Resin composition and metal-base copper-clad laminate

Abstract

To provide a resin composition that yields a cured product having superior solder crack resistance and having superior adhesion strength to a metal plate or copper foil, and also to provide a metal-base copper-clad laminate comprising a resin layer composed of the resin composition as a stress-relief layer.SOLUTION: A resin composition of the present invention is a resin composition used to form a stress-relief layer of a metal-base copper-clad laminate, which comprises a metal plate, the stress-relief layer, and a copper foil laminated in this sequence. The resin composition comprises (A) an epoxy resin including an epoxy resin (a1) having a polyether structure, (B) a phenoxy resin, and (C) a heat-dissipating filler, wherein the storage modulus at 30°C is 0.01 GPa or more and 2.0 GPa or less, when a dynamic viscoelasticity analyzer is used to perform measurements on a sample of the resin composition heat-treated at 190°C for 70 minutes, under conditions of temperature range 0°C to 100°C, heating rate 5°C / min, frequency 1 Hz, in tension mode; and the flow rate calculated under prescribed conditions is less than 50%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a resin composition and a metal-based copper-clad laminate. [Background technology]

[0002] Various developments have been made in the field of metal-based copper-clad laminates. For example, the techniques described in Patent Documents 1 and 2 are known as such techniques. Patent Document 1 describes a high heat dissipation lead frame substrate in which a metal plate (copper), an insulating material (containing a thermosetting resin and a high heat dissipation filler), and a lead frame material (copper) are laminated in this order.

[0003] Patent Document 2 discloses a resin composition used to form a stress relief layer of a metal-based copper-clad laminate that is constructed by laminating a metal plate, a stress relief layer, and a copper foil in this order, and describes that the resin composition contains an epoxy resin having a polyether structure, a phenoxy resin, and a heat dissipating filler, and further has a storage modulus within a predetermined range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-99574 A [Patent Document 2] International Publication No. 2020 / 137339 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the metal-based copper-clad laminates described in Patent Documents 1 and 2 have room for improvement in terms of solder crack resistance and adhesive strength with a metal plate or copper foil. [Means for solving the problem]

[0006] The present inventors have studied and found that a cured product of a resin composition containing a specific component has properties suitable for use as a stress relief layer disposed between a metal plate and a copper foil. Based on this knowledge, the inventors have further intensively studied and found that by appropriately controlling the storage modulus and a specific flow rate in the cured product of the resin composition, it is possible to improve the solder crack resistance and the adhesive strength with the metal plate or the copper foil in a metal-based copper-clad laminate constituted by laminating a metal plate, a stress relief layer, and a copper foil in this order, and have completed the present invention. That is, the present invention can be shown as follows.

[0007] [1] A resin composition used to form a stress relaxation layer of a metal-based copper-clad laminate comprising a metal plate, a stress relaxation layer, and a copper foil laminated in this order, comprising: (A) an epoxy resin containing an epoxy resin (a1) having a polyether structure; (B) a phenoxy resin; (C) a heat dissipating filler; Including, The resin composition is heated at 190°C for 70 minutes, and the storage modulus at 30°C is measured using a dynamic viscoelasticity measuring device under conditions of a measurement temperature of 0°C to 100°C, a heating rate of 5°C / min, and a frequency of 1 Hz in a tensile mode. The storage modulus is 0.01 GPa or more and 2.0 GPa or less, and the flow rate calculated under the following conditions is less than 50%. (conditions) The resin composition was applied to a copper foil in a thickness of 100 to 110 μm, dried, brought to a B-stage, and then cut into a circle of 113 mm diameter. Five of these were stacked, and a pressure of 1.5 MPa was applied at 170° C. for 5 minutes. The ratio (%) by weight of the resin composition remaining on the copper foil to the weight of the resin composition applied on the copper foil was calculated by the following formula to obtain the flow rate. TIFF2025076593000001.tif13153[2] [1] The resin composition according to the present invention, A resin composition, comprising: a metal-based copper-clad laminate including a metal plate, a stress relief layer made of the resin composition, and a copper foil laminated in that order; wherein the peel strength between the copper foil and the stress relief layer, as measured in accordance with JIS C6481-1996, is 1.0 kN / m or more and 3.0 kN / m or less. [3] The resin composition according to [1] or [2], A resin composition, in which a metal-based copper-clad laminate is constructed by laminating a metal plate which is an aluminum plate, a stress relief layer made of the resin composition, and a copper foil in that order, has a value represented by the following formula of 6500 or less. Formula: (difference between the average linear expansion coefficient of the aluminum plate and the average linear expansion coefficient of the stress relaxation layer (ppm / °C)) x (130°C) x (storage modulus (GPa)) (In the formula, the average linear expansion coefficient of the aluminum plate is 20 ppm / °C.) [4] The resin composition according to any one of [1] to [3], A resin composition, wherein the weight average molecular weight of the epoxy resin (a1) having a polyether structure is 400 to 1,200. [5] The resin composition according to any one of [1] to [4], A resin composition, wherein the heat dissipating filler (C) contains alumina. [6] The resin composition according to [5], The resin composition, wherein the alumina contains at least one of spherical alumina and polyhedral alumina. [7] The resin composition according to any one of [1] to [6], A resin composition comprising 50% by volume to 70% by volume of a heat dissipating filler (C). [8] The resin composition according to any one of [1] to [7], A resin composition comprising 10% by mass to 60% by mass of an epoxy resin (a1) having a polyether structure, relative to 100% by mass in total of an epoxy resin (A) and a phenoxy resin (B). [9] A metal plate that functions as a heat dissipation member; A stress relief layer provided on the metal plate; a thick film copper foil for forming a circuit provided on the stress relaxation layer; A metal-based copper-clad laminate comprising: The stress relaxation layer is composed of a resin layer made of the resin composition according to any one of [1] to [8]. Effect of the Invention

