Abstract: Coherent illumination is used to illuminate a symmetrical alignment mark with an image rotation interferometer producing two images of the alignment mark, rotating the images 1800 with respect to each other, and recombining the images interferometrically. The recombined images interfere constructively or destructively, in an amplitude and or polarization sense depending upon the method of recombination, when the alignment sensor is located at the center of the alignment mark. The rotation interferometer is preferably a solid glass assembly made of a plurality of prisms. A detector extracts the alignment information from the image rotation interferometer. The resulting center of the alignment mark is accurately determined. A relatively large number of different alignment mark patterns may be utilized, as long as the alignment mark patterns exhibit one hundred and eighty degree symmetry. Parallel lines, a grid pattern, or a checkerboard grating may be used.

Abstract: A lithography system include a lithography patterning chamber, a wafer exchange chamber separated from the lithography patterning chamber by a first gate valve, and at least one alignment load-lock separated from the wafer exchange chamber by a second gate valve. The alignment load-lock includes an alignment stage that aligns a wafer during pump-down. The alignment load-lock can be uni-directional or bi-directional. The lithography system can include more than one alignment load-locks.

Abstract: An optical reduction system with polarization dose sensitive output for use in the photolithographic manufacture of semiconductor devices having variable compensation for reticle retardation before the long conjugate end. The variable compensation component(s) before the reticle provides accurate adjustment of the polarization state at or near the reticle. The variable compensation components can be variable wave plates, layered wave plates, opposing mirrors, a Berek's compensator and/or a Soleil-Babinet compensator. The catadioptric optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: Coherent illumination is used to illuminate a symmetrical alignment mark with an image rotation interferometer producing two images of the alignment mark, rotating the images 1800 with respect to each other, and recombining the images interferometrically. The recombined images interfere constructively or destructively, in an amplitude and or polarization sense depending upon the method of recombination, when the alignment sensor is located at the center of the alignment mark. The rotation interferometer is preferably a solid glass assembly made of a plurality of prisms. A detector extracts the alignment information from the image rotation interferometer. The resulting center of the alignment mark is accurately determined. A relatively large number of different alignment mark patterns may be utilized, as long as the alignment mark patterns exhibit one hundred and eighty degree symmetry. Parallel lines, a grid pattern, or a checkerboard grating may be used.

Abstract: An optical reduction system with polarization dose sensitive output for use in the photolithographic manufacture of semiconductor devices having variable compensation for reticle retardation before the long conjugate end. The variable compensation component(s) before the reticle provides accurate adjustment of the polarization state at or near the reticle. The variable compensation components can be variable wave plates, layered wave plates, opposing mirrors, a Berek's compensator and/or a Soleil-Babinet compensator. The catadioptric optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: An optical reduction system for use in the photolithographic manufacture of semiconductor devices having one or more quarter-wave plates operating near the long conjugate end. A quarter-wave plate after the reticle provides linearly polarized light at or near the beamsplitter. A quarter-wave plate before the reticle provides circularly polarized or generally unpolarized light at or near the reticle. Additional quarter-wave plates are used to further reduce transmission loss and asymmetries from feature orientation. The optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: Coherent illumination is used to illuminate a symmetrical alignment mark with an image rotation interferometer producing two images of the alignment mark, rotating the images 180 ° with respect to each other, and recombining the images interferometrically. The recombined images interfere constructively or destructively, in an amplitude and or polarization sense depending upon the method of recombination, when the alignment sensor is located at the center of the alignment mark. The rotation interferometer is preferably a solid glass assembly made of a plurality of prisms. A detector extracts the alignment information from the image rotation interferometer. The resulting center of the alignment mark is accurately determined. A relatively large number of different alignment mark patterns may be utilized, as long as the alignment mark patterns exhibit one hundred and eighty degree symmetry. Parallel lines, a grid pattern, or a checkerboard grating may be used.

Abstract: Apparatus for measuring angular changes in the direction of travel of a light beam comprising at least one beam shearing assembly for separating, preferably orthogonally polarized, components of the light beam and introducing a lateral shear between them. An analyzer operates on the components to provide them with a common polarization state. A lens focuses the commonly polarized components of the light beam to a spot in a detector plane, and a detector operates to generate an electrical signal having a phase that varies in accordance with the angular change of the light beam in at least one plane. Electronic means receive the electrical signal, determines the phase therefrom, and converts the phase to the angular change in the direction of travel of the light beam.

