摘要:
Eine Positionsregelschaltung umfaßt eine erste Vorrich tung (116) zum Erzeugen einer Phasendifferenz zwischen einem Referenzsignal und einem darauf bezogenen Ein gangssignal, das durch ein Regelsignal bestimmt ist, und eine zweite, mit der ersten Vorrichtung gekoppelte Vorrich tung zum Erzeugen eines Positionsregelsignals, das propor tional zur Phasendifferenz zwischen dem Referenzsignal und dem Eingangssignal ist.
摘要:
Full aperture focus detection apparatus produces an amplified differential signal having a magnitude and a polarity indicative of the extent and direction, relative to the image plane of a projection lens, that a selected portion of the upper surface of a semiconductive wafer is out of focus with respect to that image plane. Lens positioning apparatus moves the projection lens by an amount and in a direction corresponding to the magnitude and polarity of this signal to position the image plane of the projection lens at the selected portion of the upper surface of the semiconductive wafer. A chuck on which the semiconductive wafer is held may be differentially leveled at three selected off-center locations by leveling apparatus so that the chuck may be raised or lowered at any of those locations to position the selected portion of the upper surface of the semiconductive wafer in a plane parallel to the image plane of the projection lens.
摘要:
Eine Positionsregelschaltung umfaßt eine erste Vorrichtung (116) zum Erzeugen einer Phasendifferenz zwischen einem Referenzsignal und einem darauf bezogenen Eingangssignal, das durch ein Regelsignal bestimmt ist, und eine zweite, mit der ersten Vorrichtung gekoppelte Vorrichtung zum Erzeugen eines Positionsregelsignals, das proportional zur Phasendifferenz zwischen dem Referenzsignal und dem Eingangssignal ist.
摘要:
A projection lens (26) and a source (24 or 164) of illumination and exposure light are employed for projecting an image of a reticle (12) onto a first reference mark (32) or a semiconductive wafer (14), both of which are movably supported in the image plane of the projection lens (26). Optical apparatus (46 or 234), including a source of nonexposure light (108), is provided and is operable with the projection lens (26) for imaging a second adjustable reference mark (116) onto the first reference mark (32) or the semiconductive wafer (14) to facilitate use of the projection lens (26) in aligning a semiconductive wafer (14) covered with a photoresist opaque to exposure light. Additional optical apparatus (200, 214, 216a & 216b), including an objective lens unit (214) and an imaging lens (200), may be provided for imaging light from the source (164) of illumination and exposure light at the reticle (12) and for reimaging reflected light from the semiconductive wafer (14) at the objective lens unit (214).
摘要:
A projection lens (18) is disposed directly above a vacuum chuck (131) for projecting an image of an illuminated portion of a semiconductive wafer (14) held thereby to an image plane (79) where that image may be viewed through a pair objective lenses (88) of a compound microscope (22). Microcircuitry contained on a reticle (12) held by a holder (17) positioned above the projection lens (18) is photometrically printed onto the semiconductive wafer (14) by passing exposure light through the reticle (12) and the projection lens (18) to the semiconductive wafer (14). At least one fiber optic source (140; 156) of illuminating light and one or more optical lenses (142, 144; 152; 158, 160) are employed for projecting an image of the fiber optic light source (140; 156) through the objective lens (88) to an entrance pupil of the projection lens (18) without passing through the reticle (12) to provide uniform illumination of the semiconductive wafer (14) and facilitate direct wafer alignment prior to photometrically printing on the semiconductive wafer (14).
摘要:
In an optical alignment and exposure machine, particularly suited for printing microelectronic circuit patterns on semi-conductive wafers, two stages of wafer prealignment are performed, In the first stage of prealignment the periphery of the wafer engages three belt-driven rollers which turn the wafer to align a flat edge thereof with two of the rollers. A transfer arm then picks up the prealigned wafer and transfers itto a rotatable chuck on an X-Y addressable work stage. In the second stage of prealignment a pair of alignment members carried by the chuck index with the flat edge of the wafer, and another pair of alignment members carried by the chuck indexes either the center or a rounded edge of the wafer to a predetermined position. An optical alignment system permits rotation of the chuck to align alignment marks on the wafer with respect to projected images of alignment marks on the mask. The addressable work stage carrying the chuck includes apparatus for selectively moving the chuck and wafer into engagement with a stop carried by the work stage for accurately positioning the plane of an emulsion on the wafer with respect to a focal plane of the optical alignment system.