GPU accelerated Monte-Carlo simulation of SEM images for metrology

T. Verduin, S. R. Lokhorst, C. W. Hagen

    Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

    9 Citations (Scopus)

    Abstract

    In this work we address the computation times of numerical studies in dimensional metrology. In particular, full Monte-Carlo simulation programs for scanning electron microscopy (SEM) image acquisition are known to be notoriously slow. Our quest in reducing the computation time of SEM image simulation has led us to investigate the use of graphics processing units (GPUs) for metrology. We have succeeded in creating a full Monte-Carlo simulation program for SEM images, which runs entirely on a GPU. The physical scattering models of this GPU simulator are identical to a previous CPU-based simulator, which includes the dielectric function model for inelastic scattering and also refinements for low-voltage SEM applications. As a case study for the performance, we considered the simulated exposure of a complex feature: an isolated silicon line with rough sidewalls located on a at silicon substrate. The surface of the rough feature is decomposed into 408 012 triangles. We have used an exposure dose of 6 mC/cm2, which corresponds to 6 553 600 primary electrons on average (Poisson distributed). We repeat the simulation for various primary electron energies, 300 eV, 500 eV, 800 eV, 1 keV, 3 keV and 5 keV. At first we run the simulation on a GeForce GTX480 from NVIDIA. The very same simulation is duplicated on our CPU-based program, for which we have used an Intel Xeon X5650. Apart from statistics in the simulation, no difference is found between the CPU and GPU simulated results. The GTX480 generates the images (depending on the primary electron energy) 350 to 425 times faster than a single threaded Intel X5650 CPU. Although this is a tremendous speedup, we actually have not reached the maximum throughput because of the limited amount of available memory on the GTX480. Nevertheless, the speedup enables the fast acquisition of simulated SEM images for metrology. We now have the potential to investigate case studies in CD-SEM metrology, which otherwise would take unreasonable amounts of computation time.

    Original languageEnglish
    Title of host publicationProceedings of SPIE
    Subtitle of host publicationMetrology, Inspection, and Process Control for Microlithography XXX
    EditorsM.I. Sanchez, V.A. Ukraintsev
    PublisherSPIE
    Number of pages15
    Volume9778
    ISBN (Electronic)978-151060013-3
    DOIs
    Publication statusPublished - 2016
    Event30th Conference on Metrology, Inspection, and Process Control for Microlithography - San Jose, United States
    Duration: 22 Feb 201625 Feb 2016

    Conference

    Conference30th Conference on Metrology, Inspection, and Process Control for Microlithography
    Country/TerritoryUnited States
    CitySan Jose
    Period22/02/1625/02/16

    Keywords

    • CUDA
    • Dimensional metrology
    • Monte Carlo methods
    • Scanning electron microscopy
    • Simulation

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