Development status of EUVL mask blanks

Kazuaki Shiromo

doi:10.1117/12.801427

17 October 2008 Development status of EUVL mask blanks

Kazuaki Shiromo

Proceedings Volume 7122, Photomask Technology 2008; 712225 (2008) https://doi.org/10.1117/12.801427
Event: SPIE Photomask Technology, 2008, Monterey, California, United States

Abstract

Extreme ultraviolet lithography (EUVL) is the most promising lithographic technology to fabricate the next generation devices with a 20~30 nm feature size or smaller. The production of the EUVL mask blank is one of the critical issues to realize the EUVL because of various kinds of stringent requirements. For instance, a <+/-5 ppb/K thermal expansion coefficient (CTE) and a <30 nm surface flatness of the polished substrate, a high and uniform reflectivity at the 13~14 nm wavelength of the reflective multilayer film, and a low defect density as small as 30nm of the blank. Most of these requirements are different from the optical lithography mask blank and some are specific to the EUVL blank. We have continuously been developing all of key materials and processes essential to prepare the EUVL mask blank, and we showed a good progress in its performance improvement. Our low thermal expansion material (LTEM) showed the CTE properties requirements defined in SEMI P37, which were 0 +/- 5 ppb/K mean CTE at 22°C and < +/-3 ppb/K CTE spatial variation across 6 inch square substrate. ~30nm flatness was demonstrated on both front and back surfaces of the LTEM polished substrate, which was very close to the most stringent flatness requirement of SEMI P37. Ta-based absorber film and anti-reflective film were also developed. Their film properties almost met SEMI P38 class A, and the absorbers showed good etching and patterning performances with the inductively coupled plasma etching process. In addition, the thinner resist coating process was developed. As a consequence, Asahi Glass has a capability to deliver the ready-to-write EUVL blank which is the most suitable for the EUVL process developments by using the full field exposure tools.

Citation Download Citation

Kazuaki Shiromo "Development status of EUVL mask blanks", Proc. SPIE 7122, Photomask Technology 2008, 712225 (17 October 2008); https://doi.org/10.1117/12.801427

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