Apparatus and method for compensating for errors in temperature measurement of semiconductor wafers during rapid thermal processing
US4969748A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 1989 |
| Grant date | Nov 13, 1990 |
| Priority date | — |
| Expiry date | Apr 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J5/802
- WIPO fieldMeasurement
- WIPO sectorInstruments
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 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.