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. 21, 1987
Filed:
Aug. 27, 1986
Atul Goel, Ft. Collins, CO (US);
Keith G Bartlett, Ft. Collins, CO (US);
W R Trutna, Atherton, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
An improved method for automatically focusing an integrated circuit manufacturing projection step and repeat photolithography printer employing an optical signal to focus the printer is disclosed. The automatic focusing is achieved by reflecting an optical signal off a photoresist layer on the surface of a wafer and converting the reflected optical signal into an electronic signal employed to focus the printer. According to the preferred embodiment of the present invention, a dye which absorbs light at the wavelength the optical signal is added to the photoresist layer to improve the quality of the reflected optical signal thereby considerably reducing or eliminating focusing errors.