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:
Jan. 02, 1990
Filed:
Jan. 19, 1989
John W Reeds, Thousand Oaks, CA (US);
Hughes Aircraft Company, Los Angeles, CA (US);
Abstract
A positioning stage is disclosed which achieves high-speed step-and-repeat alignment of a semiconductor wafer to a mask with a full six degrees of freedom. A precision planar translational stage is mounted on a rotating stage to allow a single-laser interferometric system to be utilized to make precise measurements of translational (X and Y) and rotational (.theta.) positions. The entire X-Y-.theta. stage system can also be moved vertically in a Z direction, or tilted with respect to the X-Y plane, by independently adjustable flexible mounts. The center of rotation of the rotational stage is on the beam axis, so that registration of the wafer to a mask is simplified. Because the mass of the rotating stage is not moved during high-speed X- and Y-positioning steps, fast response is possible. In lithography applications, one rotational correction at the beginning of the writing procedure suffices for all the chips on the wafer, if all the rows and columns of chips are perfectly straight. Besides its usefulness in lithography with a flood ion beam, the invention is also useful in direct-write electron- or ion-beam lithography systems with focused beams, to obviate the need for high-speed electronic scan rotation.