JP6909551B2 - Photosensitive resin composition - Google Patents

Description

The present invention is a photosensitive resin composition used as a coating material, for example, an insulating coating material for coating a conductor circuit pattern of a printed wiring board having a conductor circuit pattern such as a copper foil formed on a rigid substrate or a flexible substrate. The present invention relates to a dry film having a coating film obtained by applying the photosensitive resin composition to a film, and a printed wiring board coated with a cured product obtained by photocuring the photosensitive resin composition.

A circuit pattern of a conductor (for example, copper foil) is formed on the substrate, electronic components are mounted on the soldered lands of the circuit pattern by soldering, and the circuit part excluding the soldered lands is covered with an insulating film as a protective film. It is covered. As the insulating film, a cured film of a photosensitive resin composition containing a carboxyl group-containing photosensitive resin, an epoxy compound, and a photopolymerization initiator may be used. Moreover, in recent years, due to the high performance of electronic devices, electronic components are mounted on printed wiring boards at an increasing density. Therefore, the insulating coating may be required to have excellent resolution. In order to impart excellent resolution to the insulating film, it may be required to suppress the occurrence of undercut in the insulating film.

Examples of the photosensitive resin composition for suppressing the undercut of the cured film include (A) a carboxyl group-containing photosensitive resin, (B) a photopolymerization initiator, (C) an epoxy resin, and (D) (meth) acrylic. An alkali-developable photosensitive resin composition containing a monomer, which contains an acylphosphine oxide-based photopolymerization initiator as (B) a photopolymerization initiator and (C) as an epoxy resin, bisphenol A novolac. An alkali-developable photosensitive resin composition containing a type epoxy resin has been proposed (Patent Document 1).

On the other hand, a printed wiring board designed so that the height of the conductor circuit pattern is higher than usual (for example, a height of about 40 μm) may be used, and such a printer wiring board is also coated with an insulating coating. There is a need. In this case, it is necessary to apply a thick insulating coating (for example, a thickness of 40 μm or more) to the printed wiring board.

However, when the insulating coating is applied with a thick thickness (for example, a thickness of 40 μm or more), it becomes difficult for the active energy rays (for example, ultraviolet rays) to penetrate to the lower part of the coating film of the photosensitive resin composition. If it becomes difficult for the active energy rays to penetrate to the lower part of the coating film, the photocuring at the lower part of the coating film becomes insufficient, and an undercut occurs in the cured coating film. In particular, if the exposure amount of the active energy rays is reduced in order to improve production efficiency or the like, undercuts are likely to occur in the cured coating film. In Patent Document 1, there is room for improvement in improving the photocurability at the lower part of the thickly coated coating film and suppressing undercut.

Japanese Unexamined Patent Publication No. 2015-064546

In view of the above circumstances, the present invention is a photosensitive resin composition capable of suppressing undercut of a cured coating film even if a thick coating film (for example, a thickness of 40 μm or more) is formed on the substrate. An object of the present invention is to provide a dry film having a coating film coated with an object, and a printed wiring board having a photocurable film of the photosensitive resin composition.

The gist of the structure of the present invention is as follows.
[1] Containing (A) a carboxyl group-containing photosensitive resin, (B) an epoxy compound, (C) a reactive diluent, and (D) a photopolymerization initiator.
The maximum value of the absorbance of the (A) carboxyl group-containing photosensitive resin in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.000 or more. A photosensitive resin composition containing a carboxyl group-containing photosensitive resin having a maximum absorbance of 360 nm or more of 0.050 or less.
[2] The maximum value of the absorbance of the (A) carboxyl group-containing photosensitive resin in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1. The photosensitive resin composition according to [1], which contains a carboxyl group-containing photosensitive resin having an amount of .500 or more.
[3] The maximum absorbance of the epoxy compound (B) in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 3.000 or more. The photosensitive resin composition according to [1] or [2], which contains an epoxy compound having a maximum absorbance of 360 nm or more and 0.070 or less.
[4] The maximum value of the absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using the 0.1 mass% ethyldiglycol acetate solution is 3.000 or more and the maximum value of the absorbance of 360 nm or more. The photosensitive resin composition according to [3], wherein the epoxy compound having a value of 0.070 or less is a naphthalene-type epoxy resin.
[5] The photosensitive resin composition according to any one of [1] to [4], wherein the (D) photopolymerization initiator contains an α-aminoalkylphenone-based photopolymerization initiator.
[6] The above-mentioned one of [1] to [4], wherein the (D) photopolymerization initiator contains an α-aminoalkylphenone-based photopolymerization initiator and an oxime ester-based photopolymerization initiator. Photosensitive resin composition.
[7] A dry film having a coating film coated with the photosensitive resin composition according to any one of [1] to [6].
[8] A printed wiring board having a photocurable film of the photosensitive resin composition according to any one of [1] to [6].

According to the aspect of the photosensitive resin composition of the present invention, the (A) carboxyl group-containing photosensitive resin is 300 nm or more and 360 nm measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution. By containing a carboxyl group-containing photosensitive resin having a maximum absorbance of 1.000 or more and 360 nm or more and a maximum absorbance of 0.050 or less in the following range, the substrate is thickened (for example, 40 μm or more). Thickness) Even if a cured coating film is formed, undercutting of the cured coating film can be suppressed.

According to the aspect of the photosensitive resin composition of the present invention, the (A) carboxyl group-containing photosensitive resin is 300 nm or more and 360 nm measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution. By containing a carboxyl group-containing photosensitive resin having a maximum absorbance in the following range of 1.500 or more, undercutting of the cured coating film is surely suppressed even if a thick cured coating film is formed on the substrate. can.

According to the aspect of the photosensitive resin composition of the present invention, the epoxy compound (B) is in the range of 300 nm or more and 360 nm or less as measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution. By containing an epoxy compound having a maximum absorbance of 3.000 or more and a maximum absorbance of 360 nm or more and 0.070 or less, even if a thick cured coating is formed on the substrate, the cured coating is under. Cutting can be suppressed more reliably, and a better line shape can be obtained.

According to the aspect of the photosensitive resin composition of the present invention, the photopolymerization initiator (D) contains an α-aminoalkylphenone-based photopolymerization initiator and an oxime ester-based photopolymerization initiator on the substrate. Even if a thick cured coating film is formed, the undercut of the cured coating film can be suppressed more reliably.

