Pattern transfer can be performed with improved exposure accuracy, by reducing the contamination caused by the attachment of a photosensitive agent or the like on an optical member of a projection optical member or the like. The pattern transfer onto a substrate W is performed after cleaning the objective member OB disposed at a given position by a cleaning device 8 at the time when pattern transfer is not performed, or while making flow a gas in a space between the substrate W and the optical member OB by a contamination protection device 98. Alternatively, the optical member OB disposed at a given position is inspected for contamination by a contamination inspection device 84 at the time when pattern transfer is not performed, and the pattern transfer or the cleaning or replacement of the optical member is performed based on the result.

The present invention relates to a projection exposure apparatus and a projection exposure method. More specifically, the present invention relates to a projection exposure apparatus and a projection exposure method both useful for projection exposure of a pattern defined on a mask onto a substrate in the manufacture of a semiconductor device, a liquid crystal display device or the like by a photolithography process.
In a projection exposure apparatus used in a photolithography process for the manufacturing a semiconductor device, a liquid crystal display device, a thin-film magnetic head or the like, a circuit pattern with fine and narrow line width formed on a mask (e.g., a reticle) is projectionally exposed onto a photosensitive substrate (e.g., a wafer; hereinafter, a xe2x80x9cwaferxe2x80x9d is used an exemplary substrate for the description below) with a resist layer applied thereon, via a projection optical system with a high resolution. A wafer stage is moved vertically (i.e., upward and downward) along the optical axis of the projection optical system to align the wafer surface on the wafer stage to the focal position of the projection optical system. The wafer stage is then moved in specific directions two-dimensionally on a plane orthogonal to the optical axis of the projection optical system. For example, in a step-and-repeat type of projection exposure apparatus, the wafer stage is stopped at such a position that the center of the exposure field (i.e., the optical axis) of the projection optical system coincides with the center of each shot region on the wafer, where the exposure operation is performed. In such a projection exposure process, a photosensitive resin (e.g., a novolak resin) is usually applied on the wafer as the resist layer.
Recently, in such a type of apparatus, for addressing the demand for a more miniscule circuit patterns, the resolution of the apparatus has been improved. For this purpose, a light with a short wavelength in the UV zone has been generally used as the exposure illumination light. It has also been demanded to improve the workability of the projection exposure apparatus, which depends on the exposure time period. For this purpose, an exposure illumination light with a high illuminance has been used to shorten the exposure time period. Therefore, for pattern transfer, the surface of the substrate (e.g., a wafer, a glass plate) applied with a photosensitive agent (e.g., a photoresist) is irradiated with a light with a high energy density.
When a light with a high energy density is irradiated onto the surface of the substrate applied with a photosensitive agent, so-called xe2x80x9cablationxe2x80x9d may occur in which the photosensitive agent or a reduction product thereof (hereinafter, referred to as a xe2x80x9cphotosensitive agent or the likexe2x80x9d) is scattered or vaporized and then evaporated. During the projection exposure process, the photosensitive agent released from the substrate partly reaches onto the optical member disposed in the vicinity of the substrate, and deposited on the surface opposed to the substrate (hereinafter, simply referred to as the xe2x80x9csubstrate-opposed surface) of the optical member, sometimes resulting in contamination of the surface of the optical member.
The deposits (e.g., a photosensitive agent or the like) on an optical member exhibit the behavior of optical contamination on the optical member. For example, in the case of an optical member as a component of a projection optical system, at the time of pattern transfer, the illuminance on an area of the substrate surface (applied with a photosensitive agent) corresponding to the contaminated area of the optical member may be decreased compared to that corresponding to the non-contaminated area of the optical member. That is, regional unevenness in amount of exposure light may occur in the pattern transferred onto the substrate surface applied with a photosensitive agent. As a result, for example, the line of a pattern designed to have an even line width may be transferred unevenly. For the manufacture of an integrated circuit pattern, such uneven pattern line transfer may ultimately cause functional failure of the finished product.
In addition, when the deposits on the optical member can absorb the illumination light, the temperature of the optical member is increased as the deposits are heated by the absorption of the illumination light during pattern transfer. Consequently, the optical characteristics of the optical member are altered, ultimately resulting in the alternation of the total imaging characteristics of the entire projection optical system.
In order to overcome this defect, in a projection exposure apparatus, it has been conventionally required to wipe the surface of an optical member of a projection optical system by an operator manually (cleaning process). It has also be proposed to provide a replaceable cover glass or polymer film between an optical member and a wafer to thereby prevent the approach of contaminants to the optical member (Japanese Patent Application Laid-open No. 6-140304).
It is the recent trend to increase the numerical aperture (NA) of a projection optical system to the maximum for the purpose of increasing the resolution of the system to the maximum. In this case, the maximum of the incident angle of the exposure illumination light upon the wafer is more increased. Then, it has been proposed to bring the projection optical system close to the wafer at the time of pattern transfer, thereby decreasing the diameter of the optical system of the exposure apparatus. This technique is also beneficial for the reduction in aberration for optical design of the exposure apparatus.
However, when the projection optical system is brought closer to the wafer at the time of pattern transfer, the deposition of contaminants (e.g., a photosensitive agent and the like) are released from the wafer onto the optical member of the projection optical member. Thus, the contamination of the optical member in the projection optical system is a serous problem. Moreover, the use of an exposure illumination light with a shorter wavelength and a higher illuminance for the purpose of improving resolution and workability of the apparatus makes this problem more serious.
In a prior art technique for disposing a replaceable contamination protection member between a projection optical system and a wafer, the space between the projection optical system and the exposure surface of the wafer has a three-layered structure, at the time of pattern transfer, which consists of a layer of the atmosphere between the projection optical system and the contamination protection member, a layer of the contamination protection member, and a layer of the atmosphere between the contamination protection member and the exposure surface of the wafer. Therefore, there is a limitation in bringing the projection optical system close to the wafer at the time of pattern transfer.
In addition, because of the increased demand for high transfer accuracy, the installation repeatability for a replaceable contamination protection member and the permissible optical variability of the contamination protection member become very critical. Therefore, the application of a cover glass (which has an even thickness) as the replaceable contamination protection means has its limit. That is, when a contamination protection member is replaced with a new one, it is inevitable to re-adjust the total aberration balance of the projection optical system; which is not suitable for practical use.
When a polymer film is used as the replaceable contamination protection member, the re-adjustment of the aberration balance of the projection optical system is not necessary. However, among the components of the exposure illumination light, the transmittance on the film of components having a large incident angle upon a polymer film are decreased. Particularly, the transmittance of an S-polarized light (which is largely responsible for an imaging characteristic) is remarkably increased, resulting in poor imaging performance. Moreover, a polymer film is generally difficult to be applied with an anti-reflection coating; which is not also suitable for practical use.
Under these circumstances, the present invention has been accomplished. The first object of the projection exposure apparatus according to the present invention, therefore, is to provide a projection exposure apparatus with improved precision by reducing the contamination caused by the deposition of a photosensitive agent or the like on an optical member of a projection optical system or the like.
The second object of the projection exposure apparatus according to the present invention is to provide a projection exposure apparatus with improved accuracy, by cleaning an optical member of a projection optical system or the like at the time when pattern transfer is not performed.
The third object of the projection exposure apparatus according to the present invention is to provide a projection exposure apparatus with improved accuracy by inspecting an optical member of a projection optical system or the like for contamination and, based on the inspection result, cleaning or replacing the optical member at the time when pattern transfer is not performed.
The fourth object of the projection exposure apparatus according to the present invention is to provide a projection exposure apparatus with improved accuracy by protecting an optical member of a projection optical system or the like for contamination during pattern transfer is performed.
The object of the projection exposure method according to the present invention is to provide a projection exposure method for performing the pattern transfer operation satisfactorily under the condition where the contamination caused by the deposition of a photosensitive agent or the like on an optical member of a projection optical system is reduced.
The invention is directed to a projection exposure apparatus for transferring a pattern defined on a mask onto a wafer via a projection optical system, the apparatus including a cleaning device for cleaning an optical member disposed at a given position.
According to the projection exposure apparatus of the present invention, the contamination of the substrate-opposed surface of the optical member at the time of pattern transfer can be reduced and the exposure accuracy can be improved by, prior to the pattern transfer, removing the contaminants (e.g., a photosensitive agent), caused by the previous pattern transfer, on the substrate-opposed surface of the optical member arranged at the predetermined position in the vicinity of the exposure surface of the substrate.
The cleaning may be performed every time pattern transfer is performed. However, if the contamination of the optical member caused by one pattern transfer is very small, then the cleaning may be performed at any time when the contamination level falls within a predetermined permissible range, for example, every time pattern transfer is performed for a predetermined number of times, or at regular intervals.
In the projection exposure apparatus of the present invention, various configurations may be employed. For example, the cleaning device may be disposed on a stage for holding the substrate, or the cleaning device may be mounted on a movable mechanism distinct from the stage for holding the substrate.
According to the projection exposure apparatus of the present invention, the cleaning member necessary for the cleaning operation can be driven by a conventionally employed stage which is for holding the substrate and is used for moving the substrate for performing pattern transfer. Therefore, the cleaning operation can be performed in a simple manner.
In the projection exposure apparatus of the present invention, it is preferable that the cleaning device be mounted on a vertical movement drive device provided on the stage.
According to the projection exposure apparatus of the present invention, the cleaning device and the optical member can be placed in contact with each other or [separate] can be separated from each other by a drive device.
According to the projection exposure apparatus of the present invention, the cleaning device is moved to the cleaning position by a movement mechanism distinct from the stage for holding the substrate. Therefore, both the cleaning function and the pattern transfer function are performed while maintaining the accuracy and the cleanliness of the stage for holding the substrate.
According to the projection exposure apparatus of the present invention, various types of cleaning devices may be employed. For example, the cleaning device may comprise an ultrasonic cleaning device for ultrasonically cleaning a part to be cleaned of the optical member by immersing the part in a cleaning solution with ultrasonic vibration. Alternatively, the cleaning device may comprise a cleaning member which contacts the substrate-opposed surface of the optical member to the substrate-opposed surface or the cleaning device may comprise a solution injector for emitting a cleaning solution onto the substrate-opposed surface of the optical system.
In the projection exposure apparatus of the present invention, it is preferable that the cleaning device is a soft member which has a surface to be placed in contact with the substrate-opposed surface so that it causes no damage to the optical member when they are in contact with each other. The cleaning device may be further provided with a drive unit for driving the cleaning member so that the substrate-opposed surface contacts the soft member so that the substrate-opposed surface is rubbed against the soft member. As such a soft member, a porous material capable of being impregnated with a cleaning solution may be used.
In the projection exposure apparatus of the present invention, it is preferable to employ, as the solution injector, an injector capable of emitting the cleaning solution applied with ultrasonic vibration.
On the other hand, an optical cleaning device for irradiating an irradiation light having an optically cleaning effect onto the surface of the optical member can be used.
The invention is further characterized in that the optical cleaning device comprises a gas supply means for supplying an oxidation-enhancing gas in the vicinity of the surface of the optical member. Therefore, the optical cleaning effect can be improved, since an oxidation-enhancing gas is supplied in the vicinity of the surface of the optical member during the cleaning operation by the cleaning device.