[0008] According to the present invention, it is possible to provide a resin composition which gives a cured product having excellent solder crack resistance and adhesion strength to a metal plate or copper foil, and a metal-based copper-clad laminate having a resin layer made of the resin composition as a stress relief layer. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a schematic example of a metal-based copper-clad laminate according to an embodiment of the present invention. [Diagram 2] 1 is a cross-sectional view illustrating an example of an electronic device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments of the present invention will be described with reference to the drawings. In all drawings, the same components are denoted by the same reference numerals, and the description will be omitted as appropriate. For example, "1 to 10" means "1 or more" to "10 or less" unless otherwise specified.

[0011] The resin composition of the present embodiment contains an epoxy resin (A) including an epoxy resin (a1) having a polyether structure, a phenoxy resin (B), and a heat dissipating filler (C), and is used to form the stress relief layer of a metal-based copper-clad laminate that is constructed by laminating a metal plate, a stress relief layer, and a copper foil in this order. Furthermore, the resin composition of the present embodiment has a storage modulus at 30°C of 0.01 GPa or more and 2.0 GPa or less, measured using a dynamic viscoelasticity measuring device under conditions of a measurement temperature of 0°C to 100°C, a heating rate of 5°C / min, a frequency of 1 Hz, and a tensile mode, for a sample obtained by heat-treating the resin composition at 190°C for 70 minutes; Furthermore, the flow rate calculated under the following conditions is less than 50%. (conditions) The resin composition was applied to a copper foil in a thickness of 100 to 110 μm, dried, brought to a B-stage, and then cut into a circle of 113 mm diameter. Five of these were stacked, and a pressure of 1.5 MPa was applied at 170° C. for 5 minutes. The ratio (%) by weight of the resin composition remaining on the copper foil to the weight of the resin composition applied on the copper foil was calculated by the following formula to obtain the flow rate. TIFF2025076593000002.tif13153

[0012] The resin composition of the present embodiment contains the specified components (A) to (C), and thus the cured product of the resin composition can be suitably used as a stress relief layer to be disposed between a metal plate and copper foil. Furthermore, by appropriately controlling the storage modulus and flow modulus at 30°C of the cured product so that they are both within specified ranges, a metal-based copper-clad laminate constituted by laminating a metal plate, a stress relief layer, and copper foil in this order has excellent solder crack resistance and adhesion strength to the metal plate or copper foil. The resin composition of the present embodiment has excellent solder crack resistance because the storage modulus of the cured product is within a predetermined range, and has excellent adhesion to a metal plate or copper foil while maintaining the thermal conductivity of the heat dissipating filler (C) because the flow rate is less than a predetermined value. That is, the present invention has been made in consideration of the demand for high product reliability for metal-based copper-clad laminates, and the storage modulus and flow rate can be used as indicators of solder crack resistance and adhesion to a metal plate or copper foil.

[0013] In this embodiment, the upper limit of the storage modulus at 30°C is, for example, 2.0 GPa or less, preferably 1.5 GPa or less, more preferably 1.0 GPa or less. This can improve solder crack resistance and adhesion strength. On the other hand, the lower limit of the storage modulus at 30°C is, for example, 0.01 GPa or more, preferably 0.05 GPa or more, more preferably 0.10 GPa or more. An appropriate storage modulus may be selected according to the linear expansion coefficient of the metal plate in the metal-based copper-clad laminate. In this embodiment, the upper limit of the flow rate is, for example, less than 50%, preferably 45% or less, more preferably 40% or less. This can improve solder crack resistance and adhesion strength. On the other hand, the lower limit of the flow rate is not particularly limited, but is 10% or more.

[0014] In this embodiment, the storage modulus and flow rate can be controlled by appropriately selecting, for example, the type and amount of each component contained in the resin composition, the method for preparing the resin composition, and the like.

[0015] According to this embodiment, a structure with excellent connection reliability can be provided in an electronic device including electronic components mounted on a metal-based copper-clad laminate. Hereinafter, each component contained in the resin composition of the present embodiment will be described.

[0016] [Epoxy resin (A)] The epoxy resin (A) of the present embodiment contains an epoxy resin (a1) having a polyether structure, which can reduce the storage modulus of the cured product of the resin composition and can increase the adhesive strength with a metal plate or copper foil.

[0017] The epoxy resin (a1) having a polyether structure preferably contains a compound represented by the following general formula (I): The compound represented by the following general formula (I) has a polyether structure of appropriate length, which can reduce the elastic modulus of the cured product, and has reactive functional groups (e.g., epoxy groups) at both ends, which can increase reactivity and improve adhesion strength with a metal plate or copper foil.

[0018] [ka]

[0019] In the above general formula (I), R 1 and R 2each independently represents a hydrogen atom or a methyl group, and G represents a glycidyl group. m and n each independently represent an integer of 1 or more and satisfy the relationship represented by 2≦(m+n)≦20.

[0020] In addition, by including the epoxy resin (a1) having a polyether structure, the stress relaxation force of the metal-based copper-clad laminate can be improved. For example, when manufacturing an electronic device, even under a rapid heating / cooling environment, the occurrence of defects such as cracks at or near the solder joints that join the electronic components and the metal-based copper-clad laminate can be suppressed. In this way, the heat cycle characteristics of the metal-based copper-clad laminate can be improved.