Next, the photosensitive resin composition of the present invention will be described in detail below. The photosensitive resin composition of the present invention contains (A) a carboxyl group-containing photosensitive resin, (B) an epoxy compound, (C) a reactive diluent, and (D) a photopolymerization initiator. The maximum absorbance of the carboxyl group-containing photosensitive resin (A) in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.000 or more. It contains a carboxyl group-containing photosensitive resin having a maximum absorbance of 360 nm or more and 0.050 or less.

(A) Carboxylic group-containing photosensitive resin The carboxyl group-containing photosensitive resin has a maximum absorbance in the range of 300 nm or more and 360 nm or less as measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution. Contains a carboxyl group-containing photosensitive resin having a maximum absorbance of 1.000 or more and 360 nm or more and 0.050 or less. (A) As the carboxyl group-containing photosensitive resin, the carboxyl group-containing photosensitive resin having the above-mentioned absorbance is used, so that it is irradiated with ultraviolet rays (for example, in the wavelength range of 300 to 400 nm) and is thick (for example, 40 μm) on the substrate. (Thickness above) When forming the photocurable film, the photosensitivity of the photosensitive resin composition is improved, which contributes to suppressing undercut.

The carboxyl group-containing photosensitive resin has a maximum absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution as long as it is 1.000 or more. Although not particularly limited, 1.200 or more is more preferable, 1.400 or more is further preferable, and 1.500 or more is particularly preferable, from the viewpoint of further improving the photosensitivity to ultraviolet rays and further suppressing undercut. On the other hand, the upper limit of the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution of a carboxyl group-containing photosensitive resin is not particularly limited. However, for example, 3.000 can be mentioned.

The carboxyl group-containing photosensitive resin is particularly limited as long as the maximum value of absorbance of 360 nm or more measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 0.050 or less. However, from the viewpoint of further improving the photosensitivity of the photosensitive resin composition to ultraviolet rays, 0.040 or less is more preferable, 0.035 or less is further preferable, and 0.020 or less is particularly preferable. On the other hand, the lower limit of the maximum value of the absorbance of 360 nm or more measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution of a carboxyl group-containing photosensitive resin is not particularly limited, but for example. 0.001 is mentioned.

The chemical structure of the carboxyl group-containing photosensitive resin is not particularly limited, and examples thereof include resins having one or more photosensitive unsaturated double bonds and a free carboxyl group. Examples of the carboxyl group-containing photosensitive resin include acrylic acid and methacrylic acid (hereinafter, "(meth) acrylic acid") in at least a part of the epoxy groups of the polyfunctional epoxy resin having two or more epoxy groups in one molecule. A radically polymerizable unsaturated monocarboxylic acid such as) is reacted to obtain a radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as epoxy (meth) acrylate, and the resulting radically polymerizable unsaturated monocarboxylic acid is obtained. A polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin such as a polybasic acid-modified epoxy (meth) acrylate obtained by reacting a hydroxyl group of a carboxylic oxide epoxy resin with a polybasic acid or an anhydride thereof. Can be mentioned.

The chemical structure of the polyfunctional epoxy resin is not particularly limited as long as it is a bifunctional or higher functional epoxy resin. The epoxy equivalent of the polyfunctional epoxy resin is not particularly limited, and for example, the upper limit thereof is preferably 3000 g / eq, more preferably 2000 g / eq, further preferably 1000 g / eq, and particularly preferably 500 g / eq. On the other hand, the lower limit is preferably 100 g / eq, and particularly preferably 200 g / eq.

Examples of the polyfunctional epoxy resin include rubber-modified epoxy resins such as biphenyl aralkyl type epoxy resin, phenyl aralkyl type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, and silicone-modified epoxy resin, ε. -Caprolactone-modified epoxy resin, bisphenol A type epoxy resin, phenol novolac type epoxy resin such as bisphenol F type epoxy resin, cresol novolac type epoxy resin such as ortho-cresol novolac type, bisphenol A novolac type epoxy resin, cyclic aliphatic polyfunctional Examples thereof include epoxy resins, glycidyl ester-type polyfunctional epoxy resins, glycidylamine-type polyfunctional epoxy resins, heterocyclic polyfunctional epoxy resins, bisphenol-modified novolak-type epoxy resins, and polyfunctional-modified novolac-type epoxy resins. Further, those resins in which halogen atoms such as Br and Cl are further introduced may be used. These polyfunctional epoxy resins may be used alone or in combination of two or more.

The radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and examples thereof include (meth) acrylic acid, crotonic acid, tiglic acid, angelic acid, and cinnamic acid. Of these, (meth) acrylic acid is preferable because it is easy to obtain and handle. These radically polymerizable unsaturated monocarboxylic acids may be used alone or in combination of two or more.

The method for reacting the polyfunctional epoxy resin with the radically polymerizable unsaturated monocarboxylic acid is not particularly limited, and for example, the polyfunctional epoxy resin and the radically polymerizable unsaturated monocarboxylic acid are dissolved in an appropriate diluent. There is a method of heating.

The polybasic acid or polybasic acid anhydride undergoes an addition reaction with a hydroxyl group generated by the reaction of the polyfunctional epoxy resin with the radically polymerizable unsaturated monocarboxylic acid to form a radically polymerizable unsaturated monocarboxylic oxide epoxy resin. A free carboxyl group is introduced. The polybasic acid or polybasic acid anhydride is not particularly limited, and either saturated or unsaturated can be used. Polybasic acids include, for example, succinic acid, maleic acid, adipic acid, citric acid, phthalic acid, tetrahydrophthalic acid, 3-methyltetrahydrophthalic acid, 4-methyltetrahydrophthalic acid, 3-ethyltetrahydrophthalic acid, 4-. Tetrahydrophthalates such as ethyltetrahydrophthalic acid, hexahydrophthalic acid, 3-methylhexahydrophthalic acid, 4-methylhexahydrophthalic acid, 3-ethylhexahydrophthalic acid, hexahydro such as 4-ethylhexahydrophthalic acid Examples thereof include tetrahydrophthalic acids such as phthalic acids, methyltetrahydrophthalic acid, endomethylenetetrahydrophthalic acid and methylendomethylenetetrahydrophthalic acid, trimellitic acid, pyromellitic acid and diglycolic acid. Examples of the polybasic acid anhydride include the above-mentioned polybasic acid anhydride. These compounds may be used alone or in combination of two or more. The method for reacting the radically polymerizable unsaturated monocarboxylic oxide epoxy resin with the polybasic acid or the polybasic acid anhydride is not particularly limited, and for example, the radically polymerizable unsaturated monocarboxylic oxide epoxy resin is reacted with the polybasic acid or poly. Examples thereof include a method in which the basic acid anhydride is dissolved in an appropriate diluent and heated.