The invention is further characterized in that the optical cleaning device comprises a shield means for shielding the atmosphere including the optical path of the irradiation light in the vicinity of the surface of the optical member, against the external environment. Therefore, the cleaning effect can be increased by the action of the oxidation-enhancing gas, since the atmosphere in the vicinity of the surface of the optical member is shielded from the external environment by a shield means in such a way that includes the optical path of the irradiation light.
The invention is further characterized in that the optical cleaning device is one capable of irradiating an irradiation light onto the optical member through a replaceable window. Therefore, the optical cleaning device can be protected by the window, and the optical cleaning effect can be satisfactorily maintained by replacing the window with a new one if the window is contaminated.
The invention is further characterized in that the apparatus includes a contamination inspection device for inspecting the optical member for contamination. The invention is further characterized in that the cleaning device comprises a judging unit for determining whether or not cleaning of the optical member is necessary based on the inspection result obtained in the contamination inspection device.
The present invention is further directed to a projection exposure apparatus for transferring a pattern defined on a mask onto a substrate via a projection optical system, wherein there is provided a contamination inspection device for inspecting the optical member disposed in a given position for contamination. The contamination inspection device may be provided singly or in combination with the cleaning device.
When the contamination inspection device is provided in combination with the cleaning device, prior to the pattern transfer operation, the optical member may be inspected for contamination to determine whether or not the cleaning of the optical member is necessary. Based on the inspection result obtained in the contamination inspection device, it can be ensured that the cleaning operation for the optical member is performed at any time when it is required, and the cleaning effect can be confirm. Thus, the exposure accuracy can be improved.
When the contamination inspection device is provided singly, prior to the pattern transfer operation, the optical member may be inspected for contamination to determine whether or not the replacement of the optical member is necessary. Based on the inspection result obtained in the contamination inspection device, it can be ensured that the optical member is replaced with a new one at any time when it is required. Therefore, the exposure accuracy can be improved.
For the contamination inspection device, various types of constructions may be possible. For example, the contamination inspection device may comprise: an irradiation optical system for irradiating light to the optical member; a photodetector for detecting the light from the optical member; and a contamination inspection processing unit for inspecting the optical member for contamination based on the detection result from the photodetector.
As the inspection light for the inspection, an exposure illumination light may be available. In this case, it is required to chose an optical member capable of transmitting an UV light as the optical member of the inspection optical system. Such a requirement limits the range of choices for the optical member. Therefore, it is preferable that the contamination inspection device be adapted to irradiate the inspection light onto the surface facing the substrate of the optical member, and that the inspection light detect a spectrum of a reflection component reflected on the optical member.
The invention is further characterized in that an inspection means for determining the contamination level of the surface of the optical member disposed in the vicinity of the projection optical system of the projection exposure apparatus. Therefore, the contamination level of the surface of the optical member at the vicinity of the substrate in the projection optical system is determined by the inspection means. Based on the determined result, before the cleaning operation, the necessity of the cleaning operation can be determined, while after the cleaning operation, the contamination removal level by the cleaning operation can be known.
The invention is further characterized in that the inspection device measures a reflectance of a reflection light reflected on the surface of the optical member or a transmittance of a transmission light passed through the surface of the optical member, and then determines the contamination level of the surface of the optical member based on the measurement result. Therefore, the inspection for contamination can be performed by determining the reflectance or transmittance on the surface of the optical member to be inspected.
The invention is further characterized in that the inspection device determines the contamination level of the surface of the optical member based on the comparison result between a preset given reflectance of transmittance and an actually measured real reflectance or transmittance, respectively. The predetermined reflectance or transmittance may be defined as a reflectance or transmittance on the surface of the optical member which is determined when the contamination level of the surface of the optical member falls within a predetermined permissible range. Therefore, the contamination level can be determined in such a manner that a reflectance or transmittance on the surface of the optical member to be inspected is previously determined (which is defined as the predetermined reflectance R0 or transmittance), and the contamination level is then determined based on the difference between an actually determined real reflectance Rr or real transmittance and the predetermined reflectance R0 or transmittance, respectively.
The invention is further characterized in that the inspection device measures a reflectance of a reflection light reflected on the surface of the optical member or a transmittance of a transmitted light passed through the surface of the optical member, and then determines a real reflectance Rr or transmittance from the comparison result between a photoelectric signal for the irradiation light received after reflected on the surface of the optical member or after passed through the surface of the optical member and a photoelectric signal for the irradiation light received without the presence of the optical member. Therefore, for example, when the irradiation light is irradiated for several times at intervals during the cleaning operation, the variation with every cleaning operation in contamination removal level can be reflected as the real reflectance Rr or transmittance.
The invention is further characterized in that both the above-mentioned contamination inspection device and the above-mentioned cleaning device for the optical member are provided. The invention is further characterized in that the cleaning device comprises an optical cleaning device for irradiating an irradiation light having an optical cleaning effect onto the surface of the optical member. Therefore, when it is determined that xe2x80x9cthe cleaning operation is necessaryxe2x80x9d based on the result obtained in the projection optical system inspection device, a given irradiation light is emitted from the optical cleaning device to remove the contamination on the surface of the optical member.
The present invention is also directed to a projection exposure apparatus for transferring a pattern defined on a mask onto a substrate via a projection optical system, the apparatus including a contamination protection device for making a gas flow between the optical member disposed in the vicinity of the exposure surface of the substrate and the substrate to prevent the approach of contaminants generated from the substrate toward the optical member.
According to the projection exposure apparatus of the present invention, the contamination protection device makes gas flow between the substrate and the optical member to prevent the approach of the contaminants released from the substrate toward the optical member. Therefore, the presence of any intermediate other than the gas is not needed between the optical member and the substrate on the traveling path of the exposure illumination light. Therefore, the contamination of the substrate-opposed surface of the optical member can be reduced and the exposure accuracy can be improved.
For the contamination inspection device, various constructions may be employed. For example, the contamination protection device may comprise: a flow-path setting member for setting the flow path of the gas in the vicinity of the substrate-opposed surface of the optical member; and a gas supply unit for supplying the gas to the flow path set by the flow-path setting member.
The above-described variations of the present invention may be applicable for various types of optical members. For example, the optical member may be one disposed on the optical path of the exposure illumination light in the vicinity of the substrate, or it may be one disposed at the end part of an optical system for alignment of the substrate.
As the optical system for alignment of the substrate, an alignment optical system for alignment of the substrate in the direction vertical to the optical axis of the projection optical system or a focus detection optical system for alignment of the substrate in the direction parallel to the optical axis of the projection optical system may be employed, for example.
According to the projection exposure apparatuses of the present invention, there is no need of apprehension of the contamination of the optical member which is arranged on the optical path of the exposure illumination light and in the vicinity of the substrate caused by the attachment of contaminants during pattern transfer. In addition, it becomes possible to design a projection exposure apparatus with a projection optical system disposed close to a substrate. Therefore, a projection exposure optical system with higher numerical aperture can be readily manufactured.
According to the projection exposure apparatuses of the present invention, the optical member arranged at the end part of an optical system for alignment of the substrate, which is likely to become adhered with a photosensitive agent or the like, is the target of the cleaning, the contamination inspection or the contamination protection. Therefore, the contamination of the optical member can be reduced and the exposure accuracy can be improved.
The present invention is further directed to a projection exposure method for transferring a pattern defined on a mask onto a substrate via a projection optical system, the method comprising: a cleaning step for removing the contamination on an optical member disposed at a given position; and a pattern transfer step for transferring a pattern defined on the mask onto the substrate via the projection optical system.
The present invention may be applicable for various types of optical members. For example, the optical member may be one disposed on the optical path of the exposure illumination light and in the vicinity of the substrate.
According to the projection exposure method noted above, prior to the pattern transfer step, the cleaning step is first performed to remove the contaminants (e.g., a photosensitive agent), as a result of the previous pattern transfers, attached on the optical member disposed near the exposure surface of the substrate, thereby making the optical member clean. Therefore, the pattern transfer can be satisfactorily performed under the condition where the contamination of the optical member is reduced and any intermediate other than the atmosphere is not present between the projection optical system and the substrate.
The cleaning operation may be performed every time the pattern transfer operation is performed. However, if the contamination of the optical member caused by one pattern transfer is small, it may also be possible to perform, prior to the cleaning step, a contamination evaluation step for determining the relation between the contamination level of the optical member and the number of pattern transfer operations and then determining the limit in number of pattern transfer operations, which is the number of exposure operations during which the clean substrate-opposed surface of the optical member is contaminated to a predetermined impermissible level; and the cleaning step is performed before the number of pattern transfer operations performed after the previous cleaning step exceeds the limit.
According to the projection exposure method of the present invention, the cleaning step can be performed at any time when the contamination level falls within a predetermined permissible range, for example, every time pattern transfer is performed for a predetermined number of times or at regular intervals. Therefore, the workability of the apparatus can be improved.
The invention is further directed to a projection exposure method for transferring a pattern defined on a mask onto a substrate via a projection optical system, the method comprising: a contamination inspection step for inspecting an optical member disposed at a predetermined position for contamination; and a judging step for determining whether or not pattern transfer will be performed based on the inspection result obtained in the inspection step.
According to the just described projection exposure method, prior to pattern transfer, the contamination inspection step is performed to inspect the optical member for contamination. In the judging step, based on the result obtained in the contamination inspection step, it is determined whether or not the contamination level of the optical member caused by the pattern transfer operations exceeds a predetermined permissible limit. When it is estimated that the contamination level of the optical member exceeds the predetermined permissible limit, the cleaning or replacement of the optical member is performed. When it is estimated that the contamination level of the optical member does not exceed the predetermined permissible limit, the pattern transfer is performed. In this manner, based on the result obtained in the contamination inspection step, it can be ensured that the optical member is cleaned or replaced with a new one at any time when it is required. Therefore, the exposure accuracy can be improved and the workability of the apparatus can also be improved.
The invention is further characterized in that, in the above-noted cleaning step, an irradiation light having an optical cleaning effect is irradiated onto the contamination on the optical member. The invention is further characterized in that a cleaning step for removing the contamination on the optical member based on the inspection result obtained in the inspection step is further included.
The invention is further directed to a method for assembling a projection exposure apparatus for transferring a pattern defined on a mask onto a substrate via a projection optical system, the method comprising: providing a cleaning device for cleaning an optical member disposed at a given position relative to the projection exposure apparatus. The invention is further characterized in that the cleaning device is an optical cleaning device for irradiating an irradiation light having an optical cleaning effect onto the contamination on the optical member. The invention is further characterized in that the projection exposure apparatus is further provided with a contamination inspection device for inspecting the optical member for contamination.

