Positive resist composition and pattern-forming method using the same

1. A positive resist composition, which comprises a resin having a structure showing a basicity and capable of increasing the solubility in an alkali developer by the action of an acid, and wherein the resin has the structure showing a basicity at a side chain, the resin has a lactone group, and the resin comprises a repeating unit having a partial structure containing an alicyclic hydrocarbon represented by formula (pI) or (pII):

wherein Z represents an atomic group necessary to form an alicyclic hydrocarbon group with a carbon atom; R 11 represents a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or a sec-butyl group; R 12 , R 13 and R 14 each represents a straight chain or branched chain alkyl group having from 1 to 4 carbon atoms, or an alicyclic hydrocarbon group, provided that at least one of R 12 to R 14 represents an alicyclic hydrocarbon group; and

wherein the resin comprises a repeating unit represented by formula (AI) as the repeating unit having the lactone group:

wherein R b0 represents a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; A′ represents a single bond, an ether group, an ester group, a carbonyl group, an alkylene group, or a divalent linking group combining these groups; and B 2 represents a group represented by formula (Lc) or formula (III-1):

wherein R a1 , R b1 , R c1 , R a1 and R e1 each represents a hydrogen atom or an alkyl group; m and n each represents an integer of from 0 to 3, and m+n is from 2 to 6; R 1b , R 2b , R 3b , R 4b , and R 5b each represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkylsulfonylimino group or an alkenyl group, and two of R 1b to R 5b may be bonded to form a ring.

2. The positive resist composition as claimed in claim 1 , wherein the structure showing a basicity is a structure including at least one selecting from the group consisting of a primary, secondary or tertiary aliphatic amine, an aromatic amine, and a heterocyclic amine.

3. The positive resist composition as claimed in claim 1 , which comprises (B) a compound capable of generating an acid upon irradiation with an actinic ray or radiation.

4. The positive resist composition as claimed in claim 1 , wherein the resin comprises a repeating unit represented by any of formulae (P1), (P2) and (P3) as the repeating unit having the structure showing a basicity:

wherein X 1 represents a hydrogen atom or an alkyl group; X 2 represents a single bond or a divalent linking group; R 1 represents a structure showing basicity; R 2 represents a hydrogen atom or an alkyl group, and R 1 and R 2 may be linked to each other to form a ring.

5. The positive resist composition as claimed in claim 1 , wherein the resin comprises a repeating unit represented by any of formulae (P4), (P5), (P6), (P7), (P8), (P9), and (P10) as the repeating unit having the structure showing a basicity:

wherein X 1 represents a hydrogen atom or an alkyl group; R 3 to R 9 each independently represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, or an aralkyl group; R 3 and R 4 may be bonded to each other to form a ring; R 5 and R 6 and R 7 and R 8 may be bonded to each other to form a ring; and Z represents alkylene or —NH—.

6. The positive resist composition as claimed in claim 1 , wherein in formula (pI), R 11 represents a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, or a sec-butyl group, and the content of the repeating unit having a partial structure containing an alicyclic hydrocarbon represented by formula (pI) and/or (pII) is from 20 to 65 mol % in all the repeating structural units of the resin.

7. The positive resist composition as claimed in claim 1 , wherein the resin contains only the repeating unit having a partial structure containing an alicyclic hydrocarbon represented by formula (pI) and/or (pII) as an acid-decomposable group, and in formula (pI), R 11 represents a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an isobutyl group, or a sec-butyl group.

8. A pattern-forming method, which comprises forming a resist film with the positive resist composition as claimed in claim 1 ; and exposing and developing the resulting resist film.

9. The pattern-forming method as claimed in claim 8 , wherein the resist film is subjected to an exposure through an immersion liquid.

10. A pattern-forming method which comprises the steps of:

providing a positive resist composition as claimed in claim 3 ;

forming a resist film with the positive resist composition;

pattern-wise exposing the resist film through an immersion liquid; and

developing the resulting resist film.