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:
Dec. 10, 1991
Filed:
Nov. 25, 1988
Yoshiaki Matsushita, Yokohama, JP;
Moriya Miyashita, Kitakami, JP;
Makiko Wakatsuki, Yokohama, JP;
Norihiko Tsuchiya, Tokyo, JP;
Atsuko Kubota, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
First, silicon wafers are formed by cutting silicon monocrystalline ingot into slices. Then back side and main surfaces of the wafers are subjected to lapping and etching processes. Next, the wafers are submerged into substantially pure water and ultrasonic waves are applied to the wafer surface via the water to clean at least one of the surfaces of each of the wafers and form gettering damage on the wafer surface. After this, the main surfaces of the wafers which have been subjected to the cleaning and damage-forming process and on which semiconductor elements are to be formed are polished into mirror finish.