Projection exposure apparatus and method


The present invention provides a high-intensity LED as a light source for use in hands-free illumination devices. In one embodiment, one or more high-intensity LEDs are incorporated in, or added to, headgear, such as an aircraft headset. The LEDs may be powered by a battery, an external power source, or both. Also provided is a kit and method of installation for retrofitting existing headgear with LEDs.

Conventional portable illumination systems, such as flashlights, include an incandescent light bulb and conventional drycell batteries enclosed in a housing typically constructed of a body section and a head section. Though portable, illumination systems of this type are often bulky and cumbersome, and thus often are not carried on the person. This presents a problem when the need for illumination arises unexpectedly, such as during a power failure at night, and no portable illumination system is readily available. The problem is exacerbated when, for instance, the person does not have a hand available to search for, aim and operate a conventional flashlight.
There have been some variations on portable, hands-free illumination systems. Underground coal miners have long mounted large conventional incandescent lights with large, heavy battery packs to the front of hard hats, allowing them to work with both hands while the light on the hat illuminated the area in front of them. U.S. Pat. No. 3,032,647 to Wansky provides an example of a hat-mounted light. U.S. Pat. No. 4,616,297 to Liu also provides an example of a hands-free flashlight, which mounts conventional incandescent light bulbs and conventional drycell batteries to a bulky frame to be worn like spectacles. U.S. Pat. Nos. 5,217,294 to Liston and U.S. Pat. No. 5,412,545 to Rising describe hands-free operation of a conventional flashlight by strapping the flashlight to the user's head.
While any of these devices, if worn by a user, might function as a hands-free illumination device, such devices are even more bulky and cumbersome than conventional flashlights. Moreover, such devices are not suitable for use in conjunction with other headgear.
Conventional hands-free portable illumination systems are bulky primarily because they use incandescent light bulbs, which suffer from poor efficiency in converting electrical power into radiated visible light. Most of the electrical energy incandescent light bulbs consume is wasted in the form of heat energy, while less than 7% of the energy they consume is typically radiated as visible light. This has severe negative consequences for portable illuminator applications, such as hands-free illumination devices, where the amount of power available for lighting systems is limited. In these applications, electrical power is usually provided by batteries which are periodically replaced, as in the case of a flashlight. Such a mechanism for providing electrical power is inherently bulky, heavy, and/or expensive due at least in part to poor power-conversion efficiency in generating visible light.
As already noted, incandescent lamps generate large amounts of heat for an equivalent amount of generated light as compared to other sources. This results in very high bulb-wall temperatures typically in excess of 250 degrees Celsius and large heat accumulations which must be dissipated properly by radiation, convection, or conduction to prevent damage or destruction to the illuminator support members, enclosure, optics or to other nearby components. Providing room for the necessary heat dissipation requires additional bulkiness. This high heat signature of common incandescent light sources in illuminators is particularly problematic for hands-free light sources, where the light source is in close proximity to the user's body, for instance, the user's head.
Incandescent light bulbs, or lamps, are also disadvantageous because they are fragile and have a short life. Even in stable environments incandescent lamps must be replaced frequently, sometimes at great inconvenience, hazard, and/or expense. In addition to their short life, incandescent lamps are susceptible to damage from mechanical shock and/or vibration. Such occurrences can damage the delicate filaments from which incandescent light emissions originate, or can damage the surrounding glass casing, which can result in air entering the casing and quick burning out of the filament. Incandescent lamps can also be easily damaged by exposure to liquid moisture, due to the thermo-mechanical stress associated with contact between the hot glass bulb wall and cooler fluids. Thus, incorporating an incandescent lamp into a hands-free illumination device requires substantial or extreme measures to protect the light bulb from shock, vibration, moisture and other hazards while still allowing for removal of the bulb or light fixture when it burns out, is permanently damaged or otherwise loses power.
Incandescent light bulbs or lamps also exhibit certain electrical characteristics which make them inherently difficult to incorporate in small, lightweight applications, like hands-free illumination devices. For instance, when an incandescent light source is first energized by a voltage source, there is an initial surge of current which flows into the filament. This inrush current, which is typically 12 to 20 times the normal operating current, limits the lifetime of the lamp thus further amplifying the need for an illuminator structure which allows for frequent replacement. Inrush current also necessitates unusual consideration when designing supporting electrical circuits which contain them. Fuses, relays, mechanical or electronic switches, wire harnesses, and connectors electrically connected to such lamps must be capable of repeatedly carrying this extreme transient.
In addition, the voltage-current (V-I) characteristic of incandescent lamps is notoriously non-linear, as are each of the relationships between light output and voltage, current, or power. The luminous intensity, color temperature, and service life of incandescent lamps varies exponentially as a function of applied current or voltage. This sensitivity to power source variation makes electronic control of incandescent lamps a particularly difficult problem. They are further susceptible to significant reliability and field service life degradation when subjected continuously to DC electrical power, pulse-width modulated DC power, simple on/off switching of any sort, or any over-voltage conditions, however minor. Incandescent lamps also possess significant inductance which, when combined with their relatively high current load, complicates electronic switching and control greatly due to inductive resonant voltage transients.


An interlock for an enclosure can include a primary door activator with an activator arm, a secondary door activator, and a rotatable arrangement that links the primary and secondary door activators. The activator arm can block a primary door of the enclosure from being closed when the activator arm is in an open configuration. The activator arm can be configured to rotate with the rotatable arrangement in a first direction towards the open configuration as the primary door is opened, and in a second direction away from the open configuration as the primary door is closed. The secondary door activator can be configured to engage the rotatable arrangement to prevent rotation of the rotatable arrangement when the secondary door is open, and to permit rotation of the rotatable arrangement when the secondary door is closed.

Electrical equipment can be installed in enclosures with doors to allow users to access the equipment. In some installations, it may be useful to selectively prevent one or more doors from being opened, or to prevent certain doors from being closed before others. For example, in some installations, it may be useful to prevent a main door from being closed until secondary doors are also closed, or to prevent a main door from being opened unless power to the enclosure has been appropriately disconnected.


