Method of manufacturing semiconductor device includes forming photoresist layer over substrate. Photoresist layer is selectively exposed to radiation, and selectively exposed photoresist layer developed. Photoresist composition includes photoactive compound, crosslinker, copolymer. The copolymer is A1 and A2 are independently direct link, C6-C15 phenyl group, C7-C15 benzyl group, C1-C15 alkyl group, C3-C15 cycloalkyl group, C1-C15 hydroxyalkyl group, C2-C15 alkoxy group, C3-C15 alkoxy alkyl group, C2-C15 acetyl group, C3-C15 acetyl alkyl group, C1-C15 carboxyl group, C2-C15 alkyl carboxyl group, C4-C15 cycloalkyl carboxyl group, C3-C15 saturated or unsaturated hydrocarbon ring, C2-C15 hetero chain, C3-C15 heterocyclic ring, or three dimensional ring structure; R1 is thermal or acid labile group including C4-C15 alkyl, cycloalkyl, hydroxyalkyl, alkoxy, or alkoxy alkyl group, or three dimensional ring structure; R2 is substituted or unsubstituted C4-C10 cycloalkyl group; Ra and Rb are independently H or CH3; and 0