The resist underlayer film forming composition for lithography comprising a polymer having a polycyclic aliphatic ring

PROBLEM TO BE SOLVED: To provide a resist underlayer film which does not cause intermixing with a photoresist layer, forms a good resist pattern even when the resist underlayer film is made thin to meet the demand for a thinner photoresist film, improves focal depth margin, and has a small extinction coefficient (k value). SOLUTION: A resist underlayer film forming composition used in a lithography process for the manufacture of a semiconductor device is used. The composition contains a polymer containing a repeating unit structure having a polycyclic aliphatic ring in a main chain thereof, wherein: the polycyclic aliphatic ring is an adamantane ring or a norbornene ring; the polymer is a polyester; and the polymer has a crosslinking bond forming group. The composition further contains a crosslinking agent, and the composition further contains an acid generator. COPYRIGHT: (C)2009,JPO&INPIT