Observation of phase defect on extreme ultraviolet mask using an extreme ultraviolet microscope

Tsuyoshi Amano, Tsuneo Terasawa, Hidehiro Watanabe, Mitsunori Toyoda, Tetsuo Harada, Takeo Watanabe, Hiroo Kinoshita

    Research output: Contribution to journalArticlepeer-review

    3 Citations (Scopus)


    Influences of phase defect structures on extreme ultraviolet (EUV) microscope images were examined. Phase defects on the bottom of a multilayer (ML) do not always propagate vertically upward to the ML's top surface. For this study, two types of masks were prepared. One was an EUV blank with programmed phase defects made of lines in order to analyze the inclination angle of the phase defects. The other was an EUV mask that consists of programmed dot type phase defects 80 nm wide and 2.4 nm high with absorber patterns of halfpitch 88-nm lines-and-spaces. The positions of the phase defects relative to the absorber lines were designed to be shifted accordingly. Transmission electron microscope observations revealed that the line type phase defects starting from the bottom surface of the ML propagated toward the ML's top surface, while inclined toward the center of the EUV blank. At the distances of 0 and 66 mm from the center of the EUV blank, the inclination angles varied from 0 to 4 deg. The impacts of the inclination angles on EUV microscope images were significant even though the positions of the phase defect relative to the absorber line, as measured by a scanning probe microscope, were the same.

    Original languageEnglish
    Article number023012
    JournalJournal of Micro/Nanolithography, MEMS, and MOEMS
    Issue number2
    Publication statusPublished - 2014 Apr


    • compensation repair
    • defect mitigation
    • extreme ultraviolet
    • extreme ultraviolet microscope
    • phase defect

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Atomic and Molecular Physics, and Optics
    • Condensed Matter Physics
    • Mechanical Engineering
    • Electrical and Electronic Engineering


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