The above-mentioned polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin can also be used as a carboxyl group-containing photosensitive resin, but a part of the carboxyl groups of the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin obtained as described above. A polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy obtained by further adding a radically polymerizable unsaturated group, which is obtained by an addition reaction of a compound having one or more radically polymerizable unsaturated groups and an epoxy group. A resin may be used. The polybasic acid-modified radically polymerizable unsaturated monocarboxylic oxide epoxy resin to which a radically polymerizable unsaturated group is further added has a radically polymerizable unsaturated group further introduced into the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin. Therefore, it is a carboxyl group-containing photosensitive resin having further improved photosensitivity as compared with the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin.

Examples of the compound having one or more radically polymerizable unsaturated groups and an epoxy group include glycidyl compounds. Examples of the glycidyl compound include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, pentaerythritol triacrylate monoglycidyl ether, pentaerythritol trimethacrylate monoglycidyl ether and the like. In addition, a plurality of glycidyl groups may be contained in one molecule. The above-mentioned compound having one or more radically polymerizable unsaturated groups and an epoxy group may be used alone or in combination of two or more. The method for reacting the polybasic acid-modified unsaturated monocarboxylic oxide epoxy resin with a compound having one or more radically polymerizable unsaturated groups and an epoxy group is not particularly limited, and for example, the polybasic acid-modified unsaturated group is used. Examples thereof include a method in which a saturated monocarboxylic oxide epoxy resin and a compound having one or more radically polymerizable unsaturated groups and an epoxy group are dissolved in an appropriate diluent and heated.

Further, as the carboxyl group-containing photosensitive resin, an acid-modified urethanized unsaturated monocarboxylic oxide epoxy resin such as an acid-modified urethanized epoxy (meth) acrylate resin may be used. The acid-modified urethane-modified unsaturated monocarboxylic oxide epoxy resin is, for example, obtained by obtaining a radically polymerizable unsaturated monocarboxylic oxide epoxy resin as described above, and the generated hydroxyl group is mixed with the above-mentioned polybasic acid or polybasic acid anhydride. It has a chemical structure obtained by reacting with a compound having two or more isocyanate groups in one molecule.

The compound having two or more isocyanate groups in one molecule is not particularly limited, and for example, hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), methylene diisocyanate (MDI), methylenebiscyclohexylisocyanate, etc. Examples thereof include diisocyanates such as trimethylhexamethyl diisocyanate, hexane diisocyanate, hexamethylamine diisocyanate, methylenebiscyclohexylisocyanate, toluenediisocyanate, 1,2-diphenylethanediisocyanate, 1,3-diphenylpropanediisocyanate, diphenylmethane diisocyanate and dicyclohexylmethyldiisocyanate. These compounds may be used alone or in combination of two or more.

In the present invention, the above-mentioned acid-modified urethane-modified unsaturated monocarboxylic oxide epoxy resin can also be used as a carboxyl group-containing photosensitive resin, but if necessary, the above-mentioned carboxyl of the acid-modified urethane-modified unsaturated monocarboxylic oxide epoxy resin can be used. By reacting the above-mentioned compound having one or more radically polymerizable unsaturated groups with an epoxy group, a radically polymerizable unsaturated group is further introduced, and a carboxyl group-containing photosensitive member having further improved photosensitivity is introduced. It may be a sex resin.

Further, as the carboxyl group-containing photosensitive resin, a) a polyfunctional epoxy resin having two or more epoxy groups in one molecule and b) at least one carboxylic acid having 10 or more carbon atoms per carboxyl group. And c) A long-chain hydrocarbon structure obtained by adding d) a polybasic acid and / or a polybasic acid anhydride to an unsaturated carboxylic oxide epoxy resin which is a reaction product with a radically polymerizable unsaturated monocarboxylic acid. Containing resin can be mentioned. Since the long-chain hydrocarbon structure-containing resin has a long-chain hydrocarbon structure, it is possible to impart excellent flexibility and insulation reliability to the cured product.

a) Polyfunctional epoxy resin having two or more epoxy groups in one molecule Examples of the polyfunctional epoxy resin having two or more epoxy groups in one molecule include the above-mentioned various polyfunctional epoxy resins. Of these, the biphenyl aralkyl type epoxy resin and the dicyclopentadiene type epoxy resin are preferable from the viewpoint of the photosensitivity, flexibility and insulation reliability of the cured product of the photosensitive resin composition.

b) At least one carboxylic acid having 10 or more carbon atoms per carboxyl group A carboxylic acid having 10 or more carbon atoms per carboxyl group reacts with the epoxy group of the polyfunctional epoxy resin. By introducing the long-chain hydrocarbon structure derived from the carboxylic acid into the epoxy resin, the flexibility and insulation reliability of the cured product of the photosensitive resin composition containing the photosensitive resin can be improved. The carboxylic acid having 10 or more carbon atoms per carboxyl group is not particularly limited, and either saturated or unsaturated can be used, and either linear or branched can be used. Examples of the carboxylic acid include a monobasic acid having 10 or more carbon atoms and a dibasic acid having 20 or more carbon atoms. From the viewpoint of both flexibility and dryness to the touch, the monobasic acid and diprotic acid are used. The acid is preferably linear or branched with two or less side chains having 2 or less carbon atoms.

Further, while introducing a long-chain hydrocarbon structure derived from a long-chain carboxylic acid into an epoxy resin, different epoxy groups of the epoxy resin are bonded to each other via a carboxylic acid having a long-chain hydrocarbon structure to form an epoxy resin. The relatively rigid skeleton of the long-chain carboxylic acid can be covalently bridged with a highly flexible long-chain hydrocarbon skeleton derived from a long-chain carboxylic acid. As a result, the long-chain carboxylic acid may contain at least one dibasic acid from the viewpoint of imparting a structure excellent in flexibility, heat resistance and chemical resistance to the cured product to the epoxy resin. Further, in the present invention, the flexibility of the cured product can be improved by introducing a large amount of highly flexible long-chain hydrocarbon skeleton derived from a long-chain carboxylic acid. However, the carbon per carboxyl group described above can be improved. By using a monobasic acid having 10 or more carbon atoms per carboxyl group in combination with a dibasic acid having 10 or more, a long-chain carboxylic acid, a polyfunctional epoxy resin, and an ethylenically unsaturated group are used in combination. The molecular weight of the reaction product with the contained carboxylic acid can be appropriately controlled while improving the composition ratio of the component derived from the long-chain carboxylic acid. By appropriately adjusting the molecular weight in this way, it is possible to achieve both the touch-drying property of the coating film after drying, the solubility in a weak alkaline developer (that is, the alkaline developability), and the flexibility of the cured product. Become.

