In-situ acoustic thermometry and tomography for rapid thermal processing

Temperature dependent velocity of acoustic waves guided by the silicon wafer is used to measure its temperature from 20/spl deg/C to 1000/spl deg/C with attainable accuracy of /spl plusmn/1/spl deg/C. The acoustic temperature sensor has been installed and tested in a rapid thermal processing environment. Temperature mapping is obtained by measuring the acoustic wave velocity along different paths on the wafer and applying tomographic inversion techniques.<>