深紫外光刻照明系统的微反射镜阵列公差分析

Tolerance Analysis of Micromirror Array in Deep Ultraviolet Lithography Illumination System

为满足45 nm及其以下节点光刻技术对照明系统的需求,将深紫外光刻照明系统的光束整形单元所采用的微反射镜阵列(MMA)作为关键器件,以实现满足光源-掩模联合优化(SMO)技术需求的任意照明光源。根据MMA结构参数和加工制造调整特性,分析MMA角度误差类型。在此基础上,利用蒙特卡罗公差分析法模拟实际加工制造调整的过程,通过分析微反射镜角度误差对曝光结果的影响,制定了满足曝光要求的角度公差。结果显示,当MMA在正交方向上的角度调整公差和加工角度公差分别在(±0.04°,±0.06°)、(±0.04°,±0.04°)范围内时,系统曝光得到的特征尺寸误差(CDE)在98.1%的置信概率下小于0.33 nm。

To meet the illumination system requirements of 45 nm and below node lithography technology, the micromirror array(MMA) used in the beam shaping unit of deep ultraviolet lithography illumination system is used as the key device to produce the freeform source required by the source-mask optimization(SMO) technology. Based on the structural parameters of MMA as well as the manufacture and adjustment characteristics, the angle error types of MMA are analyzed. On this basis, the Monte-Carlo tolerance analysis method is used to simulate the actual manufacture and adjustment processes. After the influence of the micromirror angle error on the exposure results is investigated, the angle tolerance that meets the exposure requirements is established. The results show that when the angle adjustment tolerance and the process angle tolerance of MMA in the orthogonal direction are within the scope of(±0.04°, ±0.06°) and(±0.04°, ±0.04°), respectively, the critical dimension error(CDE) obtained by exposure is less than 0.33 nm at a confidence probability of 98.1%.