面向浸没式光刻机的超精密光学干涉式光栅编码器位移测量技术综述

Review of ultra-precision optical interferential grating encoder displacement measurement technology for immersion lithography scanner

超精密平面光栅编码器位移测量技术是32~7 nm节点浸没式光刻机的核心技术。通过分析浸没式光刻机平面光栅位置系统的需求和布局,提出了光刻机专用超精密平面光栅编码器的基本需求。针对现有的光栅编码器,开展了基本测量光路方案、相位探测方案、分辨率增强光路方案、离轴/转角允差光路方案、死程误差抑制光路方案的综述分析,提出了现有设计方案面向光刻机应用所需要解决的关键问题。面向亚纳米级测量精度的需求,针对光栅编码器的仪器误差,对周期非线性误差、死程误差、热漂移误差和波前畸变误差进行了综述分析,提出了平面光栅编码器实现亚纳米精度所需要解决的关键问题。本综述为光刻机专用超精密平面光栅编码器的研制提供了参考。

The ultra-precision grid encoder is the key technology of the immersion lithography scanner for 32-7 nm node.Firstly,by analyzing the requirements and layout of the grid encoder position measurement system of the immersion lithography scanner,the basic requirement of a special grid encoder for the scanner is proposed.Secondly,for the present grating encoder,research on the basic optical path,phase detection,resolution multiplication,off-axis/rotation tolerance,and dead-path restrain scheme is reviewed and analyzed.Then,the key problems of the present scheme in the application of the lithography scanner are proposed.Thirdly,to address the required nanometer accuracy for the instrumental error of the grid encoder,the research on nonlinearity,dead-path,thermal drift,and wave-front distortion error are reviewed and analyzed;and the key problems to achieve sub-nanometer accuracy for the grid encoder are proposed.Finally,the above review is summarized,which can serve as a reference for the special grid encoder of immersion lithography scanner.