content_image/928003.jpg content_image/928004.jpg content_image/928005.jpg content_image/928006.jpg content_image/928007.jpg content_image/928008.jpg content_image/928009.jpg content_image/928010.jpg
[0141] Specific examples of the structural unit (al) include structural units represented by general formulas (al-1) to (al-4) shown below. 

[Chemical Formula 9] 

<img src='content_image/928003.jpg'>

<img src='content_image/928004.jpg'>

<img src='content_image/928005.jpg'>

<img src='content_image/928006.jpg'>

In the formulas, X 1 represents a tertiary alkyl ester-type acid dissociable, dissolution inhibiting group; Y represents an alkyl group of 1 to 5 carbon atoms or an aliphatic cyclic group; n represents an integer of O to 3; Y 2 represents a divalent linking group; R is the same as defined above; and each ofR $^{11 }$and R $^{21 }$independently represents a hydrogen atom or an alkyl group of 1 to 5 carbon atoms. 

(al-1) 

(al-2) 

(al-3) 

(al-4) 

[0142] Examples of the tertiary alkyl ester-type acid disso› ciable, dissolution inhibiting group for X 1 include the same tertiary alkyl ester-type acid dissociable, dissolution inhibit› ing groups as those described above for X 1 . 

[0143] As R 11 , R 21 , n and Y are respectively the same as defined for R 11 , R 21 , n and Y in general formula (p 1) described above in connection with the "acetal-type acid dissociable, dissolution inhibiting group". 

[0144] As examples of Y 2 , the same groups as those described above forY 2 in general formula (al-0-2) can be given. 

[0145] Specific examples of structural units represented by general formula (al-1) to (al-4) are shown below. 

[0146] In the formulas shown below, R"’ represents a hydro› gen atom, a methyl group or a trifluoromethyl group. 

[Chemical Formula 10] 

<img src='content_image/928007.jpg'>

<img src='content_image/928008.jpg'>

<img src='content_image/928009.jpg'>

<img src='content_image/928010.jpg'>

(al-1-1) 

(al-1-2) 

(al-1-3) 

(al-1-4) 

