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Positive working resists sensitive to visible light, I: poly( tert ‐butyl and 2‐phenylpropyl‐2 methacrylates) sensitized with diphenyliodonium salt — p ‐aminobenzylidene dye system
Author(s) -
Ohe Yasushi,
Ichimura Kunihiro
Publication year - 1992
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.1992.220030102
Subject(s) - methacrylate , copolymer , polymer , materials science , salt (chemistry) , polymer chemistry , resist , solvent , solubility , methyl methacrylate , side chain , photochemistry , chemistry , organic chemistry , nanotechnology , layer (electronics) , composite material
Visible‐light‐sensitive positive type resists have been developed. The chemistry to form images is based on the cleavage of side chain ester bonds of poly(methacrylates) catalyzed by an acid which is generated on sensitized photodecomposition of a diphenyliodonium (DPI) salt. Homopolymers and copolymers of tert‐butyl methacrylate (BMA) and 2‐phenylpropyl‐2 methacrylate (PPMA) were used as acid labile polymers. Exposure of thin films of the poly(methacrylates) containing DPI salt and p‐dimethylaminobenzylidene derivatives to an Ar laser beam emitting 488 nm light and subsequent heat treatment resulted in solubility alteration of the polymers, which became soluble in a protic solvent system. Considerable reduction of film thickness was observed after heating an image‐wise exposed thin film of PPMA polymers. The minimum exposure energies of 488 nm light for the positive image formation were 60 mJ/cm 2 and 40 mJ/cm 2 for BMA and PPMA homopolymers, respectively.