The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 30, 1987
Filed:
Nov. 27, 1985
Edward H Phillips, Middleton, CA (US);
Compact Spindle Bearing Corp., Middletown, CA (US);
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.