Resist underlayer compositions and pattern formation methods using such compositions

A polymer for a resist underlayer composition, comprising

• a polymer backbone,
• a substituted or unsubstituted C50 to C120 fullerene group pendent to the polymer backbone, and
• a linking group bonded to the polymer backbone and the fullerene group, wherein the linking group comprises a ring structure that utilizes two or more atoms on the fullerene group,
• wherein the polymer is self-crosslinkable, wherein the self-crosslinkable polymer refers to a polymer capable of undergoing a crosslinking reaction between units thereof without an aid of an additive catalyst or a crosslinking agent, and
• wherein the polymer is a polyalkylene, a polyalkylene oxide, a polypyrene, a Novolac polymer, a vinyl aromatic polymer, a (meth)acrylate polymer, a polyester, a norbornene polymer, a polyimide, a polymer comprising a group represented by Formula 3, a combination thereof, or a copolymer thereof:
• wherein,
• R6 and R7 are each independently deuterium, a substituted or unsubstituted C1-20 linear or branched alkyl group, a substituted or unsubstituted C6-20 aryl group, a substituted or unsubstituted C7-20 arylalkyl group, a substituted or unsubstituted C3-20 heteroaryl group, a substituted or unsubstituted C3-30 heteroarylalkyl group, a substituted or unsubstituted C3-30 cycloalkyl group, a substituted or unsubstituted C3-30 heterocycloalkyl group, a C1-20 alkoxy group, a hydroxy group, —NRR′ (wherein R and R′ are each independently hydrogen or a C1-20 linear or branched alkyl group), an isocyanate group, a halogen, —ROR′ (wherein R is a substituted or unsubstituted C1-20 alkylene group and R′ is hydrogen or a C1-20 linear or branched alkyl group), —RC(═O)X (wherein R is a substituted or unsubstituted alkylene group and X is a halogen), —C(═O)OR′ (wherein R′ is hydrogen or a C1-20 linear or branched alkyl group), —CN, —OC(═O)R′ (wherein R′ is hydrogen or a C1-20 linear or branched alkyl group), —OC(═O)NRR′ (wherein R and R′ are each independently hydrogen or a C1-20 linear or branched alkyl group), —S(═O)R′ (wherein R′ is hydrogen or a C1-20 linear or branched alkyl group), or —S(═O)2R′ (wherein R′ is hydrogen or a C1-20 linear or branched alkyl group),
• any two adjacent groups selected from R6 are optionally connected to form a ring,
• any two adjacent groups selected from R7 are optionally connected to form a ring,
• n2 and n3 are each independently 0, 1, 2, 3, or 4,
• * indicates a point of direct or indirect attachment to the fullerene group, and
• ** indicates a point of attachment to a polymer backbone.

A method of forming a pattern, the method comprising:

• (a) applying a layer of the resist underlayer composition over a substrate;
• (b) curing the applied resist underlayer composition to form a resist underlayer;
• and (c) forming a photoresist layer over the resist underlayer,
• wherein the resist underlayer composition comprises:
• a polymer comprising a polymer backbone and a substituted or unsubstituted C50 to C120 fullerene group pendant to the polymer backbone, and
• a solvent in an amount of from 50 to 99.9 weight % based on the total resist underlayer composition,
• wherein the resist underlayer composition is free of additive crosslinking compounds,
• wherein the polymer further comprises a linking group bonded to the fullerene group and to the polymer backbone, wherein the linking group comprises a ring structure that utilizes two or more atoms on the fullerene group, and
• wherein the polymer is a polyalkylene, a polyalkylene oxide, a polyarylene, a Novolac polymer, a vinyl aromatic polymer, a (meth)acrylate polymer, a polyester, a norbornene polymer, a polyimide, a combination thereof, or a copolymer thereof.