Plasma-surface interactions of model polymers for advanced photoresists using C[sub 4]F[sub 8]∕Ar discharges and energetic ion beams

Plasma based transfer of photoresist (PR) patterns into underlying films and substrates is basic to micro- and nanofabrication but can suffer from excessive surface and line edge roughness in the photoresist and resulting features. The authors have studied the interaction of a set of adamantyl methacrylate-based model polymers with fluorocarbon∕Ar discharges and energetic Ar+ ion beams. Through systematic variation of the polymer structure, the authors were able to clarify the contributions of several critical polymer components on the chemical and morphological modifications in the plasma environment. Etching rates and surface chemical and morphological changes for the model polymers and fully formulated 193 and 248nm photoresists were determined by ellipsometry, atomic force microscopy, time of flight static secondary ion mass spectrometry, and x-ray photoelectron spectroscopy. The polymer structure in the near surface region (∼10nm) of all materials is destroyed within the first seconds of exposure to ...