Positive resist composition, method of forming resist pattern, and polymeric compound

1. A positive resist composition, comprising a base component (A) which exhibits increased solubility in an alkali developing solution under action of acid, and an acid-generator component (B) which generates acid upon exposure, wherein

said base component (A) comprises a polymeric compound (A1) containing a structural unit (a0) having an aromatic group, a structural unit (a5) represented by general formula (a5-1) shown below, and a structural unit (a1) containing an acid-dissociable, dissolution-inhibiting group:

wherein R 1 represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, R 2 represents a divalent linking group, and R 3 represents a cyclic group containing —SO 2 — within a ring skeleton thereof.

2. The positive resist composition according to claim 1 , wherein

said structural unit (a0) having an aromatic group is a structural unit represented by general formula (a0-1) shown below:

wherein R 81 represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, X S represents a single bond or a divalent linking group, and R aryl represents an aromatic group which may have a substituent.

3. The positive resist composition according to claim 1 , wherein R 3 represents a cyclic group containing —O—SO 2 — within a ring skeleton thereof.

4. The positive resist composition according to claim 1 , wherein R 3 is represented by general formula (5-1) shown below:

wherein A′ represents an oxygen atom, a sulfur atom, or an alkylene group of 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, a represents an integer of 0 to 2, and R 6 represents an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group or a cyano group, and R″ represents a hydrogen atom or an alkyl group.

5. The positive resist composition according to claim 2 , wherein R aryl is an aromatic group in which at least one hydrogen atom is substituted with a hydroxyl group or an alkylcarbonyloxy group.

6. The positive resist composition according to claim 1 , further comprising a nitrogen-containing organic compound (D).

7. A method of forming a resist pattern, comprising: applying a positive resist composition according to claim 1 onto a substrate to form a resist film on said substrate, conducting exposure of said resist film, and alkali-developing said resist film to form a resist pattern.

8. A polymeric compound, comprising a structural unit (a0) having an aromatic group, a structural unit represented by general formula (a5-1) shown below, and a structural unit (a1) containing an acid-dissociable, dissolution-inhibiting group:

wherein R 1 represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, R 2 represents a divalent linking group, and R 3 represents a cyclic group containing —SO 2 — within a ring skeleton thereof.

9. The polymeric compound according to claim 8 , wherein said structural unit (a0) having an aromatic group is a structural unit represented by general formula (a0-1) shown below:

wherein R 81 represents a hydrogen atom, an alkyl group of 1 to 5 carbon atoms or a halogenated alkyl group of 1 to 5 carbon atoms, X S represents a single bond or a divalent linking group, and R aryl represents an aromatic group which may have a substituent.

10. The polymeric compound according to claim 8 , wherein R 3 represents a cyclic group containing —O—SO 2 — within a ring skeleton thereof.

11. The polymeric compound according to claim 8 , wherein R 3 is represented by general formula (5-1) shown below:

wherein A′ represents an oxygen atom, a sulfur atom, or an alkylene group of 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, a represents an integer of 0 to 2, and R 6 represents an alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR″, —OC(═O)R″, a hydroxyalkyl group or a cyano group, and R″ represents a hydrogen atom or an alkyl group.

12. The polymeric compound according to claim 9 , wherein R aryl is an aromatic group in which at least one hydrogen atom is substituted with a hydroxyl group or an alkylcarbonyloxy group.