Acidic Polyester Imides as Thermally Stable Binder Polymers for Negative-Tone Black Photoresist

Polyimides are well-known for their high chemical inertness and thermal stability.However, it is usually challenging to synthesize UV-curable polyimides since the imidization reaction requires such harsh conditions that acrylate type double bonds cannot withstand.In this work, synthetic methods are developed to obtain polyester-imide type binder polymers with high thermal stability, high compatibility with the other components of the black photoresist, and fine photolithographic patterning property for the negative-tone black photoresist.The syntheses of diimide-diacid or diimide-diol intermediates for the polyesterification with dianhydride gave polyester imides which meets this requirement.The photolithographic tests have shown that the patterning of the micron-sized PDL of the organic light emitting diode (OLED) panel could be obtained.This work will interest the researchers working on the design and optimization of thermally stable binder polymers.