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:
Jun. 21, 1988
Filed:
Jan. 28, 1987
Franklin R Koenig, Palo Alto, CA (US);
Tencor Instruments, Mountain View, CA (US);
Abstract
A system for finding the orientation of a substantially circular disk shaped wafer with at least one flat region on an edge thereof, in which the wafer is spun one 360 degree turn on a chuck and the edge position is measured by a linear array to obtain a set of data points at various wafer orientations. The rotation axis may differ from the wafer center by an unknown eccentricity. The flat angle is found by fitting a cosine curve to the data, subtracting the expected data derived from the cosine curve from the actual data to obtain a deviation. The angle of maximum deviation of the data from the cosine curve is a first estimate of the flat angle. The estimate may be corrected for errors due to a finite number of data points and wafer eccentricity by calculating an adjustment angle from data points on the wafer flat. After determining the flat angle, the wafer is spun to the desired orientation. The wafer eccentricity may be calculated from four of the data points located away from the flat edge region, and the wafer is then centered.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile