JP2016212258A - Photosensitive thermosetting resin composition, dry film and printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photosensitive thermosetting resin composition that is developable with a weak alkaline sodium carbonate aqueous solution and excellent in mechanical characteristics such as impact resistance and flexibility, a dry film and a printed wiring board.SOLUTION: The photosensitive thermosetting resin composition comprises: (A) a polyamide imide resin obtained by reacting a reaction raw material comprising a diisocyanate compound and an imidized compound obtained by reacting a diamine containing a diamine having an ether bond and a carboxyl group-containing diamine with an acid anhydride (a1) comprising an acid anhydride having at least three carboxyl groups in which at least two carboxyl groups are anhydrous; (B) a monomer having an unsaturated double bond or a resin having an unsaturated double bond and a carboxyl group; (C) an epoxy resin; and (D) a photopolymerization initiator.SELECTED DRAWING: None

Description

  The present invention relates to a photosensitive thermosetting resin composition (hereinafter also simply referred to as “resin composition”), a dry film, and a printed wiring board, which can be developed with an aqueous alkali solution and have excellent properties of a cured film.

  Conventionally, as a material used for a solder resist of a printed wiring board, a photosensitive resin composition that can be developed with an alkaline aqueous solution has been used. As a method for forming a solder resist using such an alkali-developable photosensitive resin composition, a photosensitive resin composition is applied to a substrate and dried to form a resin layer, and a pattern is formed on the resin layer. A method of forming the film by irradiating the film with light and then developing with an alkali developer is common.

In such a method for forming a solder resist, the alkali developer includes sodium carbonate (Na ₂ CO ₃ ) aqueous solution, potassium carbonate aqueous solution (K ₂ CO ₃ ), sodium hydroxide (NaOH) aqueous solution, tetramethylammonium hydride ( An alkaline aqueous solution such as a TMAH solution may be mentioned. In the production of a printed wiring board, a weak alkaline sodium carbonate or potassium carbonate aqueous solution is usually used from the viewpoint of the reliability of the substrate and the working environment. Therefore, in the photosensitive resin composition for printed wiring boards, it is extremely important that development is possible with a weak alkaline sodium carbonate aqueous solution.

  On the other hand, in order to improve the physical properties of the resulting cured film, conventionally, the type of resin used in the photosensitive resin composition has been appropriately selected, but depending on the type of resin, weakly alkaline sodium carbonate Development with an aqueous solution may not be possible. For example, general-purpose polyimide resins and polyamide-imide resins are excellent in mechanical properties and heat resistance due to their structures, but because of their poor solubility, it is very difficult to apply the composition to development with an aqueous sodium carbonate solution. It was difficult. On the other hand, imparting developability to these polyimide resins and polyamide-imide resins has also been studied, but it has been necessary to cope with this by sacrificing mechanical properties peculiar to imides. This point can also be understood from the fact that development is performed with a strong alkaline aqueous sodium hydroxide solution in the example of Patent Document 1 that discloses an invention relating to a photosensitive resin composition containing a polyimide resin.

JP 2004-317725 A

  In addition, various studies have been made on the application of polyamic acid, which is a precursor of polyimide resin, to development using an aqueous sodium carbonate solution, but the resin composition using polyamic acid has a high reactivity derived from the structure. The storage stability as a composition often deteriorates, or a high temperature reaction is necessary for the ring-closing reaction, so that there are still few applications to printed wiring boards.

  Accordingly, an object of the present invention is to provide a photosensitive thermosetting resin composition, a dry film, and a printed wiring board, which can be developed with a weak alkaline sodium carbonate aqueous solution and have excellent mechanical properties such as impact resistance and flexibility. It is to provide.

  As a result of intensive studies, the present inventors have solved the above-mentioned problems of mechanical properties and developability by using a photosensitive thermosetting resin composition using a polyamideimide resin having a specific structure, and completed the present invention. It came.

That is, the photosensitive thermosetting resin composition of the present invention comprises (A) a diamine having an ether bond and a diamine containing a carboxyl group-containing diamine, and at least three carboxyl groups, two of which are dehydrated. A polyamideimide resin obtained by reacting an imidized product obtained by reacting an acid anhydride containing an acid anhydride (a1) and a diisocyanate compound with a reaction raw material,
(B) a monomer having an unsaturated double bond, or a resin having an unsaturated double bond and a carboxyl group,
(C) an epoxy resin, and
(D) a photopolymerization initiator,
It is characterized by containing.

  In the resin composition of the present invention, the acid anhydride (a1) includes one or both of trimellitic anhydride and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. It is preferable. The diisocyanate compound preferably has an aliphatic skeleton. Furthermore, it is preferable that the reaction raw material further includes an acid anhydride (a2) having at least three carboxyl groups, two of which are anhydrous, more preferably the acid anhydride (a2). ) Includes either one or both of trimellitic anhydride and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Furthermore, the mass average molecular weight Mw of the (A) polyamideimide resin is preferably 10,000 or less. Furthermore, the (C) epoxy resin preferably contains an epoxy resin that is liquid at room temperature. Furthermore, the (D) photopolymerization initiator preferably contains a photopolymerization initiator that also functions as a photobase generator.

  Moreover, the dry film of this invention has a resin layer which consists of the said photosensitive thermosetting resin composition of this invention, It is characterized by the above-mentioned.

  Furthermore, the printed wiring board of the present invention is characterized by comprising a cured product formed using the photosensitive thermosetting resin composition of the present invention or the dry film of the present invention.

  According to the present invention, it is possible to develop a photosensitive thermosetting resin composition, a dry film, and a printed wiring board that can be developed with a weak alkaline aqueous sodium carbonate solution and that have excellent cured film properties. It became.