[0021] The weight average molecular weight of the epoxy resin (a1) having a polyether structure is not particularly limited, but is preferably 400 to 1200, more preferably 450 to 1000, and further preferably 500 to 800. This can improve the stress relaxation force of the metal-based copper-clad laminate. The weight average molecular weight of the epoxy resin (a1) is a value calculated in terms of polystyrene measured by gel permeation chromatography (GPC).

[0022] The resin composition may further contain, as another epoxy resin, a liquid epoxy resin (a2) that is liquid at room temperature (25° C.). The resin composition of the present embodiment contains the liquid epoxy resin (a2), which allows the resin composition to exhibit sheet flexibility when brought to a B-stage, and also allows the heat resistance of the resin layer 102 to be improved.

[0023] As the liquid epoxy resin (a2), an epoxy compound having at least one of an aromatic ring structure and an alicyclic structure (alicyclic carbon ring structure), and having two or more epoxy groups, and being liquid at room temperature of 25°C can be used.

[0024] The liquid epoxy resin (a2) may include, for example, one or more selected from the group consisting of bisphenol type epoxy resins such as bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol S type epoxy resins, bisphenol E type epoxy resins, bisphenol M type epoxy resins, bisphenol P type epoxy resins, and bisphenol Z type epoxy resins; novolac type epoxy resins such as phenol novolac type epoxy resins, cresol novolac type epoxy resins, and tetraphenol group ethane type novolac type epoxy resins; aryl alkylene type epoxy resins such as biphenyl type epoxy resins and phenol aralkyl type epoxy resins having a biphenylene skeleton; epoxy resins such as naphthalene type epoxy resins; alicyclic epoxy resins; and resins obtained by modifying a part of the above resins to a flexible skeleton.

[0025] In this embodiment, the content of the epoxy resin (A) is, for example, 30% by mass to 80% by mass, preferably 40% by mass to 75% by mass, and more preferably 45% by mass to 70% by mass, relative to 100% by mass of the total amount of the epoxy resin (A) and the phenoxy resin (B).

[0026] The resin composition preferably contains an epoxy resin (a1) having a polyether structure and a liquid epoxy resin (a2) as the epoxy resin (A). In this case, the content of the epoxy resin (a1) having a polyether structure / the content of the liquid epoxy resin (a2) in the resin composition is 0.8 to 4.0, preferably 0.9 to 3.5, and more preferably 1.0 to 3.0. By keeping it within such a range, it is possible to achieve a balance between the coatability of the resin composition and the low elastic modulus as a film.

[0027] In this embodiment, the solid content of the resin composition refers to the non-volatile content in the resin composition, and refers to the remainder excluding volatile components such as water, solvent, etc. When a solvent is included, the content relative to the total solid content of the resin composition refers to the content relative to the total solid content (100 mass%) of the resin composition excluding the solvent.

[0028] [Phenoxy resin (B)] The resin composition contains a phenoxy resin (B). By containing the phenoxy resin (B), the bending resistance of the cured product can be improved, and therefore the deterioration of the handleability caused by the high loading of the heat dissipating filler (C) can be suppressed.

[0029] Examples of the phenoxy resin (B) include phenoxy resins having a bisphenol skeleton, phenoxy resins having a naphthalene skeleton, phenoxy resins having an anthracene skeleton, phenoxy resins having a biphenyl skeleton, etc. Phenoxy resins having a structure having a plurality of these skeletons can also be used.

[0030] Among these, it is preferable to use a phenoxy resin of bisphenol A type or bisphenol F type. A phenoxy resin having both a bisphenol A skeleton and a bisphenol F skeleton may also be used.

[0031] The weight average molecular weight of the phenoxy resin (B) is not particularly limited, but is preferably 4.0×10 4 Above 8.0×10 4 The following is preferred: The weight average molecular weight of the phenoxy resin (B) is a value calculated in terms of polystyrene measured by gel permeation chromatography (GPC).

[0032] The content of the phenoxy resin (B) is, for example, 15% by mass to 60% by mass, preferably 18% by mass to 55% by mass, and more preferably 20% by mass to 50% by mass, relative to 100% by mass of the total solid content of the resin composition excluding the heat-dissipating filler (C).

[0033] In the resin composition, the content of the epoxy resin (a1) having a polyether structure / the content of the phenoxy resin (B) is 0.7 to 4.0, preferably 0.8 to 3.0, and more preferably 0.9 to 2.5. By keeping it within such a range, the stress relaxation force of the film made of the resin composition can be made appropriate, and the solder crack resistance, adhesive strength with a metal plate or copper foil, and insulation reliability can be improved.

[0034] In this embodiment, the epoxy resin (a1) having a polyether structure may be preferably contained in an amount of 10% by mass to 60% by mass, more preferably 20% by mass to 50% by mass, and even more preferably 30% by mass to 45% by mass, based on the total of the epoxy resin (A) and the phenoxy resin (B) being 100% by mass. By keeping the amount within such a range, the stress relaxation force of the film made of the resin composition can be made appropriate, and the solder crack resistance, adhesive strength with a metal plate or copper foil, and insulation reliability can be improved.

[0035] [Heat dissipating filler (C)] The resin composition contains a heat dissipating filler (C), which can improve the thermal conductivity of the cured product.

[0036] As the heat-dissipating filler (C), a known filler having excellent heat conductivity, such as alumina, can be used. These may be used alone or in combination of two or more kinds.

[0037] Alumina may have two or more components with different average particle sizes. For example, alumina may be a mixture of three components with different average particle sizes (large, medium, and small), where the large particle size component is spherical and the medium and small particle size components are polyhedral.

