Positive electron-beam resist behavior for methacrylonitrile and methyl α-chloroacrylate polymers and copolymers

The positive electron beam resist exposure characteristics of poly (methacrylonitrile) (PMCN), poly(methyl α-chloroacrylate) (PMCA), and two MCA/MCN copolymers have been obtained using conventional techniques. The 1:1 MCA/MCN copolymer is found to be four to five times more sensitive than PMMA reference under equivalent conditions. PMCN, PMCA, and 2.3:1 MCA/MCN copolymer are also found to be more sensitive than PMMA, but less sensitive than the 1:1 MCA/MCN copolymer. The relatively low observed sensitivities for PMCA and the 2.3:1 MCA/MCN copolymer is attributed to a low Gs/Gx ratio as observed from other studies. PMCN and the 1:1 MCA/MCN copolymer exhibit significantly lower plasma etch rates than PMMA and therefore should be good ’’dry process’’ resists.