A New Negative-Type Photosensitive Polyimide Based on Poly(hydroxyimide), a Cross-Linker, and a Photoacid Generator

Abstract

A negative working photosensitive polyimide based on poly(hydroxyimide) (PHI), 2,6-bis(hydroxymethyl)-4-methylphenol (BHMP) as cross-linker, and photoacid generator diphenyliodonium 9,10-dimethoxyanthracene-2-sulfonate (DIAS) has been developed. The PHI was prepared by the ring-opening polyaddition of 4,4‘-hexafluoroisopropylidenebis(phthalic anhydride) and 4,4‘-diamino-4‘‘-hydroxytriphenylmethane, followed by thermal cyclization in refluxing xylene. The PHI film showed excellent transparency to UV light. The photosensitive polyimide containing 70 wt % PHI, 20 wt % BHMP, and 10 wt % DIAS showed a sensitivity of 70 mJ/cm2 and a contrast of 3.8 when it was exposed to 365 nm light and postbaked at 120 °C, followed by developing with a 2.5% aqueous tetramethylammonium hydroxide solution at 40 °C. The mechanistic study on the formation of images is also discussed.

Recent Development in Photosensitive Polyimide (PSPI)

“…System of Chemical Amplification based on PHI(Negative-type : Cross-linking reaction) [20] The negative-type alkaline developable PSPI has also been reported.…”

Highly Dielectric and Photo-patternable Gate Insulators for Organic Field-effect Transistors

“…The patterning process is shown in Scheme 2. It is assumed that sulfonic acids generated in the exposed area catalyze the formation of benzylic carbocation species, which undergo electrophilic substitution on the aromatic rings and hydroxyl group to produce C-and O-alkylated polymers [16,17]. These reactions convert the alkaline soluble PVPCM into cross-linked PVPCM as shown in Scheme 2.…”

Photo-Induced Polarity Change of Photosensitive Polyimide with o-Nitrobenzyl Ester Side Chain

“…For micro-fabrication of polyimide, photosensitive polyimide (PSPI) is one of the best materials because it can simplify the micro-fabrication process compared to the conventional system using additional photoresist layer [1][2][3][4][5]. Most of research in PSPI employed photochemical reactions that can induce large solubility change.…”

“…However, it is difficult to introduce o-nitrobenzyl group to all side chain because o-nitrobenzyl group was introduced by post-polymerization reaction. In our previous report, we found chemoselective esterification of 5,5'-Methylenebis (2-aminobenzoic acid) (MBAA) with alkyl halide by using 1,8-diazabicylro [5,4,0]undec-7-ene (DBU) [9][10][11]. By using the functionalized diamine monomer, a series of polyimides with functional group at all side chain was successfully synthesized.…”