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:
Mar. 22, 1983
Filed:
Aug. 03, 1981
Richard A Coppock, San Jose, CA (US);
GTE Products Corporation, Stamford, CT (US);
Abstract
In a printed circuit formation process, a positive photoresist layer on a semiconductor substrate surface is exposed to light in a projection exposure system through a transparent liquid-gate which has an index of refraction n.sub.L closer to the index of refraction n.sub.R of the resist layer than is the index of refraction of air. This reduces reflection of light from the resist layers and thus minimizes standing waves in the layer, which waves produce a deleterious layered resist structure and require critical dependence of exposure time on absolute resist thickness. By using photo developer liquid in the gate as the index matching medium together with a reflex viewing system, visual monitoring of the expose/develop process in real time is realized.