Method and apparatus for real-time wafer temperature and thin film growth measurement and control in a lamp-heated rapid thermal processor
AssigneeDuke University
InventorsHisham Z. Massoud, Ronald K. Sampson
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Abstract
An ellipsometer measures/monitors the change in polarization of light upon reflection from a wafer sample. The temperature of the wafer substrate surface and the film thickness are then simultaneously determined in situ using ellipsometry where the true wafer temperature is determined in real-time by the computer from a calculation based on the known temperature dependence of the refractive index of the wafer. The power output to the lamps is then adjusted accordingly to raise or lower the wafer temperature within the apparatus. This process continues automatically to maintain the desired temperature and film growth rate until the desired film thickness is achieved.
Claims9
A method for determining and adjusting temperature of a semiconductor wafer in a rapid thermal processing system comprising the steps of:
- (a) determining the ellipsometric parameters .psi. and .DELTA. in real-time with an ellipsometer;
- (b) calculating the temperature and film thickness from said ellipsometric parameters of .psi. and .DELTA. of a semiconductor wafer positioned in a thermal processing chamber;
- (c) comparing said measured temperature and film thickness to predetermined temperature and film thickness vs. time data;
- and
- (d) adjusting the amount of heat provided to said semiconductor wafer by a lamp module in response to said steps (a)-(c).
Dependencies are inferred from the claim text.