Evaluation of New Molecular Resist for EUV Lithography

• Published in: Journal of Photopolymer Science and Technology Vol. 20; no. 3; pp. 403 - 410
• Main Authors: Oizumi, Hiroaki, Tanaka, Yuusuke, Kumise, Takaaki, Shiono, Daiju, Hirayama, Taku, Hada, Hideo, Onodera, Junichi, Yamaguchi, Atusko, Nishiyama, Iwao
• Format: Journal Article
• Language: English
• Published: Hiratsuka The Society of Photopolymer Science and Technology(SPST) 01.01.2007; Japan Science and Technology Agency
• Subjects: Dispersions; EUV lithography; Inspection; LER; Lithography; molecular resist; Outgassing; Patterning; polyphenol; Polyphenols; Resists
• ISSN: 0914-9244; 1349-6336; 1349-6336
• DOI: 10.2494/photopolymer.20.403

We designed and synthesized a new partially-protected polyphenol, 25X-MBSA-M, for which the position and number of protected hydroxyl groups have no dispersion, and evaluated the EUV patterning performance of a chemically amplified positive-tone resist based on it. EUV imaging experiments were performed using the high-numerical-aperture (NA = 0.3), small-field EUV exposure tool (HINA) at ASET and coherent illumination (σ = 0.0). Patterning results showed the resolution of the resist to be 28 nm, the obtainable aspect ratio to be as high as 2, pattern collapse was markedly suppressed. The line-edge roughness (LER) to be small, with 3σ being 3.9 nm for 35-nm line-and-space patterns at an EUV exposure dose of 12.2 mJ/cm2, and an inspection length, L, of 2000 nm. In addition, we evaluated outgassing of the molecular resist during EUV exposure. The order of outgassing rate of the new molecular resist was almost as same as that of a conventional polymeric PHS-based resist.