A water-soluble resin composition of the present invention comprises at
least a water-soluble resin, an acid generator capable of generating an
acid by heating and a solvent containing water. The water-soluble resin
composition is applied on a highly water-repellant resist pattern 3
formed by a resist such as an ArF-responsive radiation sensitive resin
composition on a substrate 1 to form a coated layer 4 thereon. The resist
pattern 3 and the coated layer 4 are heat-treated to form a
developer-insoluble modified coated layer 5 in the vicinity of a surface
of the resist pattern 3. The coated layer is developed and the resist
pattern thickened by the modified layer 5 is formed. The modified layer
is a layer with sufficient thickness and is able to be formed with a high
dimensional controllability in a highly water-repellant resist pattern
such as ArF-responsive radiation sensitive resin composition. As a
result, a separation size and a hole aperture size of the resist pattern
are reduced effectively to less than a limit resolution. As the modified
layer 5 has a function of a protecting film for the resist pattern upon
electron beam irradiation, a size measurement fluctuation of a resist
pattern upon electron beam irradiation by a size measuring SEM can be
prevented.