Modeling solvent diffusion in photoresist

A semi-empirical study into the effects of residual casting solvent on the lithographic properties of photoresist is described. Solvent content of a c ommercial i-line photoresist after postapply bake has been measured using a quartz crystal microbalance and using radio-labeled solvent with scintilla tion counting. Analysis of this data has led to a calibrated model of solve nt diffusivity as a function of solvent content which can then predict solv ent content as a function of depth into the photoresist for a given bake. ( C) 1998 American Vacuum Society. [S0734-211X(98)03106-0].