M. Okazaki et al., New negative-type photosensitive polyimide based on hyperbranched poly(ether imide), a cross-linker, and a photoacid generator, CHEM LETT, (8), 2001, pp. 762-763
A new negative working photosensitive polyimide, based on hyperbranched pol
y(ether imide) (1), 4,4 ' -methylenebis[2,6-bis(hydroxymethyl)]phenol (2) a
s a cross-linker, and a photoacid generator diphenyliodonium 9,10-dimethoxy
anthracene2-sulfonate (3) has been developed. I was prepared by polycondens
ation of N-[3,5-di-(tert-butyldimethylsilyloxy)phenyl]-4-fluorophthalimide
(4), followed by deprotection of tert-butyl-dimethylsilyl group with KF-HBr
. The photosensitive polyimide containing 1 (70 wt%), 2 (20 wt%) and 3 (10
wt%) gave a clear negative pattern when it was exposed to 365 nm light and
postbaked at 120 degreesC, followed by developing with a 2.38 wt% aqueous t
etramethylammonium hydroxide (TMAH) solution at room temperature.