Positive resist composition

1. A positive resist composition comprising:

(A) a compound capable of generating an acid on exposure to active light rays or a radiation;

(B) a resin which is insoluble or sparingly soluble in an alkali and becomes alkali-soluble by an action of an acid; and

(D) an acyclic saccharide derivative having at least three groups selected from a hydroxyl group and a hydroxyl group substituted with an acid decomposable group;

wherein the resin (B) has a structure represented by formula (pA)

wherein a plurality of R groups, which may be the same or different, each represents a hydrogen atom, a halogen atom or a substituted or un-substituted straight-chain or branched alkyl group having 1 to 4 carbon atoms; A represents a single bond or one of, or a combination of two or more of, an alkylene group, a substituted alkylene group, an ether group, a thioether group, a carbonyl group, an ester group, an amide group, a sulfonamide group, a urethane group, and a urea group; and Ra represents any one of the structures represented by formula (pI) to (pVI):

wherein 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; Z represents an atomic group necessary to form an alicyclic hydrocarbon group together with the adjacent carbon atom; R 12 , R 13 , R 14 , R 15 , and R 16 each represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R 12 , R 13 , and R 14 and at least one of R 15 and R 16 represents an alicyclic hydrocarbon group; R 17 , R 18 , R 19 , R 20 , and R 21 each represents a hydrogen atom, a straight-chain or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R 17 , R 18 , R 19 , R 20 , and R 21 represents an alicyclic hydrocarbon group and that at least one of R 19 and R 21 represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group; and R 22 , R 23 , R 24 , and R 25 each represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group, provided that at least one of R 22 , R 23 , R 24 , and R 25 represents an alicyclic hydrocarbon group; and R 23 , and R 24 may be connected together to form a ring.

2. The positive resist composition according to claim 1 , wherein the resin (B) has a structure comprising a fluorine atom substituting at least one of a main chain and a side chain of a polymer skeleton and decomposes by an action of an acid to increase its solubility in an alkali developing solution.

3. The positive resist composition according to claim 1 , which further comprises (C) a basic compound.

4. The positive resist composition according to claim 1 , which further comprises (E) a surface active agent comprising at least one of fluorine and silicon.

5. The positive resist composition according to claim 1 , which further comprises (F) a mixed solvent comprising a solvent having a hydroxyl group and a solvent free from a hydroxyl group.

6. The positive resist composition according to claim 1 , wherein the acid decomposable group is selected from the group consisting of an acetal group, isopropylidene group and a cyclohexylidene group.

7. The positive resist composition according to claim 1 , wherein the acid decomposable group is selected from the group consisting of an isopropylidene group and a cyclohexylidene group.

8. A positive resist composition comprising:

(A) a compound capable of generating an acid on exposure to active light rays or a radiation;

(B) a resin which is insoluble or sparingly soluble in an alkali and becomes alkali-soluble by an action of an acid, said resin having a structure comprising a fluorine atom substituting at least one of a main chain and a side chain of a polymer skeleton and decomposing by an action of an acid to increase its solubility in an alkali developing solution; and

(D) an acyclic saccharide derivative having at least three groups selected from a hydroxyl group and a hydroxyl group substituted with an acid decomposable group.

9. The positive resist composition according to claim 8 , which further comprises (C) a basic compound.

10. The positive resist composition according to claim 8 , which further comprises (E) a surface active agent comprising at least one of fluorine and silicon.

11. The positive resist composition according to claim 8 , which further comprises (F) a mixed solvent comprising a solvent having a hydroxyl group and a solvent free from a hydroxyl group.

12. The positive resist composition according to claim 8 , wherein the acid decomposable group is selected from the group consisting of an acetal group, isopropylidene group and a cyclohexylidene group.

13. The positive resist composition according to claim 8 , wherein the acid decomposable group is selected from the group consisting of an isopropylidene group and a cyclohexylidene group.