To provide a new polymer useful as a resist material having excellent transmittance in vacuum ultraviolet rays such as ≤300 nm, especially F2 (157 nm), Kr2 (146 nm), KrAr (134 nm) or Ar2 (126 nm), especially a chemically amplified resist material and a base resin thereof and to provide a method for forming a pattern using the resist material comprising the polymer.
The polymer comprises a repeating unit represented by formula (1a) or (1b) (wherein, R1 is an acid-unstable group, an adhesive group or a fluorinated alkyl group; R2 is a hydrogen atom, a fluorine atom or an alkyl group or a fluorinated alkyl group; R3 and R4 are each a single bond or an alkylene group or a fluorinated alkylene group; R5 is a hydrogen atom or an acid-unstable group; a is 1 or 2; 0<U11<1; and 0<U12<1) and has 1,000-500,000 weight-average molecular weight. The resist material is sensitive to high energy rays and has alkali-soluble contrast and excellent plasma etching resistance without deteriorating transparency at ≤200 nm wavelength.
HATAKEYAMA JUN
KAWAI YOSHIO
SASAKO MASARU
ENDO MASATAKA
KISHIMURA SHINJI
MAEDA KAZUHIKO
KOMORIYA HARUHIKO
MIYAZAWA SATORU
MATSUSHITA ELECTRIC IND CO LTD
CENTRAL GLASS CO LTD
Saori Shigematsu
Katsunari Kobayashi
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