Thermosetting maleimide resin composition for stress relaxation layer in glass core substrates and printed circuit board containing the same

Abstract

To provide a thermosetting maleimide resin composition for stress relaxation layers for glass core substrates, which not only acts to relieve stress due to its low modulus of elasticity but also exhibits high adhesion to glass over long periods and in various environments, and a printed circuit board containing the same. [Solution] (A) Maleimide compounds having one or more hydrocarbon groups derived from one or more selected from dimer amine skeletons and trimer triamine skeletons in one molecule: 30-99% by mass of the total composition. (B) Epoxy resin having two or more epoxy groups in one molecule: 0.05 to 25 parts by mass per 100 parts by mass of component (A), (C) Anionic polymerization initiator: 0.1 to 5 parts by mass per 100 parts by mass of the total of components (A) and (B) A thermosetting maleimide resin composition for stress relaxation layers for glass core substrates containing [the specified ingredient].

Description

Technical Field

[0001] The present invention relates to a thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate and a printed wiring board including the same.

Background Art

[0002] In recent years, development using a glass substrate as a core has been active. In a glass substrate, the glass cloth that is the core of the current organic substrate has been replaced with a glass panel, and the redistribution layers (RDLs) above and below the core layer are formed in the same manner as in an organic substrate. There are roughly five advantages of using a glass substrate. The first is that the glass panel made of silicon oxide has a thermal expansion coefficient close to that of silicon, which is the base material of a silicon die or a silicon interposer, and the strain due to heat generation or the like can be reduced by half compared to an organic substrate, so that the area of the substrate can be made larger. The second is that the flatness of the glass panel is extremely high, which makes it easier to advance the miniaturization of wiring therefor. The third is that electrodes penetrating the core can be formed at a higher density than in an organic substrate. The fourth is that since the loss is less than that of an organic substrate, a semiconductor can be operated at a higher frequency. The fifth is that operation at a high temperature, which is difficult with an organic substrate, is possible, leading to further progress in power supply.

[0003] On the other hand, there are also many demerits in using a glass core substrate. For example, if materials that have been used for organic substrates so far, particularly build-up materials centered on epoxy resin compositions (Patent Documents 1 and 2), are used as they are, warpage due to stress becomes large, and there is a risk that the glass will crack. Further, the adhesion of the build-up material to glass, particularly the long-term adhesion, is insufficient.

[0004] [[ID=二十一]] In particular, regarding the improvement of stress and adhesion, these problems may be solved by using a stress-relieving layer that exhibits excellent adhesion to glass. Candidate materials for this stress-relieving layer include compositions using a maleimide compound having a dimer amine skeleton (special maleimide compound) and a radical polymerization initiator (Patent Documents 3 and 4), and compositions to which a thermoplastic resin is added (Patent Documents 5 and 6). These materials are preferable because they have advantages such as low elastic modulus and high initial adhesion, but it has been found that they also have challenges, such as a significant decrease in adhesion to glass after moisture absorption. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2010-90238 [Patent Document 2] Japanese Patent Publication No. 2011-132507 [Patent Document 3] International Publication No. 2016 / 114287 [Patent Document 4] Japanese Patent Publication No. 2018-12248 [Patent Document 5] International Publication No. 2018 / 16489 [Patent Document 6] Japanese Patent Publication No. 2022-58409 [Overview of the project] [Problems that the invention aims to solve]

[0006] Therefore, the present invention aims to provide a thermosetting maleimide resin composition for stress relaxation layers for glass core substrates, which not only acts to relax stress due to having a low modulus of elasticity but also exhibits high adhesion to glass over long periods and in various environments, as well as a printed circuit board containing the same. [Means for solving the problem]

[0007] As a result of diligent research to solve the above problems, the inventors of the present invention have found that the following thermosetting maleimide resin composition can achieve the above objectives, and have completed the present invention.

