AbstractThe three‐component photopolymers consisting of poly(p‐hydroxystyrene) (PHS) or poly(styrene‐co‐acrylic acid) (PSA) as the binder polymer, 2,2‐bis(4‐(2‐(vinyloxy)ethoxy)phenyl)propane (BPA‐DEVE) or 1,1,1‐tris(4‐(2‐(vinyloxy)ethoxy)phenyl)ethane (THPETEVE) as the crosslinking agent, and a photoacid generator were investigated with regard to their lithographic characteristics and thermal crosslinking reactivity because of the acidity of the acid component. The thermal crosslinking rate can be represented as the pseudo first‐order reaction. The PSA copolymer with an acrylic acid unit has the higher crosslinking rate and sensitivity, and the lower activation energy. Under low baking temperatures at which crosslinking does not take place, dual‐mode resist behavior is observed.