Positive photosensitive polyimides using polyamic acid esters with phenol moieties

Abstract

SYNOPSISPolyimide resists developable with basic aqueous solutions were realized by polyamic acid esters with phenol moieties ( PPh's) and naphthoquinone diazides. The polyimide precursors ( PPh's) were synthesized from diamines and dicarboxylic acids that have phenol moieties through ester linkage. A selective reaction of alcohol groups with acid dianhydride groups made the synthesis of the PPh's possible, even if the phenol groups were in the reaction mixtures. The PPh's were soluble in basic aqueous developer, but their dissolution rates were too low for use as resists. To increase the resist dissolution rate, polyamic acids were added to the PPh's. By adjusting the dissolution rates in basic aqueous developers, fine patterns could be realized. The polyimide resists had high thermal stability and reliable adhesive property to silicon substrate.

Recent Development in Photosensitive Polyimide (PSPI)

“…These polymers were formulated with DNQ to make PSPI precursors and provided positive images [12]. Although the loss of final film thickness after converting into the polyimide seems to be larger than that of conventional negative-type PSPIs, these PSPI precursors can be developed using an aqueous alkaline solution with a practical sensitivity.…”

“…To overcome this problem, the system consisting of PAA having hydrophobic structure and DNQ was investigated (eq. (11,12)). These PSPI precursors have a high sensitivity and good resolution [14].…”

A novel positive‐type photosensitive polyimide based on soluble block copolyimide showing low dielectric constant with a low‐temperature curing process

“…The curing temperature of the polyisoimide was 400°C. Hayase and coworkers14 reported another approach to developing a DNQ‐sensitized PSPI, which they accomplished by using poly(amic acid) esters with phenol moieties and DNQ. The polyimide precursors were synthesized from diamine and dicarboxylic acids that had phenol moieties through ester linkages.…”

Novel positive‐type photosensitive polyimide with low dielectric constant

“…This PSPI system possesses good sensitivity and contrast. Hayase and coworkers9 reported another DNQ sensitized approach, which was realized by polyamic acid esters with phenol moieties and DNQ. The PI precursors were synthesized from diamine and dicarboxylic acids that had phenol moieties through an ester linkage.…”