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:
Apr. 25, 1989
Filed:
May. 19, 1987
Tadashi Kiriseko, Kanagawa, JP;
Nobuo Iijima, Tama, JP;
Fujitsu Limited, Kawasaki, JP;
Abstract
In an automatic wafer process for gate array integrated circuits, it becomes necessary to identify the wafer every time at the beginning of each process. However, it is difficult for conventional methods to identify the wafer by detecting a bar code pattern because of a low contrast due to reflection of the deposited layers. The present invention provides a method in which the light source, which abundantly includes infrared rays, located on the back side of the wafer and a detector located on the front side thereof. The infrared rays are irradiated onto the wafer easily penetrate the silicon wafer. The infrared rays are received without an effect of reflection due to the deposited layers on the front side of the wafer. The first metallization layer is a very suitable layer to form the bar code pattern, which is easily marked by a laser beam scriber.