Low refractive index polymers as underlayers for silicon-containing photoresists

A method of forming a patterned material feature on a substrate, said method comprising:

• providing a material layer on a substrate;
• forming an underlayer on said material layer, said underlayer comprising a vinyl or acrylate polymer, said polymer comprising at least one substituted or unsubstituted naphthalene or naphthol moiety;
• forming a radiation-sensitive imaging layer on said underlayer;
• patternwise exposing said imaging layer to radiation, thereby creating a pattern of radiation-exposed regions in said imaging layer;
• selectively removing portions of said imaging layer and underlayer to expose portions of said material layer;
• and
• etching said exposed portions of said material layer, thereby forming said patterned material feature.

A method of forming a patterned material feature on a substrate, said method comprising:

• providing a material layer on a substrate;
• forming an underlayer on said material layer, said underlayer comprising a vinyl or acrylate polymer, said polymer comprising at least one substituted or unsubstituted naphthalene or naphthol moiety;
• forming an interlayer on said underlayer, said interlayer comprising a silicon-containing polymer;
• forming a radiation-sensitive imaging layer on said interlayer;
• patternwise exposing said imaging layer to radiation, thereby creating a pattern of radiation-exposed regions in said imaging layer;
• selectively removing portions of said imaging layer, interlayer and underlayer to expose portions of said material layer;
• and
• etching said exposed portions of said material layer, thereby forming said patterned material feature.