Real-time reflectivity and topography imagery of depth-resolved microscopic surfaces

We have constructed an interference microscope that produces, in real time, reflectivity and topography images of surfaces with depth discrimination better than 1 mu m. Intensity and phase images are obtained at the rate of 50 per second by use of a multiplexed lock-in detection and MMX assembler-optimized calculation routines. With a wavelength of 0.84 mu m, depth discrimination of 0.7 mu m and lateral resolution of 0.3 mu m were demonstrated, in good agreement with theory. Two-dimensional cross-sectional reflectivity and topography images taken at different depths in an integrated circuit are presented. (C) 1999 Optical Society of America.