A metal piece having an organic coating with improved corrosion resistance and adhesion is described which comprises a zinc or zinc alloy plated metal piece having on its surface, a chromate film deposited from an aqueous acidic chromium solution comprising trivalent chromium as substantially the only chromium ion present, and a cathodic electrocoated siccative organic coating on the chromate film. A process for obtaining such coated metal pieces also is described.

Considerable attention has been directed to providing improved corrosion protection to metallic surfaces. One method for providing this corrosion protection is by depositing one or various conversion coatings on the metal surfaces to form a coating which protects the metal against corrosion and also serves as a base for improving the adhesion of subsequently applied siccative organic finishes. Such conversion coatings are applied by treatment of the surfaces with solutions of various chemicals which react with the surface to form the desired coating. Among the commonly used conversion coating compositions are aqueous phosphate and chromate solutions.
Another method for providing improved corrosion protection to metallic surfaces involves electrodepositing a zinc or zinc alloy coating on the metal surface.
Solvent-based siccative organic coating compositions have been applied to metal surfaces such as by spraying, dipping, rolling, etc. Water-soluble and/or dispersible resin based paints and lacquers also may be utilized to coat metal surfaces, and these may be applied by electrophoresis. The electrophoretic application of paint and lacquer involves the phenomena of electro-osmosis and electrolysis, as well as electrophoresis. In this method, an electric current is passed through the paint or lacquer solution while the article to be painted is made an electrode in the paint or lacquer.
Although the above techniques have provided corrosion protection to metal surfaces, there continues to be a need for metals and metal surfaces exhibiting even higher corrosion protection and improved adhesion of siccative coatings to the metal.

Metal pieces and articles having improved corrosion resistance


A pure adversarial optical character recognition (OCR) approach in identifying text content in images. An image and a search term are input to a pure adversarial OCR module, which searches the image for presence of the search term. The image may be extracted from an email by an email processing engine. The OCR module may split the image into several character-blocks that each has a reasonable probability of containing a character (e.g., an ASCII character). The OCR module may form a sequence of blocks that represent a candidate match to the search term and calculate the similarity of the candidate sequence to the search term. The OCR module may be configured to output whether or not the search term is found in the image and, if applicable, the location of the search term in the image.

1. Field of the Invention
The present invention relates generally to computer security, and more particularly but not exclusively to methods and apparatus for identifying text content in images.
2. Description of the Background Art
Electronic mail ("email") has become a relatively common means of communication among individuals with access to a computer network, such as the Internet. Among its advantages, email is relatively convenient, fast, and cost-effective compared to traditional mail. It is thus no surprise that a lot of businesses and home computer users have some form of email access. Unfortunately, the features that make email popular also lead to its abuse. Specifically, unscrupulous advertisers, also known as "spammers," have resorted to mass emailings of advertisements over the Internet. These mass emails, which are also referred to as "spam emails" or simply "spam," are sent to computer users regardless of whether they asked for them or not. Spam includes any unsolicited email, not just advertisements. Spam is not only a nuisance, but also poses an economic burden.
Previously, the majority of spam consisted of text and images that are linked to websites. More recently, spammers are sending spam with an image containing the inappropriate content (i.e., the unsolicited message). The reason for embedding inappropriate content in an image is that spam messages can be distinguished from normal or legitimate messages in at least two ways. For one, the inappropriate content (e.g., words such as "Viagra", "free", "online prescriptions," etc.) can be readily detected by keyword and statistical filters (e.g., see Sahami M., Dumais S., Heckerman D., and Horvitz E., "A Bayesian Approach to Filtering Junk E-mail," AAAI'98 Workshop on Learning for Text Categorization, 27 Jul. 1998, Madison, Wis.). Second, the domain in URLs (uniform resource locators) in the spam can be compared to databases of known bad domains and links (e.g., see Internet URL <www dot surbl dot org).
In contrast, a spam email where the inappropriate content and URLs are embedded in an image may be harder to classify because the email itself does not contain obvious spammy textual content and does not have a link/domain that can be looked up in a database of bad links/domains.
Using OCR (optical character recognition) techniques to identify spam images (i.e., images having embedded spammy content) have been proposed because OCR can be used to identify text in images. In general, use of OCR for anti-spam applications would involve performing OCR on an image to extract text from the image, scoring the extracted text, and comparing the score to a threshold to determine if the image contains spammy content. Examples of anti-spam applications that may incorporate OCR functionality include the SpamAssassin and Barracuda Networks spam filters. Spammers responded to OCR solutions in spam filters with images deliberately designed with anti-OCR features. Other approaches to combat spam images include flesh-tone analysis and use of regular expressions.
The present invention provides a novel and effective approach for identifying content in an image even when the image has anti-OCR features.

Pure adversarial approach for identifying text content in images


A cover for an infant seat, comprising: (1) a flexible, bag-form main body having, in a top portion thereof, an opening for introducing therethrough an infant into the main body, and having a leg through-hole for allowing the leg of an infant to extend out of the main body, and (2) a flexible flap extending from a portion of the main body, which portion is positioned above the leg through-hole, wherein the flap has a free end, wherein when the flap is allowed to hang downwardly, the flap is engaged with the main body to close the leg through-hole, and wherein when the main body is installed on the seat in a manner such that the flap is placed on or wrapped around a support means provided on the seat for preventing the falling of an infant, the infant in the main body is prevented from directly contacting the support means.

Generally, infant seats (such as an infant seat installed on a shopping cart, and a stroller) provided in public places, such as a supermarket, have a support means for preventing an infant from falling from the infant seats. Generally, such a support means has a grab bar which extends at least along a forward end of the infant seat. With respect to such infant seats, reference can be made to, for example, Unexamined Japanese Patent Application Laid-Open Specification Nos. Hei 10-211880 and 9-30421. However, in many cases, such infant seats have a problem in that the infant seats are unsanitary. Specifically, when an infant is seated in the infant seat, the infant bites and licks the above-mentioned grab bar and the like, so that the seat becomes unsanitary. Further, generally, such infant seats provided in public places are repeatedly used without being washed and, hence, an infant in the infant seat is exposed to dirt and germs which adhere to the infant seat.
For solving the above-mentioned problems, various proposals have been made. For example, U.S. Pat. No. 5,829,835 discloses a convertible combination of shopping cart seat liner and diaper bag for use as both a seat liner and a diaper bag (hereinafter, frequently referred to simply as "seat liner/diaper bag"), the convertible combination comprising: a flexible, upstanding container for accommodating therein an infant, which has two leg openings; a seat liner and diaper bag converting means; and a handle for enabling a user to readily carry the flexible, upstanding container when configured as the diaper bag. When the seat liner/diaper bag is used as a seat liner, the flexible, upstanding container prevents an infant seated in an infant seat from directly contacting the infant seat. Further, this patent document describes a pad which is used for covering the leg openings (hereinafter, referred to as "leg openings-covering pad") when the above-mentioned seat liner/diaper bag is used as a diaper bag. However, this patent document describes only one specific example of such a leg openings-covering pad, which is shown in the drawings of this patent document. In such only one specific example, a lower portion of the leg openings-covering pad is fixedly attached to an inner wall of the above-mentioned container at a portion thereof which is just below the leg openings, and an upper portion of the leg openings-covering pad is detachably attached to an inner wall of the container at a portion thereof which is just above the leg openings. The upper portion of the leg openings-covering pad is attached to the inner wall of the container by a fastening means (such as a hook and loop fastener) and, when the seat liner/diaper bag is used as a shopping car seat liner, the leg openings are uncovered by detaching the upper portion of the leg openings-covering pad. However, when the leg openings are uncovered and an infant is seated on the seat liner, the infant is caused to be seated on the fastening means, such as a hook and loop fastener, so that there is a danger that the infant seated on the fastening means feels uncomfortable or even suffers scratches. Further, even when an upper portion of the leg openings-covering pad is fixedly attached to an inner wall of the above-mentioned container at a portion thereof which is just above the leg openings, and a lower portion of the leg openings-covering pad is detachably attached to an inner wall of the container at a portion thereof which is just below the leg openings, a problem also arises in that the fastening means is caused to contact the legs of an infant seated on the seat liner. Furthermore, even when the leg openings-covering pad is attached to an outer surface of the container, problems arise in that, when the seat liner/diaper bag is used as a diaper bag, the contents of the container are likely to push the leg openings-covering pad to thereby uncover the leg openings. For avoiding this problem, it becomes necessary to use a disadvantageously complicated fastening means or a disadvantageously complicated fastening method. Further, generally, it is unlikely that a bag is used exclusively for carrying only diapers and it is of course desirable that a bag can also contain other articles than diapers. However, especially when the above-mentioned leg openings-covering pad is attached to the outer surface of the container of the seat liner/diaper bag of this patent document, the leg openings-covering pad is likely to be partially or entirely detached from the container by the deformation of the container when relatively heavy articles are accommodated in the container. For avoiding this problem, it becomes necessary to use a disadvantageously complicated fastening means or a disadvantageously complicated fastening method.
Further, U.S. Pat. No. 7,100,982 discloses a shopping cart seat cover which can be removably placed inside the extendable platform of a shopping cart for seating one or two children, which has a substantially planar padded material having a peripheral edge, which when placed inside the extendable platform, forms a seat capable of seating one or two children. The above-mentioned seat formed by the seat cover comprises a front side, a back side, a bottom side, a right side and a left side, and only the peripheral edge of the front side and the peripheral edge of the back side comprise elastic means. When the shopping cart seat cover of this patent document is placed on the above-mentioned extendable platform of a shopping cart, the elastic front and rear sides of the peripheral edge of the planar padded material are bent so that the planar padded material is formed into a seat capable of seating one or two infants thereon. In the shopping cart seat cover of this patent document, the extendable platform is fully covered by the peripheral edge of the planar padded material. Further, the above-mentioned planar padded material has two apertures for allowing the legs of one or two children to extend out from the seat, and is provided with a flap(s) capable of closing the apertures. In this patent document, the flap(s) is attached to the above-mentioned front side of the peripheral edge in substantially the same manner as in the above-mentioned U.S. Pat. No. 5,829,835. Therefore, U.S. Pat. No. 7,100,982 has the same problems as mentioned above in connection with U.S. Pat. No. 5,829,835. Furthermore, the shopping cart seat cover of this patent document has attached thereto a container for accommodating therein the planar padded material in a folded configuration. This patent document states that the shopping cart seat cover of this patent document has improved the comfort and safety of the infant(s) seated in the infant seat. However, as apparent from the structure of the shopping cart seat cover as shown in the drawings of this patent document, the shopping cart seat cover is not completely accommodated in the extendable platform of a shopping cart, but is placed on top of the extendable platform. Therefore, the shopping cart seat cover of this patent document has a problem in that it is difficult to provide a support having a height sufficient for preventing an infant from falling from the seat. If it is attempted to provide the shopping cart seat cover of this patent document with a support wall or the like, which has a sufficient height for preventing the infant from falling from the seat, the portability of the shopping cart seat cover becomes disadvantageously poor. Further, the infant seats provided on shopping carts have various sizes and various designs. However, since the shopping cart seat cover of this patent document comprises a substantially planar padded material, it is very difficult to select such an appropriate material for the planar padded material and such an appropriate design that the shopping cart seat cover of this patent document can be fittedly, stably and safely installed on top of the extendable platforms of shopping carts of various sizes and designs. In addition, when the above-mentioned shopping cart seat cover is carried, the above-mentioned planar padded material needs to be folded and accommodated in the above-mentioned container. That is, in the production of the shopping cart seat cover, it is necessary to choose such a material and a design as would be appropriate for installation on top of infant seats of various sizes and designs, and for carrying in a folded form; however, the appropriate choice of such a material and a design is very difficult. Therefore, the shopping cart seat cover of this patent document is not practical.


