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:
Jul. 05, 1994
Filed:
Nov. 09, 1992
Paul Allen, Beaverton, OR (US);
Mike Bohan, Beaverton, OR (US);
Tim Thomas, Beaverton, OR (US);
Robin Teitzel, Portland, OR (US);
ETEC Systems, Inc., Beaverton, OR (US);
Abstract
A direct-write lithography tool having improved alignment characteristics. The present invention discloses use of an optical alignment apparatus in a multi-beam lithography system. The optical alignment apparatus provides for alignment through a reduction lens utilized by the multi-beam lithography system for writing to semiconductor wafers and the like through use of optics for correction of distortion and curvature caused by viewing with a radiant energy beam of a different wavelength than the beams used for writing. Further, the alignment optics provide for multiple paths in a single optics system through use of liquid crystal retarders and beam splitters to direct the radiant energy beam through a selected optical path. In the present invention, a first optical path may provide for high magnification and a second for low magnification. Further, other optical paths may provide for bright or dark field illumination and viewing.