SynopsisTerpolymers of methyl methacrylate with methacrylic acid and methacryloyl chloride [ poly (MMA-MAA-MAC) ] were synthesized with high yields by slow radical polymerization. T h e influence of the temperature of prebaking on the changes in the chemical composition and the molecular weight characteristics of poly (MMA-5%MAA-5%MAC) was studied by infrared spectroscopy and gel permeation chromatography. It was found that resists containing terpolymer with molecular weight (Mu) of 41,000, which were prebaked a t 100°C, were able to produce high contrast images ( y = 3.3) at doses of 16 pC/cm2.