EUV mask cleans comparison of frontside and dual-sided concurrent cleaning

Lin Lee Cheong; Louis M. Kindt; Christina Turley; Dusty Leonhard; John M. Boyle; Chris F. Robinson; Jed H. Rankin; Daniel Corliss

doi:10.1117/12.2085913

19 March 2015 EUV mask cleans comparison of frontside and dual-sided concurrent cleaning

Lin Lee Cheong, Louis M. Kindt, Christina Turley, Dusty Leonhard, John M. Boyle, Chris F. Robinson, Jed H. Rankin, Daniel Corliss

Author Affiliations +

Proceedings Volume 9422, Extreme Ultraviolet (EUV) Lithography VI; 94221M (2015) https://doi.org/10.1117/12.2085913
Event: SPIE Advanced Lithography, 2015, San Jose, California, United States

Abstract

The cleaning requirements for EUV masks are more complex than optical masks due to the absence of available EUVcompatible pellicles. EUV masks must therefore be capable of undergoing more than 100 cleaning cycles with minimum impact to lithographic performance. EUV masks are created on substrates with 40 multilayers of silicon and molybdenum to form a Bragg reflector, capped with a 2.5nm-thick ruthenium layer and a tantalum-based absorber; during usage, both ruthenium and absorber are exposed to the cleaning process. The CrN layer on the backside is used to enable electrostatic clamping. This clamp side must also be free of particles that could impact printing and overlay, and particles could also potentially migrate to the frontside and create defects. Thus, the cleaning process must provide decent particle removal efficiencies on both front- and backside while maintaining reflectivity with minimal surface roughness change. In this paper, we report progress developing a concurrent patterned-side and clamped-side cleaning process that achieves minimal reflectivity change over 120 cleaning cycles, with XPS and EDS indicating the presence of ruthenium after 125 cleaning cycles. The change in surface roughness over 100 cleaning cycles is within the noise (0.0086nm) on a mask blank, and SEM inspection of 100nm and 200nm features on patterned masks after undergoing 100 cleaning cycles show no indications of ruthenium pitting or significant surface damage. This process was used on test masks to remove particles from both sides that would otherwise inhibit these masks from being used in the scanner.

Citation Download Citation

Lin Lee Cheong, Lin Lee Cheong, Louis M. Kindt, Louis M. Kindt, Christina Turley, Christina Turley, Dusty Leonhard, Dusty Leonhard, John M. Boyle, John M. Boyle, Chris F. Robinson, Chris F. Robinson, Jed H. Rankin, Jed H. Rankin, Daniel Corliss, Daniel Corliss, "EUV mask cleans comparison of frontside and dual-sided concurrent cleaning", Proc. SPIE 9422, Extreme Ultraviolet (EUV) Lithography VI, 94221M (19 March 2015); doi: 10.1117/12.2085913; https://doi.org/10.1117/12.2085913

ACCESS THE FULL ARTICLE

PERSONAL SIGN IN
Full access may be available with your subscription

Email or Username Forgot your username?

Password Forgot your password?

Show

Remember Email/Username on this computer

Remember Password

No SPIE account? Create an account
or Institutional Sign In via Shibboleth

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

Members: $14.40

Non-members: $18.00 ADD TO CART

Show All Keywords

Keywords/Phrases

Search In:

Publication Years