Application of Polyisoimide as a Polyimide Precursor to Polymer Adhesives and Photosensitive Polymers

Recent developments and application of polyisoimide (PII) to high temperature adhesive and photosensitive polymers are described. First, new high temperature adhesives based on PII have been developed. PIIs showed stronger adhesions to copper foils because of favorable anchoring between PII and copper foil due to a good flow of PII. Next, a positive working photosensitive polyimide precursor based on PII and 2,3,4-tris[1-oxo-2-diazonaphthoquinone-4-sulfonyloxy] benzophenone (5) as a photoreactive compound has been developed. The photosensitive polyimide-precursor containing 20 wt% of 5 showed a sensitivity of 250 mJ/cm2 and a contrast of 2.4 with 435 nm-light when it was postbaked at 150 °C for 10 min followed by developing with 5 % aqueous tetramethylammonium hydroxide solution at 45 °C. Further, a new amine photo-generator{[(4,5-dimethoxy-2-nitrobenzyl)oxy] carbonyl}-2,6-dimethyl piperidine (6) was prepared from 2,6-dimethyl piperidine and 4,5-dimethoxy-2-nitrobenzyl-p-nitrophenylcarbonate. The PII containing 10 wt% of 6 functioned as photosensitive resist having a sensitivity of 900 mJ/cm2 and a contrast of 3.4 with 365 nm-light when it was postbaked at 150 °C for 5 min followed by development with cyclohexanone at 45 °C.