[0008] [1] (A) Maleimide compounds having one or more hydrocarbon groups derived from one or more selected from dimer amine skeletons and trimer triamine skeletons in one molecule: 30-99% by mass of the total composition. (B) Epoxy resin having two or more epoxy groups in one molecule: 0.05 to 25 parts by mass per 100 parts by mass of component (A), (C) Anionic polymerization initiator: 0.1 to 5 parts by mass per 100 parts by mass of the total of components (A) and (B) A thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate, comprising: A thermosetting maleimide resin composition for stress relaxation layers for glass core substrates, wherein the peel strength of a test specimen prepared under the following conditions satisfies all of the following conditions (1) to (3). [Test specimen preparation conditions] A test specimen is prepared by layering a copper foil with a thickness of 18 μm and a surface roughness Rz of 0.6 μm (measured according to the method conforming to JIS B 0601) on a borosilicate glass substrate with a thickness of 1 mm. The thermosetting maleimide resin composition is coated or laminated to a thickness of 10 μm between the glass substrate and the copper foil, and cured at 180°C for 2 hours to form a stress relaxation layer. (1) The peel strength at 23°C (90° peel, crosshead speed 50 mm / min), measured in accordance with JIS C6481:1996, is 0.8 kN / m or more. (2) The peel strength (90° peel, crosshead speed 50 mm / min) measured in accordance with JIS C6481:1996 after being left at 85°C and 85% RH for 24 hours is 0.5 kN / m or more. (3) The peel strength (90° peel, crosshead speed 50 mm / min) measured in accordance with JIS C6481:1996 after being left at 150°C for 24 hours is 0.8 kN / m or more. [2] The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to [1], wherein the maleimide compound of component (A) is a maleimide compound represented by the following formula (1). [Chemical formula] (In formula (1), A is independently a tetravalent organic group having a cyclic structure, B is independently a divalent hydrocarbon group having 6 to 60 carbon atoms, D is independently a divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from a dimer diamine skeleton and a trimer triamine skeleton. However, one or more of D is a hydrocarbon group derived from one or more selected from a dimer diamine skeleton and a trimer triamine skeleton. m is 1 to 100, and n is 1 to 200. The order of each repeating unit enclosed by m and n is not limited, and the bonding mode may be alternating, block, or random. However, m and n are average repeating numbers.) [3] The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to [1], wherein the maleimide compound of component (A) is a maleimide compound represented by the following formula (2). [Chemical formula] (In formula (2), A is independently a tetravalent organic group having a cyclic structure, D is independently a divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from a dimer diamine skeleton and a trimer triamine skeleton. However, one or more of D is a hydrocarbon group derived from one or more selected from a dimer diamine skeleton and a trimer triamine skeleton. m' is 1 to 100. However, m' is an average repeating number.) [4] The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to [2], wherein A in formula (1) is any of the tetravalent organic groups represented by the following structural formulas. [Chemical formula] (The unbonded bond of the above structural formula is bonded to the carbonyl carbon of the cyclic imide structure in formula (1).) [5] (B) The epoxy resin of the component is an amino-type epoxy resin, and the thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to any one of [1] to [4]. [6] (C) The anion polymerization initiator of the component is an imidazole compound having a triazine ring, and the thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to any one of [1] to [5]. [7] A printed wiring board using the thermosetting maleimide resin composition according to any one of [1] to [6]. [Advantages of the Invention]

[0009] The composition of the present invention has a low elastic modulus, so it not only acts to relieve stress, but also has a high adhesive force to glass in the long term and various environments. Therefore, the thermosetting maleimide resin composition of the present invention is useful as a stress relaxation material for a glass core substrate and further for printed wiring board applications. [Modes for Carrying Out the Invention]

[0010] Hereinafter, the present invention will be described in more detail. [[ID=​​Component (A) of the present invention is a maleimide compound having one or more hydrocarbon groups in one molecule that are selected from one or more dimer-triamine skeletons and trimer-triamine skeletons. Because component (A) has hydrocarbon groups derived from a dimer-triamine skeleton or a trimer-triamine skeleton, the cured product of a composition containing component (A) exhibits a lower modulus of elasticity due to a decrease in crosslinking density, and the adhesion strength is improved by improved wettability to the substrate, in this case glass. Furthermore, hydrocarbon groups derived from one or more dimer-triamine skeletons and trimer-triamine skeletons are also effective in improving dielectric properties (lower dielectric constant, lower dielectric loss tangent).

[0012] Here, dimer amine refers to a liquid dibasic acid whose main component is a 36-carbon dicarboxylic acid, which is produced by dimerization of a 18-carbon unsaturated fatty acid derived from natural products such as vegetable oils, called dimer acid, and in which the carboxylic acid is aminomethylated. Dimer acid does not have a single skeleton but has multiple structures and multiple isomers. Representative dimer acids are classified as linear (a), monocyclic (b), aromatic cyclic (c), and polycyclic (d). In this specification, the dimer acid skeleton refers to a group derived from a dimer amine having a structure in which the carboxyl groups of such a dimer acid are replaced with primary aminomethyl groups. That is, component (A) is preferably a dimer acid skeleton in which, in each of the dimer acids shown in (a) to (d) below, two carboxyl groups are replaced with methylene groups. [ka]

[0013] Furthermore, in the maleimide compound of component (A), a hydrocarbon group derived from the dimer amine skeleton is more preferably one in which the carbon-carbon double bond in the hydrocarbon group derived from the dimer amine skeleton is reduced by the hydrogenation reaction, from the viewpoint of heat resistance and reliability of the cured product.

[0014] Furthermore, in this specification, trimertriamine refers to a trimer acid, which is basically a by-product generated during dimer acid synthesis, in which the carboxylic acid has been aminomethylated. Trimer acid is a tribasic acid mainly composed of a 54-carbon tricarboxylic acid, produced from trimers of 18-carbon unsaturated fatty acids derived from natural materials such as vegetable oils. Similar to dimer acid, trimer acid does not have a single skeleton but has multiple structures and multiple isomers.

[0015] Furthermore, in the maleimide compound of component (A), a hydrocarbon group derived from the trimertriamine skeleton is more preferable if, through a hydrogenation reaction, the carbon-carbon double bond in the hydrocarbon group derived from the trimertriamine skeleton is reduced, from the viewpoint of heat resistance and reliability of the cured product.