Hereinafter, embodiments of the present invention will be described in detail.
The photosensitive thermosetting resin composition of the present invention comprises (A) a diamine containing an ether bond and a diamine containing a carboxyl group, and at least three carboxyl groups, two of which are anhydrous. A polyamide-imide resin obtained by reacting an imidized product obtained by reacting an acid anhydride containing an acid anhydride (a1) with a reaction raw material containing a diisocyanate compound, and (B) having an unsaturated double bond It contains a monomer or a resin having an unsaturated double bond and a carboxyl group, (C) an epoxy resin, and (D) a photopolymerization initiator.

As described above, conventional compositions containing general-purpose imide resins and amide-imide resins have had the problem that they cannot be developed with a weak alkaline aqueous sodium carbonate solution, but in the photosensitive thermosetting resin composition of the present invention, Uses a specific (A) polyamideimide resin containing an ether bond and a carboxyl group, and (B) a monomer having an unsaturated double bond or an acrylic resin having an unsaturated double bond and a carboxyl group. Thus, the following effects can be obtained. That is, with respect to the exposed portion in patterning, a network can be formed by radical polymerization of component (B) to impart development resistance, and for the unexposed portion in patterning, the imide ring and aroma of component (A) The planar structure in which the rings are regularly arranged is relaxed by an ether bond, and the solubility in a weak alkaline aqueous solution is increased by improving the hydrophilicity by including a carboxyl group, and in addition, among the components (B), In the case of a monomer having an unsaturated double bond, developability can be assisted by decreasing the softening point, and in the case of an acrylic resin having an unsaturated double bond and a carboxyl group, increasing the carboxyl group concentration. . As a result, (A) development with a sodium carbonate aqueous solution is possible even if it contains a polyamideimide resin, and excellent cured film properties such as heat resistance due to an imide structure and toughness due to an amide bond can be exhibited. It became possible to obtain a photosensitive thermosetting resin composition.
Hereinafter, each component which comprises the photosensitive thermosetting resin composition of this invention is explained in full detail.

[(A) Polyamideimide resin]
The (A) polyamideimide resin used in the present invention comprises a diamine having an ether bond and a diamine containing a carboxyl group, and an acid anhydride having at least three carboxyl groups and two of which are anhydrous. This is obtained by reacting the acid anhydride (a1) containing to obtain an imidized product, and then reacting the reaction raw material containing the obtained imidized product and a diisocyanate compound. As described later, in addition to the imidized product and the diisocyanate compound, the reaction raw material further includes an acid anhydride (a2) having at least three carboxyl groups, two of which are anhydrous, It is preferable to contain.

(Diamine)
Examples of the diamine having an ether bond include polyoxyethylene diamine, polyoxypropylene diamine, and other polyoxyalkylene diamines containing oxyalkylene groups having different numbers of carbon chains.
The molecular weight of the diamine having an ether bond is preferably 200 to 3000, and more preferably 400 to 2000.
Examples of polyoxyalkylenediamines include polyoxyethylene diamines such as Jeffamine ED-600, ED-900, ED-2003, EDR-148, and HK-511 manufactured by Huntsman, Inc., and Jeffamine D-230 and D-400. And polyoxypropylene diamines such as D-2000 and D-4000, and those having polytetramethylene ethylene groups such as Jeffamine XTJ-542, XTJ533, and XTJ536.

  Examples of the carboxyl group-containing diamine include 3,5-diaminobenzoic acid, 2,5-diaminobenzoic acid, diaminobenzoic acids such as 3,4-diaminobenzoic acid, and 3,5-bis (3-aminophenoxy) benzoic acid. Acid, aminophenoxybenzoic acids such as 3,5-bis (4-aminophenoxy) benzoic acid, 3,3′-methylenebis (6-aminobenzoic acid), 3,3′-diamino-4,4′-dicarboxyl Carboxybiphenyl compounds such as biphenyl, 3,3′-diamino-4,4′-dicarboxydiphenylmethane, carboxydiphenylalkanes such as 3,3′-dicarboxy-4,4′-diaminodiphenylmethane, 3,3 ′ -Carboxydiphenyl ether compounds such as -diamino-4,4'-dicarboxydiphenyl ether Come, and these may be used alone or in appropriate combination.

  In the present invention, it is necessary to use a diamine having an ether bond and a carboxyl group-containing diamine as the diamine, but other diamines may be used in combination. As other diamines that can be used in combination, general-purpose aliphatic diamines and aromatic diamines can be used alone or in appropriate combination. Specifically, as other diamines, for example, p-phenylenediamine (PPD), 1,3-diaminobenzene, 2,4-toluenediamine, one benzene nucleus diamine, 4,4′-diaminodiphenyl ether, 3 , 3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, and other diaminodiphenyl ethers, 4,4'-diaminodiphenylmethane, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl- 4,4′-diaminobiphenyl, 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] Benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 3,3′-bi (3-aminophenoxy) biphenyl, 3,3′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 4,4′-bis (4-aminophenoxy) biphenyl, Aromatic diamines such as bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, 1,2 -Aliphatic diamines such as diaminoethane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7-diaminoheptane, 1,8-diaminooctane Is mentioned.

  Examples of the amino-modified silicone include BY16-205, FZ-3760, BY16-871, BY16-853U manufactured by Toray Dow Corning. From the viewpoint of improving the balance between the alkali solubility of the polyamideimide resin and the mechanical properties of the resulting cured product, the amine equivalent of the polyoxyalkylene diamine is preferably 100 g / eq or more and 1500 g / eq or less, More preferably, it is 200 g / eq or more and 1000 g / eq or less.

