Research Of Thin Film Parameter Measurement Algorithms And The Software System

Based on the literature information, in this thesis, the transmission spectrum method for determining the optical constants and thickness of thin films has been studied. The algorithms for determining both the optical constants and the thickness of thin films including adapted simulated annealing algorithm and genetic algorithm have been studied. According to the theories of thin film calculation and optimization, a new global optimization method- GASA for multilayer film thickness calculation is presented in this paper. Firstly it generates a new group of local optimums through genetic and mutation operation. Then the solutions are accepted at a certain probability and will be calculated respectively in ASA process as the initial solutions. At last conjugate gradient algorithm is utilized to search accurately and quickly. This genetic simulated annealing algorithm can effectively enhance the robustness of the algorithm and reduce the limitation of the searching area.According to the research of the algorithm, the reflectance and transmission metrology system is discussed in a complete way. The article lay out some guiding reference such as intros for some pervasive commercial device in the world, the data information for those devices and the like to help choose the related metrology device properly.Through this project, based on the reflectance and transmission metrology system we did some experiments. The experimental results show that the proposed algorithm can calculate the thickness of 3-layer and 4-layer thin film within the range of 10nm to 5μm and less than 1% calculation error.