[0016] Furthermore, the maleimide compound of component (A) is preferably a maleimide compound represented by the following formula (1). [ka] (In formula (1), A is an independent tetravalent organic group having a cyclic structure, B is an independent divalent hydrocarbon group having 6 to 60 carbon atoms, and D is an independent divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. However, one or more of D are hydrocarbon groups derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. m is 1 to 100, and n is 1 to 200. The order of each repeating unit enclosed by m and n is not limited, and the bonding pattern may be alternating, in blocks, or random. However, m and n are the average number of repeats.)

[0017] Furthermore, in formula (1) above, A independently represents a tetravalent organic group having a cyclic structure, and is preferably one of the tetravalent organic groups represented by the following formula. [ka] (The unbonded bonds in the above structural formula are those that bond to the carbonyl carbon of the cyclic imide structure in formula (1).)

[0018] In formula (1) above, n is 1 to 200, preferably 1 to 60, and more preferably 1 to 50. If n is too large, solubility and fluidity may decrease, and moldability may be poor. Furthermore, in formula (1) above, m is between 1 and 100, preferably between 1 and 60, and more preferably between 1 and 50. If m is too large, solubility and fluidity may decrease, potentially resulting in poor moldability.

[0019] Furthermore, in formula (1), D is independently a divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, preferably 8 to 60, more preferably 10 to 55 carbon atoms, or a hydrocarbon group derived from one or more selected from the dimer amine skeleton and the trimer triamine skeleton. However, one or more of D are hydrocarbon groups derived from one or more selected from the dimer amine skeleton and the trimer triamine skeleton. In addition, as the divalent alicyclic hydrocarbon group, a divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, preferably 8 to 60 carbon atoms, is preferred. Among these, a branched divalent alicyclic hydrocarbon group in which one or more hydrogen atoms in the divalent alicyclic hydrocarbon group are substituted with an alkyl group or alkenyl group having 6 to 60 carbon atoms, preferably 8 to 60, more preferably 10 to 55 carbon atoms is more preferred. The branched divalent alicyclic hydrocarbon group may be either a saturated aliphatic hydrocarbon group or an unsaturated hydrocarbon group, and may have an alicyclic structure in the middle of the molecular chain.

[0020] Furthermore, in formula (1), B is independently a divalent hydrocarbon group having 6 to 60 carbon atoms. In particular, it is independently a divalent aliphatic hydrocarbon group having 6 to 60 carbon atoms or an aromatic hydrocarbon group having 6 to 60 carbon atoms. Preferably, it is a divalent aliphatic hydrocarbon group or an aromatic hydrocarbon group having 6 to 30 carbon atoms. The divalent hydrocarbon group may include cyclic or branched structures, but it shall not include hydrocarbon groups derived from one or more selected from dimer acid skeletons and trimer acid skeletons. In addition, the divalent aromatic hydrocarbon group may have bonds directly on the aromatic ring, or it may have bonds via linear or branched divalent aliphatic hydrocarbon groups from the aromatic ring.

[0021] Furthermore, the maleimide compound of component (A) may be the maleimide compound represented by the following formula (2). [ka] (In formula (2), A is an independent tetravalent organic group having a cyclic structure, and D is an independent divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from the dimer amine skeleton and the trimer triamine skeleton. However, one or more of D are hydrocarbon groups derived from one or more selected from the dimer amine skeleton and the trimer triamine skeleton. m' is 1 to 100, where m' is the average number of repeats.)

[0022] A and D in equation (2) are the same groups as A and D in equation (1).

[0023] (A) The number-average molecular weight of the maleimide compound is not particularly limited, but from the viewpoint of handling the composition, it is preferably 1,500 to 50,000, and more preferably 2,000 to 30,000.

[0024] In this invention, the number-average molecular weight refers to the number-average molecular weight measured by gel permeation chromatography (GPC) with polystyrene as the standard substance, under the following conditions.

[0025] [Measurement conditions] Developing solvent: Tetrahydrofuran (THF) Flow rate: 0.35mL / min Detector: Differential refractive index detector (RI) Column: TSK Guardcolumn SuperH-L TSKgel SuperHZ4000(4.6mmI.D.×15cm×1) TSKgel SuperHZ3000(4.6mmI.D.×15cm×1) TSKgel SuperHZ2000 (4.6mmI.D.×15cm×2) (All manufactured by Tosoh Corporation) Column temperature: 40℃ Sample injection volume: 5 μL (THF solution with a concentration of 0.2% by mass)

[0026] (A) Component (A) may be used alone or in combination of two or more components. The amount of component (A) is 30 to 99% by mass of the total thermosetting maleimide resin composition of the present invention, and preferably 50 to 95% by mass.

[0027] [(B) Epoxy resin having two or more epoxy groups in one molecule] The thermosetting maleimide resin composition of the present invention uses an epoxy resin having two or more epoxy groups in one molecule as component (B). By incorporating this epoxy resin, it is possible to particularly enhance the adhesion of the resin composition of the present invention to glass and improve other mechanical properties.

[0028] (B) Component is preferably an epoxy resin having a glycidyl group, taking into consideration reactivity, storage properties, etc.

