Phase defect analysis with actinic full-field EUVL mask blank inspection

Takeshi Yamane; Toshihiko Tanaka; Tsuneo Terasawa; Osamu Suga

doi:10.1117/12.898898

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13 October 2011 Phase defect analysis with actinic full-field EUVL mask blank inspection

Takeshi Yamane, Toshihiko Tanaka, Tsuneo Terasawa, Osamu Suga

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Proceedings Volume 8166, Photomask Technology 2011; 81660G (2011) https://doi.org/10.1117/12.898898
Event: SPIE Photomask Technology, 2011, Monterey, California, United States

Abstract

We had developed an actinic full-field inspection system to detect multilayer phase-defects with dark field imaging. Regarding the actinic inspection of native defects, the influence of the defect's surface dimension and multilayer structure, on the intensity-signal obtained from the inspection was analyzed. Three mask blanks were inspected from which 55 defects, observed with AFM and SEM, were classified as amplitude-defects or phase-defects. The surface dimensions and SEVDs (sphere equivalent volume diameters) of the defects were measured with the AFM. In the case where their SEVDs were same as of the programmed phase-defects, they were found to produce stronger intensitysignals in comparison to the ones from the programmed phase-defects. Cross-sectional multilayer structures of two native phase-defects were observed with TEM, and those defects formed non-conformal structures in the multilayer. This result means that most of the native phase-defects tend to form a non-conformal structure, and can make large impact on the wafer image in comparison to the ones from a conformal structure. Besides phase-defects, the actinic inspection also detected amplitude-defects. Although the sensitivities of the amplitude-defects were found to be lower than those of the phase-defects, an amplitude-defect higher than 30 nm could be detected with high probability.

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Takeshi Yamane, Toshihiko Tanaka, Tsuneo Terasawa, and Osamu Suga "Phase defect analysis with actinic full-field EUVL mask blank inspection", Proc. SPIE 8166, Photomask Technology 2011, 81660G (13 October 2011); https://doi.org/10.1117/12.898898

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