Abstract: The present invention includes a lithography system comprising a lithography patterning chamber, a wafer exchange chamber separated from the lithography patterning chamber by a first gate valve, and at least one alignment load-lock separated from the wafer exchange chamber by a second gate valve. The alignment load-lock includes an alignment stage that aligns a wafer during pump-down. An alignment load-lock according to the present invention can be uni-directional or bi-directional. Likewise, a lithography system according to the present invention can include one or multiple alignment load-locks. Also disclosed is a method of patterning a wafer within a lithography system. The method can include a first step of placing the wafer on supports within an alignment load-lock. In a next step, the wafer is aligned with respect to a chuck while the wafer is supported within the alignment load-lock on the supports. In another step, the wafer is secured to the chuck.

Abstract: An optical reduction system for use in the photolithographic manufacture of semiconductor devices having one or more quarter-wave plates operating near the long conjugate end. A quarter-wave plate after the reticle provides linearly polarized light at or near the beamsplitter. A quarter-wave plate before the reticle provides circularly polarized or generally unpolarized light at or near the reticle. Additional quarter-wave plates are used to further reduce transmission loss and asymmetries from feature orientation. The optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: A focus system that includes a calibration subsystem and a control subsystem. The control subsystem, which includes a control sensor, is in close proximity to the exposing of an image. The calibration subsystem, which includes a calibration sensor and a control sensor, is located remotely from, or off-axis with respect to, the exposing of an image. By separating calibration and control functions, the functional requirements can be separated into two (or more) types of sensors.

Abstract: Wavefront information for an optical system is calculated based on the intensity of an image of a plurality of gratings having different periods and orientations taken from at least two different planes a predetermined distance apart. The image of a plurality of gratings having different spatial frequencies or periods and orientations, the location of which are precisely known, are imaged in a nominal focal plane of the optical system, and, preferably, in two additional planes displaced a predetermined distance from the nominal focal plane. The phase shift, if any, from a fundamental frequency of the image intensity, is determined based on the known location of the grating and the grating image intensity. The grating image intensity is detected and measured in a first detection plane in a nominal focal plane and in a second detection plane a predetermined distance from the nominal focal plane. From these measurements wavefront information is calculated.

Abstract: An optical reduction system for use in the photolithographic manufacture of semiconductor devices having one or more quarter-wave plates operating near the long conjugate end. A quarter-wave plate after the reticle provides linearly polarized light at or near the beamsplitter. A quarter-wave plate before the reticle provides circularly polarized or generally unpolarized light at or near the reticle. Additional quarter-wave plates are used to further reduce transmission loss and asymmetries from feature orientation. The optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: An optical reduction system with polarization dose sensitive output for use in the photolithographic manufacture of semiconductor devices having variable compensation for reticle retardation before the long conjugate end. The variable compensation component(s) before the reticle provides accurate adjustment of the polarization state at or near the reticle. The variable compensation components can be variable wave plates, layered wave plates, opposing mirrors, a Berek's compensator and/or a Soleil-Babinet compensator. The catadioptric optical reduction system provides a relatively high numerical aperture of 0.7 capable of patterning features smaller than 0.25 microns over a 26 mm×5 mm field. The optical reduction system is thereby well adapted to a step and scan microlithographic exposure tool as used in semiconductor manufacturing. Several other embodiments combine elements of different refracting power to widen the spectral bandwidth which can be achieved.

Abstract: The present invention provides a grating-grating interferometric wafer alignment system, sensor and method for microlithography. It includes: (1) an electromagnetic radiation source with collimating optics delivering a collimated beam of a coherent single or multiple discrete wavelengths or in some cases broadband electromagnetic radiation; (2) a detector of the intensity of the collimated return electromagnetic radiation; (3) x- and y-oriented independent linear gratings for the mask-mark; (3) a "checkerboard pattern" grating for the wafer-mark; and (4) software including an algorithm for determining alignment from the return electromagnetic radiation intensity measured as a function of the relative position of the wafer and mask grating, and a means such as a Fourier transform determining phase and amplitude of a known frequency component of the intensity.

Abstract: An optical system wherein a mask pattern occurring at a predetermined period is imaged with a period less than the predetermined period. Spatial filter means are disposed within the optical system for permitting only the two (positive and negative) first orders of light from an illumination source diffracted by the mask pattern to pass therethrough.

Abstract: There are disclosed method and apparatus for precisely aligning the pattern of an opaque mask with a previously exposed pattern on a silicon wafer. Three separate optical channels are aligned so that their axes coincide with three targets on the wafer. The objectives are also adjusted to the same vertical distance from the wafer. Thereafter, the optical channels remain fixed. The wafer is retracted a short distance and is replaced by the mask which also has three targets. The mask is then shifted to align the targets with the prealigned optical axes. When mask alignment is completed, the mask and the wafer are removed as a unit to an exposure station.