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An aqueous‐base developable photoresist based on light‐induced cationic polymerization: Resist performance of poly(glycidyl methacrylate‐ co ‐methacrylic acid)
Author(s) -
Naitoh Kazuhiko,
Koseki Ken'ichi,
Yamaoka Tsuguo
Publication year - 1993
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1993.070500205
Subject(s) - cationic polymerization , glycidyl methacrylate , methacrylic acid , polymer chemistry , copolymer , monomer , photoresist , polymerization , vinyl ether , aqueous solution , methacrylate , chemistry , materials science , polymer , organic chemistry , layer (electronics)
An aqueous‐base developable photoresist based on photoinduced cationic polymerization has been prepared by copolymerization of glycidyl methacrylate (GMA) and methacrylic acid (MAA). The copolymer containing 83 mol% of GMA unit is soluble in an aqueous base and crosslinked in the presence of photogenerated acid caused by acid‐initiated ring‐opening polymerization of pendant epoxide groups. Exposure results in the generation of acid and the subsequent baking process promotes the diffusion of photogenerated acid, which initiates the cationic crosslinking of the epoxide rings. It was also found that the sensitivity of the copolymer was remarkably enhanced when a divinyl ether monomer is added as a bifunctional crosslinker. The sensitivity enhancement may be caused by the high reactivity of the divinyl ether monomer in the presence of acid. The resist comprised of the copolymer, the vinyl ether monomer, and diphenyliodonium 9,10‐dimethoxy‐an‐thracene‐2‐sulfonate as photoacid generator exhibited the sensitivity of 20 mJ/cm 2 . A good pattern profile with high resolution was attained by exposure to a 365 nm light followed by a postexposure bake at 60°C for 3 min. © 1993 John Wiley & Sons, Inc.