Seh America, Inc.

Brazel G Preece

Yi Pan

A method of measurement of wafers to isolate wafer support-related defects involves Scanning Infrared Depolarization (SIRD) measurement of multiple processed wafers, each oriented differently on the wafer support, to obtain and characterize depolarization stress defects. The method mounts first and second wafers in first and second orientations and performs a SIRD scan of each. The results are correlated to isolate orientation dependent defects from non-orientation dependent defects. Orientation dependent defects are characterized as wafer support-related defects. Analysis of such wafer support-related defects may then be used to identify and correct the corresponding wafer support defect.

Method for isolation of wafer support-related crystal defects

An improved method for lapping the opposed major surfaces of a wafer is provided. In this regard, a multi-step lapping process is provided in which lapping continues while transitioning from a first slurry having larger abrasive particles to a second slurry having smaller abrasive particles so as to reduce the overall length of the lapping process. In addition, the multi-step lapping process is optimized so as to remove no more than about 90 microns in total thickness from the opposed major surfaces of the wafer. By completing the lapping with slurry having smaller abrasive particles, subsequent etching of the wafers produces shallower surface pitting. As such, the wafers generally require less polishing than required by conventional processes.

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Vancouver, WA, United States of America

Brazel G Preece