Abstract: A laser pattern generator for semiconductor mask making or direct writing of features on a semiconductor wafer uses a pulsed laser source to achieve high power and short wavelength (e.g. 263 nm or less) radiation, for writing very small-sized features. The laser pulse frequency is either synchronous or asynchronous to the writing grid of the features being written, in various embodiments.

Abstract: A small field scanning photolithography system uses opposing motion of a reticle and a blank to compensate for image reversal by a projection system such as a conventional Wynne-Dyson optical system which forms a reverted image on a blank. The reticle has a reverted pattern. During scanning, the reticle moves along a reverted axis in a direction opposite the direction in which the blank moves. The opposing motions can either expose a stripe on the blank or index the reticle and blank for exposure of a next stripe. In one embodiment of the invention, the reticle and blank are on independently movable precision air bearing stages. Typically, the blank and reticle move together perpendicular the reverted axis and in opposite direction along the reverted axis. The stages can move the reticle and blank different amounts to correct for shrinkage and temperature changes which cause the size of the reticle and blank to differ.

Abstract: Magnification correction for small field scanning of large blanks is provided by adding magnification adjusting elements (lenses) to a double pass Wynne-Dyson lens or other type of one-to-one projection lens. The magnification adjusting optical elements includes two pairs of low power lenses, one associated with each of the input and output prisms of a Wynne-Dyson lens. Movement of the magnification adjusting optics provides positive or negative magnification as needed to correct for any expansion or compaction of the blank relative to the reticle (mask) and hence maintain alignment. Further magnification correction is provided by a small velocity relative movement between the reticle and the blank by means of a secondary stage in the scan direction. This corrects for any alignment error in the scan direction and may be used independently of the optical correction technique with any type of projection lens.

Abstract: A small field scanning photolithography system has a double pass Wynne-Dyson optical system which provides an erect, non-reverted, unmagnified image. An optical path through the system passes from an object, reflects off an input reflector, passes through a first quadrant of a lens, reflects off a concave mirror, passes through a second quadrant of the lens into folding optics where an intermediate image forms, passes from the folding optics through a third quadrant of the lens, reflects off the concave mirror a second time, passes through a fourth quadrant of the lens, and finally reflects off an output reflector to a plane where a final image forms. Typically, the input and output reflectors and the folding optics are prisms. A field stop may be provided in the folding optics where the intermediate image forms. Magnification adjusting optics can be added to the input and output prisms or to the folding optics.

Abstract: Magnification correction for small field scanning of large blanks is provided by adding magnification adjusting elements (lenses) to a double pass Wynne-Dyson lens or other type of one-to-one projection lens. The magnification adjusting optical elements includes two pairs of low power lenses, one associated with each of the input and output prisms of a Wynne-Dyson lens. Movement of the magnification adjusting optics provides positive or negative magnification as needed to correct for any expansion or compaction of the blank relative to the reticle (mask) and hence maintain alignment. Further magnification correction is provided by a small velocity relative movement between the reticle and the blank by means of a secondary stage in the scan direction. This corrects for any alignment error in the scan direction and may be used independently of the optical correction technique with any type of projection lens.

Abstract: An improved laser pattern generation apparatus. The improved pattern generation apparatus of the present invention uses a laser beam to expose a radiant sensitive film on the workpiece to print circuit patterns on a substrate. The laser beam is aligned using a beam steering means. The laser beam is split into 32 beams to create a brush. The brush scans the workpiece through use of a rotating polygonal mirror. Each beam of the brush may have one of seventeen intensity values. The beams are modulated by an Acousto-Optical Modulator. Signals provided to the Acousto-Optical Modulator define the pattern to be generated. These signals are created by a rasterizer. Increased print speed is accomplished through the use of a wider brush and a print strategy that eliminates physical stage passes.

Abstract: A method and apparatus for printing arbitrarily large circuit patterns using small field optics. The use of small field imaging optics allows the use of high NA lens designs capable of printing smaller geometries than otherwise would be possible. The field size in a first axis is extended by scanning an object and image past the lens; the field size in a second axis is extended by stitching the scans together in an overlapped fashion. This overlapped printing technique averages many random and systematic errors and allows the placement of field adjacencies within die boundaries. The effective field size of such a system is limited only by reticle size and stage mechanics. The apparatus further includes error correction loops for enhancing stage synchronization accuracy and for reducing field adjacency errors.

Abstract: A method and apparatus for printing arbitrarily large circuit patterns using small field optics. The use of small field imaging optics allows the use of high NA lens designs capable of printing smaller geometries than otherwise would be possible. The field size in a first axis is extended by scanning an object and image past the lens; the field size in a second axis is extended by stitching the scans together in an overlapped fashion. This overlapped printing technique averages many random and systematic errors and allows the placement of field adjacencies within die boundaries. The effective field size of such a system is limited only be reticle size and stage mechanics. The apparatus further includes error correction loops for enhancing stage synchronization accuracy and for reducing field adjacency errors.

Abstract: An improved pattern generation system. The pattern generation system of the present invention discloses an improved optical system for correcting problems of astigmatism and ellipticity in a radiant energy beam used for generating patterns on a workpiece. The present invention further discloses improved control circuitry for controlling modulation of said beams. The control circuitry corrects for problems of isofocal bias caused by non-linearities in the turn-on/turn-off of the beams.

Abstract: An apparatus for splitting radiant energy beams produced by a laser or other light source. The apparatus comprises a plurality of mirrors, each aligned to reflect a beam or plurality of beams from one mirror to the next. Each mirror comprises a glass body with a layer of 50% reflective coating and a layer of anti-reflecting coating on one side of the body. A layer of 100% reflective coating is on the other side of the body. A beam is, thus, 50% reflected from the first reflective layer and allowed 50% to pass through the layer. The remainder of the beam is reflected from the 100% reflective layer.

Abstract: A laser pattern generation apparatus particularly suited for semiconductor applications. The laser beam is split into a plurality of beams and modulated with acousto-optic modulators. A rotating mirror having a plurality of facets causes the beam to scan the workpiece.

Abstract: A Malone-type final stage for utilization in a Stirling cycle cryogenic cooler apparatus includes a displacer slidable within a vessel. .sup.4 He, .sup.3 He, or a mixture thereof is made to flow in a pulsating unidirectional manner through a regenerator in the displacer by utilization of check valves in separate fluid channels. Stacked copper screen members extend through the channels and through a second static thermodynamic medium within the displacer to provide efficient lateral heat exchange and enable cooling to temperatures in the range of 3-4 K. Another embodiment utilizes sintered copper particles in the regenerator. Also described is a final stage that has a non-thermally conducting displacer having passages with check valves for directing fluid past a regenerator formed in the surrounding vessel.

Abstract: A heat transfer device is described that can be operated as a heat pump or refrigerator, which utilizes a working fluid that is continuously in a liquid state and which has a high temperature-coefficient of expansion near room temperature, to provide a compact and high efficiency heat transfer device for relatively small temperature differences as are encountered in heating or cooling rooms or the like. The heat transfer device includes a pair of heat exchangers that may be coupled respectively to the outdoor and indoor environments, a regenerator connecting the two heat exchangers, a displacer that can move the liquid working fluid through the heat exchangers via the regenerator, and a means for alternately increasing and decreasing the pressure of the working fluid. The liquid working fluid enables efficient heat transfer in a compact unit, and leads to an explosion-proof smooth and quiet machine characteristic of hydraulics.