[0038] From the viewpoint of the effects of the present invention, the alumina preferably contains at least one type of spherical alumina and polyhedral alumina.

[0039] The alumina may include large particle size alumina having an average particle size in a first particle size range of 5.0 μm or more and 50 μm or less, preferably 5.0 μm or more and 25 μm or less, and a circularity of 0.80 or more and 1.0 or less, preferably 0.85 or more and 0.95 or less.

[0040] The alumina may also include medium-particle-size alumina having an average particle size in a second particle size range of 1.0 μm or more and less than 5.0 μm, and a circularity of 0.50 or more and 0.90 or less, preferably 0.70 or more and 0.80 or less.

[0041] The alumina may also include small particle size alumina having an average particle size in a third particle size range of 0.1 μm or more and less than 1.0 μm, and a circularity of 0.50 or more and 0.90 or less, preferably 0.70 or more and 0.80 or less.

[0042] Here, the particle size can be measured using a laser diffraction particle size distribution analyzer SALD-7000 by dispersing alumina in water through ultrasonic treatment for 1 minute.

[0043] By using alumina with an appropriate particle size, the packing property of the alumina can be improved, and the contact area between the alumina particles can be made larger. As a result, the thermal conductivity of the cured product can be further improved. Furthermore, the solder heat resistance, bending resistance, and insulating properties of the cured product can be further improved. In addition, by using such alumina, the adhesion between the stress resin layer and the metal plate or copper foil can be further improved. These synergistic effects can further increase the insulating reliability of the metal-based copper-clad laminate.

[0044] The content of the heat dissipating filler (C) (or alumina) is, for example, 50% by volume to 70% by volume, preferably 52% by volume to 60% by volume, and more preferably 55% by volume to 60% by volume, based on 100% by volume of the resin composition. By setting the content of the heat dissipating filler to the lower limit or more, the thermal conductivity of the cured product can be increased, and an electronic device with excellent heat dissipation can be realized. On the other hand, by setting the content of the heat dissipating filler (C) to the upper limit or less, a balance with other properties can be achieved. In addition, production stability can be improved.

[0045] [Adhesion Aid (D)] The resin composition may further contain an adhesion aid (D). The adhesion aid (D) can improve the wettability at the interface between the epoxy resin (A) and the heat dissipating filler (C). As the adhesion aid (D), a known adhesion aid can be used within the scope of the effects of the present invention, and examples thereof include monofunctional silane coupling agents and polyfunctional silane coupling agents.

[0046] Examples of polyfunctional silane coupling agents include bis(triethoxysilylpropyl) disulfide, bis(triethoxysilylpropyl) tetrasulfide, 1,4-bis(triethoxysilyl)benzene, bis(triethoxysilyl)ethane, 1,6-bis(trimethoxysilyl)hexane, 1,8-bis(triethoxysilyl)octane, 1,2-bis(trimethoxysilyl)decane, and bis(triethoxysilylpropyl)amine. These may be used alone or in combination of two or more.

[0047] Examples of monofunctional silane coupling agents include trimethoxysilane, tetramethoxysilane, diethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, butyltrimethoxysilane, hexyltrimethoxysilane, octyltrimethoxysilane, decyltrimethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, tolyltrimethoxysilane, chloromethyltrimethoxysilane, γ-chloropropyltrimethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, cyanoethyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxy ... Examples of the silane include propyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-chloropropyltrimethoxysilane, and γ-ureidopropyltriethoxysilane. These can be used alone or in combination of two or more.

[0048] In the present embodiment, the adhesion aid (D) preferably contains a monofunctional silane coupling agent, and more preferably the monofunctional silane coupling agent is at least one selected from a diethoxysilane coupling agent and a trimethoxysilane coupling agent. By including the adhesion aid (D) in the composition of the present embodiment, it is possible to provide a cured product having superior adhesive strength to a metal plate or copper foil.

[0049] The amount of the adhesion aid (D) added depends on the specific surface area of ​​the heat-dissipating filler (C) and is not particularly limited, but is preferably 0.05 parts by mass or more and 3 parts by mass or less, and more preferably 0.1 parts by mass or more and 2 parts by mass or less, per 100 parts by mass of the heat-dissipating filler (C).

[0050] [Curing catalyst (E)] The resin composition may further contain a curing catalyst (E). Examples of the curing catalyst (E) include organic metal salts such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt(II), and trisacetylacetonate cobalt(III); amine-based curing catalysts such as dicyandiamide, diethylenetriamine, triethylenetetramine, metaxylylenediamine, diaminodiphenylmethane, diaminodiethyldiphenylmethane, metaphenylenediamine, diaminodiphenylsulfone, isophoronediamine, norbornenediamine, triethylamine, tributylamine, and diazabicyclo[2,2,2]octane; 2-phenyl-imidazole, 2-phenyl-4-methylimidazo imidazole-based curing catalysts such as 2-ethyl-4-methylimidazole, 2-ethyl-4-ethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4,5-dihydroxyimidazole, and 2-undecylimidazole; organic phosphorus compounds such as triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenylborate, triphenylphosphine triphenylborane, and 1,2-bis-(diphenylphosphino)ethane; phenolic compounds such as phenol, bisphenol A, and nonylphenol; organic acids such as acetic acid, benzoic acid, salicylic acid, and paratoluenesulfonic acid, or mixtures thereof. As a curing agent, one of these, including derivatives, can be used alone, or two or more of these, including derivatives, can be used in combination.

