The technique of spectroscopic ellipsometry was employed to study the effects of residual solvents in chemically amplified photoresists on the dissolution characteristics and optical constants of the spin-cast film. Ellipsometric measurements were made for resist films with no bake, with soft bakes, and with both soft bakes and post-exposure bakes, at various baking temperatures. Exposures of these films were performed using a KrF excimer laser (248 nm) with a beam splitter lens element to increase the exposure area. To increase the accuracy of the experimental data, measurements were made at three different angles over a sampling wavelength range of 200 nm to 800 nm. Resist thickness and optical parameters (n and k) were extracted by fitting the experimental data to a theoretical model.
Chan, Michael Y.
"Resist Performance Using Spectroscopic Ellipsometry,"
Journal of the Microelectronic Engineering Conference: Vol. 7
, Article 18.
Available at: http://scholarworks.rit.edu/ritamec/vol7/iss1/18