content_image/912545.jpg content_image/912546.jpg content_image/912547.jpg content_image/912529.jpg content_image/912530.jpg
<img src='content_image/912545.jpg'>

The present invention preferably includes, as the structural unit ( al 1 ), at least one structural unit selected from the group consisting of structural units represented by general formula (al-0-11) shown below, structural units represented by gen› eral formula (al-0-12) shown below, structural units repre› sented by general formula (al-0-13) shown below, and struc› tural units represented by general formula (al-0-2) shown below. Among these structural units, at least one structural unit selected from the group consisting of structural units represented by formula (al-0-11), structural units repre› sented by formula (al-0-12) and structural units represented by general formula (al-0-2) is particularly desirable. 

<img src='content_image/912546.jpg'>

<img src='content_image/912547.jpg'>

-continued 

<img src='content_image/912529.jpg'>

<img src='content_image/912530.jpg'>

In the above formulas, R represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, R$^{21 }$represents an alkyl group, R$^{22 }$rep- resents a group that forms an aliphatic monocyclic group together with the carbon atom to which R$^{22 }$is bonded, R 23 represents a branched alky 1 group, R $^{24 }$represents a group that forms an aliphatic polycyclic group together with the carbon atom to which R$^{24 }$is bonded, R$^{25 }$represents a linear alkyl group of 1 to 5 carbon atoms, Y$^{2 }$represents a divalent linking group, and X $^{2 }$represents an acid-dissociable group. 

In each of the above formulas, R, Y$^{2 }$and X$^{2 }$are the same as defined above. 21 

In formula (al-0-11), examples of the alkyl group for R include the same alkyl groups as those described above for R $^{14 }$in the formulas (1-1) to (1-9), and a methyl group, ethyl group or isopropyl group is preferred. 22 

In terms of R , examples of the aliphatic monocyclic group that is formed together with the carbon atom to which R 22 is bonded include the monocyclic groups among the aliphatic cyclic groups described above in connection with the tertiary alkyl ester-type acid-dissociable groups. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a 3- to I I-membered ring, more preferably a 3- to 8-membered ring, still more prefer› ably a 4- to 6-membered ring, and most preferably a 5- or 6-membered ring. 

A portion of the carbon atoms that constitute the ring of the monocycloalkane may or may not be substituted with an ether group (---0-). 

Further, the monocycloalkane may include an alkyl group of 1 to 5 carbon atoms, a fluorine atom, or a fluorinated alkyl group of 1 to 5 carbon atoms as a substituent. 

Examples of the R$^{22 }$group that constitutes the aliphatic monocyclic group include linear alkylene groups which may have an ether group (-0-) interposed between the carbon atoms of the alkylene chain. 

Specific examples of the structural units represented by formula (al-0-11) include structural units represented by the above formulas (al-1-16) to (al-1-23), (al-1-27) and (al-1- 31). Among these, structural units represented by general formula ( al-1-02) shown below, which includes the structural 

-continued 

