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. 09, 1991
Filed:
Oct. 16, 1989
Masami Nakano, Annaka, JP;
Takao Abe, Annaka, JP;
Shin-Etsu Handotai Co., Ltd., Tokyo, JP;
Abstract
A method of inspecting bonded wafers, which involves obtaining a Lang topograph of bonded wafers as a sample by using a Lang camera, or further treating an image thereon, thereby detecting unbonded regions at the interface of the bonded wafers. In bonding two silicon wafers to each other, an one-side surface of each silicon wafer is finished into a mirror surface and then is cleaned to a sufficient extent. Subsequently, both the mirror surfaces of the two silicon wafers are superposed one upon the other and then the superposed wafers are subjected to high-temperature heat treatment. The high-temperature heat treatment is conducted mainly for the purpose of removing distortions on the bonded surfaces, making the bonding interface monolithic, and, absorbing and diffusing a very small amount of atmospheric gas.