Bulk effects of thermal flow resists

Abstract

In the semiconductor lithography process, the thermal flow process after development can pattern sub-100-nm contact holes and saves the cost of using resolution enhancement technology. In this study, the resist flowing behavior and the contact hole shrinkage are described by using the level-set method and the thermal reflow length. The viscosity variable affects the shrinkage of the critical dimension. This variable is extracted from the experimental data by using a proposed equation. Our simulation results are in good agreement with the experimental results for various baking temperatures and times. Although the most effective process of a 193-nm chemically amplified resist is the post exposure bake process, the inhibition reaction order of the enhanced Mack model, which is a parameter of the development process, is shown to be the most controllable parameter for the critical dimension. In the resist reflow process, the side-wall angle of the resist profile is decreased by the surface tension. This phenomenon is,shown to be similar to that in the spin coating process by modeling a dimensionless parameter in spin coating.