A field effect transistor having a thin polycrystalline silicon layer as a channel region, a lower gate electrode beneath the silicon layer, and upper gate electrode with an offset above the silicon layer, and a gate dielectric layer between the lower gate electrode and the silicon layer, and a gate dielectric layer between the upper gate electrode and the silicon layer.

(1) Field of the Invention
This invention relates to improved thin film transistors, more particularly to thin film field effect transistors, provided with dual gate electrodes, one of which has an offset. The invention also relates to methods of fabricating dual gate transistors.
(2) Description of Prior Art
Many different types of semiconductor devices that can store binary information, or data in terms of electric charges, have been developed and are at present used in various computer memories. The list includes, static memories, dynamic memories, read only memories and the like. Semiconductor device memories are widely used because they have the capability of high integration density, and are relatively inexpensive. Among these memories, the static type semiconductor memory has found wide application as a random access memory (RAM), because it can retain stored data without periodic refresh operations.
The static random access memory (SRAM) can be implemented by a large number of flip-flop circuits, each of which stores one bit of information. CMOS flip-flop circuits, each normally composed of a pair of N-channel MOS field effect transistors, and a pair of P-channel MOS field effect transistors, are widely utilized as memory cells because power consumption of the device is very low. However, initially CMOS flip-flop memories necessitated a relatively large area on a semiconductor substrate, making high integration density difficult to attain.
A general circuit structure of the CMOS type static memory cell may be understood by reference to U.S. Pat. No. 4,980,732 and is shown in FIG. 1. In FIG. 1, N-channel MOS transistors QN1, QN2 and P-channel MOS transistors QP1 and QP2 form a CMOS flip-flop circuit in which the transistors QP1 and QN1 having electrically common gates G1 form a first CMOS inverter, and the transistors QP2 and QN2 having electrically common gates G2 form a second CMOS inverter. Output nodes N1 and N2 of the first and second CMOS inverters are connected to a pair of digit lines DL and DL, via a pair of N-channel transfer gate transistors QN3 and QN4, controlled by a word line, WL.
In order to reduce the area that each CMOS circuit occupied on the device, it was proposed to form a pair of P-channel MOS transistors as thin film transistors (TFTS), such as silicon-on-insulator (SOI) structure, with the other pair of N-channel transistors formed in the body of the device. With this structure, the P-channel transistors can overlap a part of the N-channel MOS transistors, and therefore the integration scale of the SRAM is enlarged.
An example of how a thin film transistor is embodied in a CMOS structure is illustrated in FIG. 2. In FIG. 2, a P-type silicon substrate 10 is overlaid with a gate insulator film 16, on which a gate electrode 14 of polycrystalline silicon is formed. In silicon substrate 10 on both sides of the gate electrode 14, N-type diffused regions 14A and 14B at an impurity concentration of between 10.sup.20 and 10.sup.21 Cm.sup.-3 are formed as source and drain regions of transistor QN1. The gate electrode 14 and the N-type diffused regions 14A, 14B constitute the N-channel transistor QN1 in FIG. 1. Accordingly, the N-type diffused region 14A is connected to the ground potential. In FIG. 2, a gate insulator film 17 is formed on the gate electrode 14, and an N-type silicon thin film 13 is formed on the gate insulator films 16 and 17. P-type diffused region 13S and 13D of an impurity concentration of between 10.sup.19 and 10.sup.21 Cm.sup.-3 are formed in the ports of the silicon thin film 13 on both the sides of the gate electrode 14, and the P-channel transistor QP1 in FIG. 1 is formed by the SOI structure by the gate electrode 14 and the P-type diffused regions 13S, 13D. The P-type diffused layer 13S is connected to power source potential Vcc by a lead out electrode 11 composed of aluminum. The P-type diffused layer 13D and the N-type diffused region 14B are connected by a conductive layer 18 of aluminum at node N1. Symbols 12A, 12B and 12C denote thick insulator films, and numeral 15 denotes a port of gate electrode G2 of the second inverter which is formed of P-channel transistor QP2 and N-channel transistor QN2 in FIG. 1.
However, the crystalline characteristics of the polycrystalline silicon film, or the monocrystalline silicon film formed on the semiconductor substrate over an insulating layer is not good, and a P-N junction formed in the silicon film is very leaky. Therefore, power consumption, that is standby current of the SRAM employing the aforementioned SOI type transistors, is relatively large.
A solution to reduce the leakage in a polycrystalline silicon layer of a thin film transistor is set forth in U.S. Pat. No. 4,980,732 and is illustrated in FIG. 3. In FIG. 3 the elements corresponding to the elements shown in FIG. 2 are denoted by the same reference numerals. Note that the P-N junction 20 between the channel region 13 and drain region 13D is spaced from the gate electrode 16. In contrast, corresponding P-N junction 19 in FIG. 2 is directly above gate electrode 16. This space between the channel and the drain reduces the Gate-induced Drain Leakage which is caused by the band-to-band tunneling in the gate overlap region of the drain.
As is believed apparent, the locating of the blocking mask for ion implanting the impurities into the polycrystalline film that forms the source and drain regions of the transistor is very exacting. The accuracy of defining the geometry of offset region is limited by the overlay accuracy of photo lithography process which could be large compared with its typical value.
FIG. 4 illustrates a modification of the structure shown in FIG. 3 as given in the U.S. Pat. No. 4,980,732. In FIG. 4 the elements corresponding to the elements shown in FIGS. 2 and 3 are denoted by the same reference numerals. FIG. 4 illustrates a different placement of the thin film P-channel transistor, i.e. over a thick oxide layer 16A. Gate electrode 19 is provided which is electrically connected to gate 14 of the N-channel transistor.
In such very small Thin Film Devices (TFT) with very short channel length, the leakage through the devices in the off state, presents formidable problems. This presents more of a problem, since the medium in the body of the transistor is polycrystalline silicon, as contrasted with monocrystalline silicon. Dual gate electrodes positioned on opposite sides of the polycrystalline layer are known and have materially increased the on current. But the dual gate without offset will still suffer from the large off current, because existence of large gate to drain electric field.
The use of a single gate electrode with an offset region in thin film transistors is also known and has been implemented to reduce the leakage in the off condition. This TFT structure is described in U.S. Pat. No. 4,980,732.
The offset could reduce the electric field between gate and drain and thus reduce the induced leakage current, which is also known as gate induced drain leakage (GIDL).
While the prior art recognizes the need to minimize or eliminate leakage current in thin film transistors, and has separately used the two aforedescribed structures to meet the objective, further reduction is very desirable.

Offset dual gate thin film field effect transistor

Industrial Technology Research Institute


A saw blade is formed from a blank which has an edge. Inserts, such as tungsten carbide are inserted in apertures in the blank and a finishing cut is then made along the line to produce a series of teeth, each having a point within the body of the insert, and thus formed by the relatively hard material of the insert. Fingers of the inserts provide a root which holds the insert in position during use.

