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:
Jan. 24, 1995
Filed:
Mar. 26, 1993
Akira Tokui, Itami, JP;
Maria O DeBeeck, Itami, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
A photomask for projecting a transfer pattern onto a wafer having a plurality of regions with different surface levels includes a transparent substrate; a shielding member on the transparent substrate having a plurality of patterns for projection onto respective regions of the wafer; and an optical-path-length varying layer on at least one of the patterns corresponding to a region of the wafer other than a reference region of the wafer for changing the optical path length of light transmitted through the pattern by a length corresponding to the difference in surface level between the corresponding region and the reference region of the wafer. A pattern transfer method using such a photomask includes directing light onto the photomask; effecting a change in the position of the apparent object-side image surface for at least one pattern including the optical-path-length varying layer; and simultaneously forming on surfaces of the wafer regions image formation planes respectively corresponding to at least two patterns by image projection using light transmitted through the patterns.