A resist underlayer film-forming composition exhibits a satisfactory etching resistance and heat resistance, and satisfies various other properties, e.g., curability, amount of sublimate generation, in-plane uniformity of film thickness, planarization, embeddability, and so forth; the resist underlayer film-forming composition contains a novolac resin and a solvent, and the novolac resin contains an aromatic ring-bearing unit structure A; this unit structure A is represented by formula (A): and contains a single species or two or more species of bis(azaaryl condensed ring) structural units, which are a structural unit in which two azaaryl condensed rings are bonded via a linker group L. A method forms a resist pattern using this composition and a method produces a semiconductor device using this composition.

##STR00001##

A resist underlayer film-forming composition exhibits a satisfactory etching resistance and heat resistance, and satisfies various other properties, e.g., curability, amount of sublimate generation, in-plane uniformity of film thickness, planarization, embeddability, and so forth; the resist underlayer film-forming composition contains a novolac resin and a solvent, and the novolac resin contains an aromatic ring-bearing unit structure A; this unit structure A is represented by formula (A): and contains a single species or two or more species of bis(azaaryl condensed ring) structural units, which are a structural unit in which two azaaryl condensed rings are bonded via a linker group L. A method forms a resist pattern using this composition and a method produces a semiconductor device using this composition.

##STR00001##

The invention provides radiation sensitive compositions and substrates coated with radiation sensitive compositions wherein the composition comprises a combination of metals and/or metalloid compounds, a functionalized or unfunctionalized acetylenic compound, and other optional ingredients such as amelioration agents. The invention further provides radiation sensitive devices for detection or measurement of radiation comprising substrates coated with these radiation sensitive compositions. The radiation sensitive compositions and devices have applications in dentistry, non-destructive testing, oncology, radiology, and radiotherapy, among others.