Using detailed metrology and modeling,the excimer beam may be completely characterized making it possible to achieve good agreement among various test methods and allowing accurate prediction of the beam performance in photolithographic and other applications. Full characterization consists of determining the intensity envelope, wavefront error, and detailed speckle structure statistics. The numerical model consists of a series of exact 2D instantaneous representations of the complex amplitude propagated through the beam train, with time varying speckled structure and integration to generate the time-averaged beam envelope. The detailed description provides a means to validate simpler, but more appropriate, theories and to determine the limits of accuracy of these simpler methods for various experiment configurations. We also show results of very recent time-resolved experiments of near-field and focal plane profiles.
Jesse D. Buck,
"Numerical modeling of the excimer beam", Proc. SPIE 3677, Metrology, Inspection, and Process Control for Microlithography XIII, (14 June 1999); doi: 10.1117/12.350856; https://doi.org/10.1117/12.350856