore, a seal ring having high sealing performance can be provided.
The invention is preferably constituted so that the sensor member is arranged so as not to contact with the inner peripheral surface of the outside member and so as to substantially contact with the outer peripheral surface of the annular body.
In this case, since resin is interposed between the outside member and the sensor member, even if a gap is generated on a surface between the outside member and the outer case and water penetrates from the gap, the water does not contact with the sensor member. As a result, electrically short-circuit of the sensor member can be prevented securely.
The present invention is preferably constituted so that the sensor member is arranged so as not to substantially contact with the outer peripheral surface of the annular body.
The present invention is preferably constituted so that the sensor member is arranged so as not to substantially contact with the inner peripheral surface of the outside member.
In these cases, since resin is interposed between the annular body and the sensor member, even if a gap is generated on a boundary surface between the outside member and the outer case and water penetrates from the gap, the water does not contact with the sensor member. As a result, electrically short-circuit of the sensor member can be prevented securely.
The present invention is preferably constituted so that an elastic lip, which is brought into contact with the outer peripheral surface of the inside member or a member attached to the outer peripheral surface so as to form a contact sealing section, is provided to the annular body.
In this case, since the contact sealing section is formed by the elastic lip, the sealing performance of the seal ring is heightened.
The present invention is preferably constituted so that a harness for covering signal lines connected with the sensor member is embedded into the outer case.
With this structure, even if a slight gap is generated on a boundary surface between the harness and the resin-made outer case and the water penetrates through the gap, the water does not reach a contact portion between the sensor member and the signal lines.
In the case where the harness is not embedded into the resin-made outer case and only the signal lines are embedded, if a slight gap is generated on a boundary surface between a jacket of the signal lines and the resin-made outer case and the water penetrates from the gap, the water goes along the jacket and conductors of the signal lines and reaches the connected portion of the sensor member and the signal lines. As a result, there possibly arises a defect that the sensor member is electrically shorted-circuited.
On the contrary, it is preferable that the harness is embedded into the outer case because the above-mentioned defect is prevented securely.

Seal ring, sealing apparatus and bearing apparatus


A capillary electrophoresis detector assembly including a separation column in which the components of a mixed sample are separated; an exit column which completes the connection to the terminal buffer reservoir; and a support sleeve which includes precisely positioned radial bores therethrough to allow insertion of optical fibers in the form of an input fiber which transmits the incoming radiation from an illumination source and an exit fiber which receives the radiation and relays same to a detector.. In fabricating the assembly, a precision wire is partially inserted into the output end of the separation column. The column/wire combination is inserted into one end of the sleeve. The exit column is threaded onto the precision wire and also inserted into the opposite end of the sleeve. The input and exit fibers are inserted into the radial bores in the sleeve until they touch the precision wire in opposition. Thus, the precision wire serves to establish the spacing between the optical fibers (as determined by the diameter of the wire). This technique affords a known, reproducible, optical path distance between the ends of the fibers. The capillary columns are further slide into the sleeve until they touch the optical fibers. The assembly of the sleeve and fibers is then bonded together whereupon the precision wire is removed.

1. Field of the Invention
This invention is directed to capillary electrophoresis detection, in general, and to precision detector assemblies using optical detection, in particular.
2. Prior Art
Capillary electrophoresis is an important emerging new technology. It offers significant advantages in separation of a wide range of compounds ranging from small ions to hole cells. The separation can be accomplished in several ways. The solution can be supplied to a medium of paper, gel starch or a liquid carrier buffer. The preferred method of interest herein is the latter method. That is, a solution is prepared which comprises a carrier buffer and a sample to be evaluated. This solution is stored in an input reservoir and, selectively, transported to an output reservoir. Typically, the solution is transported through a tube which is transparent (or at least translucent). The solution can be caused to be transported through the tube by applying a pressure or an electrical differential between the respective reservoirs. As the solution passes through the tube, it tends to separate. This is a well-known technique in the art.
One of the difficulties associated with the technology lies in the detection of the separated components as they migrate along the capillary column.
In the past, a technique reported by Tiselius (circa 1929) utilized an open U-tube filled with a buffer liquid and the sample. (This is sometimes referred to as the Schlieren technique.) In this arrangement, the separation of the sample components in the U-tube was visually observed. Obviously, this technique was extremely crude and provided relatively low accuracy results. For example, the tube was relatively large in diameter which did not cause the sample to separate to a fine degree. Also, the optics involved provided relatively gross observations and little detailed analysis.
Later (circa 1974), in a technique reported by Virtannen, separation of the samples in the observation tube was enhanced. This technique, referred to as isotachophoresis, improved the sample separation, but the optical observation apparatus was not significantly improved.
In or around 1980, Hjerten and Jorgenson developed the small bore tube (or capillary) technique for separation. This capillary approach was a significant development in electrophoresis technique. It provided several advantages including a minimizing effect of diffusion, a high number of theoretical plates and a smaller diameter observation field.
In this technique, light was directed across the capillary to enhance viewing of the sample. However, in this arrangement the light source and receiver were disposed outside the capillary tube. Moreover, the light source and receiver were, typically, disposed outside of a support sleeve in which the capillary was mounted. Thus, significant optical problems existed. For example, the perturbations and wall effects produced by the sleeve and/or capillary created some distortions and/or anomalies in the observed data. Because the sleeve and/or capillary presented cylindrical surfaces and because of the differences in indices of refraction, some of the incident light rays completely missed the sample. Likewise, some of the incident light rays traversed paths which were less than the entire sample. While these effects can be calculated to some degree and factored into the resultant data, this information is less than perfect and subject to question.
In 1987, Karger developed the gel column which has a significant sieving effect on the sample. However, the optics in this system are not significantly better than the other prior art devices.
The physical properties of the optics in such systems is important as the absorbance detection of samples is dependent upon the molar extinction (at a known wavelength) of the absorbing material, the concentration of the specimen and the path length through which the radiation must pass.
In other words, the equivalent absorbance A in this sample measuring technique is defined as EQU A=kcl
where
k=the molar extinction coefficient;
c=concentration; and
1=path length through solution.
In a given analysis situation, the only component of this equation which can be effectively controlled is 1. This factor is controlled by the optics of the apparatus. Thus, an improved optical arrangement is highly desirable in the electrophoresis measuring technology.
One of the problems in optical detection systems is stray light which, in general, may be described as any energy which reaches the detector without having been affected by the sample. Stray light can arise from either the direct optical path or from an external path.
The small size of the capillary column demands accuracy in placement of an optical detection system since most optical systems presently employed are located outside the capillary.
With the capillaries of vanishingly small dimensions (5-200 microns), extreme precision is required to assure that interrogating radiation passes through the bore of the capillary where the sample to be detected is located and, as well, to avoid any radiation "piping" around the bore through the capillary material or even passing by the capillary totally.
With optical fibers, there is an angle of acceptance which contains and propagates the light. A numerical aperture, which is the sine of half the angle of acceptance for the fiber, defines the angle of propagation through the fiber. Light entering the fiber at angles greater than this value leaks away and is not propagated to the output end.
The present invention provides an apparatus with the optical detection system inside the capillary column, thereby eliminating alignment difficulties, and other advantages disclosed herein.

Fiber optic flow cell for detection of electrophoresis separation with a capillary column and method of making same