Negative-tone deep-ultraviolet resists containing benzylic crosslinkers: Experimental and simulation studies of the crosslinking process

Dissolution rate and resolution measurements are used to show that a novel acid-hardened deep-ultraviolet photoresist ML93, based on a benzylic crosslinker, has excellent dissolution and reasonable resolution characteristics. Experimentally, we have observed that ML93 resist is about 20 times more sensitive than Shipley SNR248. While the high sensitivity is a promising result, it has made experimental reproducibility more difficult. In addition, the effect of the crosslinker structure on dissolution is examined with three more resists, ML239, ML240, and ML241, all analogous to ML93 except for variations in the structure of the crosslinker. A kinetic model describing negative resist lithography is applied to ML93 and ML239, and some profile cross sections are simulated using sample. The kinetic model has provided a reasonable fit to the dissolution characteristics of ML93 and ML239 separately, but comparison indicates that the basic role played by the active sites in the dissolution process needs further investigation.