根据薄膜光学计算理论和最优化理论,本文提出了一种测量多层薄膜厚度的新的全局优化算法。首先利用遗传的种群性去寻找多个局部极值,然后将较优和较差的种群按一定概率接收并作为模拟退火的初值进行搜索。最后结合共轭梯度算法来提高收敛速度,使整体搜索效率进一步提高。这种遗传退火算法有效地提高了算法的稳定性,减少了算法对膜厚搜索范围的限制。文章最后以3 层和4 层光学薄膜为例,利用该算法在10 nm 至5 μm的大范围内搜索,所取得的结果,其测量误差小于1%。

According to the theories of thin film calculation and optimization, a new global optimization method for multilayer film thickness calculation is presented. Firstly, a new group of local optimums is found out through genetic and mutation operation. Then, the solutions are accepted at a certain probability and will be calculated respectively in Adapted Simulated Annealing (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. The experimental results show that the proposed algorithm can calculate the thickness of 3-layer and 4-layer thin film within the range of 10 nm~5 μm and less than 1% calculation error