Topography Evolution of Dielectric Thin Films on Grating Surfaces in Oblique Deposition by Multiple Sources (ODMS)

Optical properties of a reflective grating depend sensitively on the microscopic profile of grating surfaces. In manufacturing processes of reflective gratings, dielectric thin film deposition may be used to form desired surface profiles of gratings that are made from the standard molding processes. To predict surface profiles of dielectric films deposited by sputtering processes, a numerical simulation code based on the shock-tracking method has been developed and applied to TiO ₂ thin film deposition processes by the oblique deposition by multiple sources (ODMS) method. From the comparison of simulation data with experimental observations, the numerical simulation code has been confirmed to be able to predict the overall profiles of deposited films with reasonable accuracy. Sample simulation and experimental results are presented, and a possibility of further improvement of the simulation algorithm is discussed