Novel low thermal expansion material for EUV application

Mitsuhiro Kawata; Akira Takada; Hideaki Hayashi; Naoki Sugimoto; Shinya Kikugawa

doi:10.1117/12.655931

23 March 2006 Novel low thermal expansion material for EUV application

Mitsuhiro Kawata, Akira Takada, Hideaki Hayashi, Naoki Sugimoto, Shinya Kikugawa

Proceedings Volume 6151, Emerging Lithographic Technologies X; 61511A (2006) https://doi.org/10.1117/12.655931
Event: SPIE 31st International Symposium on Advanced Lithography, 2006, San Jose, California, United States

Abstract

In extreme ultraviolet (EUV) lithography technology, ultra low thermal expansion material is required as photomask substrate. We have previously developed Ti-doped silica glass which exhibits both ultra low coefficient of thermal expansion (CTE) and high homogeneity for EUV substrate. On the other hand, we have been investigating other candidate materials which have low CTE, from the viewpoint of structural chemistry. Silica glass is well-known as a low thermal expansion material and the reason is explained that in the open structure of silica glass two factors, expansion and shrinkage, compete with each other with increase in temperature. The network of silica glass consists of tetrahedra like quartz crystal. In this structure, Si is stably present with a valence of 4 and a coordination number of 4. We have carried out an atomistic simulation and estimated the volume change of oxide materials which may have the same structural transformation mechanism as SiO₂. As a result, the volume of SnO₂ with quartz structure (quartz-SnO₂), in which Sn was present with a valance of 4 and a coordination number of 4, decreased with increase in temperature, that is, the density of quartz-SnO₂ increased. Thus, it was indicated that the glass with lower CTE than that of silica glass could be obtained with substituting Sn for Si. Based on this hypothesis, we have prepared Sn-doped silica glass by Asahi silica glass producing method. The synthesized Sn-doped silica glass exhibited lower CTE than that of an ordinary silica glass.

Citation Download Citation

Mitsuhiro Kawata, Akira Takada, Hideaki Hayashi, Naoki Sugimoto, and Shinya Kikugawa "Novel low thermal expansion material for EUV application", Proc. SPIE 6151, Emerging Lithographic Technologies X, 61511A (23 March 2006); https://doi.org/10.1117/12.655931

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available