Development of inspection system for EUV mask with novel projection electron microscopy (PEM)

Masahiro Hatakeyama; Takeshi Murakami; Kenji Terao; Kenji Watanabe; Shoji Yoshikawa; Tsuyoshi Amano; Ryoichi Hirano; Susumu Iida; Tsuneo Terasawa; Hidehiro Watanabe

doi:10.1117/12.2027733

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9 September 2013 Development of inspection system for EUV mask with novel projection electron microscopy (PEM)

Masahiro Hatakeyama, Takeshi Murakami, Kenji Terao, Kenji Watanabe, Shoji Yoshikawa, Tsuyoshi Amano, Ryoichi Hirano, Susumu Iida, Tsuneo Terasawa, Hidehiro Watanabe

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Proceedings Volume 8880, Photomask Technology 2013; 888028 (2013) https://doi.org/10.1117/12.2027733
Event: SPIE Photomask Technology, 2013, Monterey, California, United States

Abstract

In order to realize EUV mask pattern defect inspection in 16nm node, we have developed new optics on a novel projection electron microscopy (PEM) and a new inspection system with the new optics and a new mask handling and imaging units, e.g., a high precision stage, an imaging detector, an imaging processing system, and so. on. This inspection system enables us to make the inspection in high resolution and high speed as compared with conventional DUV and EB inspection systems. The new optics on the novel PEM comprises an exposure and an imaging electron beam optics (EOs). The optics is based on the new design concept to meet the required progress for 1Xnm EUV mask inspection as compared to the current inspection system for 2Xnm node; The concept employs new techniques to achieve the features: high energetic electron imaging optics to have low aberration, high transmittance efficiency, e.g., on the ratio of exposure current/emitted current, in the exposure and the imaging optics, respectively. The new handling and imaging system are also based on the design concept of imaging in high resolution by combination operation among the new optics on the novel PEM, the stage, and the detector. In this paper, we describe the basic performance evaluation as concerning these features and the operation: 1) MTF inclination in hp44~100nm L/S pattern of the developed imaging optics. 2) Secondary electron imaging by the integrated optics, i.e., both of the exposure and the imaging EOs, on the novel PEM, 3) Secondary electron image acquisition operation in still mode on the new inspection system assembled with the new optics on the novel PEM, the high precision stage, the detector, and so. on.. The results show the new optics on the novel PEM is capable to meet the required progress for 1Xnm EUV mask inspection and the new inspection system with the novel PEM operates in much feasibility in the electron image acquisition.

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Masahiro Hatakeyama, Takeshi Murakami, Kenji Terao, Kenji Watanabe, Shoji Yoshikawa, Tsuyoshi Amano, Ryoichi Hirano, Susumu Iida, Tsuneo Terasawa, and Hidehiro Watanabe "Development of inspection system for EUV mask with novel projection electron microscopy (PEM)", Proc. SPIE 8880, Photomask Technology 2013, 888028 (9 September 2013); https://doi.org/10.1117/12.2027733

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