High-speed inline profiler using a modified Fourier transform method for measuring integrated circuit surface profiles

摘要

We propose a high-speed surface profiler using a modified Fourier transform profilometry (FTP) approach. Our system geometry is different from a conventional profiler in that the fringe-projection lens and the imaging lens are at different heights from a reference plane. FTP computer simulation and experimental data are provided that supports our theoretical development. Our profiler provides a 1 σ rms error of about 4 μm for an integrated circuit chip sample in an area of 14 mm × 6.5 mm with a 0.13 second data acquisition time. It is shown that our theoretical derivation is suitable for a micrometer scale object measurement.