content_image/907511.jpg content_image/907512.jpg
branched or cyclic alkoxycarbonyl group, mis an integer of 1 to 4, and n is an integer of Oto 3. 

3. The resist composition of claim 1, further comprising an organic solvent. 

4. The resist composition of claim 1, wherein the polymer further comprises recurring units having the formula (bl) or (b2): 

<img src='content_image/907511.jpg'>

<img src='content_image/907512.jpg'>

wherein RA is independently hydrogen or methyl, Y 1 is a single bond, phenylene group, naphthylene group, or a 

C$_{1 }$-C$_{12 }$ linking group contmmng an ester moiety and/or lactone ring, Y 2 is a single bond or ester group, R$^{11 }$and R 12 are each independently an acid labile group, R $^{13 }$is halogen, trifluoromethyl, cyano, C$_{1 }$-C$_{6 }$ straight, branched or cyclic alkyl or alkoxy group, or C$_{2}$-C$_{7 }$ straight, branched or cyclic acyl, acyloxy or alkoxycarbonyl group, R$^{14 }$is a single bond or C$_{1 }$-C$_{6 }$ straight or branched alkylene group in which at least one carbon atom may be substituted by an ether or ester moiety, p is 1 or 2, and q is an integer of O to 4. 

5. The resist composition of claim 4, further comprising a dissolution inhibitor, the resist composition being a chemi› cally amplified positive tone resist composition. 

6. The resist composition of claim 1 wherein the polymer is free of an acid labile group. 

7. The resist composition of claim 6, further comprising a crosslinker, the resist composition being a chemically amplified negative tone resist composition. 

8. The resist composition of claim 1, further comprising a surfactant. 

9. A process for forming a pattern comprising the steps of applying the resist composition of claim 1 onto a substrate, baking to form a resist film, exposing the resist film to high-energy radiation, and developing the exposed film in a developer. 

10. The process of claim 9 wherein the high-energy radiation is ArF excimer laser radiation of wavelength 193 nm or KrF excimer laser radiation of wavelength 248 nm. 

11. The process of claim 9 wherein the high-energy radiation is electron bemn or extreme ultraviolet radiation of wavelength 3 to 15 nm. 

* * * * * 

