Relationship between Remaining Solvent and Acid Diffusion in Chemically Amplified Deep Ultraviolet Resists

Abstract

A numerical method is described for calculating the first-order response of an electron distribution to changes of field or scattering rate or for deriving the time development of any small distortion of the distribution. The initial state may be in thermal equilibrium or may be modified by biasing fields. The technique simplifies the analysis of transport problems in which low symmetry perturbations distort a basic system of higher symmetry. The application of the method to the calculation of the galvanomagnetic properties of materials for small electric fields is set out as a detailed example and is illustrated by reference to n-type GaAs.

Chemical and physical aspects of the post-exposure baking process used for positive-tone chemically amplified resists

“…As noted above, because diffusion is accompanied by reaction, the extraction of diffusion kinetics independent of deprotection kinetics is not simple. Numerous investigations of acid diffusion in positive-tone chemically amplified resist systems have been reported using the following to elucidate the coupled reaction-diffusion process: multilayer structures of acidified polymer or a layer of pure acid on pure polymer [20 -22]; linewidth measurements [23,24]; ionic conductivities [23,[25][26][27]; and spectroscopic probes of polymer chemistry changes during or after post-exposure bake [22, 23, 28 -30]. Diffusion coefficients are typically obtained from the experimental measurements in one of three ways.…”

Monte Carlo study of surface and line-width roughness of resist film surfaces during dissolution

“…However, the same effect is accompanied by resist line profile distortion, especially in the resist/line case [32,38]. Simulations [5] have also predicted the same, and this has been justified in terms of the acid diffusion, which softens the difference in exposure between neighboring regions of the resist line to the intermediate region between exposed and un-exposed film.…”

Novel Diffusion Analysis in Advanced Chemically Amplified DUV Resists Using Photometric Methods.

“…By pre baking above 120°C, these traces should have been removed almost completely from the film. T. Itani [25] found that a higher remaining solvent content was associated with a longer acid diffusion length. This indicates that the remaining solvent contributes to one of the diffusion channels within the resist film.…”