Positive photosensitive composition and method of pattern formation with the same

1 . A positive photosensitive composition comprising:

(A) a compound which generates an acid upon irradiation with actinic rays or a radiation;

(B) a resin which decomposes by an action of an acid to come to have an enhanced solubility in an alkaline developing solution; and

(F) a solvent,

wherein the resin as the component (B) is a resin that has a repeating unit (Ba) having a diamantane structure, and

wherein the resin as the component (B) has a weight-average molecular weight of from 3,000 to 30,000 and a dispersity ratio of from 1.1 to 3.0.

2 . The positive photosensitive composition according to claim 1 ,

wherein the resin as the component (B) further has a repeating unit having an adamantane structure.

3 . The positive photosensitive composition according to claim 1 ,

wherein the resin as the component (B) further has a non-acid-decomposable repeating unit.

4 . The positive photosensitive composition according to claim 1 ,

wherein the solvent (F) comprises an alkylene glycol monoalkyl ether carboxylate.

5 . The positive photosensitive composition according to claim 4 ,

wherein the solvent (F) further comprises at least one solvent selected from solvents having at least one functional group selected from a hydroxyl group, a ketone group, a lactone group, an ester group, an ether group and a carbonate group.

6 . The positive photosensitive composition according to claim 5 ,

wherein the solvent (F) comprises: propylene glycol monomethyl ether acetate; and at least one solvent selected from propylene glycol monomethyl ether, cyclohexanone, γ-butyrolactone, butyl acetate and ethyl lactate.

7 . The positive photosensitive composition according to claim 1 ,

wherein the resin as the component (B) is a resin synthesized by dropping polymerization.

8 . The positive photosensitive composition according to claim 1 ,

wherein the compound which generates an acid upon irradiation with actinic rays or a radiation (A) is a compound represented by formula (ZI), (ZII) or (ZIII):

wherein R 201 , R 202 and R 203 each independently represents an organic group;

X − represents a non-nucleophilic anion; and

R 204 to R 207 each independently represents an aryl group, an alkyl group or a cycloalkyl group.

9 . A method of pattern formation, which comprises:

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

exposing the photosensitive film to light, so as to form an exposed photosensitive film; and

developing the exposed photosensitive film.