Abstract: A fluid purging assembly (10) that purges a first fluid (16) from an assembly cavity (12) of an optical assembly (14). The fluid purging assembly (10) includes a control housing (22) that defines a housing chamber (78) which is sized and shaped to enclose at least a portion of the optical assembly (14). The fluid purging assembly (10) also includes a housing pressure controller (24) for controlling a housing pressure in the housing chamber (78). As provided herein, during the fluid purging process, the fluid purging assembly (10) controls the housing pressure in the housing chamber (78) so that the housing pressure is substantially equal to a cavity pressure in the assembly cavity (12). This prevents damage to optical elements (32) within the optical assembly (14). Preferably, a cavity control system (90) is used to control the cavity pressure in the assembly cavity (12) of the optical assembly (14) so that the cavity pressure is substantially equal to an atmospheric pressure near the optical assembly (14).

Abstract: A support assembly (12) for an exposure apparatus (10) includes a frame assembly (34), an elevator assembly (36) and a pivot assembly (38) for supporting at least one subassembly above an isolation base (32). The elevator assembly (36) selectively lifts the frame assembly (34) and the subassembly relative to the isolation base (32). Further, the pivot assembly (38) allows a portion of the frame assembly (34) and the subassembly to be rotated relative to the isolation base (32). As a result of this design, the subassemblies of the exposure apparatus (10) can be removed relatively easily for service and adjustment.

Abstract: The invention includes a two-dimensional electric motor having two arrays of permanent magnets and at least two coils. The arrays of permanent magnets each have north and south poles distributed in both longitudinal and latitudinal directions along a plane. North poles in the first array are aligned with south poles in the second array, and south poles in the first array are aligned with north poles in the second array. The coil has a portion between the two arrays of permanent magnets. In another embodiment, the two-dimensional electric motor has an array of permanent magnets and two sets of two coils. The two sets of two coils are positioned on two different sides of the array. The invention permits simpler control methods, more stable motion, increased efficiency, and reduced stray magnetic fields. The invention should be particularly useful in semiconductor processing equipment.

Abstract: A fluid bearing suitable for use in vacuum region comprises a fluid passageway for introducing a fluid into the bearing, a pump-out slot for evacuating the fluid from the bearing, and a bearing seal disposed along a periphery of the bearing to restrict fluid from escaping from the bearing into the vacuum region. The bearing seal comprises a bridge structure including a first base, a second base, a transverse member fixed at one end to the first base and movably disposed in a slot defined by the second base, and a sealing sheet extending from the transverse member between the first and second bases. The sealing sheet forms a compliant mechanical wall around the periphery of the bearing. The seal further includes an adjustable spring force element which exerts a force on the sealing sheet to ensure marginal contact with a bearing support surface to form a low-frictional seal.

Abstract: A projection exposure apparatus for exposing a semiconductor wafer to a pattern, formed on a reticle, using a projection lens system. An alignment optical system is disposed at a backside of the wafer which is remote from the projection lens system. The alignment optical system detects an alignment mark provided on the frontside of the wafer from the backside of the wafer. Thus the wafer alignment mark is detected without being adversely affected by integrated circuit layers, e.g. photoresist, metallization, etc. applied to the principal surface (frontside) of the wafer, and the reticle and wafer can be aligned accurately. Any tilting or wedging of the wafer, i.e. non-normality to the incident light beam, is detected and corrected for.

Abstract: A two-axis stage assembly includes a generally planar horizontally mounted base plate; a stage plate generally parallel to the base plate, the stage plate having a first axis and second orthogonal axis; a set of spaced bearings depending from a bottom surface of said stage plate, the bearings each having an arcuate bottom surface in rocking contact with a facing support surface of the base plate; a joint attached to the bottom surface of the stage plate and pivotably mounting each bearing, the joint being positioned at the center of curvature of the arcuate bottom surface of the associated bearing; and where an axial movement of the stage plate rocks the bearing arcuate bottom surfaces with respect to the facing support surface of the base plate.

Abstract: A fluid bearing suitable for use in a vacuum region comprises a fluid passageway for introducing a fluid into the bearing, a pump-out slot for evacuating the fluid from the bearing, and a bearing seal disposed along a periphery of the bearing to restrict fluid from escaping from the bearing into the vacuum region. The bearing seal comprises a bridge structure including a first base, a second base, a transverse member fixed at one end to the first base and movably disposed in a slot defined by the second base, and a sealing sheet extending from the transverse member between the first and second bases. The sealing sheet forms a compliant mechanical wall around the periphery of the bearing. The seal further includes an adjustable spring force element which exerts a force on the sealing sheet to ensure marginal contact with a bearing support surface to form a low-frictional seal.

Abstract: A two-axis stage assembly includes a generally planar horizontally mounted base plate; a stage plate generally parallel to the base plate, the stage plate having a first axis and second orthogonal axis; a set of spaced bearings depending from a bottom surface of said stage plate, the bearings each having an arcuate bottom surface in rocking contact with a facing support surface of the base plate; a joint attached to the bottom surface of the stage plate and pivotably mounting each bearing, the joint being positioned at the center of curvature of the arcuate bottom surface of the associated bearing; and where an axial movement of the stage plate rocks the bearing arcuate bottom surfaces with respect to the facing support surface of the base plate.

