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:
Jun. 23, 1992
Filed:
Apr. 04, 1991
Thomas B Faure, Georgia, VT (US);
Kurt R Kimmel, Essex, VT (US);
James G Ryan, Essex Junction, VT (US);
Timothy D Sullivan, Underhill, VT (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An X-ray mask substrate includes a silicon wafer having a square, central region etched to a thin, tensile membrane and a highly tensile film deposited on the bottom surface of the substrate to reduce substrate warpage. The square, central region of the substrate is adapted to support X-ray absorbing material during the lithography process. A layer of highly tensile film such as tungsten is deposited on the lower side of the substrate to induce a bending moment on the substrate opposite that induced during the substrate fabrication process. The thickness of the film layer is directly proportional to the amount of warpage induced in the substrate during the fabrication process. A support ring is bonded to the peripheral region of the substrate to provide integrity and support.