[0051] Among these, amine-based curing catalysts and imidazole-based curing catalysts are preferred because they have excellent adhesion, react at a relatively low temperature, and give cured products with excellent heat resistance, and imidazole-based curing catalysts are more preferred from the viewpoint of reducing the elastic modulus.Of the imidazole-based curing catalysts, 2-undecylimidazole is more preferred from the viewpoint of reducing the elastic modulus.

[0052] The content of the curing catalyst (E) is not particularly limited, but is, for example, 0.05% by mass or more and 3.0% by mass or less with respect to 100% by mass of the total solid content of the resin composition.

[0053] The resin composition of the present embodiment contains components (A) to (E), and in particular contains a combination of an epoxy resin (A) containing an epoxy resin (a1) having a polyether structure, an adhesion aid (D), and a curing catalyst (E), and thus can be suitably used in a stress relief layer disposed between a metal plate and copper foil. In a metal-based copper-clad laminate constituted by laminating a metal plate, a stress relief layer, and copper foil in this order, the resin composition can improve both the solder crack resistance and the adhesion strength with the metal plate or copper foil.

[0054] [Other ingredients] The resin composition may contain other components, such as an antioxidant and a leveling agent, within the scope of not impairing the effects of the present invention.

[0055] <Resin composition> The resin composition of the present embodiment can be obtained by mixing the above components by a known method. The resin composition of the present embodiment further has the following properties.

[0056] In a metal-based copper-clad laminate constructed by laminating a metal plate which is an aluminum plate, a stress relief layer made of the resin composition, and a copper foil in this order, the peel strength between the copper foil and the stress relief layer, measured in accordance with JIS C6481-1996, can be 1.0 kN / m or more and 3.0 kN / m or less, preferably 1.0 kN / m or more and 2.0 kN / m or less, and more preferably 1.0 kN / m or more and 1.5 kN / m or less. In a metal-based copper-clad laminate having a stress relief layer made of the resin composition of this embodiment, the peel strength is within the above range, resulting in excellent adhesion between the copper foil and the stress relief layer, and improving the product reliability of the metal-based copper-clad laminate.

[0057] In a metal-based copper-clad laminate constructed by laminating a metal plate which is an aluminum plate, a stress relief layer made of the resin composition, and a copper foil in that order, the value represented by the following formula can be 6500 or less, preferably 5500 or less, and more preferably 4500 or less. Formula: (difference between the average linear expansion coefficient of the aluminum plate and the average linear expansion coefficient of the stress relaxation layer (ppm / °C)) x (130°C) x (storage modulus (GPa)) (In the formula, the average linear expansion coefficient of the aluminum plate is 20 ppm / °C.) In a metal-based copper-clad laminate having a stress relaxation layer made of the resin composition of this embodiment, the balance between the difference in average linear expansion coefficients and the storage modulus of the metal plate and the stress relaxation layer is important, and when the numerical value obtained by the above formula is within the above range, the adhesion between the metal plate and the stress relaxation layer is excellent, thereby further improving the product reliability of the metal-based copper-clad laminate.

[0058] The average linear expansion coefficient of the stress relaxation layer is measured as follows. From the metal-based copper-clad laminate obtained by the method described below, both metal layers (aluminum plate and copper foil) are removed by etching to obtain an insulating resin layer (stress relaxation layer). Using a thermomechanical analyzer, measurements are performed under the conditions of a measurement temperature of -50°C to 150°C, a heating rate of 10°C / min, and a load of 50mN, and the average linear expansion coefficient (ppm / °C) between -30°C and 100°C is obtained at the second heating.

[0059] The metal-based copper clad laminate can be prepared as follows. The varnish-like resin composition of the present embodiment is applied to the roughened surface of a 35 μm-thick copper foil using a comma coater, and the copper foil is dried by heating at 80° C. for 5 minutes and at 120° C. for 5 minutes to obtain a resin-coated copper foil having a resin thickness of 100 μm. The resin-coated copper foil obtained is laminated with a metal plate such as an aluminum plate having a thickness of 1.5 mm, and pressed in a vacuum press under conditions of a pressure of 1.5 MPa, 190° C., and 70 minutes to obtain a metal-based copper-clad laminate (insulating resin layer thickness: 100 μm) consisting of a metal plate, a stress relaxation layer made of the resin composition, and copper foil laminated in that order.

[0060] <Metal-based copper-clad laminate> Next, the metal-based copper-clad laminate 100 will be described. FIG. 1 is a cross-sectional view showing a schematic example of a metal-based copper-clad laminate 100. As shown in FIG.

[0061] The metal-based copper-clad laminate 100 in Fig. 1 has a metal plate 101, a resin layer (stress relaxation layer) 102, and a metal layer 103. The metal plate 101, the resin layer 102, and the metal layer 103 are laminated in this order to form a laminated structure. The metal plate 101 functions as a heat dissipation member. The resin layer 102 serves as a stress relaxation layer. The metal layer 103 is used to form a circuit.

[0062] The metal plate 101 is a plate-shaped member made of a metal material containing Ag or Cu as a main component. The main component means that the content ratio in the metal material is, for example, 80 mass % or more, more preferably 85 mass % or more. The metal plate 101 may be a plate-shaped substrate made of metal, or a plate-shaped substrate made of an alloy containing other semiconductor elements or metal elements. Examples of other semiconductor elements or metal elements include Si, Fe, Cu, Mn, Mg, Cr, Zn, Ti, etc. These may be used alone or in combination of two or more.

[0063] Among these, the metal plate 101 can be an aluminum plate or an aluminum alloy plate from the viewpoint of light weight and low cost compared to a copper substrate.

