Synthesis of photocrosslinkable hyperbranched polyesters with terminal methacryloyl groups by the one-pot polyaddition of bis(oxetane)s with 1,3,5-benzenetricarboxylic acid and methacrylic acid

The hyperbranched poly(ester)s with pendant primary hydroxy, methacryloyl, and oxetanyl groups were synthesized by the one-pot method for the polyaddition of bis(oxetane)s with 1,3,5-benzenetricarboxylic acid (TMA) and methacrylic acid (MA) in the presence of tetraphenylphosphonium chloride (TPPC) as a catalyst. A alkaline-developable photo-reactive hyperbranched polymer (P-4b) was prepared by the addition reaction of the synthesized hyperbranched poly(ester) P-4a with cis-1,2,3,6-tetrahydrophthalic anhydride (THPA). A resist composed of 58 wt% P-4b, 12 wt% dilute monomer, 5 wt% Irgacure907 (R) as a photo-initiator, 24 wt% epoxy resin, and 1wt% dicyandiamide achieved a resolution of a 55 pm line pattern and a 27 mu m space pattern by UV irradiation (1000 mJ) when 6 mu m thick film is used.