Multiparameter optimization design of chemical mechanical polishing for planar optics

The processing parameters directly affect the polishing quality of planar optics in chemical mechanical polishing (CMP). In this paper, a novel multiparameter optimization method based on the fuzzy theory was proposed to evaluate the manufacturing efficiency and accuracy of flat optical elements with CMP. The evaluation criteria and optimized parameters for CMP optimization were selected. The optimized objective function—combined fuzzy index of CMP (CFICMP)—was introduced to combine different criteria. A L9(34) orthogonal experimental design was implemented to improve the efficiency of experiments and analyze the effect of three parameters (polishing pressure, rotational speed of polishing pad, and slurry flow rate) on CMP. A half-normal distribution was applied to fit the trend of CFICMP. To verify the validity and feasibility of CFICMP, the material removal rate and the material removal uniformity were set as the optimized functions in verification experiments. The experimental results demonstrated that the optimal parameters of CFICMP could achieve better manufacturing efficiency and accuracy of planar optics simultaneously. The proposed method provides a feasible and effective way to select optimized processing parameters for CMP.