Micronix Corporation

Micronix Partners

Computervision Corporation

W Thomas Novak

Bernard Fay

David W Volmer

Peter R Jagusch

Vladimir E Leibovich

The positioning system, particularly useful for moving a stage mounting a semiconductor wafer for the manufacture of semiconductor devices, provides a lead screw and zero backlash nut for coarse motion of the stage. A thrust member fixedly mounts the nut and the member is flexurally mounted to a housing supporting the stage acting through a piezoelectric motor connection. This action brings the stage in a coarse adjustment mode into the capture range of the piezoelectric motor for fine adjustment by in and out movement of a pusher rod extending from the motor. Flexures allow motion of the thrust member parallel to the lead screw and protects the piezoelectric motor from undesirable side loads. A separate duplicate mechanism is used for each of x-axis and y-axis movements of the housing and stage to bring the stage to a precise position by the respective coarse and fine translationary movements of the lead screw, thrust members and piezoelectric motors.

Coarse and fine motion positioning mechanism

An optical alignment apparatus and method for a semiconductor lithography mask and wafer utilizes two monochromatic light sources of different wavelengths. The mask contains targets in the form of linear Fresnel zone plates and the wafer contains a reflecting grating. Incident illumination from the two light sources illuminates the mask targets and is reflected from the wafer gratings in various intensity depending on the physical characteristics of the wafer and mask layers and thicknesses and by the targets. A detector detects the strongest of the diffracted return beams from each of the monochromatic light sources and uses the strongest to align the targets and grating on the mask and wafer for more accurate printing of mask patterns on the wafer.

Multiple wavelength linear zone plate alignment apparatus and method

A controlled flow of X-ray attenuating gas such as helium is provided to an upper portion of a beam exposure chamber. A vent tube (21) extends from a lower portion of the chamber adjacent a mask to an exterior exit orifice (23) positioned at mask level to prevent ingress of air to the chamber and prevent mask membrane deflecton and change in the mask-to-silicon wafer substrate gap distance. The substrate (20) is positioned below the mask membrane and is surrounded by a mask-to-wafer zone into which is flowed a substrate fabrication process gas which is vented either by a gas flange (25) in spaced gapped relation to the mask holder and mask, or by a vent tube (46) extending from the zone to an orifice end (46a) approximate the level of the mask. There is then no pressure differential on the top and bottom surfaces of the mask membrane affecting the mask-to-wafer gap distance (8) during substrate fabrication operations.

Gas control for X-ray lithographic system

A mask loading apparatus and method employing a cassette (200) detachably mounted on an in-out cassette holder (212). The cassette is made of low Z-materials, and comprises a cover (211) and a bottom mask-supporting tray (202) locked by machine-operable locking members (224) to the cover. A lift cylinder (218) has a vacuum cup (216) which is raised to support and hold the underside (213) of the tray and, when the tray is unlocked from the cover, to move the vacuum cup, tray and mask downwardly and then laterally by a transport arm (203) to a fixed location under a mask holder (205, 220) in a lithographic apparatus. The lift cylinder then raises the cup, tray and mask to abut the mask holder and to transfer the mask to the mask holder. The lift cylinder and empty tray is then lowered and removed from a position blocking the mask as it is to be used in the lithography processing. A reversal of the sequence of steps is utilized to unload the mask from its use mode and return it to its cassette cover. An anti-rotation pin (222) prevents tray movement in the cassette and pins (236) prevent mask movement on the tray. Indication bar code or read hole or clear window (231, 232 and 230) automatically show whether a mask or calibration plate is in a cassette to be transported.

Mask loading apparatus, method and cassette

A lithography system for X-ray or other beam printing on a substrate such as a silicon semiconductor wafer comprises a beam chamber (301), a beam source (302), means (309) for mounting a mask, means (308) for mounting an image sensing means (342) interiorly of the chamber, means (317, 318), for mounting a substrate (307) in multiple including six degrees of freedom and means (308, 292, 320-322) including the image sensing means to align the mask and substrate relative to one another utilizing alignment patterns on the mask and substrate, images of which are brought into registration and sensed by the image sensing means. In a preferred embodiment three sets of target images are provided so as to adjust the substrate and mask relative orientation in six degrees of freedom. The mask seals helium within the chamber. The mask and the substrate are aligned in situ in the same position in which the mask and substrate are to be exposed to the beam. Means (313, 314, 311, 312) are provided for loading masks, calibration assemblies and substrate-holding means. The source-to-substrate distance is adjustable as is the mask-to-substrate gap. To conserve helium volume adjustable optic objectives (342) are provided in the chamber to sense registration of alignment targets on each of the mask and substrate, with essentially the remainder of the optics outside the chamber. Improved compression optics (408) are also provided in the alignment system.

Lithography system

A projection aligner is provided wherein the image position can be shifted by employing a bending mirror which makes a slight change in the magnification.

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San Jose, CA, United States of America

W Thomas Novak