A novel defect detection optical system using 199-nm light source for EUVL mask

Ryoichi Hirano; Nobutaka Kikuiri; Masatoshi Hirono; Riki Ogawa; Hiroyuki Sigemura; Kenichi Takahara; Hideaki Hashimoto

doi:10.1117/12.848679

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1 April 2010 A novel defect detection optical system using 199-nm light source for EUVL mask

Ryoichi Hirano, Nobutaka Kikuiri, Masatoshi Hirono, Riki Ogawa, Hiroyuki Sigemura, Kenichi Takahara, Hideaki Hashimoto

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Proceedings Volume 7638, Metrology, Inspection, and Process Control for Microlithography XXIV; 76382Z (2010) https://doi.org/10.1117/12.848679
Event: SPIE Advanced Lithography, 2010, San Jose, California, United States

Abstract

Lithography potential expands for 45nm node to 32nm device production by the development of immersion technology and the introduction of phase shift mask. We have already developed the mask inspection system using 199nm wavelength with simultaneous transmitted illumination and reflected illumination optics, and is an effectual candidate for hp 32nm node mask inspection. Also, it has high defect sensitivity because of its high optical resolution, so as to be utilized for leading edge mask to next generation lithography. EUV lithography with 13.5nm exposure wavelength is dominant candidate for the next generation lithography because of its excellent resolution for 2x half pitch (hp) node device. But, applying 199nm optics to complicated lithography exposure tool option for hp2x nm node and beyond, further development such as image contrast enhancement will be needed. EUVL-mask has different configuration from transmitted type optical-mask. It is utilized for reflected illumination type exposure tool. Its membrane structure has reverse contrast compared with optical-mask. This nature leads image profile difference from optical-mask. A feasibility study was conducted for EUV mask pattern defect inspection using DUV illumination optics with two TDI (Time Delay Integration) sensors. To optimize the inspection system configuration, newly developed Nonlinear Image Contrast Enhancement method (NICE) is presented. This function capability greatly enhances inspectability of EUVL mask.

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Ryoichi Hirano, Nobutaka Kikuiri, Masatoshi Hirono, Riki Ogawa, Hiroyuki Sigemura, Kenichi Takahara, and Hideaki Hashimoto "A novel defect detection optical system using 199-nm light source for EUVL mask", Proc. SPIE 7638, Metrology, Inspection, and Process Control for Microlithography XXIV, 76382Z (1 April 2010); https://doi.org/10.1117/12.848679

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