Translator Disclaimer
15 March 2006 Studies of consequences of photo-acid generator leaching in 193nm immersion lithography
Author Affiliations +
Leaching of resist components into the water has been reported in several studies. Potential effects of photo-acid generator (PAG) dissolved in water include photocontamination of the last optical surface and the formation of particulate defects on the wafer surface. In order to determine the impact of these phenomena on lithographic performance, such as optics lifetime and yield, we have initiated a set of controlled studies, where predetermined amounts of PAG were introduced into pure water and the results monitored quantitatively. One set of studies identified the complex, nonlinear paths leading to photocontamination of the optics. At concentrations typical of leached PAG, below 500 ppb, the in-situ self-cleaning processes prevent contamination of the optics. On the other hand, initial experiments with a nano-dropper show that micron-scale particles from the dissolved PAG are formed on the wafer surface when water evaporates. This phenomenon requires further systematic studies both at the fundamental science and the engineering levels.
© (2006) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
V. Liberman, M. Switkes, M. Rothschild, S. T. Palmacci, and A. Grenville "Studies of consequences of photo-acid generator leaching in 193nm immersion lithography", Proc. SPIE 6154, Optical Microlithography XIX, 615416 (15 March 2006);

Back to Top