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Method for recycling wafers used for quality assurance testing of integrated circuit fabrication equipment
U.S. Patent Number: 6140211
Abstract: A method for recycling a used silicon wafer on which ICs have been formed by IC fabrication equipment comprised of first grinding the wafer using a coarse grinding apparatus and then grinding the wafer suing a fine grinding apparatus. The coarse grinding apparatus and the fine grinding apparatus are identical to one another except for the nature of the respective grinding they perform. Deionized water is used during both grinding processes to reduce friction and to control dust. The used wafer is first mounted on a chuck of the coarse grinding apparatus that rotates at a first predetermined speed. A diamond wheel mounted on a grinding wheel holder of the coarse grinding apparatus rotates at a second predetermined speed that is faster than the first speed. The rotating wheel and the rotating wafer are brought into contact with one another and the wafer is ground until a predetermined amount of semiconductor material is removed from the face of the wafer. The wafer is then placed in the fine grinding apparatus and subjected to an identical grinding process. The loss of wafer thickness from both the coarse and fine grinding processes is no more than 50 microns. The resulting wafer is suitable for reuse in IC fabrication processes and has performance characteristics comparable with those of virgin wafers. The recycling process of the present invention typically takes only about 30-40 seconds.
Inventors: Nanda; Arun K. (Orlando, FL), Rodriguez; Jose O. (Orlando, FL)
Assignee: Lucent Technologies Inc. (Murray Hill, NJ)
Application Number: 09/122,276
Issued: 2000-10-31
Expired: 2004-10-31
Classes: 438/465 ; 257/E21.237; 438/500; 438/584; 438/691
Field of search: 438/465,500,691 437/225
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