2005 Volume 18 Issue 2 Pages 313-318
A novel positive type photosensitive polyimide based on soluble block copolyimide (Bco-PI) with alicyclic dianhydride has been developed. The base Bco-PI was prepared by a direct one-pot polycondensation of cyclohexanetetracarboxylic dianhydride (H-PMDA), 2, 2-Bis (3-amino-4-hydroxyphenyl)hexafluoropropane (Bis-AP-AF) and bis(4-(3-aminophenoxy)phenyl)sulfone (m-BAPS) in the presence of a γ-valerolactone and pyridine catalyst system and N-methyl-2-pyrrolidone(NMP) was used as solvent. The resulting film was transparent and colorless. It exhibited the cutoff at 290nm, and the refractive index was 1.55. The Tg and CTE were 278°C and 39 ppm/°C. As alicyclic dianhydride, H-PMDA, contributed to the resulting Bco-PI film with good thermal properties and excellent optical properties.
By the addition of 20wt% 1,2-Naphthoqiunonediazide-5-sulfonic acid p-cresol ester (PC5) to the Bco-PI, It was found to be a positive type photosensitive polyimide. It showed a sensitivity of 350mJ/cm2 and a contrast of 2.42 when it was exposed to UV light, followed by development with 5% tetramethylammonium hydroxide (TMAH) aqueous solution at room temperature.
