tert-Butyl methacrylate (TBMA) was copolymerized with various comonomers that were selected from methyl methacrylate (MMA), n-butyl acrylate (NBA), acrylic acid (AA), and 2-hydroxyethyl methacrylate (HEMA). From film physical properties, poly(TBMA-co-HEMA) and poly(TBMA-co-AA-co-NBA), were selected as resin binders. To introduce unsaturated double bonds onto the side chain of copolymers, they were further functionalized with acryloyl chloride and glycidyl methacrylate. Copolymers synthesized in this investigation were all identified by using FTIR and NMR. The thermal decomposition temperature of functionalized poly(TBMA-co-HEMA) showed obvious difference before and after crosslinking. Adding a small amount of EGDMA as the crosslinking agent could increase the degree of crosslinking and obviously improve the physical properties. Functionalized paly(TBMA-co-HEMA) was used as a binder resin and composed with a photoacid generator for positive photoresists. From exposure characteristics. the optimal lithographic condition was achieved when exposed for 90 s, FEB at 100 degreesC for 2.5 min. and developed in 10 wt % Na2CO3 developer for 30 s. After completing the lithography process, the residual pattern of positive photoresist was further treated at 140 degreesC for 30 min to cure the pendant unsaturated groups. The resolution of the positive photoresist was analyzed by an optical microscope and SEM technique.