[0064] The thickness of the metal plate 101 may be set to a level sufficient to function as a supporting member for a substrate, and is, for example, 0.5 mm to 3.0 mm, and more preferably 1.0 mm to 2.0 mm. The metal plate 101 may be configured as a single layer or a laminate of multiple layers.

[0065] The resin layer 102 is a stress relaxation layer made of the above-mentioned resin composition. Specifically, the resin layer 102 is made of a cured product of the above-mentioned resin composition.

[0066] The thickness of the resin layer 102 can be appropriately selected, but is, for example, 30 μm to 300 μm, preferably 30 μm to 200 μm, and more preferably 50 μm to 120 μm.

[0067] The metal layer 103 is made of copper foil, more preferably thick-film copper foil. The metal layer 103 may be made of a metal material mainly composed of Cu, and may contain other metal elements such as Al, Ni, Fe, Sn, etc. These may be used alone or in combination of two or more kinds.

[0068] The thickness of the metal layer 103 is, for example, 10 μm to 80 μm, and preferably 15 μm to 70 μm. By making the metal layer 103 thicker, the resistance can be reduced, and therefore a metal-based copper-clad laminate 100 that is applicable to large currents can be realized.

[0069] Next, a method for manufacturing the metal-based copper-clad laminate 100 will be described.

[0070] On the prepared metal plate 101, a resin layer in a B-stage state made of a resin composition is formed. The resin layer may be formed by applying the above-mentioned resin composition to the metal layer 103 and drying it, or by laminating a film-like resin layer. Next, a metal plate 101 is formed on the surface of the resin layer. The method for forming the metal plate 101 may be a method in which the resin layer and the metal plate 101 are subjected to a pressure and heat treatment using a press or the like. If the resin layer is in a B-stage state during this pressure and heat treatment, the resin layer may be cured. In this manner, a metal-based copper-clad laminate 100 is obtained.

[0071] Thereafter, if necessary, the metal layer 103 may be etched into a predetermined pattern to form a metal circuit layer 105. In this manner, a metal-based copper-clad laminate 100 having the metal plate 101, the resin layer 102, and the metal circuit layer 105 is obtained.

[0072] The metal-based copper-clad laminate 100 may have a multi-layer structure in which a plurality of unit structures, each of the metal plate 101, the resin layer 102, and the metal circuit layer 105, are laminated. Furthermore, the metal-based copper-clad laminate 100 may have a solder resist layer as the outermost layer. The solder resist layer may have openings for exposing electrode parts that can be connected to electronic components described below.

[0073] Next, the electronic device 1 of the present embodiment will be described. FIG. 2 is a cross-sectional view illustrating an example of the electronic device 1. As shown in FIG.

[0074] The electronic device 1 in Fig. 2 includes a metal-based copper-clad laminate 100, an electronic component 11 provided on the metal-based copper-clad laminate 100, and a connection portion (solder 15) that connects them. The electronic device 1 may include other known members not shown in Fig. 2. For example, the electronic device 1 may include a sealing member that seals the electronic component 11.

[0075] The electronic components 11 are various heat generating elements such as semiconductor elements such as transistors and light emitting diodes (LEDs), resistors, capacitors, etc. These may be used alone or in combination of two or more kinds.

[0076] The electronic device 1 is an electronic device used for mounting on vehicles such as hybrid cars, fuel cell cars, and electric cars, airplanes, rockets, etc., and for mounting in narrow spaces such as inside mobile devices, etc. The electronic device 1 is, for example, a semiconductor device such as a power semiconductor device, an LED lighting device, or an inverter device.

[0077] According to this embodiment, even if the electronic device 1 is placed in an environment with rapid temperature changes for a long period of time or repeatedly, the resin layer 102, which is a stress relief layer, can stably reduce the stress generated due to the difference in thermal expansion coefficient between the metal-based copper-clad laminate 100 and the electronic component 11.

[0078] When the metal plate 101 of the metal-based copper-clad laminate 100 is composed of an aluminum plate or an aluminum alloy plate, aluminum is lightweight but has the property of expanding and contracting significantly depending on the ambient temperature, so that the difference in thermal expansion coefficient between the metal plate 101 and the electronic component 11 in the aluminum-based copper-clad laminate becomes large. The inventors' investigations have revealed that the resin layer 102 is required to have higher stress relaxation properties than when a copper plate is used. In contrast, by using a cured resin composition having a low elastic modulus and therefore excellent stress relaxation properties as the resin layer 102, it is possible to suppress the occurrence of cracks in the solder 15 due to a mismatch in the thermal expansion coefficients.

[0079] Furthermore, the resin layer 102 formed from the cured product of the above-mentioned resin composition can have excellent properties such as adhesive strength with a metal plate or copper foil, thermal conductivity, and insulating properties.

[0080] Therefore, the metal-based copper-clad laminate 100 can be suitably used as a heat dissipation circuit board for mounting electronic components 11 such as LEDs.

[0081] In addition, since the electronic device 1 has a structure in which the electronic components 11 are mounted on the metal-based copper-clad laminate 100, it has excellent solder crack resistance and excellent connection reliability even in harsh environments ranging from low temperature environments to high temperature environments or environments fluctuating between these temperatures.

