Polymers and photoresist compositions

A polymer comprising:

• a first repeating unit comprising a tertiary ester acid labile group;
• and
• a second repeating unit of Formula (1):
• wherein
• R1 is hydrogen, a substituted or unsubstituted C1-12 alkyl, a substituted or unsubstituted C6-14 aryl, a substituted or unsubstituted C3-14 heteroaryl, a substituted or unsubstituted C7-18 arylalkyl, a substituted or unsubstituted C4-18 heteroarylalkyl, or a substituted or unsubstituted C1-12 haloalkyl,
• R2 and R3 are each independently a straight chain or branched C1-20 alkyl, a straight chain or branched C1-20 haloalkyl, a monocyclic or polycyclic C3-20 cycloalkyl, a monocyclic or polycyclic C3-20 heterocycloalkyl, a monocyclic or polycyclic C6-20 aryl, a C7-20 aryloxyalkyl, or a monocyclic or polycyclic C4-20 heteroaryl, each of which is substituted or unsubstituted, provided that R2 and R3 together do not form a ring,
• R4 is a substituted or unsubstituted C1-12 alkyl, a substituted or unsubstituted C7-18 arylalkyl, a substituted or unsubstituted C4-18 heteroarylalkyl, or a substituted or unsubstituted C1-12 haloalkyl,
• R5 is hydrogen, fluorine, a substituted or unsubstituted C1-5 alkyl, or a substituted or unsubstituted C1-5 fluoroalkyl,
• each A is independently a halogen, a carboxylic acid or ester, a thiol, a straight chain or branched C1-20 alkyl, a monocyclic or polycyclic C3-20 cycloalkyl, a monocyclic or polycyclic C3-20 fluorocycloalkenyl, a monocyclic or polycyclic C3-20 heterocycloalkyl, a monocyclic or polycyclic C6-20 aryl, or a monocyclic or polycyclic C4-20 heteroaryl, each of which is substituted or unsubstituted, and
• m is an integer of 0 to 4.