Positive resist composition for immersion exposure and pattern-forming method using the same

1. A positive resist composition for immersion exposure comprising:

(A) a resin containing at least one repeating unit having a fluorine atom and increasing a solubility of the resin in an alkali developer by an action of an acid; and

(B) a compound capable of generating an acid upon irradiation with one of an actinic ray and radiation,

wherein the repeating unit having a fluorine atom contained in resin (A) is at least one repeating unit selected from the group consisting of formulae (IV), (V), (VII), (VIII) and (IX):

wherein X 1 represents an oxygen atom or a sulfur atom; X 2 represents a methylene group, an oxygen atom or a sulfur atom; Rx represents a hydrogen atom, a fluorine atom, a chlorine atom, a cyano group, an alkyl group, or -L 3 -Ra; L 3 represents an alkylene group, —CH 2 O— or —CH 2 O(C═O)—; Ra represents a hydroxyl group, a lactone group or a fluoroalkyl group; Rf, Rf 1 and Rf 2 each independently represents a group having at least one or more fluorine atoms, and Rf 1 and Rf 2 may be linked to each other to form a ring having —(CF 2 )n 1 -; n 1 represents an integer of 1 or higher; and j represents an integer of from 1 to 3.

2. The positive resist composition for immersion exposure as claimed in claim 1 , wherein a fluorine atom number contained in the repeating unit having a fluorine atom is 6 or more per one repeating unit.

3. The positive resist composition for immersion exposure as claimed in claim 1 wherein the repeating unit having a fluorine atom is contained in the resin (A) in an amount of 10 mol % to 30 mol %.

4. A pattern-forming method comprising:

forming a resist film with a resist composition as claimed in claim 1 ;

exposing the resist film by immersion exposure, so as to form an exposed resist film; and

developing the exposed resist film.