(Acid anhydride (a1) and acid anhydride (a2))
The acid anhydride (a1) and the acid anhydride (a2) each include an acid anhydride having at least three carboxyl groups, two of which are anhydrous. Examples of the acid anhydride include those having at least one of an aromatic ring and an aliphatic ring, and trimellitic anhydride (trimellitic anhydride) (benzene-) having an aromatic ring. Hydrogenated trimellitic anhydride (cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride) having an aliphatic ring such as 1,2,4-tricarboxylic acid 1,2-anhydride, TMA) For example, H-TMA). These acid anhydrides may be used individually by 1 type, and may be used in combination of 2 or more type.

  In this invention, although it is necessary to use the said acid anhydride, you may use together carboxylic dianhydride. Examples of the carboxylic dianhydride include tetracarboxylic anhydrides such as pyromellitic dianhydride and 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride. Moreover, both terminal type carboxylic anhydride modified silicone etc. are mentioned.

(Diisocyanate compound)
As the diisocyanate compound, diisocyanates such as aromatic diisocyanates and isomers and multimers thereof, aliphatic diisocyanates, alicyclic diisocyanates and isomers thereof, and other general-purpose diisocyanates can be used. Is not to be done. These diisocyanate compounds may be used alone or in combination.

  Examples of the diisocyanate compound include aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate (MDI), tolylene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, biphenyl diisocyanate, diphenyl sulfone diisocyanate, diphenyl ether diisocyanate, and isomers and multimers thereof. , Aliphatic diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate, trimethylhexamethylene diisocyanate (TMDI), or alicyclic diisocyanates and isomers hydrogenated with the above aromatic diisocyanates, or others General-purpose diisocyanates can be mentioned.

  As described above, in addition to the imidized product and the diisocyanate compound, the reaction raw material for obtaining the polyamideimide resin further contains the same acid anhydride (a2) as used when obtaining the imidized product. May be. In this case, the content of the acid anhydride (a2) in the reaction raw material is not particularly limited. From the viewpoint of improving the balance between the alkali solubility of the polyamideimide resin and the mechanical properties of the resulting cured product, the acid in the reaction raw material relative to the amount of diamine used to obtain the imidized product in the reaction raw material. The molar ratio of the amount of anhydride (a2) is preferably 0.25 or more and 4 or less, more preferably 0.5 or more and 2 or less, and particularly preferably 0.6 or more and 1.5 or less. preferable.

  The content of the diisocyanate compound in the reaction raw material is not particularly limited. From the viewpoint of improving the balance between the alkali solubility of the polyamideimide resin and the mechanical properties of the resulting cured product, the amount of the diisocyanate compound in the reaction raw material was used to obtain an imidized product in the reaction raw material. The molar ratio with respect to the sum of the amount of diamine and the amount of acid anhydride (a2) contained in the reaction raw material as required is preferably 0.3 or more and 1.0 or less, and 0.4 or more and 0.95 or less. More preferably, it is more preferably 0.50 or more and 0.90 or less.

  In the present invention, in particular, (A) polyamideimide resin obtained by using diamine having an ether bond and H-TMA which is an alicyclic trimellitic acid has increased alkali solubility and developability. Is preferable, because it is improved. For the same reason, it is also preferable to use an aliphatic diisocyanate compound in the second-stage reaction. As described above, polyimide resin and polyamide-imide resin have excellent heat resistance and mechanical properties due to the regular arrangement of imide rings and aromatic rings, and have a low solubility in solvents and alkaline aqueous solutions. However, by effectively incorporating a fatty chain or alicyclic structure into the structure as in the present invention, it has become possible to increase the alkali solubility without greatly degrading the characteristics.

  In the present invention, the (A) polyamideimide resin preferably has an aliphatic structure and an ether bond. Examples of the aliphatic structure in this case include linear hexane or cyclic cyclohexane. Moreover, it is preferable that the said ether bond is a polyether structure whose molecular weight is 200 or more. Most of the imide resins have strong alkali / solvent developability, but by introducing an aliphatic structure or an ether bond, particularly a polyether structure, the (A) polyamideimide resin can be developed with a weak alkaline aqueous solution, It can have deep resolution and flexibility. The aliphatic structure can be introduced, for example, by using an acid anhydride having an aliphatic ring or an isocyanate having an aliphatic structure, and the ether bond is, for example, a diamine having an ether bond. It can be introduced.

  In addition, the amide bond of the (A) polyamideimide resin may be obtained by reacting isocyanate and carboxylic acid, or may be caused by other reaction. The (A) polyamideimide resin may further have a bond composed of other addition and condensation.

  In the present invention, as the compounding ratio of the respective components when obtaining the (A) polyamideimide resin, the acid anhydride is preferably 2.0 to 2.4 mol, based on 1 mol of the diamine. Preferably it is 2.0-2.2 mol. Although the reaction temperature at the time of making diamine and an acid anhydride react and imidating by dehydration ring closure is not specifically limited, It is preferable to exist in the range of 140 degreeC-200 degreeC. The reaction temperature between the imidized product obtained by reacting the diamine with the acid anhydride and the diisocyanate compound is not particularly limited, but is preferably in the range of 130 ° C to 200 ° C.

  In order to correspond to the alkali development step, the (A) polyamideimide resin preferably has an acid value of 50 mgKOH / g or more, more preferably 50 to 200 mgKOH / g, and 70 to 130 mgKOH / g. More preferably it is. When the acid value is 50 mgKOH / g or more, the solubility in alkali is increased, the developability is improved, and further, the degree of crosslinking with the thermosetting component after light irradiation is increased, so that sufficient development contrast is obtained. be able to. On the other hand, when the acid value is 200 mgKOH / g or less, drawing of an accurate pattern becomes easy.

