Preparation and characterization of (monomethyl itaconate)-(methyl methacrylate) and of (itaconic anhydride)-(methyl methacrylate) copolymers

The free radical copolymerizations and thermal characterization of monomethyl itaconate (MMI)-methyl methacrylate (MMA) and of itaconic anhydride (IT.ANH)-MMA have been investigated in order to prepare samples suitable for assessment as thermally crosslinkable electron beam resist materials. For the copolymerization of MMI and MMA in solution in benzene at 70°, monomer reactivity ratios r_MMI = 0.16 ± 0.09 and r_MMA = 1.08 ± 0.5 were found using a non-linear least squares curve fitting technique. For the copolymerization of IT.ANH with MMA in bulk at 70°, r_IT.ANH = 0.99 ± 0.40 and r_MMA = 0.18 ± 0.7. The glass transition temperatures and thermal stabilities of each series of copolymers have been investigated using differential scanning calorimetry and thermogravimetric analysis techniques in order to determine suitable conditions for resist processing. © 1991.