NA1.35浸没式光刻照明系统是超大规模集成电路的核心设备, 为了实现从ArF激光器发出的光束经过一系列模块传输后到达掩模面的能量满足光刻曝光系统的要求, 需要在系统中引入非球面透镜, 以减少镜片数量, 提高能量利用率。为解决现在非球面透镜具有的加工难度和控制精度不足的缺陷,设计出一种优化控制保证非球面加工和检测的方法。在光学系统设计中优化非球面的形状, 保证非球面度, 满足非球面变化率在可加工和检测的范围内, 并控制非球面拐点的产生。照明系统中镜片数量最多的模块是耦合镜组, 通过非球面的优化, 镜片数量从12片减少到9片, 系统能量利用率提高近25%。此外, 提高了系统像质NA一致性, 像方远心度, 弥散斑直径和畸变, 满足了曝光光学系统对掩模面的能量要求, 故该非球面控制技术具有良好的可加工性和可检测性。

NA1.35 immersion lithography lighting system is the core of the very large scale integrated circuit device. In order to satisfy the high resolution requirement of lithography exposure optical system, aspheric lens could be added to decrease the lenses number and increase the energy usage ratio. To solve disadvantages of processing difficulty and low control accuracy of aspheric lenses, the optimization control and testing method of aspheric surface were proposed. By optimizing the aspheric shape to guarantee steradian as well as aspheric inflection point, processing and texting control range could be also satisfied. The illumination system had the largest number of module coupling lenses. By optimization of aspheric lenses, number of lenses decreased from 12 to 9, and energy utilization increased about 25%. In addition, prosperities of NA consistency, image telecentic rate, dispersion spot diameter and distortion were improved, which satisfied the exposure energy requirements on the mask surface of the optical system. So, the aspheric control technology had good processability and detectability.