Photosensitive resin composition, dry film, printed wiring board, and method for producing printed wiring board

1 . A photosensitive resin composition comprising (A) a photopolymerizable compound having an ethylenically unsaturated group and an acid substituent, (B) a curing agent, (C) a photopolymerization initiator, and (D) a photopolymerizable compound, wherein the photopolymerizable compound (D) is a polyfunctional monomer which has a skeleton (X) derived from a polyhydric alcohol and having three or more bonding groups (a), each bonded to another structure and corresponding to a hydroxy group from which the hydrogen atom has been removed, and which has three or more (meth)acryloyl groups bonded directly or indirectly to the bonding groups (a), and wherein at least one (meth)acryloyl group of the three or more (meth)acryloyl groups is bonded to the bonding group(s) (a) via a linking group.

2 . The photosensitive resin composition according to claim 1 , wherein the linking group is a divalent group comprising an alkylene oxide structural unit, or a divalent group derived from a hydroxy acid.

3 . The photosensitive resin composition according to claim 2 , wherein the alkylene oxide structural unit is an alkylene oxide structural unit having 2 to 4 carbon atoms, and the hydroxy acid is an aliphatic hydroxy acid having 2 to 10 carbon atoms.

4 . A dry film comprising a carrier film and a photosensitive layer using a photosensitive resin composition comprising:

(A) a photopolymerizable compound having an ethylenically unsaturated group and an acid substituent,

(B) a curing agent,

(C) a photopolymerization initiator, and

(D) a photopolymerizable compound, wherein the photopolymerizable compound (D) is a polyfunctional monomer which has a skeleton (X) derived from a polyhydric alcohol and having three or more bonding groups (a), each bonded to another structure and corresponding to a hydroxy group from which the hydrogen atom has been removed, and which has three or more (meth)acryloyl groups bonded directly or indirectly to the bonding groups (a), wherein at least one (meth)acryloyl group of the three or more (meth)acryloyl groups is bonded to the bonding group(s) (a) via a linking group, and wherein the linking group is a divalent group comprising an alkylene oxide structural unit having 2 to 4 carbon atoms.

5 . The dry film according to claim 4 , wherein the skeleton (X) is a skeleton derived from a polyhydric alcohol selected from the group consisting of glycerin, diglycerin, trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipentaerythritol.

6 . The dry film according to claim 4 , wherein, in the photopolymerizable compound (D), the number of the (meth)acryloyl groups, bonded to the bonding groups (a) via the linking group, is 3 to 10.

7 . The dry film according to claim 4 , wherein the photopolymerizable compound (A) having an ethylenically unsaturated group and an acid substituent is an acid-modified ethylenically unsaturated group-containing epoxy derivative obtained by reacting a resin (A′), which has been obtained by reacting an epoxy resin (a) and an ethylenically unsaturated group-containing organic acid (b), with a saturated or unsaturated group-containing polybasic acid anhydride (c).

8 . The dry film according to claim 7 , wherein the epoxy resin (a2) is at least one selected from the group consisting of a novolac epoxy resin different from the bisphenol novolac epoxy resin (a1), a bisphenol A epoxy resin, a bisphenol F epoxy resin, a triphenol methane epoxy resin, and a biphenyl epoxy resin.

9 . The dry film according to claim 7 , wherein the photopolymerizable compound (A) having an ethylenically unsaturated group and an acid substituent comprises a photopolymerizable compound (A1) having an ethylenically unsaturated group and an acid substituent, obtained by using a bisphenol novolac epoxy resin (a1) as the epoxy resin (a), and a photopolymerizable compound (A2) having an ethylenically unsaturated group and an acid substituent, obtained by using an epoxy resin (a2), which differs from the bisphenol novolac epoxy resin (a1), as the component (a).

10 . The dry film according to claim 4 , wherein the photopolymerization initiator (C) is at least one selected from the group consisting of an alkylphenone photopolymerization initiator, a thioxanthone photopolymerization initiator having a thioxanthone skeleton, a benzophenone photopolymerization initiator, an oxime ester photopolymerization initiator, and an acylphosphine oxide photopolymerization initiator.

11 . The dry film according to claim 4 , wherein the photosensitive resin composition further comprises (E) an inorganic filler.

12 . The dry film according to claim 4 , wherein the content of the photopolymerizable compound (A) having an ethylenically unsaturated group and an acid substituent, the content of the curing agent (B), the content of the photopolymerization initiator (C), and the content of the photopolymerizable compound (D) are 20 to 80% by mass, 2 to 40% by mass, 0.2 to 15% by mass, and 1 to 15% by mass, respectively, based on the total solid content of the photosensitive resin composition.

13 . A printed wiring board having a surface protective film or an interlayer insulating layer formed from the photosensitive resin composition according to claim 1 .

14 . The printed wiring board according to claim 13 , wherein the surface protective film or the interlayer insulating layer has a thickness of 5 μm or more.

15 . A method for producing a printed wiring board, comprising the sequential steps of: providing a photosensitive layer on a substrate by using the photosensitive resin composition according to claim 1 or the dry film according to claim 4 ; forming a resist pattern by using the photosensitive layer; and curing the resist pattern to form a surface protective film or an interlayer insulating layer.

16 . A method for producing a printed wiring board, comprising the sequential steps of: providing a photosensitive layer on a substrate by using the dry film according to claim 4 ; forming a resist pattern by using the photosensitive layer; and curing the resist pattern to form a surface protective film or an interlayer insulating layer.