Resist compositions for forming resist patterns

A resist composition for forming resist patterns which comprises:

• A. a (meth)acrylate copolymer having a weight average molecular weight of 2,000 to 1,000,000, said copolymer comprising the following repeating units:
• (a) a vinyl monomer unit which contains, in a side chain thereof, at least one carbon--carbon double bond which does not concern itself with any polymerization reaction, but is able to be crosslinked with a crosslinking agent which is used in combination with said copolymer, said monomer unit being able to be copolymerized with an acrylic acid or methacrylic acid ester and being in an amount of more than 0 mole % and not more than 50 mole % based on said copolymer,
• (b) an acrylamide or methacrylamide monomer unit in an amount of more than 0 mole % and not more than 70 mole % based on said copolymer,
• (c) an acrylic acid or methacrylic acid monomer unit in an amount of more than 0 mole % and not more than 30 mole % based on said copolymer,
• (d) an acrylic acid or methacrylic acid adamantyl monomer unit in an amount of more than 0 mole % and not more than 70 mole % based on said copolymer, and
• B. a crosslinking agent capable of being decomposed upon exposure to a patterning radiation and then causing a crosslinking reaction of said copolymer upon subsequent heating.