Positive resist composition for use with electron beam, EUV light or X ray, and pattern formation method using the same

1. A positive resist composition for use with an electron beam, an EUV light or an X ray, the positive resist composition comprising:

(A) at least one compound that generates an acid upon treatment with one of an actinic ray and radiation; and

(B) a resin that increases a solubility of the resin (B) in an alkaline developer by an action of an acid,

wherein the resin (B) consists essentially of a repeating unit represented by formula (II) and having an alicyclic group connected with a fluorine-substituted alcohol residue and a repeating unit represented by formula (B3):

wherein Ra and Rb each independently represents a hydrogen atom, an alkyl group, a cyano group, a chlorine atom or a fluorine atom;

A 1 to A 3 each independently represents a hydrogen atom, an alkyl group or a fluorine atom;

R 1 to R 6 each independently represents a hydrogen atom or a fluorine atom, provided that at least one of R 1 to R 6 represents a fluorine atom;

Z represents an alkylene group, an oxygen atom or a sulfur atom;

m represents an integer of 0 to 2; and

Rc represents a hydrogen atom or an unsubstituted methyl group;

2. The positive resist composition according to claim 1 ,

wherein R 1 to R 6 each represents a fluorine atom.

3. The positive resist composition according to claim 1 ,

wherein the resin (B) further comprises at least one of a repeating unit represented by formula (B1) and a repeating unit represented by formula (B2):

wherein B 1 and B 2 each represents a group capable of decomposing by an action of an acid, or a group including a group capable of decomposing by an action of an acid to generate a carboxyl group or a hydroxyl group; and

B 3 represents a hydrogen atom, a methyl group, a halogen atom or a cyano group.

4. The positive resist composition according to claim 3 ,

wherein B 1 and B 2 each includes a cyclic structure.

5. A pattern formation method comprising:

forming a resist film from a positive resist composition according to claim 1 ;

exposing the resist film with an electron beam, an EUV light or an X ray, so as to form an exposed resist film; and

developing the exposed resist film.

6. The positive resist composition according to claim 1 , which contains said at least one compound (A) in an amount of from 6 to 20% by weight based on a total solid content of the positive resist composition.

7. The positive resist composition according to claim 1 ,

wherein said at least one compound (A) comprises: a compound that generates a sulfonic acid upon treatment with one of an actinic ray and radiation; and a compound that generates a carboxylic acid upon treatment with one of an actinic ray and radiation.