Novel Structures of Novolak Resins Designed to Improve Resist Alkaline Dissolution, Resolution, Thermal Resistance and Ease of Manufacturing

Activated phenolic monomers modified with hydroxymethyl groups were used to prepare a number of novolak resins described in this paper. In most cases the starting repeat units and final novolaks were prepared in situ from their corresponding methylolated phenols. The synthesis and characterization of four specific novolak structures are presented. The resist performance based on one novolak system was investigated as a function of the novolak composition. Repeat units produced by the condensation of 3,5-dimethyl phenol and 4-hydroxybenzyl alcohol provided the basis for this novolak structure. FT-IR spectroscopy was used to investigate the types of hydrogen bonds and their interactions within this system.