1 January 2006 Contamination transport in immersion lithography
Author Affiliations +
Abstract
In immersion lithography at 193 nm, water is inserted between a resist-coated wafer and the final lens element to improve resolution and depth of focus. Experiments have shown that some chemicals in the resist, particularly the photoacid generators, are soluble and therefore will leach out of the resist layer when exposed to water. Diffusion of this contamination across the lens-wafer gap may, over time, build up on the lens and therefore degrade the performance of the tool. We present models that describe the transport of contaminants in the under-lens region of an immersion tool. The mass flux of contaminants onto the lens is quantified for a reasonable range of parameters under various 2-D steady-state and transient flow conditions. A critical mass flux is estimated to provide a context for interpreting these results; the critical mass flux is defined as the level of mass flux that might, over a period of one year, result in a layer of contamination that is sufficiently thick so as to affect the optical transmission of the system.
Gregory F. Nellis, Mohamed S. El-Morsi, Chris K. Van Peski, Andrew Grenville, "Contamination transport in immersion lithography," Journal of Micro/Nanolithography, MEMS, and MOEMS 5(1), 013007 (1 January 2006). https://doi.org/10.1117/1.2167947
JOURNAL ARTICLE
10 PAGES


SHARE
RELATED CONTENT

High-n immersion lithography
Proceedings of SPIE (March 07 2008)
Development of ArF immersion exposure tool
Proceedings of SPIE (May 12 2004)
Full-field exposure tools for ArF immersion lithography
Proceedings of SPIE (March 21 2006)
Studies on leaching of photoresist components by water
Proceedings of SPIE (May 04 2005)
Feasibility of 37 nm half pitch with ArF high index...
Proceedings of SPIE (March 26 2007)
Development status of a 193-nm immersion exposure tool
Proceedings of SPIE (March 15 2006)

Back to Top