12 April 2001 Two-photon equivalent weighting of spatial excimer laser beam profiles
Author Affiliations +
Damage in optical materials for semiconductor lithography applications caused by exposure to 248 or 193 nm light is usually two-photon driven, hence it is a nonlinear function of incident intensity. Materials should be tested with flat- topped temporal and spatial laser beam profiles to facilitate interpretation of data, but in reality this is hard to achieve. Sandstrom provided a formula that approximates any given temporal pulse shape with a two- photon equivalent rectangular pulse (Second Symposium on 193 nm Lithography, Colorado Springs 1997). Known as the integral-square pulse duration, this definition has been embraced as an industry standard. Originally faced with the problem of comparing results obtained with pseudo-Gaussian spatial profiles to literature data, we found that a general solution for arbitrarily inhomogeneous spatial beam profiles exists which results in a definition much similar to Sandstrom's. In addition, we proved the validity of our approach in experiments with intentionally altered beam profiles.
© (2001) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Eric Eva, Eric Eva, Harry H. Bauer, Harry H. Bauer, K. Metzger, K. Metzger, A. Pfeiffer, A. Pfeiffer, } "Two-photon equivalent weighting of spatial excimer laser beam profiles", Proc. SPIE 4347, Laser-Induced Damage in Optical Materials: 2000, (12 April 2001); doi: 10.1117/12.425074; https://doi.org/10.1117/12.425074

Back to Top