content_image/897711.jpg content_image/897709.jpg
<img src='content_image/897711.jpg'>

[0221] The content of the repeating unit (A) in the resin (P) is preferably in the range of0.5 mo!% to 80 mo!% to all the repeating units in the resin (P), more preferably in the range of 1 mo! % to 60 mo! %, and still more preferably in the range of 3 mo! % to 40 mo! %. 

## [Repeating Unit (B)] 

[0222] It is preferred that the resin (P) further contains a repeating unit (B) having a group capable of decomposing by an action of an acid to generate a polar group. 

[0223] The group capable of decomposing by the action of an acid to generate a polar group (hereinafter also referred to as "acid-decomposable group") preferably has such a struc› ture that a polar group is protected with a group capable of decomposing and leaving by the action of an acid. 

[0224] The resin (P) is a resin whose polarity changes by the action of an acid, specifically a resin capable of increasing the solubility in an alkali developer or decreasing the solubil› ity in a developer containing an organic solvent by the action ofan acid. 

[0225] The examples of the polar groups include a phenolic hydroxyl group, a carboxyl group, a fluorinated alcohol group, a sulfonic acid group, a sulfonamide group, a sulfo› nylimide group, a (alkylsulfonyl)(alkylcarbonyl)methylene group, an (alkylsulfonyl)(alkylcarbonyl)imide group, a bis (alkylcarbonyl)methylene group, a bis(alkylcarbonyl)imide group, a bis(alkylsulfonyl)methylene group, a bis(alkylsulfo› nyl)imide group, a tris(alkylcarbonyl)methylene group, and a tris(alkylsulfonyl)methylene group. 

[0226] As preferred polar groups, a carboxyl group, a flu› orinated alcohol group (preferably a hexafluoroisopropanol group), and a sulfonic acid group are exemplified. 

[0227] The repeating unit (B) is preferably a repeating unit represented by the following formula (a). 

<img src='content_image/897709.jpg'>

[0228] In formula (a), each of Rsi, Rs$_{2 }$ and Rs$_{3 }$ indepen› dently represents a hydrogen atom, an alkyl group, a monova› lent aliphatic hydrocarbon cyclic group, a halogen atom, a 

cyano group, or an alkoxycarbonyl group. Rs$_{2 }$ and Ls may be bonded to each other to form a ring (preferably a 5- or 6-mem› bered ring), and Rs$_{2 }$represents an alkylene group in that case. 

[0229] Ls represents a single bond or a divalent linking group, and represents a trivalent linking group in the case of forming a ring with Rs$_{2}$ - 

[0230] Rs$_{4 }$ represents an alkyl group. Rss and Rs$_{6 }$indepen› dently represents a hydrogen atom, an alkyl group, a monova› lent aliphatic hydrocarbon cyclic group or an aromatic cyclic group. Rss and Rs$_{6 }$ may be bonded to each other to form a ring, provided that Rss and Rs$_{6 }$ do not represent a hydrogen atom at the same time. 

[0231] Formula (a) is described in further detail. 

[0232] The alkyl group of Rs$_{1 }$ to Rs$_{3 }$ in formula (a) is preferably an alkyl group having 20 or less carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, or a dodecyl group, all of which groups may have a substituent, more preferably an alkyl group having 8 or less carbon atoms, and especially preferably an alkyl group having 3 or less carbon atoms. 

[0233] The alkyl group contained in the alkoxycarbonyl group is preferably the same alkyl group as in Rs$_{1 }$ to Rs$_{3}$ . 

[0234] The monovalent aliphatic hydrocarbon cyclic group is a monocyclic or polycyclic monovalent aliphatic hydrocar› bon cyclic group. Preferably, a monocyclic monovalent ali› phatic hydrocarbon cyclic group having 3 to 8 carbon atoms, such as a cyclopropyl group, a cyclopentyl group, and a cyclohexyl group, which groups may have a substituent, can be exemplified. 

[0235] The halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, and a fluorine atom is especially preferred. 

[0236] The examples of substituents for the above each group include, e.g., an alkyl group, a monovalent aliphatic hydrocarbon cyclic group, an aryl group, an amino group, an amido group, a ureido group, a urethane group, a hydroxyl group, a carboxyl group, a halogen atom, an alkoxy group, a thioether group, an acyl group, an acyloxy group, an alkoxy› carbonyl group, a cyano group, and a nitro group, and the carbon atom number of these substituents is preferably 8 or less. 

(a) 

[0237] When Rs$_{2 }$ represents an alkylene group, the alky› lene group is preferably an alkylene group having 1 to 8 carbon atoms, such as a methylene group, an ethylene group, a propylene group, a butylene group, a hexylene group, or an octylene group, more preferably an alkylene group having 1 to 4 carbon atoms, and especially preferably an alkylene group having 1 or 2 carbon atoms. 

