Synthesis and Characterization of <scp>EPBT</scp> Low Temperature Cured Cationic Photosensitive Resin

ABSTRACT This paper addresses the issue of high post‐baking temperature (230°C) in the photolithography process of liquid crystal displays under ultraviolet irradiation by designing and preparing a low‐temperature curing cationic photosensitive resin. First, a monomer containing carbon – carbon double bonds and bis‐epoxy groups, (Z)‐1,4‐bis(oxiran ‐ 2‐ylmethoxy)but‐2‐ene (EPBT), was synthesized via the Williamson ether synthesis method. Subsequently, poly(methacrylic acid/methylmethacrylate/ N‐ phenylmaleimide/(Z)‐1,4‐bis(oxiran ‐ 2‐ylmethoxy)but‐2‐ene/oxetane methacrylate) photosensitive resin (PMMENL) was prepared by radical polymerization of various monomers. The structure of the EPBT monomer and the polymer was characterized, along with their properties. Finally, the prepared resin was uniformly mixed with photoinitiators, solvents, and other components, and micro‐patterns on the mask were obtained through the photolithography process. The resolution and morphology of the patterns were examined. The results indicate that the thermal stability of the resin improved after the incorporation of N‐ phenylmaleimide, with a thermal decomposition temperature of approximately 225°C when the weight loss reached about 10%. Compared to the conventional post‐baking temperature of 230°C required for LCD photoresists, the post‐baking temperature of PMMENL resin with EPBT monomer was significantly reduced to 150°C, while maintaining an adhesion strength of 8 MPa, equivalent to that of commercially available polyacrylic photosensitive resins baked at 230°C.