Understanding the onset of EUV resist chemical stochastics

Abstract

The ability of chemically amplified resists to transfer an aerial image at increasingly smaller dimensions is critical to extreme ultraviolet (EUV) lithography success at increasingly smaller process nodes. Stochastic inhomogeneities in resist exposure and patterning have been studied, which include photon shot noise and resist surface roughness. However, previous work has indicated that inhomogeneities and defectivity are present in multicomponent resists beyond those predicted by random statistics. This is thought to be due to self-segregation of components in the multi-component chemically amplified resist (CAR). The results in this paper show that the most critical part of the resist chemical segregation occurs during the spin coating process after a significant amount of the solvent has evaporated, but while there is still enough solvent to enable molecular mobility within the resist.