Specific examples of carboxylic acids having 10 or more carbon atoms per carboxyl group include capric acid (decanoic acid: C10), undecanoic acid (C11), and lauric acid (dodecanoic acid: C12) as monobasic acids. , Tridecanoic acid (C13), myristic acid (C14), pentadecanoic acid (C15), palmitic acid (hexadecanoic acid: C16), margaric acid (heptadecanoic acid: C17), stearic acid (C18), tubercrostearic acid (C19) , Arakidic acid (C20), behenic acid (C22), tricosyl acid (C23), tetracosanoic acid (C24), hexacosanoic acid (C26), octacosanoic acid (C28), triaconic acid (C30) and the like.

Examples of the dibasic acid include eikosan diic acid (C20), ethyl octadecane diic acid (C20), eikosadien diic acid (C20), vinyl octadecaene diic acid (C20), dimethyleicosa diene diic acid (C22), and the like. Examples thereof include C36 dimer acid produced by a dimerization reaction of unsaturated fatty acids such as dimethyleicosane diic acid (C22), diphenylhexadecan diic acid (C28) and oleic acid (C18). The above-mentioned carboxylic acid having 10 or more carbon atoms per carboxyl group may be used alone or in combination of two or more. If necessary, at least one carboxylic acid having 10 or more carbon atoms per carboxyl group, and at least one monobasic acid having 9 or less carbon atoms per carboxyl group and / or Alternatively, a dibasic acid may be used in combination.

The ratio (preparation ratio) of the carboxylic acid having 10 or more carbon atoms per carboxyl group in the photosensitive resin is not particularly limited, but the lower limit thereof further improves flexibility and insulation reliability. Further, 15% by mass is preferable, and 18% by mass is particularly preferable, from the viewpoint of adjusting the introduction amount of the polybasic acid and / or the polybasic acid anhydride to adjust the solid acid value. On the other hand, the upper limit is that the amount of the ethylenically unsaturated group-containing carboxylic acid introduced (that is, photosensitive) is maintained, and the amount of the polybasic acid and / or the polybasic acid anhydride introduced is adjusted to be solid. From the viewpoint of adjusting the acid anhydride value, 25% by mass is preferable, and 20% by mass is particularly preferable.

c) Radical-polymerizable unsaturated monocarboxylic acid Examples of the radical-polymerizable unsaturated monocarboxylic acid include the above-mentioned various radical-polymerizable unsaturated monocarboxylic acids. The ratio (preparation ratio) of the radically polymerizable unsaturated monocarboxylic acid in the photosensitive resin is not particularly limited, but the lower limit thereof further improves the sensitivity and polybasic acid and / or polybasic acid anhydride. 2.0% by mass is preferable, and 3.0% by mass is particularly preferable, from the viewpoint of adjusting the amount of the substance introduced and the solid acid value. On the other hand, the upper limit is maintained by maintaining the amount of carboxylic acid having 10 or more carbon atoms per carboxyl group, and adjusting the amount of polybasic acid and / or polybasic acid anhydride introduced. From the viewpoint of adjusting the solid content acid value, 10% by mass is preferable, and 5.0% by mass is particularly preferable.

d) Polybasic acid and / or polybasic acid anhydride Examples of the polybasic acid and polybasic acid anhydride include the above-mentioned various polybasic acids and polybasic acid anhydrides. The ratio (preparation ratio) of polybasic acid and / or polybasic acid anhydride in the photosensitive resin is not particularly limited, but the lower limit thereof is from the viewpoint of adjusting good alkali developability and solid acid value. 7.0% by mass is preferable, and 9.0% by mass is particularly preferable. On the other hand, the upper limit value is preferably 16% by mass, particularly preferably 14% by mass, from the viewpoint of surely preventing a decrease in insulation reliability and adjusting the solid acid value.

The acid value of the carboxyl group-containing photosensitive resin is not particularly limited, and for example, the lower limit thereof is preferably 30 mgKOH / g and particularly preferably 40 mgKOH / g from the viewpoint of reliably obtaining alkali developability. On the other hand, the upper limit of the acid value is preferably 200 mgKOH / g from the viewpoint of preventing dissolution of the exposed portion by the alkaline developer, and 150 mgKOH / g from the viewpoint of preventing deterioration of the moisture resistance and electrical characteristics of the photocured product. Especially preferable.

The mass average molecular weight of the carboxyl group-containing photosensitive resin is not particularly limited. For example, the lower limit thereof is preferably 6000, more preferably 7000, and 8000 from the viewpoint of toughness and dryness to the touch of the photocured product. Is particularly preferable. On the other hand, the upper limit of the mass average molecular weight is, for example, preferably 200,000, more preferably 100,000, and particularly preferably 50,000 from the viewpoint of smooth alkali developability. The "mass average molecular weight" means a mass average molecular weight measured at room temperature using gel permeation chromatography (GPC) and calculated in terms of polystyrene.

The carboxyl group-containing photosensitive resin may be synthesized in the above reaction step using each of the above raw materials, or a commercially available carboxyl group-containing photosensitive resin may be used. Examples of the carboxyl group-containing photosensitive resin on the market include "KAYARAD ZCR-1569H" (Nippon Kayaku Co., Ltd.).

As the carboxyl group-containing photosensitive resin of component A, the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.000 or more. It suffices to contain a carboxyl group-containing photosensitive resin having a maximum absorbance of 360 nm or more of 0.050 or less. Therefore, a carboxyl group-containing photosensitive resin having the above absorbance and a carboxyl group having no absorbance. It may be used in combination with the contained photosensitive resin.

(B) Epoxy compound The epoxy compound is for increasing the crosslink density of the cured coating film to obtain a cured coating film having sufficient strength. Examples of the epoxy compound include an epoxy resin. The epoxy resin is not particularly limited, and is, for example, a rubber-modified epoxy such as a biphenyl aralkyl type epoxy resin, a phenyl aralkyl type epoxy resin, a biphenyl type epoxy resin, a naphthalene type epoxy resin, a dicyclopentadiene type epoxy resin, or a silicone modified epoxy resin. Resin, ε-caprolactone-modified epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin and other phenol novolac type epoxy resin, ortho-cresol novolac type and other cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, cyclic fat Group polyfunctional epoxy resin, glycidyl ester type polyfunctional epoxy resin, glycidylamine type polyfunctional epoxy resin, heterocyclic polyfunctional epoxy resin, bisphenol modified novolac type epoxy resin, polyfunctional modified novolac type epoxy resin, dimer acid glycidyl ester type Epoxy resin and the like can be mentioned. These compounds may be used alone or in combination of two or more.

