Laser-Acoustic Techniques for Temperature Measurements in Semiconductor Processing

다국어 초록 (Multilingual Abstract)

An acoustics-based technique for measuring temperature in a rapid thermal processing environment is investigated. A silicon wafer is placed in a rapid thermal processor with the back side facing the heating lamp. A transducer designed to provide a 170 kHz acoustic signal is placed perpendicular to the plane of the wafer. An acoustic wave launched parallel to the wafer surface is detected at two areas using two probe-beam deflection detectors. By measuring the attenuation and phase difference between the signals detected at the two points, the velocity of the acoustic wave can be accurately determined. The strong temperature dependence of the acoustic wave velocity can be exploited to obtain temperature measurements.