9361178 Zaidi Laser application for noncontact temperature measurement of a semiconductor wafer is proposed. The technique can be applied for either chemical vapor deposition or rapid thermal processing systems. The method is based on thermal expansion of a semiconductor wafer, and uses speckle patterns generated from the back side (rough surface) of the wafer. Speckle patterns are generated by coherent illumination by two symmetrically incident laser beams. Speckle patterns are recorded at various temperatures and subtracted from an initial frame stored at a known temperature. Speckle decorrelation takes place as number of fringes approaches typical speckle size. Signal-to-noise ratio of the speckle fringes is improved by incorporating single-step phase shift in our data acquisition and processing system. Temperature measurements up to 400-deg are demonstrated with a single reference stored frame. Fast Fourier Transform of speckle fringe patterns is applied for calculation of speckle fringe period of extract temperature information. A detailed investigation of these techniques is proposed for speckle temperature measurements up to 1000-deg. 1. Potential applications in RTP and CVD systems. 2. Improvement in material synthesis using better temperature during fabrication. *** v s t I $ $ ( F / ! ! / 1 Courier Symbol & Arial 5 Courier New ! X X X " h B % B % ( C R:WW20USERABSTRACT.DOT Denise Henry Denise Henry