Of these, when a thick (for example, 40 μm or more) photocurable film is formed on the substrate by irradiating with ultraviolet rays (for example, in the wavelength range of 300 to 400 nm), the absorbance of the photosensitive resin composition becomes high. The maximum value of the absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 2.000 from the viewpoint of improving and contributing to the suppression of undercut. The epoxy compound having a maximum absorbance of 360 nm or more is 0.100 or less is preferable, and the maximum absorbance in the range of 300 nm or more and 360 nm is 2.500 or more and the maximum absorbance of 360 nm or more is 0.080. The following epoxy compounds are more preferable, and the epoxy compounds having a maximum absorbance in the range of 300 nm or more and 360 nm or less of 3.000 or more and a maximum absorbance of 360 nm or more of 0.070 or less are particularly preferable. Further, as an epoxy compound having a maximum absorbance of 3.000 or more and 360 nm or more and a maximum absorbance of 0.070 or less in the range of 300 nm or more and 360 nm or less, undercut can be suppressed more reliably. Naphthalene type epoxy resin is particularly preferable.

Regarding the epoxy compound, the upper limit of the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is not particularly limited, and examples thereof include 5.000. The lower limit of the maximum value of the absorbance of the epoxy compound of 360 nm or more is not particularly limited, and examples thereof include 0.001.

The blending amount of the epoxy compound is not particularly limited, but for example, the lower limit thereof is 15 with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin (solid content) from the viewpoint of obtaining the strength of the photocurable film more reliably. It is preferably parts by mass, more preferably 18 parts by mass, and particularly preferably 20 parts by mass. On the other hand, the upper limit of the blending amount of the epoxy compound is preferably 100 parts by mass, more preferably 50 parts by mass, and 30 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of obtaining excellent developability. Part is particularly preferable.

(C) Reactive Diluent The reactive diluent is, for example, a photopolymerizable monomer and is a compound having at least one polymerizable double bond per molecule, preferably two or more polymerizable double bonds per molecule. The reactive diluent reinforces the photocuring of the photosensitive resin composition and contributes to obtain a cured product having sufficient resolution, acid resistance, heat resistance, alkali resistance and the like.

Examples of the reactive diluent include a monofunctional (meth) acrylate compound and a bifunctional or higher functional (meth) acrylate compound. Examples of the (meth) acrylate compound include 2-hydroxyethyl (meth) acrylate, phenoxyethyl (meth) acrylate, diethylene glucol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylic rate and the like. Monofunctional (meth) acrylate compound, 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, neo Pentyl glycol adipate di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, dicyclopentanyl di (meth) acrylate, ethylene oxide-modified di (meth) acrylate, cyclohexyl di (meth) acrylate, Bifunctional (meth) acrylate compounds such as isocyanurate di (meth) acrylate, trimethyl propantri (meth) acrylate, ditrimethylolpropantetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth). Trifunctional or higher functional acrylates, propylene oxide-modified trimethylolpropantri (meth) acrylates, tris (acryloxyethyl) isocyanurates, propionic acid-modified dipentaerythritol penta (meth) acrylates, dipentaerythritol hexa (meth) acrylates, etc. Meta) acrylate compounds can be mentioned. Further, monofunctional or bifunctional or higher functional urethane (meth) acrylate compounds and the like can be mentioned. These may be used alone or in combination of two or more. The content of the reactive diluent is not particularly limited, but is preferably 5.0 parts by mass to 100 parts by mass, and particularly preferably 10 parts by mass to 50 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin.

(D) Photopolymerization Initiator The chemical structure of the photopolymerization initiator is not particularly limited, and any of them can be used, but an α-aminoalkylphenone-based photopolymerization initiator and / or an oxime ester-based photopolymerization initiator may be used. It is preferable to contain it. By blending an α-aminoalkylphenone-based photopolymerization initiator and / or an oxime ester-based photopolymerization initiator as the photopolymerization initiator, a thick (for example, a thickness of 40 μm or more) photocurable film is formed on the substrate. At that time, the photosensitivity of the photosensitive resin composition of the present invention to ultraviolet rays is further improved, which contributes to the suppression of the increase in the line width of the photocured product and the more reliable suppression of the undercut. It is considered that this is related to the fact that the α-aminoalkylphenone-based photopolymerization initiator and the oxime ester-based photopolymerization initiator both exhibit their functions mainly at wavelengths of 380 nm or more. Of these, it is more preferable to contain at least an α-aminoalkylphenone-based photopolymerization initiator, and it is particularly preferable to contain an α-aminoalkylphenone-based photopolymerization initiator and an oxime ester-based photopolymerization initiator.

Examples of the α-aminoalkylphenone-based photopolymerization initiator include 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, 2-methyl-1- [4- (methylthio). Phenyl] -2-morpholinopropan-1-one and the like can be mentioned. These α-aminoalkylphenone-based photopolymerization initiators may be used alone or in combination of two or more.

The oxime ester-based photopolymerization initiator is a photopolymerization initiator having an oxime ester group in the molecule. Examples of the oxime ester-based photopolymerization initiator include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], and ethanone 1- [9-ethyl-6- (2). -Methylbenzoyl) -9H-carbazole-3-yl] -1- (0-acetyloxime), 2- (acetyloxyiminomethyl) thioxanthene-9-one, 1,8-octanedione, 1,8-bis [9-Ethyl-6-nitro-9H-carbazole-3-yl]-, 1,8-bis (O-acetyloxime), 1,8-octanedione, 1,8-bis [9- (2-ethylhexyl) ) -6-Nitro-9H-carbazole-3-yl]-, 1,8-bis (O-acetyloxime), (Z)-(9-ethyl-6-nitro-9H-carbazole-3-yl) ( 4-((1-methoxypropan-2-yl) oxy) -2-methylphenyl) metanone O-acetyloxime and the like can be mentioned. These oxime ester-based photopolymerization initiators may be used alone or in combination of two or more.

When the α-aminoalkylphenone-based photopolymerization initiator and the oxime ester-based photopolymerization initiator are contained, the mass ratio of the α-aminoalkylphenone-based photopolymerization initiator / oxime ester-based photopolymerization initiator is not particularly limited. , 10-50 is preferred, 20-40 is more preferred, and 25-35 is particularly preferred.

