The invention provides a high-resolution resist material comprising an
acid generator that has high sensitivity and high resolution with respect
to high-energy rays of 300 nm or less, has small line-edge roughness, and
is superior in heat stability and in shelf stability, and provides a
pattern forming method that uses this resist material. The invention
further provides a chemically amplified positive resist material
comprising a base resin, an acid generator and a solvent in which the
acid generator generates an alkylimidic acid containing a fluorine group,
and provides a pattern forming method comprising a step of applying the
resist material to the substrate, a step of performing exposure to a
high-energy ray of a wavelength of 300 nm or less through a photomask
following heat treatment, and a step of performing development by a
developing solution following heat treatment.