Dissolution Inhibition of Phenolic Resins by Diazonaphthoquinone: Effect of Polymer Structure

In order to understand the basic mechanisms working in the dissolution of phenolic resin/diazonaphthoquinone (DNQ) positive photoresists, several polyhydroxystyrene derivatives have been studied in terms of their dissolution capabilities. The influence of the structure and the molecular weight distributions of phenolic resins on the inhibition effect were examined. In phenolic resins which have alkyl groups ortho to the hydroxy group a strong dissolution inhibition effect is found. As for the molecular weight distribution, the mixtures of a higher-molecular-weight polymer with lower dissolution rate and a lower-molecular-weight polymer with higher dissolution rate give strong dissolution inhibition by DNQ.