Further, in the present invention, a photopolymerization initiator (another photopolymerization initiator) other than the α-aminoalkylphenone-based photopolymerization initiator and the oxime ester-based photopolymerization initiator may be blended as the photopolymerization initiator. .. Further, in addition to the α-aminoalkylphenone-based photopolymerization initiator and / or the oxime ester-based photopolymerization initiator, another photopolymerization initiator may be further blended. As other photopolymerization initiators, known ones can be used, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, dimethylaminoacetophenone, 2, 2-Dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1-hydroxycyclohexylphenylketone, 4- (2-hydroxy) Ethoxy) Phenyl-2- (hydroxy-2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-terchary butyl anthraquinone , 2-Aminoanthraquinone, 2-Methylthioxanthone, 2-Ethylthioxanthone, 2-Chlorthioxanthone, 2,4-Dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetphenonedimethylketal, ethyl P-dimethylaminobenzoate Estel, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide , (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide and the like. These other photopolymerization initiators may be used alone or in combination of two or more.

The blending amount of the photopolymerization initiator is not particularly limited, but for example, the lower limit thereof is preferably 0.7 parts by mass with respect to 100 parts by mass of the carboxyl group-containing photosensitive resin from the viewpoint of further suppressing undercut. 1.0 part by mass is particularly preferable. On the other hand, the upper limit of the blending amount of the photopolymerization initiator is, for example, the carboxyl group-containing photosensitive resin 100 from the viewpoint of surely preventing the line width of the cured coating film from increasing and the dimensional accuracy from decreasing. 10 parts by mass is preferable with respect to parts by mass, and 6.0 parts by mass is particularly preferable.

In the present invention, in addition to the above components (A) to (D), other components such as extender pigments, flame retardants, curing accelerators, additives, colorants, and non-reactive diluents are required. Etc. may be appropriately blended.

Examples of the extender pigment include talc, barium sulfate, hydrophobic silica, alumina, aluminum hydroxide, mica and the like.

Examples of the flame retardant include a phosphorus-based flame retardant. Examples of phosphorus-based flame retardants include tris (chloroethyl) phosphate, tris (2,3-dichloropropyl) phosphate, tris (2-chloropropyl) phosphate, tris (2,3-bromopropyl) phosphate, and tris (bromo). Halogen-containing phosphates such as chloropropyl) phosphate, 2,3-dibromopropyl-2,3-chloropropyl phosphate, tris (tribromophenyl) phosphate, tris (dibromophenyl) phosphate, and tris (tribromoneopentyl) phosphate. Esters; non-halogen aliphatic phosphates such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate; triphenyl phosphate, credyl diphenyl phosphate, dicredyl phenyl phosphate, tricresyl phosphate, trixylate Nylphosphate, xylenyldiphenyl phosphate, tris (isopropylphenyl) phosphate, isopropylphenyldiphenyl phosphate, diisopropylphenylphenyl phosphate, tris (trimethylphenyl) phosphate, tris (t-butylphenyl) phosphate, hydroxyphenyldiphenyl phosphate, octyldiphenyl phosphate Non-halogen aromatic phosphates such as aluminum trisdiphenylphosphine, aluminum trismethylethylphosphine, aluminum trisdiphenylphosphine, zinc bisdiphenylphosphine, zinc bismethylethylphosphine, zinc bisdiphenylphosphine, bisdiethyl Metal salts of phosphinic acids such as titanyl phosphine, titanium tetrakisethyl phosphine, titanyl bismethylethyl phosphine, titanium tetrakismethylethyl phosphine, titanyl bisdiphenylphosphine, titanium tetrakisdiphenyl phosphine, diphenylvinylphosphine oxide, triphenyl Examples thereof include phosphine oxide-based compounds such as phosphine oxide, trialkylphosphine oxide, and tris (hydroxyalkyl) phosphine oxide.

Examples of the curing accelerator include dicyandiamide (DICY) and its derivatives, melamine and its derivatives, boron trifluoride-amine complex, organic acid hydrazide, diaminomaleonitrile (DAMN) and its derivatives, guanamine and its derivatives, and amineimide (AI). In addition, polyamine and the like can be mentioned.

Examples of the additive include silicone-based, hydrocarbon-based and acrylic-based defoaming agents, thixotropy agents, antioxidants and the like.

The colorant is not particularly limited, such as a pigment and a pigment. Further, as the color of the colorant, any color such as a white colorant, a blue colorant, a green colorant, a yellow colorant, a purple colorant, a black colorant, and a red colorant can be used. Examples of the colorant include inorganic colorants such as titanium oxide which is a white colorant, carbon black which is a black colorant, and acetylene black. In addition, organic colorants such as phthalocyanine green which is a green colorant and phthalocyanine type such as phthalocyanine blue and lionol blue which are blue colorants can be mentioned.

The non-reactive diluent is for adjusting the viscosity, dryness, coatability, etc. of the photosensitive resin composition. Examples of the non-reactive diluent include organic solvents. Examples of the organic solvent include ketones such as methyl ethyl ketone, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, n-propanol, isopropanol and cyclohexanol, and alicyclic hydrocarbons such as cyclohexane and methylcyclohexane. Classes, cellosolves such as cellosolve and butylcellosolve, carbitols such as carbitol and butylcarbitol, ethyl acetate, butyl acetate, cellosolve acetate, butyl cellosolve acetate, carbitol acetate, butyl carbitol acetate, diethylene glycol monomethyl ether acetate, ethyl di Examples thereof include esters such as glycol acetate. These may be used alone or in combination of two or more.

The method for producing the photosensitive resin composition of the present invention described above is not limited to a specific method. For example, after blending each of the above components in a predetermined ratio, at room temperature (for example, 25 ° C.), a three-roll or ball mill , Sand mill or the like, or kneading or mixing by a stirring means such as a super mixer or a planetary mixer. Further, before the kneading or mixing, pre-kneading or pre-mixing may be performed, if necessary.

Next, an example of how to use the photosensitive resin composition of the present invention described above will be described. Here, first, the photosensitive member of the present invention is exposed on a printed wiring board having a circuit pattern having a large dimension in the height direction (for example, a circuit pattern having a height of about 40 μm) formed by etching a conductor foil such as copper foil. A method of applying the sex resin composition to form an insulating film (for example, a solder resist film) will be described as an example.