This application is the U.S. national phase of international application PCT/GB01/01882 filed Apr. 30, 2001, which designated the U.S.
The present invention relates to saw blades and in particular, to a method of making a saw blade blank and a saw blade therefrom.
The invention provides a method of making a saw blade blank, in which at least one aperture is formed in a strip of relatively soft material and an insert of relatively hard material is fixed in the aperture, the insert causing material of the blank to be displaced as the insert is introduced, and material being removable from the edge of the blank to form a saw blade with a tooth, leaving at least part of the insert exposed to form a cutting portion of the tooth.
The aperture may be formed by the insertion of the insert, or may be formed prior to insertion of the insert.
Preferably the entire circumference of the aperture is spaced from the edge of the blank.
Preferably a plurality of apertures are formed for respective inserts. The apertures may be regularly spaced along the blank and may be equally spaced from the edge of the blank. Alternatively, the apertures may be spaced by different distances from the edge of the blank, to allow composite teeth to be formed with cutting portions at different separations from the body of the blank. The pitch of the apertures along the blank may vary along the blank.
The or each aperture may be circular. The insert may be non-circular. The insert may comprise a main body from which at least one projection extends, the projection serving to displace material of the strip when the insert is introduced, and thereafter to remain embedded within the material of the strip. Preferably a plurality of projections as aforesaid are provided on the insert. The projections may each have a convex extremity and be separated from neighbouring projections by a concave portion of the outline of the insert.
A portion of the outline of the insert may have the shape of the required cutting portion, prior to insertion. The aperture may open to the edge of the blank, the insert being positioned in the aperture to leave the shaped portion exposed.
Preferably at least one dimension of the insert is less than the corresponding dimension of the aperture in the plane of the blank, to cause a gap to be left between the blank and the insert when positioned in the aperture, the gap serving to receive additional material for fixing the insert in the aperture. The fixing material may be weld or brazing flux.
Preferably the inserts are tungsten carbide, and may be sintered. The blade may be steel.
The invention also provides a saw blade blank manufactured according to the method set out above.
The invention also provides a saw blade blank comprising a strip of relatively soft material, an aperture formed in the strip, an insert of relatively hard material fixed in the aperture and sufficiently large to cause material of the blank to be displaced by the introduction of the insert, whereby material may be removed from the edge of the blank to form a tooth, at least part of the insert being exposed in the finished blade to form a cutting portion of the tooth.
The blade blank may have any of the features set out above.
The invention also provides a method of making a saw blade from a saw blade blank manufactured according to the method as set out above, comprising removing material from the edge of the blank to form a tooth, at least part of the insert being exposed in the finished blade to form a cutting portion of the tooth.
The invention also provides a saw blade manufactured according to the method set out above.
The invention also provides a saw blade comprising a strip of relatively soft material, an insert of relatively hard material fixed in an aperture in the strip and sufficiently large to cause material of the blank to be displaced by the introduction of the insert, and the strip having material removed from its edge to form a tooth, at least part of the insert being exposed in the blade to form a cutting portion of the tooth.
The blade may have any of the features set out above.


An object is to provide a scintillator plate exhibiting even sharpness, and further exhibiting enhanced sharpness by use of CsI crystals. Disclosed is a scintillator plate for radiation comprising a support and provided thereon a phosphor layer emitting light caused upon exposure to radiation, wherein the phosphor layer comprises a plurality of phosphor columnar crystals, and any two phosphor columnar crystal diameters represented by a and b (a≧b) satisfy the following inequality of 1.0≦a/b<1.5. Further disclosed is a scintillator plate for radiation comprising a support and provided thereon a phosphor layer emitting light caused upon exposure to radiation, wherein the phosphor layer comprises a phosphor made from cesium iodide (CsI) as a base material and an activator, and a most dominant growth direction in the phosphor is (n 0 0) plane (where n=1, 2 or 3).

Generally, radiographic images such as X-ray images have been commonlly utilized for diagnoses of condition of a patient at medical scenes. In particular, radiographic images by an intensifying screen-film system, as a result of achievement of a high sensitivity and a high image quality during the long improvement history, are still utilized at medial scenes all over the world as an image pick-up system provided with the both of high reliability and superior cost performance.
However, the image information is so-called analogue image information, and it is impossible to perform free image processing and image transmission in a moment as with digital image information which has been ever developing in recent years.
Therefore, in recent years, a radiographic image detector system such as computed radiography (CR) and flat-panel type radiation detector (FPD) has come to be in practical use. Since these can directly obtain a digital radiographic image and directly display the image on an image display device such as a cathode ray tube and a liquid crystal panel, there is not necessarily required image formation on photographic film. As a result, these digital X-ray image detector systems have decreased necessity of image formation by silver salt photography and significantly improved convenience of diagnostic works at hospitals and clinics.
CR has come to be in practical use in medical scenes at present as one of digital technologies of X-ray images. However, the sharpness is not sufficient nor the spatial resolution is, and CR has not achieved an image quality of a screen-film system. In addition, flat plate X-ray detector system (FPD) employing thin film transistor (TFT), described in such as "Amorphous Semiconductor Usher in Digital X-ray Imaging" by John Rawlands, Physics Today, 1997 Nov., p. 24, and "Development of a High Resolution, Active Matrix, Flat-Panel Imager with Enhanced Fill Factor" by L. I. Anthonuk, SPIE, 1997, vol. 32, p. 2, as a further new digital X-ray image technology has been developed.
It is a feature that such a FPD is smaller in size than a CR and is superior in image quality of image pick-up at a high dose. However, on the other hand a FPD produced a problem such that an SN ratio is decreased at image pick-up at a low dose, accompanied with a insufficient image quality, because of electric noise caused by providing a TFT as well as a circuit.
In such a FPD, utilized is a scintillator plate, which is prepared by employing an X-ray fluorescent material provided with a property of emitting via radiation to convert radiation into visible light, and it is necessary to utilize a scintillator plate having a high emission efficiency to improve an SN ratio in image pick-up at a low dose. Generally, the emission efficiency of a scintillator plate is determined by a thickness of a fluorescent layer and an X-ray absorption coefficient of a fluorescent material, however, the thicker the fluorescent layer thickness, the more sharpness is decreased due to scattering of emission light in a fluorescent layer.
Cesium iodide (CsI) here has a relatively high conversion ratio from X-ray to visible light and the fluorescent material is possible to be formed into a columnar crystal structure by vacuum evaporation. An optical guide effect, in which luminescence within the crystals that is emitted from the side surfaces of the columnar crystals is reduced, can be obtained by providing a phosphor composed of columnar crystals. That is, the scattering of luminescence as well as the sharpness drop is suppressed. It is accordingly possible that the thickness of a phosphor layer is made thicker without degrading sharpness. A CsI columnar crystal diameter is generally 3-20 μm, and the thinner the columnar crystal diameter is, the higher the optical guide effect is obtained, resulting in enhanced sharpness.
Incidentally, it is strongly desired to uniform an image quality distribution within a detector plane, since the detection area of FPD is large. In other words, it is desired to uniform the distribution within the plane concerning various phosphor properties in order to improve the image quality, since the distribution within the plane depends largely on an image distribution. Specifically, it is also desired to uniform the phosphor columnar crystal diameter within the detector plane since sharpness depends largely on a phosphor columnar crystal diameter.
Therefore, as described in Patent Document 1, known is a scintillator plate for radiation in which the phosphor columnar crystal diameter becomes larger from the center of a phosphor layer toward the periphery. According to such the scintillator plate for radiation, no damage is to occur during adhesion employing a roller and a sensor panel equipped with a photoelectric transducer section when phosphor is strengthened by making phosphor columnar crystals at the periphery thicker, whereby an image with no blur together with no damage of phosphor at the production stage can be obtained.
Also known is a scintillator plate which is fixed by covering a phosphor layer with films after preparing phosphor composed of columnar crystals by employing CsI, as described in Patent Document 2. Such the scintillator plate is capable not only of controlling degradation of sharpness, but also of protecting the phosphor to be covered with the films.
(Patent Document 1) Japanese Patent O.P.I. Publication No. 2003-66147
(Patent Document 2) Japanese Patent O.P.I. Publication No. 63-215987


A method for fabricating a semiconductor device and the device made thereof are disclosed. In one aspect, the method includes providing a substrate comprising a semiconductor material. The method further includes patterning at least one fin in the substrate, the fin comprising a top surface, at least one sidewall surface, and at least one corner. A supersaturation of point defects is created in the at least one fin. The at least one fin is annealed and then cooled down such that semiconductor atoms of the semiconductor material migrate via the point defects.

