New norbornene-based monomers having β-keto ester group (methyl(5- norbornenyl)-3-oxopropionate (MNOP), 2-tert-butylcarboxylate-5,8-methanooctal one) (TBCMO)) were synthesized. Methyl(5-norbornenyl)-3-oxopropionate (MNOP) and 2-tert-butylcarboxylate-5,8-methanooctalone (TBCMO) were copolymerized with maleic anhydride (MA) and 2-tert-butyl-5-norbornene-2-carboxylate(TBNC). And 2-tert-butylcarboxylate-5,8-methanooctalone (TBCMO) was copolymerized with maleic anhydride (MA). The decomposition temperature of the resulting polymers were measured. The glass transition temperature of the resulting polymers did not detected. The polymers showed excellent transmittance at 248 nm, but high absorbance at 193 nm. The work of adhesion of the polymers were measured. The resist formulated with poly(2-tert-butylcarboxylate-5,8-methanooctalone-co-maleicanhydride) (poly(TBCMO-co-MA)) and poly(2-tert-butylcarboxylate-5,8-methanooctalone-co-maleicanhydride-co-2-tert-butyl-5-norbornene-2-carboxylate) (poly(TBCMO-co-MA-co-TBNC)) did not gave fine patterns due to keto-enol tautomerism and acidity of a-hydrogen. Poly(methyl(5-norbornenyl)-3-oxopropionate-co-maleic anhydride-co-tert-butyl-5-norbornene-2-carboxylate) (poly(MNOP-co-MA-co-TBNC)) was evaluated as a resist for an ArF excimer laser lithography. And a 0.6μm line/space pattern profiles obtained using the Deep UV exposures with a filter transmitting light between 220 nm and 260 nm.