[0029] Examples of component (B) include phenol novolac type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, naphthol type epoxy resin, xylylene type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, trisphenolmethane type epoxy resin, alicyclic type epoxy resin, glycidylamine type epoxy resin, dicyclopentadiene type epoxy resin, stilbene type epoxy resin, sulfur atom-containing epoxy resin, phosphorus atom-containing epoxy resin, amino type epoxy resin, etc. (B) When component (B) is used in a liquid state at room temperature (25°C), it is preferable from the viewpoint of compatibility and wettability to the substrate, and among these, glycidylamino type epoxy resin is more preferable.

[0030] The amount of component (B) is 0.05 to 25 parts by mass per 100 parts by mass of component (A), with 0.1 to 20 parts by mass being preferable. Within this range, the curing speed during molding is appropriate and preferable. In addition, the balance of heat resistance, moisture resistance, and low modulus of elasticity of the resulting cured product is improved, and the adhesion to glass is also easily enhanced.

[0031] The epoxy resin of component (B) may be used alone or in combination of two or more types.

[0032] [(C) Anionic polymerization initiator] The anionic polymerization initiator in component (C) is added to initiate and accelerate the curing reaction of the maleimide compound in component (A). Examples of anionic polymerization initiators include basic compounds such as imidazoles and tertiary amines, and organophosphorus compounds, with imidazoles (for example, 2-undecylimidazole (C11Z, Shikoku Chemicals Holdings)) being preferred.

[0033] On the other hand, radical polymerization initiators may be used to promote the reaction of the functional groups in component (A). Generally, radical polymerization initiators are also used to cure thermosetting resins that do not react with anionic polymerization initiators, or to accelerate the curing of maleimide compounds, and radical polymerization initiators may be used in combination, but in the present invention, it is preferable to use only anionic polymerization initiators.

[0034] Furthermore, among the imidazoles, imidazole compounds having a triazine ring are more preferred. The triazine ring is not only effective in improving adhesion, but also provides appropriate curability and storage stability. Examples of imidazole compounds having a triazine ring include 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine (trade name 2MZ-A, manufactured by Shikoku Chemicals Holdings Co., Ltd.), 2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine (trade name C11Z-A, manufactured by Shikoku Chemicals Holdings Co., Ltd.), 2,4-diamino-6-[2'-ethyl-4'methylimidazolyl-(1')]-ethyl-s-triazine (trade name 2E4MZ-A, manufactured by Shikoku Chemicals Holdings Co., Ltd.), and 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct (trade name 2MA-OK, manufactured by Shikoku Chemicals Holdings Co., Ltd.). Examples of tertiary amines include triethylamine, benzyldimethylamine, α-methylbenzyldimethylamine, and 1,8-diazabicyclo[5.4.0]undecene-7.

[0035] The amount of component (C) is 0.1 to 5 parts by mass, preferably 0.5 to 3 parts by mass, per 100 parts by mass of the total of components (A) and (B). If the amount of component (C) per 100 parts by mass of components (A) and (B) is less than 0.1 parts by mass, the curability will be low, which is undesirable, and if it is more than 5 parts by mass, the storage stability of the composition will deteriorate, which is also undesirable. (C) Component may be used alone or in combination of two or more types.

[0036] [Other additives] The thermosetting maleimide resin composition of the present invention may further contain various additives as needed, provided that the effects of the present invention are not impaired. Examples of other additives are given below.

[0037] [Inorganic filler] The present invention may further include the addition of inorganic fillers. Inorganic fillers are added to enhance the strength and rigidity of the cured product of the thermosetting maleimide resin composition of the present invention, or to adjust the coefficient of thermal expansion and the dimensional stability of the cured product. As inorganic fillers, those commonly used in epoxy resin compositions and silicone resin compositions can be used, but silica particles such as molten and crystalline silica, or boron nitride are preferred. Furthermore, for this application, there is a high possibility that low dielectric constant and low dielectric loss tangent will be required in the future, and in such cases, hollow inorganic fillers such as hollow silica or hollow glass are more preferred. On the other hand, inorganic particles such as alumina, talc, magnesium hydroxide, and zinc oxide often have low dielectric loss tangents but high relative permittivity, or both high dielectric loss tangents and relative permittivity, which may be undesirable depending on the substrate design.

[0038] The average particle size and shape of the inorganic filler are not particularly limited, but from the viewpoint of substrate processability, spherical fillers with an average particle size of 0.5 to 5 μm are particularly preferred. The average particle size is the value obtained as the median diameter (D50, median value based on volume) in particle size distribution measurement by laser diffraction.

[0039] Furthermore, to improve the properties of the inorganic filler, it is preferable that the surface is treated with a silane coupling agent having an organic group that can react with maleimide groups or epoxy groups. Examples of such silane coupling agents include epoxy group-containing alkoxysilanes, amino group-containing alkoxysilanes, (meth)acrylic group-containing alkoxysilanes, and alkenyl group-containing alkoxysilanes. As the silane coupling agent, amino group-containing alkoxysilanes are preferably used, specifically, N-phenyl-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and the like.

