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Tetrahydropyranyl‐ and furanyl‐protected polyhydroxystyrene in chemical amplification systems
Author(s) -
Hesp Simon A. M.,
Hayashi Nobuaki,
Ueno Takumi
Publication year - 1991
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.1991.070420401
Subject(s) - trifluoromethanesulfonate , excimer laser , polymer , transmittance , materials science , excimer , resist , lithography , polymer chemistry , salt (chemistry) , laser , optics , chemistry , optoelectronics , nanotechnology , organic chemistry , physics , layer (electronics) , composite material , catalysis
Tetrahydropyranyl‐ (THP) and furanyl‐ (THF) protected polyhydroxystyrene (PHS) polymers have been investigated for their potential use in conjunction with onium salt acid precursors to yield high‐sensitivity resist systems. The synthesized polymers have high transmittance at 248 nm (the wavelength used in next‐generation excimer laser, KrF exposure tools). At 248 nm the transmittance for a 1‐μm thick film is ∼ 80% (Abs = 0.097 μm −1 ). The acid sensitivity of the acetal functionality at room temperature is high, requiring careful handling of all materials to prevent any premature deprotection of the hydroxy group. The highest lithographic sensitivities obtained so far with a system consisting of poly( p ‐tetrahydropyranyl‐oxy‐styrene) base resin and 1 mol % of bis ( p ‐ tert ‐butyl phenyl) iodinium triflate (TBIT) was ∼ 2 mJ / cm 2 . High‐resolution line and space patterns (0.35 μm) were obtained with a system comprising PHS‐ p ‐THP and an acid precursor, using an excimer laser step and repeat exposure at 248 nm.