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. 01, 1995
Filed:
Feb. 02, 1993
Satoshi Yamamoto, Kyoto, JP;
Kenji Kamei, Kyoto, JP;
Dainippon Screen Mfg. Co., Inc., Kyoto, JP;
Abstract
A semiconductor wafer placed on a table is rotated by a stepper motor stepwise by a broad pitch. At this time, a CCD line sensor transmits output signals to comparators. A CPU monitors output signals of the comparators and detects a notch formed in the wafer. After the notch is detected, the wafer is rotated stepwise by a fine pitch, and outer peripheral positional data of a notched region (outputs of an analog-to-digital converter) are sampled and stored in a RAM. The CPU computes a notch position from the outer peripheral positional data stored in the RAM. In this way, a V-shaped notch formed in a semiconductor wafer is detected speedily and with high precision.