The above photosensitive resin composition is applied onto a printed wiring board having a circuit pattern of a conductor foil by using a known method such as screen printing, spray coater, bar coater, applicator, blade coater, knife coater, roll coater, and gravure coater. It is applied to a desired thickness (for example, a thickness of 40 μm or more). After coating, if necessary, pre-drying is performed by heating at a temperature of about 60 to 100 ° C. for about 15 to 60 minutes in order to volatilize the non-reactive diluent (organic solvent) in the photosensitive resin composition. The non-reactive diluent is volatilized from the sex resin composition to make the surface of the coating film tack-free. A negative film having a translucent pattern other than the land of the circuit pattern is brought into close contact with the coated photosensitive resin composition, and ultraviolet rays (for example, a wavelength in the range of 300 to 400 nm) are irradiated from above. The coating film portion other than the land is photocured. Next, the coating film is developed by removing the non-exposed region corresponding to the land with a dilute alkaline aqueous solution. A spray method, a shower method, or the like is used as the developing method, and examples of the dilute alkaline aqueous solution used include a 0.5 to 5% by mass sodium carbonate aqueous solution. Next, by performing post-cure (thermosetting treatment) for 20 to 80 minutes in a hot air circulation type dryer or the like at 130 to 170 ° C., a solder which is a cured coating film having a desired circuit pattern on a printed wiring board. A resist film can be formed. Instead of irradiating the negative film with ultraviolet rays, the ultraviolet rays may be irradiated using a direct drawing exposure apparatus without using the negative film.

Next, the photosensitive resin composition of the present invention is applied onto a printed wiring board having a circuit pattern having a large height dimension (for example, a circuit pattern having a height of about 40 μm) formed by etching a conductor foil. A method of forming an insulating film (for example, a solder resist film) using the processed dry film will be described.

The dry film includes a support film (for example, a thermoplastic film such as a polyethylene terephthalate film or a polyester film), an insulating film coated on the support film (for example, a solder resist layer), and a cover film for protecting the insulating film (for example). , Polyethylene film, polypropylene film), and has a laminated structure. After applying the photosensitive resin composition on the support film to a desired thickness (for example, a thickness of 40 μm or more) by a known method such as a roller coating method, the coating film is dried and insulated on the support film. Form a film. After that, a dry film can be produced by laminating a cover film on the insulating film. An insulating film is formed on the printed wiring board by sticking the insulating film and the printed wiring board together while peeling off the cover film of the dry film. After that, by performing each of the exposure, development, and post-cure steps in the same manner as described above, a solder resist film having a desired circuit pattern can be formed on the printed wiring board.

Next, examples of the present invention will be described, but the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

Examples 1-9, Comparative Examples 1-4
Each component shown in Table 1 below is blended in the blending ratio shown in Table 1 below, mixed and dispersed at room temperature using three rolls, and the photosensitivity used in Examples 1 to 9 and Comparative Examples 1 to 4 is used. A sex resin composition was prepared. Unless otherwise specified, the blending amount of each component shown in Table 1 below is shown in parts by mass. In addition, the blank part of the blending amount in Table 1 below means that there is no blending. Further, in Table 2 below, the absorbance at a predetermined wavelength measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyl diglycol acetate solution of a carboxyl group-containing photosensitive resin, and 0.1 mass% ethyl of an epoxy compound. The absorbance at a predetermined wavelength measured by an ultraviolet-visible spectrophotometer using a diglycol acetate solution is described. As the ultraviolet-visible spectrophotometer, a U-3310 type spectrophotometer manufactured by Hitachi, Ltd. was used. The setting parameters of the spectrophotometer were a measurement wavelength range of 230 nm to 400 nm, a sampling interval of 1.0 nm, a slit of 2 nm, and a cell length of 10 mm.

The details of each component in Table 1 are as follows.
(A) Carboxylic group-containing photosensitive resin KAYARAD ZCR-1569H: Solid content 68% by mass, ethyl diglycol acetate 32% by mass, Nippon Kayaku Co., Ltd. Synthetic resin A-1
Biphenylaralkyl type epoxy resin NC-3000 (epoxy group: 0.383 mol, Nippon Kayaku Co., Ltd.) was placed in a 300 ml 4-port separable flask equipped with a stirring blade, a thermometer, a perfusion tube and a nitrogen introduction tube. 1 g, dodecanoic acid (carboxylic acid: 0.123 mol, Kishida Chemical Co., Ltd.) 24.6 g, adipic acid (carboxylic acid: 0.115 mol, Kishida Chemical Co., Ltd.) 8.4 g, ethyldiglycol acetate (Sanyo Kasei) 66.1 g of each was added, and the mixture was mixed and dissolved by stirring at 110 ° C. for 30 minutes in a nitrogen / oxygen mixed gas atmosphere. Next, after raising the temperature of the reaction solution to 115 ° C., 0.3 g of 4-methoxyphenol (Kishida Chemical Co., Ltd.) and acrylic acid (carboxylic acid: 0.145 mol, Osaka Organic Chemical Industry Co., Ltd.) 10. 4 g and 0.9 g of triphenylphosphine (Kishida Chemical Co., Ltd.) were added. The mixture was stirred at 115 ° C. for 8 hours, and the acid value was measured to confirm that the carboxylic acid had completely disappeared. Next, under an air atmosphere, 24.8 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride (H-TMAn-S) (carboxylic acid anhydride: 0.125 mol, Mitsubishi Gas Chemicals Co., Ltd.), After adding 16.5 g of diethyldiglycol (Nippon Embroidery Co., Ltd.) and stirring at 100 ° C. for 2 hours, the completion of the reaction is confirmed by FT-IR (infrared spectrophotometer), and the photosensitive resin to be blended in the examples. 258.0 g of A-1 was obtained. The mass average molecular weight (Mw) was 9100, and the solid content was 68% by mass.

(B) Epoxy compound ・ EPICRON 850-S, HP-4032: DIC Corporation ・ YX-4000K, jER871: Mitsubishi Chemical Co., Ltd. ・ NC-3000: Nippon Kayaku Co., Ltd.・ Ornex Co., Ltd. (D) Photopolymerization initiator ・ NCI-831: Oxym ester-based photopolymerization initiator, ADEKA Co., Ltd.
OXE-02: Oxime Ester Photopolymerization Initiator, BASF Japan Ltd. ・ Irgacare 369: α-Aminoalkylphenone Photopolymerization Initiator, BASF Japan Ltd.

Constituent pigment, Heidilite H42M: Showa Denko Co., Ltd. Flame retardant, Exolit OP-935: Clariant Japan Co., Ltd. Hardening accelerator, Melamine: Nissan Chemical Industry Co., Ltd., DICY-7: Mitsubishi Chemical Co., Ltd. Additive, X-50- 1095C: Antifoaming agent, Shin-Etsu Chemical Co., Ltd. Coloring agent / Denka Black: Denka Co., Ltd. Non-reactive diluent / EDGAC: Sanyo Kaseihin Co., Ltd.

