Process optimization for performance improvement in Mo/Si multilayers for EUV mask blanks

Katrina Rook; Paul Turner; Narasimhan Srinivasan; Tania Henry; Kenji Yamamoto; Meng H. Lee

doi:10.1117/12.2573164

15 October 2020 Process optimization for performance improvement in Mo/Si multilayers for EUV mask blanks

Katrina Rook, Paul Turner, Narasimhan Srinivasan, Tania Henry, Kenji Yamamoto, Meng H. Lee

Proceedings Volume 11517, Extreme Ultraviolet Lithography 2020; 1151708 (2020) https://doi.org/10.1117/12.2573164
Event: SPIE Photomask Technology + EUV Lithography, 2020, Online Only

Abstract

We investigate the impact of key ion-beam-deposition (IBD) process conditions on the properties of Mo/Si multilayers as reflective coatings for Extreme Ultraviolet (EUV) mask blanks. Dark-field TEM measurements imply interfacial roughness values of 80-90 picometers. Bright-field TEM measurements indicate intermixed layer thicknesses of 0.5 – 1.9nm. We present reflectivity calculations including these two multilayer imperfections and reveal that roughness at this level has insignificant reflectivity impact. However, this level of intermixing could cause a reflectivity drop of ~ 4%. Ion bombardment simulations provide estimates of the atom energy distribution arriving at the mask blank surface during Mo and Si deposition, and of stopping depths of each atom into the underlying layer. Key parameters to modify the deposition energy, and potentially the intermixing depth, are summarized: beam voltage and deposition pressure. Lower ion beam voltage or higher pressure are both predicted to reduce the intermixing depth by 20-30%. Bright-field TEM measurements of multilayers deposited at various deposition conditions confirm the predictions.

Conference Presentation

Citation Download Citation

Katrina Rook, Paul Turner, Narasimhan Srinivasan, Tania Henry, Kenji Yamamoto, and Meng H. Lee "Process optimization for performance improvement in Mo/Si multilayers for EUV mask blanks", Proc. SPIE 11517, Extreme Ultraviolet Lithography 2020, 1151708 (15 October 2020); https://doi.org/10.1117/12.2573164

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