Polymer, organic layer composition and method of forming patterns

A polymer comprising a structural unit represented by Chemical Formula 1 or Chemical Formula 2:

• wherein, in Chemical Formula 1 and Chemical Formula 2,
• E is a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 heterocyclic group, or a combination thereof,
• A is a single bond, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C6 to C30 arylene group, a substituted or unsubstituted C2 to C30 heteroarylene group, or a combination thereof,
• L is a single bond, O, S, NRa, a carbonyl group, a substituted or unsubstituted C1 to C20 alkylene group, a substituted or unsubstituted C2 to C20 alkenylene group, a substituted or unsubstituted C2 to C20 alkynylene group, a substituted or unsubstituted C6 to C30 arylene group, or a combination thereof,
• Ra and R1 are each independently a hydrogen, a hydroxy group, a halogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C2 to C30 heterocyclic group, or a combination thereof,
• p and q are each independently an integer of 0 to 4,
• r is an integer of 1 to 5, and
• is a linking point.