Photosensitive polycarbonates based on reaction development patterning (RDP)

Films of commercially available poly(bisphenol A carbonate) (BPA-PC) and po ly[bisphenol A carbonate-co-4,4'-(3,3,5-trimethylcyclohexylidene)diphenol c arbonate] (BPA-TMC-PQ containing photosensitive agent (diazonaphthoquinone (DNQ) compound) were prepared by spin-coating onto copper foil. The obtaine d films showed positive-tone behavior by UV irradiation and following devel opment with ethanolamine/N-methylpyrrolidone (NMP)/H2O mixture (1/1/1 by we ight). The scanning electron microscope (SEM) photographs of the resulting images exhibited fine patterns (similar to 10 mum line/space resolution) wi th 15-16 mum film thickness. The pattern forming mechanism is based on the Reaction Development Patterning (RDP), in which the carboxylic acid resulti ng from photo-rearrangement of DNQ in the film attracts ethanolamine in the developer and the amine reacts with carbonate in the main chain to induce degradation of the polymer. RDP, where the main pattern forming reaction oc curs during the development, is proved to be efficient for polycarbonates a s well as polyimide.