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. 03, 1990
Filed:
Feb. 25, 1988
John B Smyth, Jr, Corvallis, OR (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A new and improved method for profiling wafers, and for uniquely identifying the dies formed thereon, wherein the method includes the step of locating a set of reference points along the periphery of the wafer, relative to a predetermined coordinate system. Next, the equation of a hypothetical circle which substantially contours the periphery of the wafer, and which passes through the reference points, is defined. The coordinates of the center of the hypothetical circle, as well as the coordinates of an arbitrary reference die on the wafer, are then derived from the equation of the hypothetical circle. Subsequently, the entire surface of the wafer is mapped relative to the center or to the reference die, by utilizing predetermined stepping dimensions.