Removal of surface contamination from EUV mirrors using low-power downstream plasma cleaning

Christopher G. Morgan; Patrick P. Naulleau; Senajith B. Rekawa; Paul E. Denham; Brian H. Hoef; Michael S. Jones; Ronald Vane

doi:10.1117/12.846386

22 March 2010 Removal of surface contamination from EUV mirrors using low-power downstream plasma cleaning

Christopher G. Morgan, Patrick P. Naulleau, Senajith B. Rekawa, Paul E. Denham, Brian H. Hoef, Michael S. Jones, Ronald Vane

Author Affiliations +

Proceedings Volume 7636, Extreme Ultraviolet (EUV) Lithography; 76361Q (2010) https://doi.org/10.1117/12.846386
Event: SPIE Advanced Lithography, 2010, San Jose, California, United States

Abstract

The problem of carbon contamination on extreme ultraviolet (EUV) optics, causing unacceptably low reflectivity in mirrors, must be solved before industry will adopt the technology on a production scale. Breaking vacuum, removing and then cleaning mirrors is a time-consuming and expensive method for dealing with the problem. A safe yet effective in situ method for cleaning EUV optics and maintaining vacuum chamber cleanliness is important for progress in EUV lithography. Carbon contamination has also been a problem for the scanning electron microscopes (SEMs) leading to reduced image quality. The use of low power downstream plasma cleaner has been shown to be effective in removing carbon contamination from SEMs. The plasma dissociates oxygen molecules into neutral oxygen radicals. These radicals flow throughout the SEM vacuum chamber and chemically remove the carbon contamination. Since the process works by chemical etch and not by sputter etch, the capping layer on EUV mirrors will not be damaged by the cleaning process. The production of chemically etching oxygen radicals by plasma cleaning was measured using a quartz crystal microbalance. The effectiveness of the downstream plasma cleaning process was also tested on EUV mirrors.

Citation Download Citation

Christopher G. Morgan, Patrick P. Naulleau, Senajith B. Rekawa, Paul E. Denham, Brian H. Hoef, Michael S. Jones, and Ronald Vane "Removal of surface contamination from EUV mirrors using low-power downstream plasma cleaning", Proc. SPIE 7636, Extreme Ultraviolet (EUV) Lithography, 76361Q (22 March 2010); https://doi.org/10.1117/12.846386

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