New Positive-type Photosensitive Polyimide Having Sulfo Groups 2. Polyimides from 2,2'-oxy(or thio)bis(5-aminobenzenesulfonic acid) 4,4'-oxydianiline, and 4,4'-hexafluoro propylidene-bis(phthalic anhydride)

Abstract

New positive-working photosensitive polyimides (PSPIs) based on polyimides bearing sulfo groups (PISs) and 1-{1,1-bis[4-(2-diazo-1-(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 have been developed. PISs were prepared by ring-opening polyaddition of 2,2'-oxybis(5-aminobenzenesulfonic acid) (OBAS) or, 2,2'-thiobis(5-aminobenzenesulfonic acid) (TBAS) and 4,4'-oxydianiline (ODA), with 4,4'-hexafluoropropylidenebis(phthalic anhydride) (6FDA), followed by thermal cyclization in m-cresol. PIS containing 30wt% of S-DNQ showed a sensitivity of 100 mJ cm-2 and a contrast of 2.6, when it was exposed to 365-nm light followed by developing with 2.38 wt % aqueous tetramethylammonium hydroxide (TMAH) solution at room temperature. A fine positive image featuring 20μm line and space patterns was observed on the film of the photoresist exposed to 200 mJ cm-2 of UV-light at 365 nm by the contact mode. The positive image was successfully converted to the polyimide pattern by thermal treatment.