[0040] The inorganic filler may be used alone or in combination of two or more types. The amount of inorganic filler added is preferably 0 to 400 parts by mass, and more preferably 0 to 300 parts by mass, per 100 parts by mass of the total of components (A) and (B). It is preferable not to add an inorganic filler, as this results in better workability and superior stress relaxation performance of the thermosetting maleimide resin composition of the present invention.

[0041] [Thermosetting resins having reactive groups that can react with maleimide groups or epoxy groups] In the present invention, a thermosetting resin having reactive groups that can react with maleimide groups or epoxy groups may be added to the thermosetting resin layer. This does not limit the types of resins included, but rather includes, for example, melamine resin, silicone resin, cyclic imide resins including maleimide compounds other than component (A), urea resin, thermosetting polyimide resin, modified polyphenylene ether resin, thermosetting acrylic resin, epoxy-silicone hybrid resin, and various other resins other than component (A). Furthermore, phenol curing agents, amine curing agents, acid anhydride curing agents, and active ester curing agents, which are commonly used as curing agents for epoxy resins, are also included in this component. Furthermore, reactive groups that can react with maleimide groups and epoxy groups include maleimide groups, hydroxyl groups (including phenolic groups), acid anhydride groups, alkenyl groups such as allyl and vinyl groups, (meth)acrylic groups, and thiol groups.

[0042] [others] In addition to the above, non-functional silicone oils, reactive diluents, thermoplastic resins, thermoplastic elastomers, organic synthetic rubbers, photosensitizers, light stabilizers, polymerization inhibitors, flame retardants, pigments, dyes, adhesive aids, ion trapping materials, etc., may be incorporated. However, the use of thermoplastic resins and thermoplastic elastomers in particular is undesirable because they have poor compatibility and tend to separate. Furthermore, silane coupling agents such as epoxy group-containing alkoxysilanes, amino group-containing alkoxysilanes, (meth)acrylic group-containing alkoxysilanes, and alkenyl group-containing alkoxysilanes, which are used to surface-treat the inorganic filler described above, may be separately incorporated into the thermosetting maleimide resin composition of the present invention. On the other hand, the addition of perfluorinated compounds is undesirable from the perspective of environmental and human health impacts.

[0043] The thermosetting maleimide resin composition of the present invention can also be dissolved in an organic solvent and used as a varnish and slurry. Varnishing the composition makes it easier to form a film. The organic solvent can be used without restriction as long as it dissolves the thermosetting resin having reactive groups that can react as components (A), (B), and / or other additives. Examples include anisole, tetralin, mesitylene, xylene, toluene, tetrahydrofuran (THF), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and acetonitrile, among which aromatic organic solvents such as anisole, tetralin, mesitylene, xylene, and toluene are preferred. Ketone solvents with low boiling points below 100°C, such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK), are also often used when making varnishes and slurries, but the maleimide compound of component (A) used in the present invention has low solubility in such ketone solvents and may not be preferable. These organic solvents may be used individually or in combination of two or more.

[0044] A method for producing the thermosetting maleimide resin composition of the present invention includes mixing components (A), (B), and (C), as well as other additives as needed, using, for example, a planetary mixer (manufactured by Inoue Seisakusho Co., Ltd.) or a stirrer (manufactured by Thinky Co., Ltd.).

[0045] This thermosetting maleimide resin composition can be used to obtain an uncured resin sheet or film by coating the aforementioned varnish onto a substrate and then volatilizing the organic solvent, or by further curing it to obtain a cured resin sheet or film. The following are examples of methods for manufacturing sheets and films, but are not limited thereto.

[0046] For example, after coating a substrate with a thermosetting resin composition (varnish) dissolved in an organic solvent, the organic solvent is removed by heating at a temperature of 80°C or higher, preferably 100°C or higher, for 0.5 to 20 minutes, and then further heating at a temperature of 130°C or higher, preferably 150°C or higher, for 0.5 to 10 hours to form a resin-cured film with a flat and strong surface. The temperature in the drying step to remove the organic solvent and the subsequent heat curing step may be constant, but it is preferable to gradually increase the temperature. This efficiently removes the organic solvent from the composition and allows the resin curing reaction to proceed efficiently. Examples of varnish coating methods include spin coaters, slit coaters, spray coaters, dip coaters, bar coaters, etc., but there are no particular limitations.

[0047] A general resin substrate can be used as the base material, such as polyolefin resins like polyethylene (PE) resin, polypropylene (PP) resin, and polystyrene (PS) resin, and polyester resins like polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, and polycarbonate (PC) resin. The surface of the base material may be treated with a release agent. The thickness of the coating layer is not particularly limited, but from the viewpoint of use as a stress relaxation layer, the thickness after solvent removal is in the range of 1 to 50 μm, preferably 3 to 20 μm. Furthermore, a cover film may be used on top of the coating layer. Alternatively, the components can be pre-mixed and extruded into a sheet or film using a melt kneader for use as is.

[0048] Here, copper foil can be used as a base material, and resin-coated copper foil can be produced by forming an uncured or semi-cured film on the copper foil in the same manner as described above. Alternatively, as previously mentioned, a thermosetting resin can be dissolved in an organic solvent to make a varnish, which can then be coated onto a release-treated polyethylene terephthalate (PET) film, the solvent can be dried to produce a film, this film can be attached to the copper foil, and the PET film can be peeled off to obtain resin-coated copper foil. In this case, the lamination conditions are not particularly limited, but it is preferable to laminate while heating at a heating temperature of 80 to 130°C, at 0.1 to 1.0 MPa, for 0.5 to 5 minutes.

