Polymeric Film Deposition by Coevaporation of Polymerizable Monomer and Initiator

A novel method for patterning polymeric thin films by vapor deposition of a photosensitive layer followed by photopolymerization and development was proposed. Organic film patterns were obtained by selective polymerization of photosensitive layers that were prepared by coevaporating photoinitiators of either 4-(dimethylamino)benzophenone (DABP) or IRUGACURE 907 (IRU) with a functional monomer of 2-(9 H -carbazol-9-yl)ethylmethacrylate (CAR). IR analysis confirmed that these materials can be vapor-deposited without decomposition. After the selective polymerization by UV irradiation through a photomask, the film was patterned by removing the nonpolymerized section using tetrahydrofuran. 10 µm dot patterns were obtained with this method, indicating a structure controllability of the micron scale. The effects of irradiation power and initiator concentration were compared between DABP and IRU. This method is advantageous as a new technique for patterning polymer films without using a shadow mask for vapor deposition or a photoresist.