Synthesis and characterization of photosensitive polyimides containing alicyclic structure

A new alkali developable photosensitive poly(amic acid) (PAA-0) with transmittance at 400 nm was synthesized from cyclobutane-1,2,3,4-tetracarboxylic dianhydride, 2-(methacryloyloxy)ethyl-3,5-diamino-benzoate and 1,3-bis(3-aminopropyl)-1,1,3,3-tetramethyl disiloxane in N-methyl-2-pyrrolidinone. Photosensitivity of the PAA-O was investigated at 365-400 nm in the presence of a photoinitiator using a high pressure mercury lamp. The photo-cured poly(amic acid) was insoluble toward aqueous 2.38 wt% tetramethylammonium hydroxide solution. Negative pattern of the PAA-O with 25 mum resolution was obtained by developing with 2.38 wt% tetramethylammonium hydroxide solution after exposure of 600 mJ/cm(2) in the presence of 2,2-dimethoxy-2-phenyl- acetophenone as a photoinitiator. The patterned poly(amic acid) was converted to polyimide by thermal curing at 250 degreesC for 50 min, which showed chemical resistance against photoresist stripper as well as good transmittance at 400 nm.