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Proceedings Paper

Smooth low-stress sputtered tantalum and tantalum alloy films for the absorber material of reflective-type EUVL
Author(s): Masashi Takahashi; Taro Ogawa; Hiromasa Hoko; Eiichi Hoshino; Hiromasa Yamanashi; Naoya Hirano; Akira Chiba; Shinji Okazaki
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Paper Abstract

Tantalum (Ta) and Ta-alloy films were evaluated for use as the absorber material of masks for extreme ultraviolet lithography (EUVL). It was found that Ta film with a stress below 100 MPa, a surface roughness of less than 1 nm rms, a film density of over 14 g/cm3, and a deposition rate of more than 50 nm/min could be obtained by DC sputtering with Ar gas. Experiments on delineating mask patterns in this film by using dry etching revealed that 250-nm line-and-space patterns could be formed. The alloys evaluated were TaGe and TaN. These films were found to have some better properties than Ta film, for example, less stress, a smaller change in stress, and a smoother surface. This is confirmed to be due to the fact that the alloy films are amorphous. Of particular note is that TaN film has a lower deep ultraviolet (DUV) reflectivity than either Ta or TaGe, thus providing higher contrast between the underlying multilayer and the absorber patterns of an EUVL mask during DUV inspection. However, TaN has a lower density than the other two films. So, our current results indicate that using Ta or TaGe for the bulk absorber material and covering that with a thin layer of TaN is a promising way to obtain the film properties required for EUVL mask patterns, including film density and DUV inspection capability.

Paper Details

Date Published: 21 July 2000
PDF: 12 pages
Proc. SPIE 3997, Emerging Lithographic Technologies IV, (21 July 2000); doi: 10.1117/12.390087
Show Author Affiliations
Masashi Takahashi, Association of Super-Advanced Electronics Technologies (Japan)
Taro Ogawa, Association of Super-Advanced Electronics Technologies (Japan)
Hiromasa Hoko, Association of Super-Advanced Electronics Technologies (Japan)
Eiichi Hoshino, Association of Super-Advanced Electronics Technologies (Japan)
Hiromasa Yamanashi, Association of Super-Advanced Electronics Technologies (Japan)
Naoya Hirano, Association of Super-Advanced Electronics Technologies (Japan)
Akira Chiba, Association of Super-Advanced Electronics Technologies (Japan)
Shinji Okazaki, Association of Super-Advanced Electronics Technologies (Japan)


Published in SPIE Proceedings Vol. 3997:
Emerging Lithographic Technologies IV
Elizabeth A. Dobisz, Editor(s)

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