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Herein Xis a single bond or a C$_{1 }$-C$_{20 }$divalent linking group which may contain an ether bond, carbonyl moiety, ester bond, amide bond, sultone ring, lactam ring, carbonate bond, halogen, hydroxyl moiety or carboxyl moiety. R 1 is hydro› gen, hydroxyl, an optionally halo-substituted C$_{1 }$-C 6 alkyl group, optionally halo-substituted C$_{1 }$-C 6 alkoxy group, optionally halo-substituted C$_{2}$-C 6 acyloxy group, optionally halo-substituted C$_{1 }$-C$_{4 }$ alkylsulfonyloxy group, fluorine, chlorine, bromine, amino, nitro, cyano, -NR$^{1}$A-C(=O)› R, or -NR$^{1}$A-C(=O)-O-R 1 B, R $^{1}$A is hydrogen or a C$_{1 }$-C 6 alkyl group, RIB is a C$_{1 }$-C 6 alkyl group or C$_{2}$-C$_{5 }$ alkenyl group. R 2 and R 3 are each independently a C$_{1}$-C 6 alkyl group, R$^{2 }$andR$^{3 }$may bond together to form a ring with the carbon atom to which they are attached. R 4 and R 6 are each independently hydrogen, a C$_{1 }$-C$_{4 }$ straight or branched alkyl group, C$_{2}$ -C$_{12 }$ straight or branched alkoxycarbonyl group. CcC$_{15 }$aryloxycarbonyl group, or CcC$_{14 }$aralkyloxy› carbonyl group. R 5 is a C$_{1 }$-C 6 alkyl group, C$_{2}$-C 6 alkenyl group, C$_{2}$ -C 6 alkynyl group, or C 6 -C$_{12 }$ aryl group. R is a C$_{2}$ -C$_{10 }$alicyclic group to form a ring with the nitrogen atom, m is an integer of 1 to 5, n is an integer of 0 to 4, and lsm+ns5, and pis 1 or 2. 

[0019] The resist composition may further comprise an acid generator capable of generating a sulfonic acid, imide acid or methide acid, and an organic solvent. 

[0020] In a preferred embodiment, the base polymer com› prises recurring units having the formula (al) or recurring units having the formula (a2). 

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Herein RA is each independently hydrogen or methyl, R 11 and R$^{12 }$each are an acid labile group, Y 1 is a single bond, phenylene group, naphthylene group, or C$_{1 }$-C$_{12 }$ linking group containing at least one moiety selected from ester bond and lactone ring, and Y $^{2 }$is a single bond or ester bond. 

[0021] Typically, the resist composition is a chemically amplified positive resist composition. 

[0022] In another embodiment, the base polymer is free of an acid labile group. Typically, the resist composition is a chemically amplified negative resist composition. 

[0023] The resist composition may further comprise a surfactant. 

[0024] In a preferred embodiment, the base polymer fur› ther comprises recurring units of at least one type selected from recurring units having the formulae (fl) to (f3). 

Herein RA is each independently hydrogen or methyl. Z 1 is a single bond, phenylene group, ---O-Z 11 -, ----C(=O)› O-Z11- or ----C(=O)-NH-Z 11 -, Z 11 is a Cl-C6 alkanediyl group, C$_{2}$-C 6 alkenediyl group, or phenylene group, which may contain a carbonyl, ester bond, ether bond or hydroxyl moiety. Z 2 is a single bond, -Z$^{21}$----C(=O)› O-, -Z$^{21}$-O- or -Z$^{21}$---0----C(=O)-, Z 21 is a 

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