PATTERN FORMATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a pattern formation method by which lowering of contrast is solubility can be prevented and lowering of resolution can be suppressed even when the thickness of a resist film is made smaller than 250 nm. SOLUTION: A resist film 11 having <=250 nm thickness and comprising a chemical amplification type positive resist material comprising a base polymer having solubility in an alkaline developing solution varied by the action of an acid and an acid generator in which at least one electron withdrawing group has been introduced into the meta-positions of an aromatic ring constituting a counter anion and which generates the acid when irradiated with energy beams is formed on a semiconductor substrate 10. The resist film 11 is patternwise exposed by selective irradiation with electron beams 12 through a mask 13 and the patternwise exposed resist film 11 is developed to form the objective resist pattern 15.