[0082] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted as long as they do not impair the effects of the present invention. EXAMPLES

[0083] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these. The following components were used in the examples:

[0084] (Epoxy resin (A)) Epoxy resin 1: Polyether type epoxy resin (Rikaresin BEO-60E, manufactured by New Japan Chemical Co., Ltd., liquid at 25°C, epoxy equivalent 365g / eq) Epoxy resin 2: Bisphenol F type epoxy resin (DIC, 830S, liquid epoxy resin, liquid at 25°C, epoxy equivalent: 170g / eq) Epoxy resin 3: Bisphenol F and 1,6-hexanediol glycidyl ether copolymer epoxy resin (Mitsubishi Chemical Corporation, YX7105, liquid at 25°C, epoxy equivalent 480g / eq) Epoxy resin 4: Aliphatic polyether type epoxy resin (DER732, Olin, epoxy equivalent 320g / eq)

[0085] (Phenoxy resin (B)) Phenoxy resin 1: Phenoxy resin having a bisphenol A skeleton (Mitsubishi Chemical Corporation, 1256, weight average molecular weight 5.0 × 10 4 )

[0086] (heat dissipating filler (C)) Heat dissipating filler 1: spherical alumina (average particle size: 22 μm, circularity: 0.91, Nippon Steel & Sumikin Materials Co., Ltd., AX-25) Heat dissipating filler 2: Polyhedral alumina (average particle size: 4 μm, circularity: 0.75, Nippon Light Metal Co., Ltd., LS-210) Heat dissipating filler 3: Polyhedral alumina (average particle size: 0.7 μm, circularity: 0.71, Nippon Light Metal Co., Ltd., LS-250)

[0087] (Adhesion Aid (D)) Silane coupling agent 1: 3-glycidoxypropyltrimethoxysilane (Shin-Etsu Silicone Co., Ltd. KBM-403, minimum coverage area 330 m 2 / g) Silane coupling agent 2: 3-glycidoxypropylmethyldiethoxysilane (Shin-Etsu Silicone Co., Ltd. KBE-402, minimum coverage area 314 m 2 / g)

[0088] (Curing catalyst (E)) Curing catalyst 1: Imidazole (Shikoku Kasei Corporation, C11Z) Curing catalyst 2: Imidazole (Shikoku Kasei, 2PHZ-PW) Curing catalyst 3: Novolac phenolic resin (Sumitomo Bakelite, PR-51470)

[0089] [Examples 1 to 3, Comparative Examples 1 to 3] <Preparation of Resin Composition> According to the compounding ratios shown in Table 1, each component was dissolved and mixed in cyclohexanone and stirred using a high-speed stirrer to obtain a varnish-like resin composition with a solid content of 80 mass %.

[0090] <Creating metal-based copper-clad laminates> A 35 μm-thick copper foil (CF-T8G-UN, manufactured by Fukuda Metal Foil and Powder Co., Ltd.) was used as the metal foil. A varnish-like resin composition was applied to the roughened surface of the copper foil using a comma coater, and the copper foil was dried by heating at 80°C for 5 minutes and at 120°C for 5 minutes to obtain a resin-coated copper foil with a resin thickness of 100 μm. The obtained resin-coated copper foil was bonded to a 1.5 mm thick aluminum plate (#4045) and pressed in a vacuum press under conditions of a pressure of 1.5 MPa, 190°C, and 70 minutes to obtain a metal-based copper-clad laminate (insulating resin layer thickness: 100 μm).

[0091] (Thermal Conductivity) From the metal-based copper-clad laminate obtained by the above method, both metal layers were removed by etching to obtain an insulating resin layer. The thermal conductivity in the thickness direction of the insulating resin layer was then measured. Specifically, the thermal conductivity was calculated using the following formula from the thermal diffusion coefficient (α) measured by the laser flash method (half-time method), the specific heat (Cp) measured by the DSC method, and the density (ρ) measured in accordance with JIS-K-6911. The unit of thermal conductivity is W / m K. Thermal conductivity [W / m K] = α [m2 / s]×Cp[J / kg K]×ρ[g / cm 3 ]

[0092] (Storage modulus) From the metal-based copper-clad laminate obtained by the above method, both metal layers were removed by etching to obtain an insulating resin layer. Using a dynamic viscoelasticity measuring device, measurements were performed under the conditions of measurement temperature: 0°C to 100°C, heating rate: 5°C / min, frequency: 1Hz, and tensile mode to obtain the storage modulus (GPa) at 30°C.

[0093] (Coefficient of mean linear thermal expansion (TMA)) Both metal layers were removed by etching from the metal-based copper-clad laminate obtained by the above method to obtain an insulating resin layer. Using a thermomechanical analyzer, measurements were performed under conditions of a measurement temperature of -50°C to 150°C, a heating rate of 10°C / min, and a load of 50mN, and the average linear expansion coefficient (ppm / °C) was obtained at the second heating time between -30°C and 100°C.

[0094] (Peel strength) In the metal-based copper-clad laminate obtained by the above method, the peel strength (kN / m) between the copper foil and the insulating resin layer at 23° C. was measured. The peel strength measurement was performed in accordance with JIS C6481-1996. The insulating resin layer (cured layer) obtained from the resin composition of the examples or comparative examples was the stress relaxation layer.

[0095] (Physical properties obtained from a specific formula) For the metal-based copper-clad laminate obtained by the above method, the numerical value represented by the following formula was obtained: The insulating resin layer (cured layer) obtained from the resin composition of the Examples or Comparative Examples was the stress relaxation layer. Formula: (difference between average linear expansion coefficient of aluminum plate and average linear expansion coefficient of stress relaxation layer obtained by the above method (ppm / ℃)) × (130℃) × (storage modulus obtained by the above method (GPa)) (In the formula, the average linear expansion coefficient of the aluminum plate is 20 ppm / °C.)

