Novel positive-working aqueous-base developable photosensitive polyimide (PSPI) precursors based on partially diazonaphthoquinone (DNQ)-capped polyamic esters bearing phenolic hydroxyl groups and a DNQ photosensitive compound (PIC-3) were developed. The partially DNQ capped polyamic esters were prepared from an esterification reaction of 1,2-naphthoquinone diazide-5-sulfonyl chloride with the polyamic esters. The partially DNQ capped polyamic esters decreased the dark film loss effectively in the aqueous-base developer and were able to make thicker film resists compared to the uncapped polyamic esters. The 25 mol % DNQ-capped BisAPAF-PMDA polyamic ester and BisAPAF-ODPA polyamic ester containing 25 wt %, PIC-3 photosensitive compound showed a sensitivity of 176 and 185 MJ/cm(2), and a contrast of 1.68 and 1.02, respectively, in a 3-mum film with 1.25 wt % tetramethylammonium hydroxide developer. A pattern with a resolution of 5 mum was obtained from both PSPI precursor compositions. (C) 2003 Wiley Periodicals, Inc.