Removal of particles from lithographic masks through plasma-assisted cleaning by metastable atomic neutralization

W. M. Lytle; D. S. Szybilski; C. E. Das; R. Raju; V. Surla; M. J. Neumann; D. N. Ruzic

doi:10.1117/12.804704

4 December 2008 Removal of particles from lithographic masks through plasma-assisted cleaning by metastable atomic neutralization

W. M. Lytle, D. S. Szybilski, C. E. Das, R. Raju, V. Surla, M. J. Neumann, D. N. Ruzic

Author Affiliations +

Proceedings Volume 7140, Lithography Asia 2008; 71401S (2008) https://doi.org/10.1117/12.804704
Event: SPIE Lithography Asia - Taiwan, 2008, Taipei, Taiwan

Abstract

For extreme ultraviolet lithography (EUVL) to become a high volume manufacturing technology for integrated circuit manufacturing, the cleanliness of the system, especially the photomask, is of high importance. For EUV photomasks, which cannot be protected from contamination by the use of a pellicle, an effective and quick cleaning technology needs to be ready in order to maintain wafer throughput. There are challenges to extend current wet cleaning technologies to meet the future needs for damage-free and high efficiency mask cleaning. Accordingly, a unique process for cleaning particulates from surfaces, specifically photomasks as well as wafers, has been evaluated at the University of Illinois Urbana-Champaign. The removal technique utilizes a high density plasma source as well as pulsed substrate biases to provide for removal. Helium is used as the primary gas in the plasma, which under ionization, provides for a large density of helium metastable atoms present in the plasma. These metastable helium atoms have on the order of 20 eV of energy which can transfer to particles on the substrate to be cleaned. When the substrate is under a small flux of ion bombardment, these bonds then remain broken and it is theorized that this allows the particles to be volatilized for their subsequent removal. 100 % particle removal efficiency has been obtained for 30 nm, 80 nm, and 200 nm polystyrene latex particles. In addition, removal rate has been correlated with helium metastable population density determined by optical emission spectroscopy.

Citation Download Citation

W. M. Lytle, D. S. Szybilski, C. E. Das, R. Raju, V. Surla, M. J. Neumann, and D. N. Ruzic "Removal of particles from lithographic masks through plasma-assisted cleaning by metastable atomic neutralization", Proc. SPIE 7140, Lithography Asia 2008, 71401S (4 December 2008); https://doi.org/10.1117/12.804704

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