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:
Nov. 19, 1996
Filed:
Mar. 16, 1995
Hiroshi Mohri, Tokyo, JP;
Hiroyuki Miyashita, Tokyo, JP;
Dai Nippon Printing Co., Ltd., Tokyo, JP;
Abstract
An overlying shifter type phase shift photomask used to produce semiconductor integrated circuits of high integration density, e.g. VLSI, ULSI, etc., which is capable of transferring fine-line patterns to a wafer by projection exposure. The photomask is produced by forming at least a light-blocking layer pattern or a combination of a light-blocking layer pattern and an etching stopper layer for a shifter layer on a transparent substrate, forming a shifter layer over the whole surface of the substrate, and then patterning the shifter layer to form a shifter layer pattern. The production method includes the step of polishing away unevenness on the surface of the shifter layer caused by a step which is produced by the light-blocking layer pattern, thereby leveling the surface of the shifter layer.