Open AccessLithographic source and mask optimization with narrow-band level-set method
Author(s) -
Yongming Shen
Publication year - 2018
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.26.010065
Subject(s) - computation , computer science , immersion lithography , lithography , convolution (computer science) , subpixel rendering , convergence (economics) , computational lithography , algorithm , computational science , parallel computing , optics , computer engineering , multiple patterning , artificial intelligence , pixel , resist , physics , layer (electronics) , artificial neural network , economics , economic growth , chemistry , organic chemistry
Source and mask optimization (SMO) remains a key technique to improve the wafer image printability for technology nodes of 22 nm and beyond, enabling the continuation of the immersion lithography. In this paper, we propose a distance level-set regularized reformulation of the SMO maintaining the desired signed distance property, which secures stable curve evolution and accurate computation with a simpler and more efficient numerical implementation. Consequently, computation load caused by convolution operations and memory requirements of the electric-field caching technique (EFCT) is significantly eased by performing computation only in the narrow band; moreover, the convergence of the updating process is further improved by applying larger Euler time steps of the Courant-Friedrichs-Lewy (CFL) condition with reduced optimization dimensionality. Simulation results of the proposed narrow-band level-set based SMO prove to improve the computation efficiency, memory usage and imaging performance of the full domain methods.