  In addition, the molecular weight of the (A) polyamideimide resin is preferably 10,000 or less, more preferably 1,000 to 8,000, more preferably 2 or less, considering developability and cured coating film characteristics. More preferably, 6,000 to 6,000. When the molecular weight is 10,000 or less, the alkali solubility in the unexposed area is increased and the developability is improved. On the other hand, when the molecular weight is 1,000 or more, sufficient development resistance and cured product properties can be obtained in the exposed area.

[(B) Monomer having unsaturated double bond, or resin having unsaturated double bond and carboxyl group]
Among the components (B), the monomer having an unsaturated double bond is usually liquid, and an effect of facilitating development can be obtained by lowering the softening point of the resin composition. Moreover, the effect which improves developability can be acquired by using the resin which has an unsaturated double bond and a carboxyl group, and the density | concentration of a carboxyl group goes up.

  Among the components (B), as the monomer having an unsaturated double bond, conventionally known polyester (meth) acrylate, polyether (meth) acrylate, urethane (meth) acrylate, carbonate (meth) acrylate, epoxy (meth) An acrylate etc. are mentioned. Specifically, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate; diacrylates of glycols such as ethylene glycol, polyethylene glycol, and propylene glycol; hexanediol, trimethylolpropane, pentaerythritol, and diacrylate Polyhydric alcohols such as pentaerythritol, tris-hydroxyethyl isocyanurate or their polyvalent acrylates such as ethylene oxide adduct, propylene oxide adduct, or ε-caprolactone adduct; phenoxy acrylate, bisphenol A diacrylate, and Polyvalent acrylates such as ethylene oxide adducts or propylene oxide adducts of these phenols; And polyvalent acrylates of glycidyl ethers such as serine diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, and triglycidyl isocyanurate; and at least one of each methacrylate corresponding to the acrylate .

Examples of the resin having an unsaturated double bond and a carboxyl group include the compounds listed below (any of oligomers and polymers).
(1) Dialcohol compounds, polycarbonate-based polyols containing diisocyanates such as aliphatic diisocyanates, branched aliphatic diisocyanates, alicyclic diisocyanates, aromatic diisocyanates, and carboxyl groups such as dimethylolpropionic acid and dimethylolbutanoic acid, Containing a carboxyl group by polyaddition reaction of a diol compound such as a polyether polyol, polyester polyol, polyolefin polyol, acrylic polyol, bisphenol A alkylene oxide adduct diol, a compound having a phenolic hydroxyl group and an alcoholic hydroxyl group Photosensitive urethane resin.
(2) Diisocyanate and bifunctional epoxy resin such as bisphenol A type epoxy resin, hydrogenated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bixylenol type epoxy resin, biphenol type epoxy resin ( A carboxyl group-containing photosensitive urethane resin obtained by a polyaddition reaction of (meth) acrylate or a partially acid anhydride modified product thereof with a carboxyl group-containing dialcohol compound.
(3) A carboxyl group-containing photosensitive resin obtained by reacting a bifunctional or higher polyfunctional (solid) epoxy resin with (meth) acrylic acid and adding a dibasic acid anhydride to a hydroxyl group present in the side chain.
(4) A carboxyl obtained by reacting a polyfunctional epoxy resin obtained by epoxidizing the hydroxyl group of a bifunctional (solid) epoxy resin with epichlorohydrin with (meth) acrylic acid and adding a dibasic acid anhydride to the resulting hydroxyl group Group-containing photosensitive resin.
(5) A reaction product obtained by reacting a compound having a plurality of phenolic hydroxyl groups in one molecule with an alkylene oxide such as ethylene oxide or propylene oxide or a cyclic carbonate compound is reacted with an unsaturated group-containing monocarboxylic acid. A carboxyl group-containing photosensitive resin obtained by further reacting the resulting reaction product with a polybasic acid anhydride.
(6) A compound having an epoxy group and an unsaturated double bond in a copolymer of an unsaturated carboxylic acid such as (meth) acrylic acid and one or more other compounds having an unsaturated double bond, A carboxyl group-containing photosensitive resin obtained by adding an ethylenically unsaturated group as a pendant with (meth) acrylic acid chloride or the like.
(7) A carboxyl group-containing photosensitive resin obtained by adding a compound having one epoxy group and one or more (meth) acryloyl groups in one molecule to the above-described resins (1) to (6).

  These (B) components may be used individually by 1 type, and may be used in combination of 2 or more type.

  The blending amount of the component (B) in the photosensitive thermosetting resin composition of the present invention is preferably 5 to 150 parts by mass, more preferably 10 to 100 parts by mass of the (A) polyamideimide resin. 80 parts by mass. (B) By making the compounding quantity of the component into the said range, the improvement of the development resistance in an exposure part and the ensuring of the developability in an unexposed part can be made to make compatible favorable.

[(C) Epoxy resin]
Specific examples of the (C) epoxy resin used in the present invention include bisphenol A type epoxy resin, bisphenol F type epoxy resin, hydrogenated bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, and bisphenol S type epoxy resin. Phenol novolac type epoxy resin, cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, naphthalene type epoxy resin, dicyclopentadiene type epoxy resin, triphenylmethane type epoxy resin and the like are used. These (C) epoxy resins may be used individually by 1 type, and may be used in combination of 2 or more type.

  Moreover, in this invention, it is preferable to use what is liquid at normal temperature (20 degreeC) as (C) epoxy resin. Since the softening point of the composition affects the developability, the effect of assisting the developability can be obtained by using the (C) epoxy resin that is liquid at room temperature. Examples of epoxy resins that are liquid at 20 ° C. include bisphenol A type epoxies such as E828 (manufactured by Mitsubishi Chemical Corporation), YD-128 (manufactured by Toto Kasei Co., Ltd.), 840,850 (manufactured by DIC Corporation) Resin, 806, 807 (Mitsubishi Chemical Corporation), YDF-170 (Toto Kasei Co., Ltd.), 830, 835, N-730A (DIC Corporation) and other bisphenol F type epoxy resins, ZX- Hydrogenated bisphenol A type epoxy such as 1059 (manufactured by Tohto Kasei Co., Ltd.), etc. Resin etc. are mentioned.

