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. 23, 1979
Filed:
Jul. 12, 1977
Augustine W Chang, Wappingers Falls, NY (US);
Arun K Gaind, Fishkill, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for fabricating self-aligned regions of semiconductor devices such as bipolar or field effect transistors using three masking layers which are selectively etchable with respect to each other on the surface of the semiconductor body. A dimensional mask is deposited over the three layers so that the set of all of the self-aligned impurity regions to be formed through the surface of the body are defined by etching the upper masking layer, with the intermediate layer acting as an etch-stop. Using conventional wet or dry resist processes, each subset of similar impurity regions may then be formed selectively through the intermediate and lower layers without the need for precisely aligning any subsequent mask.