[0049] The film obtained in this way can be used as a stress-relieving layer for glass core substrates. Printed circuit boards are manufactured by processes such as lamination, thermosetting, and plating on a glass substrate, followed by lamination of a build-up film, which is mainly a thermosetting type resin composition. Known methods can be used for the processes necessary to manufacture printed circuit boards, such as the circuit formation process, desmear process, and plating process.

[0050] Furthermore, there are no restrictions on the fabrication of the stress relaxation layer; instead of laminating films, methods such as applying varnish to a glass substrate and spin-coating, or slit-coating a glass substrate and then solvent-drying, are also possible.

[0051] While there are no restrictions on the type of glass used for the core glass substrate, alkali-free glass, borosilicate glass, and quartz glass are preferably used. Generally, many thermosetting resin compositions have poor adhesion to glass substrates, and even if the initial adhesion is good, the adhesive strength often decreases significantly in long-term tests.

[0052] Given this background, materials that meet the peel strength requirements measured by the method described below are highly reliable and offer high reliability even when used in printed circuit boards. (Test specimen preparation conditions) A test specimen is prepared by layering a copper foil with a surface roughness Rz of 0.6 μm (measured according to the method conforming to JIS B 0601) and a thickness of 18 μm onto a borosilicate glass substrate (alkali-free glass is also acceptable) with a thickness of 1 mm. A resin composition is coated or laminated to a thickness of 10 μm between the glass substrate and the copper foil, and cured at 180°C for 2 hours to create a stress-relaxing layer. (Peel strength measurement and reliability test conditions) (1) The peel strength between copper foil and resin at 23°C (90° peel, crosshead speed 50 mm / min), measured in accordance with JIS C6481:1996, is 0.8 kN / m or more. (2) The peel strength between the copper foil and resin (90° peel, crosshead speed 50 mm / min), measured in accordance with JIS C6481:1996 after being left at 85°C and 85% RH for 24 hours, is 0.5 kN / m or more. (3) The peel strength between the copper foil and resin (90° peel, crosshead speed 50 mm / min), measured in accordance with JIS C6481:1996 after being left at 150°C for 24 hours, is 0.8 kN / m or more.

[0053] The thermosetting maleimide resin composition of the present invention satisfies the above conditions and has high reliability as a printed circuit board. Furthermore, it has a low modulus of elasticity and a high stress relaxation effect. In the future, build-up materials may require dielectric properties such as a low relative permittivity and a low dielectric loss tangent. The thermosetting maleimide resin composition of the present invention, by containing component (A), possesses the above dielectric properties and is therefore useful for printed circuit board applications. [Examples]

[0054] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0055] The components used in the examples and comparative examples are shown below. For products available as varnish, the solvent was removed before use. For silica slurry, the slurry was used as is.

[0056] [(A-1) Maleimide compounds] (A-1-1): Bismaleimide compound represented by the following formula (BMI-2500, manufactured by Designer Molecules Inc., solid at 25°C) [ka] n ≈ 5 (mean), m ≈ 1 (mean) -C 36 H 70 - indicates a structure derived from the dimer acid skeleton. (A-1-2): Bismaleimide compound containing hydrocarbon groups derived from a dimer acid skeleton represented by the following formula (product name: SLK-3000, manufactured by Shin-Etsu Chemical Co., Ltd., solid at 25°C) [ka] m' ≈ 5 (average value) -C 36 H 70 - indicates a structure derived from the dimer acid skeleton. (A-1-3): Bismaleimide compound containing hydrocarbon groups derived from a dimer acid skeleton represented by the following formula (product name: SLK-1500, manufactured by Shin-Etsu Chemical Co., Ltd., becomes syrup-like at 25°C) [ka] m'≒4 -C 36 H 70 - indicates a structure derived from the dimer acid skeleton.

[0057] [(A-2) Maleimide compound for comparative example] (A-2-1): Bismaleimide compound represented by the following formula (Trade name: SLK-6100, manufactured by Shin-Etsu Chemical Co., Ltd.) [ka] n1 ≈ 10 (mean), n2 ≈ 1 (mean) (A-2-2): 4,4'-Diphenylmethanebismaleimide (BMI-1000, manufactured by Yamato Chemical Industries, Ltd.) (A-2-3): Biphenylmethylene-type maleimide resin (MIR-3000, manufactured by Nippon Kayaku Co., Ltd.)

