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:
Aug. 08, 1995
Filed:
Jul. 01, 1993
Martin J Alter, Los Altos, CA (US);
Lawrence R Sample, San Jose, CA (US);
Hiu F Ip, San Jose, CA (US);
Marty E Garnett, Los Gatos, CA (US);
Helmuth R Litfin, Cupertino, CA (US);
Micrel, Incorporated, San Jose, CA (US);
Abstract
One embodiment of the invention includes multiple patterns on a single mask, where all the patterns on the single mask are used for forming a single product. In the preferred embodiment, each of four quadrants of a mask have a different process layer pattern, where each of the four patterns is associated with a different process layer for the same product. After exposure of the wafer using the mask, the mask is rotated 90.degree. for the next exposure step so that the mask pattern image for the next layer to be formed on the wafer will overlie the designated quadrant of the wafer which will contain the final product. Although, by using this technique, three-quarters of the wafer will be unusable, this partial waste of the wafer will be offset by the savings in mask costs with low volume production, in prototyping situations, and in product debugging. Using the above technique, conventional mask exposure machines may be used.