  The blending amount of the (C) epoxy resin in the photosensitive thermosetting resin composition of the present invention is such that the ratio of the epoxy equivalent to the total carboxylic acid equivalent of the component (A) and the component (B) is preferably 0.2. The amount is in the range of -3.0, more preferably in the range of 0.5-2.0.

[(D) Photopolymerization initiator]
As the photopolymerization initiator (D) used in the present invention, a known and commonly used photopolymerization initiator (D) can be used. Also suitable are photopolymerization initiators. In this PEB step, a photopolymerization initiator and a photobase generator may be used in combination.

  The photopolymerization initiator that also functions as a photobase generator is a (C) epoxy as a thermoreactive compound by changing the molecular structure upon irradiation with light such as ultraviolet light or visible light, or by cleaving the molecule. It is a compound that produces one or more basic substances that can function as a catalyst for a polymerization reaction of a resin. Examples of basic substances include secondary amines and tertiary amines.

  Examples of the photopolymerization initiator that also functions as a photobase generator include α-aminoacetophenone compounds, oxime ester compounds, acyloxyimino groups, N-formylated aromatic amino groups, and N-acylated aromatics. And compounds having a substituent such as a group amino group, a nitrobenzyl carbamate group, and an alkoxybenzyl carbamate group. Among these, an oxime ester compound and an α-aminoacetophenone compound are preferable, and an oxime ester compound is more preferable. As the α-aminoacetophenone compound, those having two or more nitrogen atoms are particularly preferable.

  The α-aminoacetophenone-based compound is not particularly limited as long as it has a benzoin ether bond in the molecule, undergoes cleavage in the molecule when irradiated with light, and generates a basic substance (amine) that exhibits a curing catalytic action. Examples of the α-aminoacetophenone compound include Irgacure 907, Irgacure 369, and Irgacure 379 manufactured by BASF Japan.

  As the oxime ester compound, any compound that generates a basic substance by light irradiation can be used. Examples of such oxime ester compounds include CGI-325, Irgacure OXE01, Irgacure OXE02 manufactured by BASF Japan, and N-1919, NCI-831 manufactured by ADEKA Corporation. Moreover, the photoinitiator which has two oxime ester groups in a molecule | numerator can also be used suitably.

  Such a photoinitiator may be used individually by 1 type, and may be used in combination of 2 or more type. The blending amount of the photopolymerization initiator in the resin composition is preferably 0.1 to 40 parts by mass, more preferably 0.3 to 20 parts by mass with respect to 100 parts by mass of the (A) polyamideimide resin. is there. In the case of 0.1 part by mass or more, the development resistance contrast between the light irradiated part and the non-irradiated part can be favorably obtained. Moreover, in 40 mass parts or less, hardened | cured material characteristic improves.

  The following components can be mix | blended with the photosensitive thermosetting resin composition of this invention as needed.

(Polymer resin)
In the resin composition of the present invention, a known and commonly used polymer resin can be blended for the purpose of improving the flexibility and dryness of the touch of the resulting cured product. Examples of such polymer resins include cellulose-based, polyester-based, phenoxy-resin-based polymers, polyvinyl acetal-based, polyvinyl butyral-based, block copolymers, and elastomers. This polymer resin may be used individually by 1 type, and may use 2 or more types together.

(Inorganic filler)
In the resin composition of the present invention, an inorganic filler can be blended in order to suppress curing shrinkage of the cured product and improve properties such as adhesion and hardness. Examples of such inorganic fillers include barium sulfate, amorphous silica, fused silica, spherical silica, talc, clay, magnesium carbonate, calcium carbonate, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, boron nitride, Neuburg Sicilius Earth etc. are mentioned.

(Coloring agent)
The resin composition of the present invention can be blended with known and commonly used colorants. As the colorant, conventionally known colorants such as red, blue, green, yellow, white, and black can be used, and any of pigments, dyes, and pigments may be used.

(Organic solvent)
In the resin composition of the present invention, an organic solvent can be used for preparing the resin composition or adjusting the viscosity for application to a substrate or a carrier film. Examples of such organic solvents include ketones, aromatic hydrocarbons, glycol ethers, glycol ether acetates, esters, alcohols, aliphatic hydrocarbons, petroleum solvents, and the like. Such an organic solvent may be used individually by 1 type, and may be used as a 2 or more types of mixture.

(Other optional ingredients)
If necessary, the resin composition of the present invention may further contain components such as a mercapto compound, an adhesion promoter, an antioxidant, and an ultraviolet absorber. As these, those commonly used in the field of electronic materials can be used. In addition, known and commonly used thickeners such as finely divided silica, hydrotalcite, organic bentonite, montmorillonite, defoamers and / or leveling agents such as silicones, fluorines and polymers, silane coupling agents, rust inhibitors Known and conventional additives such as can be blended.

  The photosensitive thermosetting resin composition of the present invention can be widely used in the field of printed wiring boards because it can be developed with an aqueous sodium carbonate solution while containing a polyamideimide resin excellent in toughness and heat resistance. For example, it can be used as a solder resist for printed wiring boards such as for packages, for vehicles, for motherboards, and for flexible use.