Abstract: An air bearing is usable in a vacuum, by restricting the air escaping from the air bearing to the immediate vicinity of the air bearing. This is accomplished by one or more pump-out slots concentrically surrounding the air bearing orifice, and by concentrically surrounding the outer pump-out slot with a sealing sheet which confines air escaping from outside the pump-out slots to within the perimeter of the sealing sheet. The sealing sheet is a compliant mechanical "wall", making only marginal contact with the bearing support surface, and is not a high friction seal. Hence free movement of the air bearing structure on the supporting surface is allowed, thus making this air bearing compatible with for instance an XY stage used in a vacuum chamber.

Abstract: The invention includes a two-dimensional electric motor having two arrays of permanent magnets and at least two coils. The arrays of permanent magnets each have north and south poles distributed in both longitudinal and latitudinal directions along a plane. North poles in the first array are aligned with south poles in the second array, and south poles in the first array are aligned with north poles in the second array. The coil has a portion between the two arrays of permanent magnets. In another embodiment, the two-dimensional electric motor has an array of permanent magnets and two sets of two coils. The two sets of two coils are positioned on two different sides of the array. The invention permits simpler control methods, more stable motion, increased efficiency, and reduced stray magnetic fields. The invention should be particularly useful in semiconductor processing equipment.

Abstract: An electron beam lithography system having a beamlet shaping section that includes a first multi-aperture array having m rows and n columns of apertures having a first shape and a second multi-aperture array with m rows and n columns of apertures having a second shape. Electron beamlets formed by the first multi-aperture array are deflected by a deflector unit before passing through the second multi-aperture array. The superposition of the electron beamlets on the second multi-aperture produces electron beamlets having a selected shape. Deflection logic on an active beam aperture array blank selected electron beamlets. The deflection logic can be updated with the next logic pattern as the current logic pattern is being executed. The unblanked electron beamlets are directed onto a surface to be exposed.

Abstract: A method and apparatus for efficiently heating for instance a semiconductor wafer or reticle substrate in either vacuum or air, by exposing the wafer or reticle to radiation whose spectrum is such that it includes only wavelengths which have been determined to be efficiently absorbed by the material of the wafer or reticle. This advantageously allows more rapid and uniform heating than is allowed by prior art broadband radiation, convection heating, or conduction. The wavelength and bandwidth of the radiation are selected to be those wavelengths efficiently absorbed by the wafer or reticle, depending on its particular material and thickness. Typical applications are to a wafer or reticle located in a vacuum where convection or conduction heating are inconvenient or absent.

Abstract: A local air duct directs a temperature-controlled stream of air across two perpendicular sets of interferometer beams which are used to measure the two dimension (X-Y) position of a precision stage in e.g. an optical lithography stepper or step and scan system, or in any other precision coordinate measuring machine. By thereby providing an additional single air flow which is azimuthally directed across both the X and Y direction interferometer beams, the precision of the interferometric measurement is maximized. In addition, a second flow of air is directed downwards from the local air duct, thus providing sufficient air circulation onto the stage when the stage is directly beneath the local duct, even though in that location the stage is otherwise blocked from receiving the main air flow through the chamber.

Abstract: A method and apparatus to analyze the aerial image of an optical system using a subwavelength slit. A slit configuration yields a higher signal-to-noise ratio than that achievable with a round aperture. The slit also allows the polarization of the aerial image to be analyzed. In an alternative embodiment a tunneling slit is used. The tunneling slit comprises an optically transparent ridge-like structure mounted to a substrate, the combined structure covered by a thin, planar metal film.

Abstract: A method and apparatus for achieving high position resolution of a moving stage in a lithographic system utilized for the manufacture of semiconductor integrated circuits. A series of values of the stage position are measured using an interferometric system, and a present position of the stage is estimated using regression analysis applied to a selected number of the series of measured values. The resulting predicted position is of higher resolution than a single stage position measurement of the interferometric system.

Abstract: A method and apparatus to analyze the aerial image of an optical system using a subwavelength slit. A slit configuration yields a higher signal-to-noise ratio than that achievable with a round aperture. The slit also allows the polarization of the aerial image to be analyzed. In an alternative embodiment a tunneling slit is used. The tunneling slit comprises an optically transparent ridge-like structure mounted to a substrate, the combined structure covered by a thin, planar metal film.

Abstract: A mechanical scanner design suitable for use in a step and scan lithography system with arbitrary image magnification includes a projection optical system (20) and a relatively rotatable platform (40). The optical system has the property that a point within a predetermined object field in a first plane is imaged with suitable magnification at a corresponding point within a corresponding image field in a second plane, parallel to the first plane. The object and image fields are displaced from each other. A light source (22) illuminates an aperture such as a slit which is imaged in the object plane, whereupon a slit image is formed in the image plane. The reticle and wafer are mounted to the platform at respective locations in the object and image planes.

Abstract: An interferometer used to measure distance to an object is provided with a laser sheath. The sheath encloses a substantial part of the measurement beam's path to provide a controlled environment which reduces environmental influences on the measured distance. The sheath is of variable length and responsive to a follower so as to maintain a sheath end nearest the object at a small distance from the object. An environmental controller controls the environment within the sheath. The environment within the sheath can be a vacuum or a suitable gas or gas mixture. A corrector can be used to compensate the interferometer's measured-distance signal for detected environmental characteristics to produce a corrected signal which indicates distance between the interferometer and the reflective surface. The apparatus and methods can be used to measure and control stage position in a projection-type wafer exposure system which is affected by variations in its atmospheric environment.