Polymer, organic layer composition, and method of forming patterns

An organic layer composition, comprising:

• a polymer including a structural unit represented by Chemical Formula 1, and
• a solvent,
• wherein, in Chemical Formula 1,
• A1 and A2 are independently a substituted or unsubstituted aromatic ring group, or a substituted or unsubstituted heteroaromatic ring group,
• B is a divalent organic group,
• X is O, S, Te, Se, or NRa, wherein Ra is hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C3 to C30 cycloalkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C7 to C30 arylalkyl group, a substituted or unsubstituted C1 to C30 heteroalkyl group, a substituted or unsubstituted C2 to C30 heterocycloalkyl group, a substituted or unsubstituted C2 to C30 heterocyclic group, a substituted or unsubstituted C2 to C30 alkenyl group, a substituted or unsubstituted C2 to C30 alkynyl group, a hydroxy group, a halogen atom, a halogen-containing group, or a combination thereof,
• Y is a substituted or unsubstituted C6 to C30 aryl group, or a substituted or unsubstituted C3 to C30 heteroaryl group, and
• * is a linking point.