论文标题
通过Seidel畸变理论解决初始结构的方法
The method of solving initial structure by Seidel aberration theory for extreme ultraviolet lithography objective
论文作者
论文摘要
在本文中，提出了一种用于解决基于SEIDEL像差理论的近距离紫外线（EUV）光刻的非轴多晶格系统初始结构的方法。通过追踪反射系统中的特征射线，可以获得每个表面上的高度和近端角，然后通过SEIDEL像差系数和这些参数之间的关系，可以解决具有良好像差性能的初始结构。我们可以通过添加不同的初始条件约束来获得不同的初始结构。在本文中，我们通过将不同的光学功率分配为不同的初始结构来解决两个不同的初始结构，在此基础上，我们优化了两个数值（NA）为0.25的两个离轴六元系统。它们的波前像差RMS值约为0.04波长，绝对失真小于1.2nm，具有良好的成像质量。我们认为，这种方法可以大大提高复杂多效率系统的设计效率和优化效果。
In this paper, a method for solving the initial structure of an off-axis multi-mirror system applied to extreme ultraviolet (EUV) lithography using a paraxial ray-tracing algorithm based on Seidel aberration theory is proposed. By tracing the characteristic rays in the reflection system, the height and paraxial angle on each surface can be obtained, then through the relationship between the Seidel aberration coefficient and these parameters, the initial structure with good aberration performance can be solved. We can obtain different initial structures by adding different initial condition constraints. In this paper, we have solved two different initial structures by assigning different optical powers as different initial structures, and on this basis, we have optimized two off-axis six-mirror systems with numerical aperture (NA) of 0.25. Their wavefront aberration RMS value is about 0.04 wavelength, and the absolute distortion is less than 1.2nm, with good imaging quality. We believe that this method can greatly improve the design efficiency and optimization effect of complex multi-mirror systems.
