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:
Feb. 22, 1983
Filed:
Jan. 14, 1980
Phillip A Hartley, Vestal, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method of fabricating a photomask having at least three distinct zones of light transmissibility is disclosed. A first mask is made from a predetermined pattern, this mask having only two distinct zones of light transmissibility. A second mask, made by contact printing of a diazo film, is formed from a selected portion of one zone of the original pattern, which zone has the greater light transmissibility. The second mask, being a contact print, is the photographic opposite of the first. The two masks are then aligned with the selected portion of the second mask superimposed over its original location in the first mask and a composite latent image thereof is formed in a suitable emulsion. This composite image is then developed and fixed on an appropriate support to form a photomask having at least three density zones.