Semiconductor wafer fabrication with improved control of internal gettering sites using rapid thermal annealing
AssigneeDNS Electronic Materials, Inc.
InventorWalter Huber
Life of this patent
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Abstract
The concentration of internal gettering sites within a semiconductor wafer is controlled by two-step thermal processing. In a concentration reduction phase, the wafer is rapidly heated to an elevated temperature in the range from about 900.degree. to 1350.degree. C., resulting in the partial or total dissolution of precipitable impurities within the wafer. In a concentration enhancement step, the wafers are subjected to a relatively low temperature anneal process where the density of potential internal gettering sites is increased. By properly controlling the processing temperatures and treatment times, the two steps may be performed in either order to obtain wafers having internal gettering site concentrations within a desired range.
Claims8
A method for imparting a desired concentration of internal gettering sites in a semiconductor substrate, said method comprising performing the following steps in a predetermined order:
- (a) rapidly heating the substrate to a temperature in the range from about 900.degree. to 1300.degree. to reduce the concentration of gettering sites, said heating being performed at a rate of at least 10.degree. C./sec;
- (b) rapidly cooling the substrate to a temperature below about 600.degree. C. to fix the reduced concentration of gettering sites;
- and
- (c) annealing the substrate at a temperature in the range from about 550.degree. C. to 850.degree. C. for a predetermined time period to increase the concentration of gettering sites.
Dependencies are inferred from the claim text.