(Dry film)
The dry film of the present invention can be produced as follows. That is, first, on the carrier film (support), the resin composition of the present invention is diluted with an organic solvent to adjust to an appropriate viscosity, and sequentially applied by a known method such as a comma coater according to a conventional method. . Then, normally, the dry film which has the resin layer formed on the carrier film can be obtained by drying for 1 to 30 minutes at the temperature of 50-130 degreeC. On this dry film, a peelable cover film can be further laminated for the purpose of preventing dust from adhering to the surface of the film. As the carrier film and the cover film, conventionally known plastic films can be used as appropriate. When the cover film is peeled off, the adhesive force between the resin layer and the carrier film may be smaller. preferable. Although there is no restriction | limiting in particular about the thickness of a carrier film and a cover film, Generally, it selects suitably in the range of 10-150 micrometers.

(Printed wiring board and manufacturing method thereof)
The printed wiring board of the present invention is characterized in that it comprises a cured product formed using the photosensitive thermosetting resin composition of the present invention or the dry film of the present invention. The printed wiring board of the present invention obtained by using the photosensitive thermosetting resin composition of the present invention containing a polyamide-imide resin has the advantage that it is tough and has high heat resistance and excellent flexibility. It is what you have.

  The printed wiring board of the present invention is manufactured by a step of forming a resin layer made of the photosensitive thermosetting resin composition of the present invention on a printed wiring board on which a conductor circuit is formed (resin layer forming step). It is a manufacturing method including a step (exposure step) of irradiating active energy rays in a pattern, and a step (development step) in which the resin layer is alkali-developed to form a patterned resin layer at once. If necessary, after the alkali development, further photocuring and heat curing (post-cure process) can be performed to completely cure the resin layer, thereby obtaining a highly reliable printed wiring board.

  Moreover, manufacture of the printed wiring board of this invention can also be performed in accordance with the following procedures. That is, a step of forming a resin layer made of the photosensitive thermosetting resin composition of the present invention on a printed wiring board on which a conductor circuit is formed (resin layer forming step), and irradiating the resin layer with active energy rays in a pattern Manufacturing step (exposure step), a step of heating the resin layer (heating (PEB) step), and a step of developing the resin layer by alkali development to form a patterned resin insulating layer (development step) Is the method. After the alkali development, further photocuring or heat curing (post-cure process) is performed to completely cure the resin layer, thereby obtaining a highly reliable printed wiring board. In particular, it is preferable to use this procedure in the present invention.

  Hereinafter, each step will be described in detail.

[Resin layer forming step]
In this step, at least one resin layer made of the photosensitive thermosetting resin composition of the present invention is formed on the printed wiring board.
Examples of the method for forming the resin layer include a coating method and a laminating method. In the case of the coating method, the resin composition of the present invention is coated on a printed wiring board by a method such as screen printing and dried to form a resin layer. In the case of the laminating method, first, the resin composition of the present invention is diluted with an organic solvent to adjust to an appropriate viscosity, applied onto a carrier film and dried to prepare a dry film having a resin layer. Next, the resin layer is bonded with a laminator or the like so as to come into contact with the printed wiring board to form a resin layer. The carrier film is peeled after the laminating step or after the light irradiation step or heating (PEB) step described later.

  Moreover, another layer can be interposed between the resin layer and the printed wiring board. The other layer is preferably made of an alkali development type photosensitive resin composition. As an alkali development type photosensitive resin composition, a well-known composition can be used, For example, the well-known composition for soldering resists can be used. Thus, by setting it as the laminated structure including another layer, the hardened | cured material which was further excellent in impact resistance and flexibility can be obtained.

[Exposure process]
This step activates the photopolymerization initiator contained in the resin layer by light irradiation in a negative pattern to cure the light irradiation portion. In this step, the photosensitive resin component contained in the resin composition is polymerized by radicals generated in the light irradiation portion, and becomes insoluble in the developer. In the case of a composition containing a photobase generator or a photopolymerization initiator that also functions as a photobase generator, a base is generated in the light irradiation part in this step.

As the light irradiator, a direct writer, a light irradiator equipped with a metal halide lamp, or the like can be used. The patterned light irradiation mask is a negative mask.
As the active energy ray used for light irradiation, it is preferable to use laser light or scattered light having a maximum wavelength in the range of 350 to 450 nm. By setting the maximum wavelength within this range, the photopolymerization initiator can be activated efficiently. If a laser beam in this range is used, either a gas laser or a solid laser may be used. Moreover, although the light irradiation amount changes with film thicknesses etc., it can generally be set as 100-1500 mJ / cm < ² >.

[Heating (PEB) process]
In this step, in the composition containing a photobase generator and a photopolymerization initiator that also functions as a photobase generator, the heat-reactive compound reacts with the base generated in the light irradiation portion in the light irradiation step, and the irradiation portion The alkali development resistance is improved. The heating temperature is, for example, 80 to 140 ° C. The heating time is, for example, 1 to 100 minutes.
Since the reaction of the resin composition in this step is, for example, a ring-opening reaction of an epoxy resin by a thermal reaction, distortion and curing shrinkage can be suppressed as compared with the case where curing proceeds by a photoradical reaction. Moreover, when the carboxyl group of the resin composition reacts and decreases, the alkali development resistance of the light irradiation portion is greatly improved.

[Development process]
In the development step, the unirradiated portion is removed by alkali development to form a negative pattern insulating film, particularly a solder resist pattern.
The developing method can be a known method such as dipping. As the developer, an aqueous alkali solution such as sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide, amines, tetramethylammonium hydroxide aqueous solution (TMAH) or a mixed solution thereof can be used. Here, in this invention, there exists a merit that it can develop with a weak alkaline developing solution of 0.3-3 mass% by using the specific polyamide imide resin as mentioned above, for example.

[Post cure process]
In this step, after the development step, the resin layer is completely thermoset to obtain a highly reliable coating film. The heating temperature is, for example, 140 ° C to 180 ° C. Further, light irradiation may be performed before or after the post cure.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not restrict | limited by these Examples and a comparative example.