1. Field of the Invention
The present invention generally relates to methods for manufacturing semiconductor devices. More specifically, the present invention relates to methods for enhancing the performance of semiconductor devices and the semiconductor devices obtained with the methods thereof. More particularly, the present invention also relates to methods for rounding corners and smoothing surfaces of semiconductor devices.
The present invention also relates to methods for manufacturing fin-based devices. More particularly, the present invention also relates to methods for rounding corners and smoothing surfaces of fin-based devices and the fin-based devices made thereof.
2. Description of the Related Technology
Scaling down of planar bulk CMOS devices has become a major challenge in the semiconductor industry. High channel doping, band-to-band tunneling across the junction and gate-induced drain leakage, short channel effects are some of the challenges that need to be overcome. Whereas at the beginning, device geometrical shrinking already gave a lot of improvements in IC performance, nowadays new techniques, methods, materials and device architectures have to be introduced beyond the 90 nm technology node. Multi-gate field effect transistor (MUGFET), also often referred to as fin-based semiconductor device or FINFET, is one of the promising candidates for further scaling down to 32 nm or less. Due to their three dimensional architecture, with the gate electrode wrapped around a thin semiconductor fin, an improved gate control (and thus less short channel effects) over the channel could be achieved by using multiple gates. Depending on the shape of the gate electrode, different types of MUGFETs can be defined. A double-gate finfet is a multi-gate device where the gate electrode only controls the conductivity of the two sidewall surfaces of the fin. Such a device is also often referred to as a double-gate device. An omega-gate finfet (Ω-gate finfet) is a multi-gate device where the gate controls the conductivity of the two sidewall surfaces and the top surface of the fin. An U-gate finfet is a multi-gate device where the gate controls the conductivity of the two sidewall surfaces and the bottom surface of the fin. A round-gate finfet is a multi-gate device where the gate controls the conductivity of the two sidewall surfaces, the top surface of the fin and the bottom surface of the fin. However with the introduction of MUGFETs, new problems arise.
One problem is related to the etching of the fin structures (typically done in the patterning process of the fins). Whereas for planar bulk CMOS devices current conducts on the top surface of the semiconductor wafer,—depending on the type of MUGFET—the current in MUGFET devices takes place not only on the top surface of the device, but also along the sidewalls of the fins. The etching of the fins induces damage of the sidewall surfaces of the fin, leading to reduced carrier mobility along these surfaces. For optimal device performance the sidewalls should be as smooth as possible. The surface roughness of the sidewalls of the fin should be as small as possible.
Another problem is the corner effect. In the corners of the fin, typically with an angle of 90 degrees, the electrical fields during device operation are different than in the planar region of the device. This leads to a different threshold voltage in the corner regions of the MUGFET compared to the threshold voltage along the sidewalls of the MUGFET, resulting in a degradation of the subthreshold characteristics. Therefore, for achieving good device performance, it is desirable to eliminate as much as possible the sharp corners in the fins.
One known approach to smooth the sidewalls and to round the corners of the fin is made through a combination oxide removal and hydrogen anneal of the fins, as explained in a paper by R. J. Zaman et al. "Effect of hydrogen annealing process conditions on nano scale silicon (011) fins," Mater. Res. Soc. Symp. Proc. Vol. 872 p. 37-41 (2005). Due to the hydrogen annealing, a reflow of the atoms at the semiconductor surface of the fin will occur tending to minimize the surface energy, thus resulting in minimizing the surface area, thus resulting in rounded corners. A disadvantage of this method however is the narrow temperature/pressure window. For example, at atmospheric pressure no reflow occurs below 875 degrees Celsius while above 925 degrees Celsius silicon evaporation occurs. Three other disadvantages of this method are: the undercut at the bottom fin which will decrease the stability of narrow fins; the control of the radius of the corner rounding which is crucial for controlling the profile of narrow fins and, as a consequence from the latter disadvantage, the limitation on fin width since small fin width variations will result in discontinuous fins because of Si migration.
As such, there is a need to overcome these disadvantages mentioned in the prior art.

Method for fabricating a semiconductor device and the semiconductor device made thereof


A pump cartridge for use in a hydraulic braking system includes a sleeve having an outer surface and an inner bore. A piston has a first portion that is coaxially received within the sleeve inner bore. A second portion of the piston extends from the sleeve and is configured to reciprocate the piston first portion relative to the sleeve in response to rotation of an eccentric. A retainer engages the sleeve and is configured to maintain the first portion of the piston within the sleeve inner bore. A filter assembly is formed as a separate component and has a bore configured to permit the piston second portion to extend through the filter bore.

This invention relates in general to vehicular braking systems and, in particular, to hydraulic braking systems having pump-operated pressurizing systems.
Hydraulic braking systems, particularly for vehicular applications, can be equipped with pump and controller systems that dynamically vary the fluid pressure in response to sensor inputs. These sensor inputs provide information relating to the dynamic operating state of the vehicle, i.e., skidding conditions, tractive effort conditions, and steering reactions, to name a few. These braking systems, sometimes referred to as antilock braking systems (ABS), traction control systems (TCS), and electro-hydraulic braking systems (EHB), use a motor-driven pump to supply fluid pressure to a wheel-end brake mechanism. The fluid pressure is modulated by a valve circuit to provide proper distribution of braking effort to each wheel in response to a particular vehicle dynamic state.
The hydraulic pumps may be piston-type hydraulic pumps that supply fluid pressure through a piston that axially reciprocates within a cylinder bore. These piston pumps generally include a plurality of components, such as pistons, cylinders, bushings, springs, filters, and seals, for example, that are assembled into a pump housing. In order to minimize the package size of the pump assembly, the pump components are often unique to a particular pump size. This, in turn, raises part inventories and assembly costs. Additionally, the several components that make up the pump need to be retained during the assembly process into the pump housing. To help minimize costs, some components are integrated into a single part. However, this integration tends to limit material selection flexibility because the integrated components are often formed with the same or compatible materials, rather than using materials optimized for specific functions. Thus, it would be desirable to provide a pump assembly for a vehicular braking system that reduces packaging size at a lower assembly cost, yet retains a high degree of material selection flexibility.

Filter and retainer assembly for piston pump


A receiver device in a vehicle includes a receiver system and a receiver module remote from the receiver system. A plurality of high-frequency signals are received or emitted via at an antenna attached to the receiver module. The high-frequency signals are transformed in the receiver module and forwarded to the receiver system.

Known receiver devices receive high-frequency signals via at least one antenna, and where appropriate via several antennas (diversity). The high-frequency signals are converted in a processing unit (in particular from a high frequency to an intermediate frequency), processed further, and then fed to the display (audibly and/or visually).
Such receiver devices are arranged in a housing, which is accommodated at a suitable location in a vehicle (in the region of the dashboard, for example). For the power supply, it is necessary to lead a power supply cable to the receiver device. Moreover, the cable of the antenna, generally a coaxial cable, must be routed to the receiver device over long distances in the vehicle. However, this is disadvantageous from the point of view of high-frequency technology.
For the processing of high-frequency signals, it is necessary to provide access authorization and/or charging. This is performed with a SIM card or the like, for example. For this purpose, the housing must be accessible for the insertion and replacement of the SIM card.
Since such receiver devices, in particular the receiver systems thereof, often operate on the basis of software, from time to time it is also necessary to update the software to the newest version or to reconfigure the entire receiver device.
Multi-receiver systems require coaxial cables (referred to as coaxial lines, and also as HF cables) for high-frequency signals. Furthermore, current and future technologies (such as 4G, 5G, DSRC, WLAN, for example) require n antennas and thus an n-fold multiplication of coaxial lines (n=number of antennas, preferably n is greater than 1).
This leads to high demands on the HF cable in relation to weight, HF damping and routing strategies in the vehicle. HF cables are regarded as costly in the motor vehicle sector. Line lengths are thus a financial consideration for the entire receiver device, in particular for the vehicle manufacturer. Furthermore, each signal processing operation, or processing, inside an appliance leads to further thermal losses, which have a negative influence on the life expectancy of individual electronic components and which can also lead to reduced reception performance.

LTE module remote from a receiver system


A new firefighting monitor has multiple pivoting conduit segments and a synchronization mechanism with engaging faces that automatically restrain pivoting of an intermediate conduit segment with respect to an upstream conduit segment when the downstream conduit segment is pivotable with respect to the intermediate conduit segment, and automatically restrain pivoting of the downstream conduit segment with respect to the intermediate conduit segment when the intermediate conduit segment is pivotable with respect to the upstream conduit segment. In a variation, an intermeshed gear train causes a downstream conduit segment to pivot proportionately with respect to an intermediate conduit segment as the intermediate conduit segment pivots with respect to the upstream conduit segment.

