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. 08, 1980
Filed:
Jan. 16, 1978
Hans P Kleinknecht, Bergdietikon, CH;
Wolfram A Bosenberg, Monmouth Junction, NJ (US);
RCA Corporation, New York, NY (US);
Abstract
An automatic photomask alignment system includes a monochromatic light source, such as a laser, a series of diffraction patterns which are located on a semiconductor substrate and keys which are located on photomasks with which the substrate is to be aligned. A light beam is directed through the key on a photomask onto the diffraction pattern to provide a pattern of light spots whose intensities at various locations are determined by the relative alignment of the mask and the diffraction grating. A feedback arrangement which employs photocells and means for moving the photomasks relative to the substrate provides the alignment of the photomasks with the substrate.