<Synthesis Example 1: Synthesis Example of Polyamideimide Resin Solution Having Polyether Structure and Cyclo Ring>
3.8 g of 3,5-diaminobenzoic acid, 2,2′-bis [4- (4-aminophenoxy) in a separable three-necked flask equipped with a stirrer, nitrogen inlet tube, fractional ring, and cooling ring 6.98 g of phenyl] propane, 8.21 g of Jeffamine XTJ-542 (manufactured by Huntsman, molecular weight 10225.64) and 86.49 g of γ-butyrolactone were charged at room temperature and dissolved.

  Next, 17.84 g of cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride and 2.88 g of trimellitic anhydride were charged and held at room temperature for 30 minutes. Next, 30 g of toluene was added, the temperature was raised to 160 ° C., the mixture was stirred for 3 hours while distilling off toluene and water, and then cooled to room temperature to obtain an imidized product solution.

  To the obtained imidized product solution, 9.61 g of trimellitic anhydride and 17.45 g of trimethylhexamethylene diisocyanate were charged and stirred at a temperature of 160 ° C. for 32 hours. Thus, a polyamideimide resin solution (PAI-1) having a carboxyl group was obtained. The solid content of the obtained resin solution (PAI-1) was 40.1% by mass, and the acid value of the solid content was 88.1 mgKOH.

<Synthesis Example 2: Synthesis Example of Polyamideimide Resin Solution Not Having Polyether Structure and Cyclocycle>
A separable three-necked flask equipped with a stirrer, a nitrogen introducing tube, a fractional ring, and a cooling ring was charged with 26.69 g of 2,2′-bis (trifluoromethyl) benzidine and 166.05 g of γ-butyrolactone at room temperature. Dissolved.

  Next, 32.02 g of trimellitic anhydride was charged and held at room temperature for 30 minutes. Further, 30 g of toluene was added, the temperature was raised to 160 ° C., water generated by the reaction was removed together with toluene, and then kept for 3 hours, and cooled to room temperature to obtain an imidized solution.

  To the obtained imidized product solution, 16.01 g of trimellitic anhydride and 25.03 g of 4,4′-diphenylmethane diisocyanate were charged and stirred at a temperature of 160 ° C. for 12 hours. Thus, a polyamideimide resin solution (PAI-2) having a carboxyl group was obtained. The obtained resin solution (PAI-2) had a solid content of 36.8% and a solid content acid value of 84.6 mgKOH / g.

<Synthesis example 3: Synthesis example of polyimide resin solution having imide ring, phenolic hydroxyl group and carboxyl group>
To a separable three-necked flask equipped with a stirrer, a nitrogen introduction tube, a fractionation ring, and a cooling ring, 22.4 g of 3,3′-diamino-4,4′-dihydroxydiphenylsulfone, 2,2′-bis [4 -(4-aminophenoxy) phenyl] propane 8.2 g, NMP 30 g, γ-butyrolactone 30 g, 4,4′-oxydiphthalic anhydride 27.9 g, trimellitic anhydride 3.8 g, The mixture was stirred at room temperature and 100 rpm for 4 hours under a nitrogen atmosphere. Next, 20 g of toluene was added and stirred for 4 hours while distilling off toluene and water at a silicon bath temperature of 180 ° C. and 150 rpm to obtain an alkali-soluble resin solution (PI-1) having an imide ring.
The obtained resin solution (PI-1) had a solid content acid value of 18 mgKOH, Mw of 10,000, and a hydroxyl group equivalent of 390.

(Examples 1-6, Comparative Examples 1-3)
In accordance with the composition described in the following table, the materials described in Examples and Comparative Examples were respectively blended, premixed with a stirrer, and then kneaded with a three-roll mill to prepare a photosensitive thermosetting resin composition. In addition, unless otherwise indicated, the value of the compounding amount in a table | surface shows the mass part of solid content.

<Surface condition of exposed area and dissolution time of unexposed area>
A printed wiring board on which a circuit having a copper thickness of 18 μm was formed was prepared, and pretreatment was performed using CZ-8100 manufactured by MEC. Then, each photosensitive thermosetting resin composition was apply | coated to the printed wiring board which performed the pretreatment so that the film thickness after drying might be set to 25 micrometers. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the film which consists of a photosensitive thermosetting resin composition.

A negative pattern was exposed at 500 mJ / cm ² using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp) on the substrate provided with the coating obtained above. Then, after 30 minutes PEB step at 90 ° C. for Examples 1 to 6 and Comparative Examples 1, 2 and 4, with 1 wt% _Na 2 CO ₃ aqueous solution 30 ° C., spray pressure 2 kg / cm ² Development was performed for 5 minutes under the conditions described above, and the surface condition of the exposed area after development was observed to evaluate the development resistance. Moreover, the dissolution time of the unexposed part was measured. The dissolution time is acceptable if it is 120 seconds or less corresponding to the development time of a general printed wiring board manufacturing process.

<Flexibility test (presence of cracks)>
A printed wiring substrate having a polyimide thickness of 25 μm and a copper thickness of 18 μm was prepared, and pretreatment was performed using CZ-8100 manufactured by MEC. On this printed wiring board, each photosensitive thermosetting resin composition was applied so that the film thickness after drying was 25 μm. Then, it dried at 90 degreeC / 30 minutes with the hot-air circulation type drying furnace, and formed the film which consists of a photosensitive thermosetting resin composition.

