Paper
1 April 2013 Dressed-photon nanopolishing for extreme ultraviolet mask substrate defect mitigation
Author Affiliations +
Abstract
Although the quality of extreme ultraviolet (EUV) mask substrates has improved by continuous refinement of the polishing processes, the yield of defect-free blanks is still very low. Dressed-photon nanopolishing (DPNP) is a novel vapor phase, photo-chemical, non-contact etching process that has been shown to locally smooth bumps and pits to below 1 nm in height/depth while not affecting the surface roughness. DPNP is based on the concept of a dressed photon, which is a quasi-particle in the optical near field of a surface that can couple with lattice phonons in nanometric regions (< 100 nm). When illuminated with light of a suitable wavelength, such coupled states are generated on a nanometrically rough material surface and impart sufficient energy to an etchant gas to enable its dissociation and etching in the rough regions only. DPNP can be the last polishing step on EUV substrates to eliminate any remnant pits and/or embedded particles on the surface to yield potentially defect-free substrates.
© (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Ranganath Teki, Arun John Kadaksham, Frank Goodwin, Takashi Yatsui, and Motoichi Ohtsu "Dressed-photon nanopolishing for extreme ultraviolet mask substrate defect mitigation", Proc. SPIE 8679, Extreme Ultraviolet (EUV) Lithography IV, 86790F (1 April 2013); https://doi.org/10.1117/12.2011260
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Cited by 5 scholarly publications.
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KEYWORDS
Extreme ultraviolet

Polishing

Particles

Etching

Surface finishing

Chemical mechanical planarization

Photomasks

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