Edge finding in wafers

Details Edge finding in wafers Edge finding in wafers

1987-01-28

1988-06-21

Smith, Jerry

Boots, shoes, and leggings

198394, 356400, 414754, 414779, 414786, B65G 4724

Patent

active

047528982

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.

REFERENCES:
patent: 4242038 (1980-12-01), Santini
patent: 4425075 (1984-01-01), Quinn
patent: 4457664 (1984-07-01), Judell et al.
patent: 4466073 (1984-08-01), Boyan et al.

Affiliated with

Also associated with

Rating

Edge finding in wafers does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Edge finding in wafers, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Edge finding in wafers will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-933455