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Low‐temperature curable, alkaline‐developable, and negative‐type photosensitive polyimide with high resolution and mechanical properties based on chain extendable poly(amic acid) and photo‐base generator
Author(s) -
Yeh YaoMing,
Karapala Vamsi K.,
Ueda Mitsuru,
Hsu ChainShu
Publication year - 2021
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.5119
Subject(s) - polyimide , materials science , curing (chemistry) , ammonium hydroxide , polymer chemistry , polymerization , bpda , polymer , aqueous solution , composite material , chemistry , organic chemistry , layer (electronics)
A negative‐type photosensitive polyimide ( PSPI ) based on a chain extendable poly(amic acid) ( PAA ) and a photo‐base generator ( PBG ) ( E )‐1‐piperidino‐3‐(2‐hydroxyphenyl)‐2‐propen‐1‐one ( PHPP ) have been developed. The chain extendable PAA was prepared from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride ( BPDA ) and 4,4′‐oxydianiline ( ODA ) and end‐capped with di‐ tert ‐butyl dicarbonate ( DIBOC ) in N ‐methyl‐2‐pyrrolidone (NMP), which has a controlled molecular weight for developing in a 2.38 wt% tetramethyl ammonium hydroxide aqueous solution ( TMAH aq ) and underwent a chain‐extending reaction during a curing stage. The PSPI was formulated with the polymerization solution (20 wt% in NMP) and PHPP (15 wt% for the polymer). The PSPI showed a sensitivity of 152 mJ cm −2 and a contrast of 5.9 when exposed to the i ‐line, followed by post exposure baking at 160°C for 2 minutes and development with the 2.38 wt% TMAH aq containing 10 wt% iPrOH at room temperature. A fine negative image with 2‐μm pattern was obtained on a 3‐μm thick film in the contact‐printed mode. After thermal curing at 200°C for 1 hour, the resulting PSPI features low curable temperature, high resolution and excellent mechanical properties.