Inline Thickness Measurement for Thick Amorphous Silicon Film by Spectroscopic Ellipsometry Method

摘要

Thick amorphous silicon (A-Si) film is widely used in CMOS and MEMS process, but its thickness cannot be accurately measured by normal Spectroscopic and Ellipsometry (SE) method, which was due to the spectral limitation of the standard metrology hardware and software. In this work Optimized SE method was developed for thick A-Si film by extend the measurement wavelength. GOF of thickness measurement by the optimized method can reach the values larger than 0.95, which indicated the reliable measurement data. And the difference between the optical SE measured data and the physical thickness is less than 3%.