[0058] [(A-3) Other resins for comparative examples (excluding epoxy resins)] (A-3-1): Modified polyphenylene ether resin (SA-9000, manufactured by SABIC) (A-3-2): Styrene-ethylene-butadiene copolymer thermoplastic resin (ToughTec H-1041, manufactured by Asahi Kasei Corporation)

[0059] [(B) Epoxy resin having two or more epoxy groups in one molecule] (B-1): Solid bisphenol A type epoxy resin (jER-1001, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 475, softening point 64℃) (B-2): Trisphenolmethane type epoxy resin (EPPN-501S, manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 166, softening point 54℃) (B-3): Amino-type epoxy resin (jER-630, manufactured by Mitsubishi Chemical Corporation, epoxy equivalent weight 95, liquid)

[0060] [(C-1) Anionic polymerization initiator] (C-1-1): 2-Undecylimidazole (C11Z, manufactured by Shikoku Chemicals Holdings Co., Ltd.) (C-1-2):2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine (C11Z-A, manufactured by Shikoku Chemicals Holdings Co., Ltd.) (C-1-3): Triphenylphosphine (TPP, manufactured by Hokko Chemical Industry Co., Ltd.)

[0061] [(C-2) Other than anionic polymerization initiators for comparative examples] (C-2-1): Dicumyl peroxide (Parcadox BC-FF, manufactured by Kayaku Nurion Co., Ltd.) (C-2-2):4-Dimethylaminopyridine (abbreviated as DMAP, manufactured by Tokyo Chemical Industry Co., Ltd.)

[0062] [(D) Inorganic filler] (D-1): Toluene slurry of spherical silica with an average particle size of 0.5 μm (5SV-CT1, manufactured by Admatex Co., Ltd., solid concentration 75% by mass)

[0063] [(E) Material for comparative example] (E-1): Epoxy resin-containing build-up film (GL-102, manufactured by Ajinomoto Co., Inc.) (Thickness: 10 μm) (E-2): Epoxy resin-containing sheet-type encapsulant (MLQ-7700, manufactured by Shin-Etsu Chemical Co., Ltd.) (Thickness: 40 μm)

[0064] <Preparation of resin varnish> Using the formulations shown in Tables 1-4, each component shown in Tables 1-4 was placed in a 500 mL four-necked flask equipped with a Liebig condenser and a stirring device, and stirred at 80°C for 2 hours to obtain a varnish-like resin composition (resin varnish).

[0065] <Preparation of uncured resin film and its film properties> For those resin varnishes successfully produced using the above procedure, the resin varnish was applied to a 50 μm thick release-treated PET film (TN-010, manufactured by Toyobo STC) as a base material using a roller coater, and dried at 120°C for 5 minutes to obtain uncured resin films with thicknesses of 10 μm and 100 μm. At this time, when the 10 μm thick uncured resin film with the base material was folded at 90°, those that showed no damage were marked with a ○, and those that showed damage such as cracks or chips were marked with a ×, and no further evaluation was performed. For comparative examples, (E-1) a 10 μm thick film and (E-2) a 40 μm thick film were used.

[0066] <Tensile modulus of elasticity, elongation> The 100 μm thick uncured resin film obtained above was used to prepare test specimens measuring 10 mm wide x 100 mm long using a vacuum press (manufactured by Nikko Materials Co., Ltd.), a 100 μm thick stainless steel frame, and PET film (TN-010). The pressing was performed under the molding conditions described in Tables 1-4, and post-curing was carried out at 180°C for 2 hours (under a nitrogen atmosphere) for all specimens. The tensile modulus and elongation to fracture were measured using a Shimadzu Autograph (AGS-500NS) under the conditions of a gripping width of 50 mm and a crosshead speed of 30 mm / min for the test specimen fixture obtained in this way.

[0067] <Peel strength> A glass substrate (Corning Eagle XG) made of borosilicate glass measuring 25 mm in width, 75 mm in length, and 1 mm in thickness, a copper foil with a surface roughness Rz of 0.6 μm (measured according to the method compliant with JIS B 0601) and a thickness of 18 μm, and the aforementioned 10 μm thick uncured resin film were prepared. The thermosetting maleimide resin composition was sandwiched between the glass substrate and the copper foil, and lamination was carried out using a vacuum laminator (Nikko Materials) under the conditions of 80-130°C, 0.5 MPa, and 60 seconds. The resulting test specimens were further cured by heat treatment at 180°C for 2 hours to prepare test specimens. To evaluate adhesion, the 90° peel adhesion strength (kN / m) of each test specimen was measured when peeling the copper foil from the glass substrate, in accordance with JIS C6481:1996 "Test Method for Copper-Clad Laminates for Printed Wiring Boards," under conditions of 90° peel, temperature 23°C, and crosshead speed 50 mm / min. At this time, the location of delamination was observed. Delamination between the copper foil and the resin composition was indicated as A, and delamination between the resin composition and the glass was indicated as B. Furthermore, the adhesive test specimens prepared using the method described above were left at 85°C and 85%RH for 24 hours, and then separately left at 150°C for 24 hours. Similarly, in accordance with JIS C6481:1996 "Test Method for Copper-Clad Laminates for Printed Wiring Boards," the 90° peel adhesion strength (kN / m) when peeling the copper foil of each test specimen from the glass substrate was measured under the conditions of 90° peel, temperature 23°C, and crosshead speed 50 mm / min. Here as well, the location of peeling was observed and recorded in the same manner as above. In this process, samples that could not be laminated even when the temperature was varied between 80 and 130°C were not evaluated.

