Process for reclaiming semiconductor wafers and reclaimed wafers
AssigneeMEMC Electronics Materials, Inc.
InventorRobert J. Falster
Life of this patent
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Abstract
The present invention is directed to a process for reclaiming for reuse a single crystal silicon wafer removed from an aborted semiconductor device fabrication process. The process includes (a) subjecting the wafer to an oxide growth step to form an oxide layer having a thickness greater than 2 nanometers, (b) thinning the wafer by removing material from substantially the entire front surface to provide a thinned wafer having a thinned precipitate free zone, and (c) polishing the front surface of the thinned wafer to a specular finish.
Claims27
A process for re-use of a silicon wafer having two major, generally parallel surfaces, one being the front surface of the wafer and the other being the back surface of the wafer, a circumferential edge joining the front and back surfaces, a central axis, a radius extending from the central axis to the circumferential edge of at least about 75 mm, a central plane approximately equidistant between the front and back surfaces, and a precipitate free zone having a thickness of at least 20 micrometers adjacent the front surface, the process comprising:
- (a) subjecting the wafer to an oxide growth step to form an oxide layer having a thickness greater than 2 nanometers,
- (b) after step (a), thinning the wafer by removing material from substantially the entire front surface to provide a thinned wafer having a thinned precipitate free zone, and
- (c) polishing the front surface of the thinned wafer to a specular finish.
Dependencies are inferred from the claim text.