Carboxyl group-containing photosensitive resin other than the component (A) ZAR-2000, FLX-2089: Nippon Kayaku Co., Ltd. RC-301: DIC Corporation

Specimen manufacturing process Substrate: Polyimide film ("ESPANEX" from Nippon Steel & Sumikin Chemical Co., Ltd., copper foil (conductor) thickness 12 μm, polyimide film thickness 25 μm)
Surface treatment: 3% by mass sulfuric acid treatment Printing method: Screen printing DRY film thickness: 20 μm and 40 μm
Pre-drying: 80 ° C, 20 minutes Exposure: 100 mJ / cm ² on the coating film, ORC Manufacturing Co., Ltd. DI UV exposure device "Mms60" (light source is high-pressure mercury lamp)
Development: 1 mass% sodium carbonate aqueous solution Temperature 30 ° C, spray pressure 0.2 MPa, development time 60 seconds Post cure: 150 ° C, 60 minutes

Evaluation items (1) Sensitometry After pre-drying the substrate coated with the photosensitive resin composition at 80 ° C. for 20 minutes, a step tablet for sensitivity measurement (14 steps of Kodak) is placed on the coating film, and a step tablet for sensitivity measurement is placed. A test pace (DRY film thickness is 20 μm) was obtained by irradiating ^{100 mJ / cm 2 of} ultraviolet rays having a wavelength main peak of 365 nm. The amount of irradiation light was measured using an integrated light meter manufactured by Oak Manufacturing Co., Ltd. After exposure to ultraviolet rays, development is carried out for 60 seconds at a spray pressure of 0.2 MPa using a 1 mass% sodium carbonate aqueous solution (temperature 30 ° C.) according to the above-mentioned test specimen preparation step, and the exposed portion is not removed. Was expressed as a number (number of steps). The larger the number of steps, the better the photosensitive characteristics.

(2) The maximum width (a) of the cross section (DRY film thickness 40 μm) of the remaining line of the exposed portion formed through the photomask having an undercut line interval of 200 μm using a metallurgical microscope (Olympus Corporation, STM6). And the minimum width (b) were measured, and the difference ((a)-(b)) was calculated to measure the undercut.

The evaluation results are shown in Table 1 above.

As shown in Tables 1 and 2 above, the maximum value of absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.000 or more and 360 nm. In Examples 1 to 9 containing the carboxyl group-containing photosensitive resin having the above maximum absorbance of 0.050 or less, the sensitivity was as good as 6 to 9 steps, and the undercut could be suppressed to 15 μm or less. .. In particular, Examples 1 and 3 in which the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is 1.591, and Examples 2 and 4 in which the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is 1.489. In comparison with, the undercut could be further suppressed.

Further, in addition to the epoxy compound in which the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is 2.547 and the maximum value of the absorbance in the range of 360 nm or more is 0.018, the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is the maximum. In Example 7 in which the epoxy compound having a value of 3.460 and 360 nm or more and the maximum value of the absorbance of 0.050 was used in combination, the epoxy compound having the maximum value of the absorbance of 0.029 in the range of 300 nm or more and 360 nm or less was used. Example 1, the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is 2.206. Example 8, the maximum value of the absorbance in the range of 300 nm or more and 360 nm or less is 0.184. As compared with Example 9 in which the above epoxy compound was used in combination, the undercut could be further suppressed.

On the other hand, the maximum absorbance in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 0.038 or less, and the maximum absorbance of 360 nm or more is In Comparative Examples 1 to 4 using the carboxyl group-containing photosensitive resin of 0.004, the undercut was 30 μm or more, and the undercut could not be suppressed.

The photosensitive resin composition of the present invention can suppress undercut of the cured coating film even if a thick cured coating film (for example, a thickness of 40 μm or more) is formed on the substrate. Therefore, the photosensitive resin composition is formed on a printed wiring board, for example. The field of protective films such as solder resists, especially the field of coating a photosensitive resin composition on a printed wiring board with a thicker copper foil than usual to form a protective film, and the field of filming a photosensitive resin composition. It is highly useful in the field of applying a dry film having a coating film applied to a substrate having a thickness of a copper foil thicker than usual.

Claims (6)

It contains (A) a carboxyl group-containing photosensitive resin, (B) an epoxy compound, (C) a reactive diluent, and (D) a photopolymerization initiator.
The maximum absorbance of the carboxyl group-containing photosensitive resin (A) in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.000 or more. The maximum value of absorbance above 360 nm is 0.050 or less .
The carboxyl group-containing photosensitive resin (A) undergoes radical polymerization by reacting at least a part of the epoxy groups of the biphenyl aralkyl type epoxy resin having two or more epoxy groups in one molecule with a radically polymerizable unsaturated monocarboxylic acid. A polybasic acid-modified radically polymerizable non-constituent obtained by obtaining a sex-unsaturated monocarboxylic oxide epoxy resin and reacting a hydroxyl group of the produced radically polymerizable unsaturated monocarboxylic oxide epoxy resin with a polybasic acid or an anhydride thereof. Saturated monocarboxylic oxide epoxy resin and / or a) biphenyl aralkyl type epoxy resin having two or more epoxy groups in one molecule and b) at least one carboxylic acid having 10 or more carbon atoms per carboxyl group. A long-chain hydrocarbon obtained by adding d) a polybasic acid and / or a polybasic acid anhydride to an unsaturated carboxylic oxide epoxy resin which is a reaction product of an acid and c) a radically polymerizable unsaturated monocarboxylic acid. It is a structure-containing resin
The maximum value of the absorbance of the epoxy compound (B) in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 3.000 or more and 360 nm or more. A photosensitive resin composition containing a naphthalene-type epoxy resin having a maximum absorbance of 0.070 or less. The maximum value of the absorbance of the (A) carboxyl group-containing photosensitive resin in the range of 300 nm or more and 360 nm or less measured by an ultraviolet-visible spectrophotometer using a 0.1 mass% ethyldiglycol acetate solution is 1.500 or more. The photosensitive resin composition according to claim 1, which contains a carboxyl group-containing photosensitive resin. The photosensitive resin composition according to claim 1 or 2 , wherein the (D) photopolymerization initiator contains an α-aminoalkylphenone-based photopolymerization initiator. The photosensitive resin composition according to claim 1 or 2 , wherein the (D) photopolymerization initiator contains an α-aminoalkylphenone-based photopolymerization initiator and an oxime ester-based photopolymerization initiator. A dry film having a coating film coated with the photosensitive resin composition according to any one of claims 1 to 4. A printed wiring board having a photocurable film of the photosensitive resin composition according to any one of claims 1 to 4.