[0068] <Warpage Measurement> On a 12-inch / 775 μm thick silicon wafer, the resin composition on the uncured resin film described above was molded using a vacuum press (manufactured by Nikko Materials), a 400 μm stainless steel frame, and PET film (TN-010) so that the molded resin thickness would be 400 μm. The molding conditions were the same as those used when molding the test specimens for tensile modulus and elongation measurement using the vacuum press. After post-curing at 180°C for 2 hours, the warpage of the wafer was measured using a shadow moiré type warpage measuring device (manufactured by Akrometrix).

[0069] <Reliability Testing> A glass substrate made of borosilicate glass measuring 100 mm x 100 mm and 0.5 mm thick, a film of a thermosetting resin composition with a thickness of 10 μm for Examples 3, 6 and Comparative Example 1, and a film of (E-1)GL-102 with a thickness of 10 μm for Comparative Example 15 were prepared. Test specimens were prepared by laminating thermosetting resin onto a glass substrate using a vacuum laminator (manufactured by Nikko Materials) according to the combinations shown in Table 5, and then curing it by heat treatment at 180°C for 2 hours. The lamination conditions are shown in Table 5. After leaving these test specimens at 85°C and 85% RH for 72 hours, they were immersed in a solder bath heated to 260°C for 20 seconds each, and then immersed in an acetone bath at 25°C for 20 seconds, repeating each process five times. The test specimens were then inspected. ○ indicated no delamination of the thermosetting resin layer, △ indicated partial delamination, and × indicated complete delamination of the thermosetting resin layer from the glass substrate. The results are shown in Table 5.

[0070] [Table 1]

[0071] [Table 2]

[0072] [Table 3]

[0073] Table 4

[0074] Table 5

Claims

1. (A) Maleimide compounds having one or more hydrocarbon groups selected from one or more dimer-triamine skeletons and trimer-triamine skeletons in one molecule: 30 to 99% by mass of the total composition. (B) Epoxy resin having two or more epoxy groups in one molecule: 0.05 to 25 parts by mass per 100 parts by mass of component (A), (C) Anionic polymerization initiator: 0.1 to 5 parts by mass per 100 parts by mass of the total of components (A) and (B) A thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate, comprising: A thermosetting maleimide resin composition for stress relaxation layers for glass core substrates, wherein the peel strength of a test specimen prepared under the following conditions satisfies all of the following conditions (1) to (3). [Test specimen preparation conditions] A test specimen is prepared by layering a copper foil with a surface roughness Rz of 0.6 μm (measured according to the method conforming to JIS B 0601) and a thickness of 18 μm onto a borosilicate glass substrate with a thickness of 1 mm. The thermosetting maleimide resin composition is coated or laminated to a thickness of 10 μm between the glass substrate and the copper foil, and cured at 180°C for 2 hours to create a stress relaxation layer. (1) The peel strength at 23°C (90° peel, crosshead speed 50 mm / min), measured in accordance with JIS C6481:1996, is 0.8 kN / m or more. (2) The peel strength (90° peel, crosshead speed 50 mm / min) measured in accordance with JIS C6481:1996 after being left at 85°C and 85% RH for 24 hours is 0.5 kN / m or more. (3) The peel strength (90° peel, crosshead speed 50 mm / min) measured in accordance with JIS C6481:1996 after being left at 150°C for 24 hours is 0.8 kN / m or more.

2. The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to claim 1, wherein the maleimide compound of component (A) is a maleimide compound represented by the following formula (1). 【Chemistry 1】 (In formula (1), A is independently a tetravalent organic group having a cyclic structure, B is independently a divalent hydrocarbon group having 6 to 60 carbon atoms, and D is independently a divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. However, one or more of D are hydrocarbon groups derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. m is 1 to 100, and n is 1 to 200. The order of each repeating unit enclosed by m and n is not limited, and the bonding mode may be alternating, in blocks, or random. However, m and n are the average number of repeats.)

3. The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to claim 1, wherein the maleimide compound of component (A) is a maleimide compound represented by the following formula (2). 【Chemistry 2】 (In formula (2), A is an independent tetravalent organic group having a cyclic structure, and D is an independent divalent alicyclic hydrocarbon group having 6 to 200 carbon atoms, or a hydrocarbon group derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. However, one or more of D are hydrocarbon groups derived from one or more selected from the dimeramine skeleton and the trimertriamine skeleton. m' is 1 to 100, where m' is the average number of repeats.)

4. A thermosetting maleimide resin composition for stress relaxation layer for glass core substrates according to claim 2, wherein A in formula (1) is any of the tetravalent organic groups shown in the following structural formula. 【Transformation 3】 (The unbonded bonds in the above structural formula are those that bond to the carbonyl carbon of the cyclic imide structure in formula (1).)

5. The thermosetting maleimide resin composition for a stress relaxation layer for a glass core substrate according to claim 1, wherein the epoxy resin of component (B) is an amino-type epoxy resin.

6. The thermosetting maleimide resin composition for stress relaxation layers for glass core substrates according to claim 1, wherein the anionic polymerization initiator of component (C) is an imidazole compound having a triazine ring.

7. A printed circuit board using the thermosetting maleimide resin composition according to any one of claims 1 to 6.

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