[0096] (Flow rate) The resin composition obtained in the Examples or Comparative Examples was applied to a copper foil in a thickness of 100 to 110 μm, dried, brought to a B-stage, and then cut into a circle of 113 mmφ. Five of these were stacked, and subjected to a pressure of 1.5 MPa at 170° C. for 5 minutes. The weight ratio (%) of the resin composition remaining on the copper foil to the resin composition applied on the copper foil was calculated using the following formula to obtain the flow rate. TIFF2025076593000004.tif13153

[0097] (Adhesion) In the metal-based copper-clad laminate obtained by the above-mentioned method, the copper foil was etched to leave a circular copper foil pattern of 25 mmφ, and the surrounding copper foil was removed to obtain a laminate. This laminate was subjected to a thermal history test and a water vapor exposure test for 100 hours under temperature and humidity conditions of 121°C and 100% RH. After the test, the circular copper foil pattern of the laminate was checked for blistering, and the adhesion was evaluated according to the following criteria. (Judgment criteria) ◯: No blister was observed in the circular copper foil pattern. △: One or two small bulges were observed in the circular copper foil pattern. ×: Three or more small bulges were observed in the circular copper foil pattern, or a large bulge was observed.

[0098] (Heat cycle properties - solder crack resistance of chip components) In the metal-based copper-clad laminate obtained by the above method, the copper foil was etched to form a circuit. A chip resistor element (3.0 mm x 1.5 mm) was soldered onto the circuit board, and a thermal cycle test was performed for 1500 cycles, with one cycle being exposed to air at -40°C for 10 minutes and then at 125°C for 10 minutes. After the test, the cross section of the soldered connection between the circuit board and the chip resistor element was observed with an electron microscope to confirm the solder crack growth rate calculated by the following formula. Formula: solder crack growth rate (%)=(length of solder crack in the longitudinal direction of the chip resistor element (mm) / total length of solder in the longitudinal direction of the chip resistor element (mm))×100 (Judgment criteria) ◯: Cross-sectional observation showed that the solder crack progression rate was within 50%. △: Cross-sectional observation showed that the solder crack growth rate was within 75%. ×: Cross-sectional observation revealed that the solder crack growth rate exceeded 75%.

[0099] [Table 1] [Explanation of symbols]

[0100] 1 Electronic equipment 11 Electronic Components 15 Solder 100 Metal-based copper-clad laminate 101 Metal Substrate 102 Resin layer 103 Metal layer 105 Metal circuit layer

Claims

1. A resin composition used to form a stress relaxation layer of a metal-based copper-clad laminate comprising a metal plate, a stress relaxation layer, and a copper foil laminated in this order, comprising: (A) an epoxy resin containing an epoxy resin (a1) having a polyether structure; (B) a phenoxy resin; (C) a heat dissipating filler; Including, The resin composition is heated at 190°C for 70 minutes, and the storage modulus at 30°C is measured using a dynamic viscoelasticity measuring device under conditions of a measurement temperature of 0°C to 100°C, a heating rate of 5°C / min, and a frequency of 1 Hz in a tensile mode, and is 0.01 GPa or more and 2.0 GPa or less. The flow rate calculated under the following conditions is less than 50%. (conditions) The resin composition was applied to a copper foil in a thickness of 100 to 110 μm, dried, brought to a B-stage, and then cut into a circle having a diameter of 113 mm. Five of these were stacked, and a pressure of 1.5 MPa was applied at 170° C. for 5 minutes. The ratio (%) by weight of the resin composition remaining on the copper foil to the weight of the resin composition applied on the copper foil was calculated by the following formula to obtain the flow rate.

2. The resin composition according to claim 1, A metal-based copper-clad laminate formed by laminating a metal plate, a stress relaxation layer made of the resin composition, and a copper foil in this order, has a peel strength between the copper foil and the stress relaxation layer of 1.0 kN / m or more and 3.0 kN / m or less, as measured in accordance with JIS C6481-1996.

3. The resin composition according to claim 1, A resin composition, in which a metal-based copper-clad laminate is constructed by laminating a metal plate which is an aluminum plate, a stress relaxation layer made of the resin composition, and a copper foil in that order, has a value represented by the following formula of 6,500 or less. Formula: (difference between the average linear expansion coefficient of the aluminum plate and the average linear expansion coefficient of the stress relaxation layer (ppm / °C)) x (130°C) x (storage elastic modulus (GPa)) (In the formula, the average linear expansion coefficient of the aluminum plate is 20 ppm / ° C.)

4. The resin composition according to claim 1, A resin composition, wherein the weight average molecular weight of the epoxy resin (a1) having a polyether structure is 400 to 1,200.

5. The resin composition according to claim 1, A resin composition, wherein the heat dissipating filler (C) contains alumina.

6. The resin composition according to claim 5, The resin composition, wherein the alumina contains at least one of spherical alumina and polyhedral alumina.

7. The resin composition according to claim 1, A resin composition comprising 50 volume % to 70 volume % of a heat dissipating filler (C).

8. The resin composition according to claim 1, A resin composition comprising 10% by mass to 60% by mass of an epoxy resin (a1) having a polyether structure, relative to a total of 100% by mass of an epoxy resin (A) and a phenoxy resin (B).

9. A metal plate that functions as a heat dissipation member; A stress relief layer provided on the metal plate; a thick film copper foil for forming a circuit provided on the stress relaxation layer; A metal-based copper-clad laminate comprising: A metal-based copper-clad laminate, wherein the stress relaxation layer is a resin layer made of the resin composition according to any one of claims 1 to 8.

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