Translational-symmetry alternating phase shifting mask grating mark used in a linear measurement model of lithographic projection lens aberrations.
A linear measurement model of lithographic projection lens aberrations is studied numerically based on the Hopkins theory of partially-coherent imaging and positive resist optical lithography (PROLITH) simulation. In this linearity model, the correlation between the mark's structure and its sensitivities to aberrations is analyzed. A method to design a mark with high sensitivity is proved and declared. By use of this method, a translational-symmetry alternating phase shifting mask (Alt-PSM) grating mark is redesigned with all of the even orders, +/-3rd and +/-5th order diffraction light missing. In the evaluation simulation, the measurement accuracies of aberrations prove to be enhanced apparently by use of the redesigned mark instead of the old ones.
Qiu
Zicheng
Z
Information Optics Laboratory, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China.
Wang
Xiangzhao
X
Bi
Qunyu
Q
Yuan
Qiongyan
Q
Peng
Bo
B
Duan
Lifeng
L