Thermal measuring and testing – Thermal calibration system
Patent
1989-04-13
1990-11-13
Cuchlinski, Jr., William A.
Thermal measuring and testing
Thermal calibration system
374 2, 374129, 374126, 374128, G01K 1500, G01K 700, G01J 510
Patent
active
049697480
ABSTRACT:
The present invention is a method and apparatus for calibrating a temperature feedback value in a wafer processing chamber to automatically compensate for variations in infrared emissions from a heated semiconductor wafer due to variations in composition and coatings from wafer to wafer. A calibration wafer with an imbedded thermocouple is used to generate a table relating actual wafer temperatures to power supplied to the heating chamber and infrared emissions detected by a pyrometer. A sample wafer of a batch to be processed is subsequently placed in the chamber at a known power level, and any difference between the detected infrared emission value and the value in the table is used to adjust the entire table according to a first predetermined formula or table. Before each wafer is processed, a known source of infrared light is reflected off the wafer and detected. The reflected light value is compared to a reflection measurement for the sample wafer. The difference in reflection measurements is correlated to emissions from heating, and the calibration table is fine-tuned with the correlation value according to a second predetermined formula or table to account for variations in emissions between individual wafers due to variances in wafer surface conditions.
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Crowley John L.
Johnson Noel H.
Kermani Ahmad
Lassig Stephan E.
Rickords Gary R.
Cuchlinski Jr. William A.
Gutierrez Diego F. F.
Peak Systems, Inc.
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