Optics: measuring and testing – By alignment in lateral direction – With registration indicia
Patent
1985-11-27
1987-06-30
Evans, F. L.
Optics: measuring and testing
By alignment in lateral direction
With registration indicia
250548, 355 53, 356358, 356363, 33 1M, G01B 1100
Patent
active
046766499
ABSTRACT:
An improved multi-axis gas bearing stage assembly is disclosed which has a base, an intermediate stage element, a stage, and a control system for controlling the movement of the intermediate stage element and the stage. The control system includes first and second Y-axes positioning sub-systems for differentially positioning first and second ends of the intermediate stage element along first and second Y-axes of motion, with respect to the base, and an X.sub.i -axis positioning sub-system for positioning the stage along an X.sub.i -axis of motion, with respect to the intermediate stage element. In one embodiment, the positioning sub-systems comprise motor-encoder driven leadscrews. In a second embodiment, the positioning sub-systems comprise linear motors, measuring scales, and read heads. In a third embodiment, the positioning sub-systems comprise linear motors and interferometer measuring systems. A method of achieving orthogonality between the Y- and X.sub.i -axes that features an orthogonality alignment standard is disclosed. In a another embodiment, the differential positioning capability of the first and second Y-axes is utilized for positioning the intermediate stage element along a .theta.-axis about a Z-direction orthogonal to both the Y- and X-axes, and a method of rotationally aligning a semiconductive wafer is disclosed. In other embodiments, two methods of kinematically positioning the improved multi-axis stage assembly within a utilization apparatus are disclosed. In another embodiment, three retroreflectors of an interferometer measuring system are mounted directly on a wafer chuck, located on the stage, and a transport system moves three interferometers rotationally, to maintain optical coupling between the interferometers and the retroreflectors. In still another embodiment, five retroreflectors are mounted directly on the wafer chuck and a five axis interferometer measuring system is utilized to eliminate all Abbe offset measurement errors in the position of a semiconductive wafer, placed upon the wafer chuck, along the X, Y, and .theta.-axes of motion.
REFERENCES:
patent: 3722996 (1973-03-01), Fox
patent: 3786332 (1974-01-01), Hepner et al.
patent: 3791739 (1974-02-01), Kawasaki
patent: 4311390 (1982-01-01), Phillips
patent: 4464030 (1984-08-01), Gale et al.
patent: 4583847 (1986-04-01), Battig et al.
Compact Spindle Bearing Corp.
Evans F. L.
Smith Joseph H.
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