Positive photosensitive resin composition, patterned cured film production method, patterned cured film, and electronic component

1. A positive photosensitive resin composition comprising the following components (a) to (e):

(a) a polybenzoxazole precursor comprising a structural unit represented by the following formula (1):

wherein in the formula, U is a divalent organic group and V is a divalent organic group comprising an aliphatic chain structure or an alicyclic structure;

(b) a cross-linking agent;

(c) a diazonaphthoquinone compound;

(d) an iodonium compound represented by the following formula (2) or (3);

wherein in the formula, R 1 to R 12 and R 14 to R 24 are independently a hydrogen atom, a chlorine atom, a bromine atom, an iodine atom, a fluorine atom, an alkyl group, an alkenyl group, an alkoxyl group, a trialkylsilyl group or a group in which a part or all of hydrogen atoms in each of the above-mentioned groups are substituted by a fluorine atom; R 13 is an alkyl group; and two R 1 s, two R 2 s, two R 3 s, two R 4 s, two R 5 s and two R 13 s may be the same as or different from each other; and

(e) a solvent.

2. The positive photosensitive resin composition according to claim 1 , wherein the component (a) is a polybenzoxazole precursor having a structure represented by the following formula (4):

wherein A and B are structural units;

U is a divalent organic group;

V is a divalent organic group comprising an aliphatic chain structure or an alicyclic structure;

W is a divalent organic group;

X is a divalent organic group which comprises neither an aliphatic structure nor an alicyclic structure; and

j and k each represent a polymerization ratio in terms of moles of the structural units A and B, j is a value of 1 or more, and j+k is 100.

3. The positive photosensitive resin composition according to claim 1 that further comprises the following component (a′):

(a′) a polybenzoxazole precursor that comprises a structural unit represented by the following formula (5) and does not comprise a structural unit represented by the above formula (1):

wherein W is a divalent organic group and X is a divalent organic group that comprises neither an aliphatic chain structure nor an aliphatic structure.

4. The positive photosensitive resin composition according to claim 1 , which is used for a surface protective film of a semiconductor device having an under-bump metal free structure.

5. A method for producing a patterned cured film comprising:

a resin film-forming step in which the positive photosensitive resin composition according to claim 1 is applied to a substrate, followed by drying to form a resin film;

a light exposure step in which the resin film is exposed to light with a prescribed pattern;

a development step in which the resin film after the light exposure is developed by using an aqueous alkaline solution to obtain a patterned resin film; and

a heat-treatment step in which the patterned resin film is heat-treated to obtain a patterned cured film.

6. The method for producing a patterned cured film according to claim 5 , wherein the thickness of the resin film is 20 μm or more, and the thickness of the patterned cured film is 15 μm or more.

7. A patterned cured film produced by the method for producing a patterned cured film according to claim 5 .

8. An electronic component comprising the patterned cured film according to claim 7 .

9. The positive photosensitive resin composition according to claim 1 , wherein the component (d) comprising the iodonium compound represented by the formula (3).