• Acta Optica Sinica
  • Vol. 41, Issue 9, 0911004 (2021)
Yijiang Shen1、*, Xiaopeng Wang1, Yanzhou Zhou1, and Zhenrong Zhang2
Author Affiliations
  • 1School of Automation, Guangdong University of Technology, Guangzhou, Guangdong 510006, China
  • 2School of Computer, Electronics and Information, Guangxi University, Nanning, Guangxi 530004, China
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    DOI: 10.3788/AOS202141.0911004 Cite this Article Set citation alerts
    Yijiang Shen, Xiaopeng Wang, Yanzhou Zhou, Zhenrong Zhang. Local Level Set Based Mask Optimization with Semi-Implicit Discretization[J]. Acta Optica Sinica, 2021, 41(9): 0911004 Copy Citation Text show less
    Schematic of vector imaging formation
    Fig. 1. Schematic of vector imaging formation
    Numerical simulation results. (a) Annular source J; (b) desired pattern I0
    Fig. 2. Numerical simulation results. (a) Annular source J; (b) desired pattern I0
    Lithographic imaging performance with multi-density mask pattern I0. (a) Simulation results without OPC and I0 as illuminated mask; (b) conventional level-set MO; (c) semi-implicit MO; (d) localized semi-implicit MO
    Fig. 3. Lithographic imaging performance with multi-density mask pattern I0. (a) Simulation results without OPC and I0 as illuminated mask; (b) conventional level-set MO; (c) semi-implicit MO; (d) localized semi-implicit MO
    Pattern error versus simulation time for desired pattern I0
    Fig. 4. Pattern error versus simulation time for desired pattern I0
    Simulation experiment running time
    Fig. 5. Simulation experiment running time
    Optimization of monitoring pixels. (a) Begin; (b) end
    Fig. 6. Optimization of monitoring pixels. (a) Begin; (b) end
    Monitoring pixel counting in x and y coordinates with respect to iteration
    Fig. 7. Monitoring pixel counting in x and y coordinates with respect to iteration
    Time to solve linear system of equations in semi-implicit and localized semi-implicit MO approaches with respect to iteration
    Fig. 8. Time to solve linear system of equations in semi-implicit and localized semi-implicit MO approaches with respect to iteration
    Mask synthesis with semi-implicit discretization
    Input is target pattern I0
    Output is synthesized mask M
    1. Initialize M as I0, ω=arccos(2|M|-1), according to Eq. (3)
    2. Set K as maximum iteration number
    3. Start iteration with k=0
    4. While k<K
    5. Construct partial differential equation according to Eq. (5)
    6. Label pixels in x coordinate with ωx>ethr as monitoring pixels
    7. Compute linear system of equations [E-2τAx(ωk)]uk+1=ωk for uk+1
    8. Label pixels in x coordinate with ωy>ethr as monitoring pixels
    9. Compute linear system of equations [E-2τAx(ωk)]vk+1=ωk for vk+1
    10. Average ωk+1=0.5(uk+1+vk+1)
    11. Update |Mk+1|=1+cos(ωk+1)2 according to Eq. (3)
    12. k=k+1
    13. end while
    14. Return M=Mk+1
    Table 1. Main work flow of proposed approach
    Yijiang Shen, Xiaopeng Wang, Yanzhou Zhou, Zhenrong Zhang. Local Level Set Based Mask Optimization with Semi-Implicit Discretization[J]. Acta Optica Sinica, 2021, 41(9): 0911004
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