The entire surface of the base material provided with the film obtained above was exposed at 500 mJ / cm ² using an exposure apparatus equipped with a high-pressure mercury lamp (short arc lamp). Then, after performing 30 minutes PEB step at 90 ° C. for Examples 1 to 6 and Comparative Examples 1, 2 and 4, with 1 wt% _Na 2 CO ₃ aqueous solution 30 ° C., spray pressure 2 kg / cm ² Development was performed for 5 minutes under the conditions described above. Thereafter, curing was performed at 150 ° C. for 60 minutes in a hot-air circulation type drying furnace to prepare a substrate provided with a cured film of the photosensitive thermosetting resin composition.

The obtained substrate was cut into about 50 mm × about 200 mm, and the flexibility was evaluated using a cylindrical mandrel tester (BYK Gardner, No. 5710). The surface on which the resin composition was applied was placed on the outside, bent around a core rod having a diameter of 2 mm, and the presence or absence of cracks was evaluated.
The evaluation results are also shown in the following table.

＊１）ＰＡＩ−１：合成例１のポリアミドイミド樹脂
＊２）ＰＡＩ−２：合成例２のポリアミドイミド樹脂
＊３）ＰＩ−１：合成例３のポリイミド樹脂
＊４）ＰＣＲ−１１７０Ｈ：カルボキシル基含有変性フェノールノボラック型エポキシ樹脂（日本化薬（株）製），酸価６４ｍｇＫＯＨ／ｇ，ＣＯＯＨ当量８９０
＊５）ＢＰＥ−９００：エトキシ化ビスフェノールＡジメタクリレート（新中村化学（株）製）
＊６）Ｅ８２８：ビスフェノールＡ型エポキシ樹脂，エポキシ当量１９０，質量平均分子量３８０（２０℃で液状のエポキシ樹脂）（三菱化学（株）製）
＊７）ＩＲＧＡＣＵＲＥ ３７９：アルキルフェノン系光重合開始剤（ＢＡＳＦ社製）
＊８）ＩＲＧＡＣＵＲＥ ＯＸＥ０２：オキシム系光重合開始剤（ＢＡＳＦ社製）

* 1) PAI-1: Polyamideimide resin of Synthesis Example 1 * 2) PAI-2: Polyamideimide resin of Synthesis Example 2 * 3) PI-1: Polyimide resin of Synthesis Example 3 * 4) PCR-1170H: Carboxyl group Containing modified phenol novolac type epoxy resin (manufactured by Nippon Kayaku Co., Ltd.), acid value 64 mgKOH / g, COOH equivalent 890
* 5) BPE-900: Ethoxylated bisphenol A dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
* 6) E828: bisphenol A type epoxy resin, epoxy equivalent 190, mass average molecular weight 380 (epoxy resin which is liquid at 20 ° C) (manufactured by Mitsubishi Chemical Corporation)
* 7) IRGACURE 379: Alkylphenone photopolymerization initiator (BASF)
* 8) IRGACURE OXE02: Oxime-based photopolymerization initiator (BASF)

  As is clear from the evaluation results shown in the above table, the (A) polyamideimide resin PAI-1 used in the resin composition of each example is excellent in solubility and has a polyether structure and a cyclo ring in the structure. It can be seen that the development property can be maintained high. By using the (A) polyamideimide resin PAI-1 and the components (B) to (D) in combination, the resin composition of each example has good developability and high flexibility. It has been.

  On the other hand, the polyamideimide resin PAI-2 that does not satisfy the requirements of the present invention does not have a polyether structure and a cyclo ring. From Comparative Examples 1 and 2, the polyamideimide resin PAI-2 and the imide resin PI-1 are It turns out that sodium carbonate development cannot be performed by itself. On the other hand, when the polyamide-imide resin PAI-2 and the imide resin PI-1 are used in combination with the (A) polyamide-imide resin PAI-1, from Examples 5 and 6, the solubility in an aqueous sodium carbonate solution is secured. Yes. Further, in Comparative Example 3, cracks occurred because no imide-based resin was contained.

Claims (10)

(A) a diamine containing an ether bond and a diamine containing a carboxyl group, and an acid anhydride (a1) containing an acid anhydride having at least three carboxyl groups and two of which are anhydrous. A polyamide-imide resin obtained by reacting a reaction raw material containing an imidized product obtained by reacting with a diisocyanate compound,
(B) a monomer having an unsaturated double bond, or a resin having an unsaturated double bond and a carboxyl group,
(C) an epoxy resin, and
(D) a photopolymerization initiator,
A photosensitive thermosetting resin composition comprising:   The photosensitive thermosetting according to claim 1, wherein the acid anhydride (a1) contains one or both of trimellitic anhydride and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Resin composition.   The photosensitive thermosetting resin composition according to claim 1, wherein the diisocyanate compound has an aliphatic skeleton.   The photosensitive heat | fever as described in any one of Claims 1-3 in which the said reaction raw material further contains the acid anhydride (a2) which has at least 3 carboxyl groups, and 2 of them are anhydrous. Curable resin composition.   The photosensitive thermosetting according to claim 4, wherein the acid anhydride (a2) includes one or both of trimellitic anhydride and cyclohexane-1,2,4-tricarboxylic acid-1,2-anhydride. Resin composition.   The photosensitive thermosetting resin composition according to claim 1, wherein the (A) polyamideimide resin has a mass average molecular weight Mw of 10,000 or less.   The photosensitive thermosetting resin composition according to claim 1, wherein the (C) epoxy resin contains an epoxy resin that is liquid at normal temperature.   The photosensitive thermosetting resin composition according to claim 1, wherein the photopolymerization initiator (D) includes a photopolymerization initiator that also functions as a photobase generator.   It has a resin layer which consists of a photosensitive thermosetting resin composition as described in any one of Claims 1-8, The dry film characterized by the above-mentioned.   A printed wiring board comprising the photosensitive thermosetting resin composition according to claim 1 or a cured product formed using the dry film according to claim 9.