Fires and risks of fires in hazardous locations often require applications of large volumes of water or other extinguishing agents such as foam, compressed air foam, clean agents (gas), or dry chemicals, or combinations thereof. For safety, firefighters prefer to dispense these fluids from a sufficiently safe distance. This requires the fluids to be dispensed at high velocities, and the velocity through the nozzle in turn causes substantial nozzle reaction forces. These forces are often higher than can be resisted by human muscle power.
To absorb these reaction forces and transmit them to the ground or a substantially stationary object, fluid projecting devices called monitors are sometimes used. These monitors are arranged to direct the fluids in any of a range of desired trajectories, generally having at least one degree of freedom. Monitors generally include flow path designs and mechanisms that enable firefighters to adjust the trajectory easily and with little force.
The structural elements that enable a monitor to deliver fluid through a range of trajectories may be broadly divided into three classifications:                Swivel joints that form rotary unions;        Flexible flow paths that are formed by hoses or bellows; and        Ball-in-socket arrangements.
The actuating mechanisms used by a firefighter to adjust these structural elements to a particular trajectory generally fall into these three classifications:                The structural elements are moved directly by human force, and remain stationary of their own accord or are secured with a means such as a locking knob, clamp, or friction slip clutch;        The structural elements are moved under mechanical advantage by a human-operated adjusting mechanism, such as a worm/worm wheel, lever, rack & pinion, screw, cables, chains, and push/pull rods; and        The structural elements are moved by force from an external source, such as a hydraulic, electric, pneumatic, or water powered drive motor with gear reduction, or by a cylinder, piston, or rotary actuator driven by oil from an external source or by water from within the monitor. These arrangements enable a firefighter to operate the monitor under power while either at the monitor or from a distance via wired or wireless operation.
Fire monitors with a wide variety of configurations have been patented over the course of time. These configurations include combinations of a wide variety of different structural elements that provide adjustability of the trajectory, in combination with various mechanisms for firefighters to use to adjust the monitor to a particular trajectory or direction.
This invention relates generally to firefighting monitors that use pivotable conduit segments, and more particularly to firefighting monitors like those described in US reissue patent RE40441. The monitor illustrated in that patent has a plurality conduit segments in the form of ball-in-socket joints that provide at least one degree of freedom for swiveling the conduit segment under pressure. In that monitor, the forces due to water pressure and nozzle reaction are borne by the pair of orthogonally arranged pivoting conduit segments, and the forces of gravity are dealt with by means of a one-way brake. The monitor offers two degrees of freedom of movement, and permits a range of travel of +/−20 degrees in both the horizontal and vertical planes. The simplicity, compact size, ease of use, and relatively low manufacturing cost of the pivoting conduit segments has proven quite useful, and has been found to offer advantages over other means for adjusting trajectories in portable monitors.
Patent RE40441 taught that "additional ball and socket combinations could be added to the double ball and socket combinations to add additional range of motion in a pivoting connector". Over time, it has become apparent that the additional range of motion suggested by the patent would prove useful. Patents such as U.S. Pat. No. 7,644,777 show efforts to increase the range of motion by using two or more consecutive pivoting conduit segments whose axes of rotation are substantially parallel. However, the nozzle reaction force acts upon the segments in such monitors in a way that causes the a downstream conduit segment to rotate with respect to an upstream conduit segment, creating, for example, a tendency for the discharge elevation to raise upwards by itself. Some have touted this tendency as a "safety feature" (because it stops unattended fire monitors from spraying at lower elevation angles), but others recognize that there are disadvantages in requiring the firefighter to exert a separate force to maintain the relative positioning of the downstream segment.
In these portable monitors, the downstream conduit segment places the nozzle reaction forces on a plane that passes above the horizontal axis between a midstream conduit segment and an upstream conduit segment, resulting in a net torque about that axis. This vertical offset also increases the overturning moment of the monitor, tending to make the front of the monitor lift off the ground and thus decreasing the stability of the monitor. Counterbalance devices described in the patents inhibit free range of travel for unattended operation of the monitor.
U.S. Pat. No. 7,802,630 shows an attempt to increase the range of motion of a firefighting monitor by using multiple pivoting fluid conduit segments in series. This monitor uses a series of identical ball-and-socket conduit segments that are each easy and cheap to manufacture. However, operation of the monitor at angles other than straight ahead results in an ever-increasing moment from nozzle reaction, which tends to straighten the assembly. With only a single actuator, the effects of nozzle reaction and gravity (which sometimes aggregate and sometime offset each other, depending upon the position of the conduit segments) tend to make the monitor whip from side to side as even slight misalignment from a straight position causes moments on the other conduit segments. On the other hand, using an actuator on multiple conduit segments (as described in connection with the embodiment seen in FIG. 6) makes the device expensive to manufacture and difficult to use.
Some of the disadvantages of these monitors were attempted to be addressed in US patent publication 2009-0277656, which shows a series of concentric pivoting elements that have a common axis of rotation. The illustrated monitor appears to be operable by hand, and would not move by itself under the forces of nozzle reaction. However, it is not evident that the pieces can be assembled as depicted, and the concept has serious flaws: the pieces are quite complex to machine from metal (even with a 5-axis CNC machining center) and each joint requires specialized seals to be molded (each of a different size). The elevation mechanism is far more complex than those used in swivel joint monitors from the same company, such as those depicted in U.S. Pat. No. 4,674,686.

Pivoting fluid conduit sequencing mechanism


An internal combustion engine (30) with a supercharger device (50, 52) for increasing the charging pressure in an air inlet system (33) has a number of cylinders (32). Each cylinder (32) has at least one exhaust valve (36) which is connected to the exhaust system (40) and at least one inlet valve (34), which is connected to the air inlet system (33). Scavenging is carried out with a valve overlap between the inlet valve (34) and the exhaust valve (36). For controlling the operation of the internal combustion engine the system monitors whether the scavenging was successful.

With modern internal combustion engines the required combustion air is often supplied to the cylinders via a supercharger with a pressure increased in relation to the ambient pressure. The pressure increase required for this can in this case typically be achieved by using a so-called mechanical supercharger. This is driven via the crankshaft of the internal combustion engine.
Also known is the practice of increasing the pressure via a so-called exhaust gas turbocharger. In this case a turbo compressor is driven with the aid of a turbine connected to the exhaust system which ensures an increase in pressure on the air inlet side of the cylinders. For this type of turbocharging it is however also known that at low engine speeds and the associated low mass throughputs a so-called turbo lag occurs. The efficiency of the turbocharger is then low in this operating range and only a relatively small motor torque can be achieved at full load.
Such a turbocharger and its use in an internal combustion engine are for example known from DE 10 2004 030 B3. This document is based on control of the internal combustion engine with a turbocharger in which, depending on a requested torque, the inlet and exhaust valves are adjusted so that these are opened simultaneously for a predetermined time, meaning that their timing overlaps. With a four-stroke engine, this valve overlapping occurs towards the end of the 4th stroke on expulsion of the exhaust gas and continues into the 1st stroke of the induction, so that the inlet valve is already open before the exhaust valve is completely closed. This means that the accelerated exhaust gas column in the exhaust manifold causes fresh fuel-air mixture to be sucked into the combustion chamber and reduces the likelihood of exhaust gas remaining in the combustion chamber.
With high-performance engines the exhaust valve opens even before bottom dead center is reached, this relaxes the gas column early, so that the subsequent upwards movement of the piston is not so heavily braked. During this upwards movement the inlet valve then also opens, so that, as mentioned, both are now simultaneously opened. Since the gas mixture has however been sharply accelerated in the direction of the exhaust valve no air is pushed back at the inlet valve, but a flushing process takes place which is also promoted by a large valve acceleration which additionally carries air with it. The exhaust valve ideally closes when the air column comes to a standstill. The inlet valve likewise remains open until the air column which is sucked in by the upwards movement of the piston comes to a standstill. Since the air is sluggish to a certain extent at high engine speeds, it now compresses itself against the piston which is already moving upwards again. This additional compression brings about a better filling.
With this process, which is also referred to as scavenging, a fall in pressure occurs from the inlet side to the outlet side across the cylinders so that a flushing through of inlet air to the exhaust side occurs. The result is that any turbo lag occurring is reduced. To increase the accuracy with which the mass of air actually remaining in the cylinder can be determined during or after a scavenging process, it is additionally proposed, if the actual Lambda value deviates from Lambda setpoint value, for a valve overlap to correct the value for the opposing exhaust pressure as a function of the deviation established.

Method for operating an internal combustion engine and a control and regulation device


A support base has adjustable slides mounted thereon. A cam arm is mounted at one end on a piston rod that is used to cause vertical movement of the cam arm. The opposing end of the cam arm has a bore that rotatably receives a sleeve therein. An electrode holder is pivotally mounted in the sleeve such that one end of the electrode holder extends beyond the end of the sleeve. The electrode holder is movable between a first normal working position and a second non working position that corresponds to movement of the cam arm. A drive motor and belt are engaged with the sleeve to cause rotation of the sleeve, electrode holder, and electrode to perform machining operations on a workpiece that the electrode is inserted into.

1. Field of the Invention
The present invention is generally related to the machining of cylindrical parts and particularly to electrical discharge machining of grooves in cylindrical parts.
2. General Background
In some industries it is required that tubular members have one or more grooves around the inner or outer diameter of the tubular members. Patents directed to the use of electric discharge machining (EDM) or some type of erosion for cutting members or forming notches or grooves that applicant is aware of include the following.
U.S. Pat. No. 4,948,933 discloses a portable electrode arc cutting tool that is releasably attachable to the work surface for cutting an internal or external precision depth notch in the work surface. The electrode member extends over a distance equal to the length of the notch to be formed. The depth of the notch is controlled by a calibrated feed control that limits the radial movement of the electrode.
U.S Pat. No. 4,476,368 discloses a metal tube wall disintegrator where the electrode moves in a path that mechanically opens and closes the circuit by alternately contacting and retracting the electrode from the work piece to produce the electrical spark erosion.
U.S. Pat. No. 4,203,018 discloses an electrode mounted on horizontal slides fed outward with a cam mechanism. U.S. Pat. No. 4,104,503 discloses an apparatus for electroerosion within a solid component where two linkage members slide relative to each other to rotate the electrode into the work.
U.S. Pat. No. 4,100,388 discloses an electroerosion method and apparatus where two electrodes are used, with the path of one electrode intersecting that of the other electrode to create a dovetail channel.
The known art of electrical discharge machining leaves a need for an apparatus capable of providing a circumferential groove around the interior or exterior diameter of a tubular member.

EDM apparatus with a cam arm for moving an electrode