Dependence of contamination rates on key parameters in EUV optics

Yashdeep Khopkar; Petros Thomas; Leonid Yankulin; Rashi Garg; Chimaobi Mbanaso; Alin Antohe; Mihir Upadhyaya; Vimal Kumar Kamineni; Yu-Jen Fan; Gregory Denbeaux; Vibhu Jindal; Andrea Wüest; Eric Gullikson

doi:10.1117/12.879491

8 April 2011 Dependence of contamination rates on key parameters in EUV optics

Yashdeep Khopkar, Petros Thomas, Leonid Yankulin, Rashi Garg, Chimaobi Mbanaso, Alin Antohe, Mihir Upadhyaya, Vimal Kumar Kamineni, Yu-Jen Fan, Gregory Denbeaux, Vibhu Jindal, Andrea Wüest, Eric Gullikson

Author Affiliations +

Proceedings Volume 7969, Extreme Ultraviolet (EUV) Lithography II; 796923 (2011) https://doi.org/10.1117/12.879491
Event: SPIE Advanced Lithography, 2011, San Jose, California, United States

Abstract

Optics contamination remains one of the challenges in extreme ultraviolet (EUV) lithography. Dependence of contamination rates on key EUV parameters was investigated. EUV tools have optics at different illumination angles. It was observed that at shallower angles, the carbon contamination rate and surface roughness was higher on the optics surface. This is a concern in EUV optics as higher roughness would increase the scattering of the EUV radiation. Secondary ion time of flight mass spectrometer (TOF-SIMS) data indicated that the carbon contamination film might be a polymer. Three chemical species were used to investigate the dependence of polymerization and reactivity on the contamination rate. Acrylic acid was found to have a measurable contamination rate above background compared to propionic acid and methyl methacrylate. Secondary electron dissociation is one of the mechanisms considered to be a cause for the growth of the carbon contamination film. Multiple experiments with two substrates having different secondary electron yields were performed. The substrate with the higher secondary electron yield was found to give a higher contamination rate.

Citation Download Citation

Yashdeep Khopkar, Petros Thomas, Leonid Yankulin, Rashi Garg, Chimaobi Mbanaso, Alin Antohe, Mihir Upadhyaya, Vimal Kumar Kamineni, Yu-Jen Fan, Gregory Denbeaux, Vibhu Jindal, Andrea Wüest, and Eric Gullikson "Dependence of contamination rates on key parameters in EUV optics", Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 796923 (8 April 2011); https://doi.org/10.1117/12.879491

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