Patent ID: 7736822

Claim:
A resist underlayer coating forming composition used for a mask blank in which a thin film for forming transfer pattern, a resist underlayer coating and a chemically-amplified type resist coating that is resist-depicted (exposed to light) by use of an electron beam accelerated with an accelerating voltage of 50 keV or more are formed on a substrate in that order, comprising a polymer compound having a halogen atom-containing repeating structural unit, and a solvent, in which the polymer compound is a compound having a halogen atom-containing repeating structural unit of formula (d), (e) or (f): wherein A is a phenyl group, a naphthyl group, an anthranyl group, benzoyl group, naphthyl carbonyl group or anthranyl carbonyl group (the phenyl group, naphthyl group, anthranyl group, benzoyl group, naphthyl carbonyl group and anthranyl carbonyl group may be arbitrarily substituted with a hydroxy group, a halogen atom or both of a hydroxy group and a halogen atom), p is an integer of 1 to 3000, n is an integer of 0 to 3, and the compound contains at least one halogen atom in the repeating units; wherein Ar 2 and Ar 3 are not identical, are a phenyl group, a naphthyl group or an anthranyl group (the phenyl group, naphthyl group and anthranyl group may be arbitrarily substituted with a hydroxy group, a halogen atom or both of a hydroxy group and a halogen atom), q and r independently of each other are an integer of 1 or more and q+r are an integer of 2 to 3000, n is an integer of 0 to 3, and the compound contains at least one halogen atom in the repeating unit containing the substituent Ar 2 , in the repeating unit containing the substituent Ar 3 , or in both the repeating unit containing the substituent Ar 2 and the repeating unit containing the substituent Ar 3 ; or wherein R 1 is hydrogen atom or C 1-4 alkyl group, R 2 is CF 3 , CCl 3 , CBr 3 , CH(OH)CH 2 OR 3 wherein R 3 is a phenyl group, a naphthyl group or an anthranyl group (the phenyl group, naphthyl group and anthranyl group may be arbitrarily substituted with a hydroxy group, a halogen atom or both of hydroxy group and a halogen atom), or CH(OH)CH 2 OC(O)R 4 wherein R 4 is phenyl group, naphthyl group or anthranyl group (the phenyl group, naphthyl group and anthranyl group may be arbitrarily substituted with a hydroxy group, a halogen atom or both of a hydroxy group and a halogen atom), g and r independently of each other are an integer of 1 or more and q+r are an integer of 2 to 3000, and the compound contains at least one halogen atom in the repeating unit containing the substituent R 2 , and a resist underlayer coating formed from the resist underlayer coating forming composition having a film thickness of 5 to 25 nm, and the resist underlayer coating has an etching rate of 1.1 to 10 times of the chemically-amplified type resist coating.