New synthetic route for photosensitive poly(benzoxazole)

A new positive working photosensitive poly(benzoxazole) (PBO) precursor based on poly(o-hydroxyazomethine) (3) and 1-{1,1-bis[4-(2-diazo-l-(2H)naphthalenone- 5-sulfonyloxy)phenyl]ethyl)-4-{1-[4- (2-diazo-1(2H)naphthalenone-5-sulfonyloxy)phenyl] methylethyl]benzene (S-DNQ) as a photosensitive compound was developed. 3 was prepared by the condensation of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with isophthalaldehyde in 1-methyl-2-pyrrolidinone/toluene under azeotropic conditions. The photosensitive PBO precursor containing 30 wt % S-DNQ showed a sensitivity of 120 mJ cm(-2) and a contrast of 2.2 when it was exposed to 436-nm light and developed with a 2.38 wt % aqueous tetramethylammonium hydroxide solution at room temperature. A fine positive image featuring 10-mum line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm(-1) ultraviolet light at 436 nm by the contact mode. The positive image was successfully converted into the PBO pattern by a thermal treatment. (C) 2002 Wiley Periodicals, Inc.