Development of negative-type photosensitive semi-alicyclic polyimide using a photobase generator

Abstract

A negative-type photosensitive polyimide (PSPI) based on a semi-alicyclic poly(amic acid) (PAA) and a photobase generator (PBG), {[(4,5-dimethoxy-2- nitrobenzyl)oxy]carbonyl}2,6-dimethyl piperidine (DNCDP) has been developed. PAA was readily prepared from cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) and 4,4′-oxydianiline (ODA) in N,N-dimethylacetamide (DMAc) at room temperature, and used directly by the addition of the PBG for photolithography. The PSPI consisting of PAA (85 wt%) and PBG (15 wt%) showed the high sensitivity of 53 mJ/cm2 and contrast of 39.5, respectively, after exposed to 365 nm UV light (i-line) and developed with 0.238 wt% tetramethylammonium hydroxide aqueous solution (TMAHaq) as a base-developer. A fine negative pattern with 6 μ m features on a silicon wafer was obtained by a contact-printing mode and converted into a PI pattern by heating at 200°C. ©2007TAPJ.