Design specific joint optimization of masks and sources on a very large scale

K. Lai*, M. Gabrani, D. Demaris, N. Casati, A. Torres, S. Sarkar, P. Strenski, S. Bagheri, D. Scarpazza, A. E. Rosenbluth, D. O. Melville, A. Wächter, J. Lee, V. Austel, M. Szeto-Millstone, K. Tian, F. Barahona, T. Inoue, M. Sakamoto

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution

12 Scopus citations


Joint optimization (JO) of source and mask together is known to produce better SMO solutions than sequential optimization of the source and the mask. However, large scale JO problems are very difficult to solve because the global impact of the source variables causes an enormous number of mask variables to be coupled together. This work presents innovation that minimize this runtime bottleneck. The proposed SMO parallelization algorithm allows separate mask regions to be processed efficiently across multiple CPUs in a high performance computing (HPC) environment, despite the fact that a truly joint optimization is being carried out with source variables that interact across the entire mask. Building on this engine a progressive deletion (PD) method was developed that can directly compute "binding constructs" for the optimization, i.e. our method can essentially determine the particular feature content which limits the process window attainable by the optimum source. This method allows us to minimize the uncertainty inherent to different clustering/ranking methods in seeking an overall optimum source that results from the use of heuristic metrics. An objective benchmarking of the effectiveness of different pattern sampling methods was performed during post-optimization analysis. The PD serves as a golden standard for us to develop optimum pattern clustering/ranking algorithms. With this work, it is shown that it is not necessary to exhaustively optimize the entire mask together with the source in order to identify these binding clips. If the number of clips to be optimized exceeds the practical limit of the parallel SMO engine one can starts with a pattern selection step to achieve high clip count compression before SMO. With this LSSO capability one can address the challenging problem of layout-specific design, or improve the technology source as cell layouts and sample layouts replace lithography test structures in the development cycle.

Original languageEnglish (US)
Title of host publicationOptical Microlithography XXIV
StatePublished - 2011
EventOptical Microlithography XXIV - San Jose, CA, United States
Duration: Mar 1 2011Mar 3 2011

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X


OtherOptical Microlithography XXIV
Country/TerritoryUnited States
CitySan Jose, CA


  • Joint optimization
  • Large scale source optimization
  • Lithographic difficulty
  • Optimization parallelization
  • Pattern clustering
  • Pattern generation
  • Pattern selection
  • Progressive deletion
  • SMO
  • Source mask optimization

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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