JPWO2015056523A1 - Epoxy resin composition, carrier material with resin layer, metal base circuit board, and electronic device - Google Patents

Abstract

The epoxy resin composition of the present invention comprises a metal substrate (101), an insulating resin layer (102) provided on the metal substrate (101), and a metal layer (103) provided on the insulating resin layer (102). Are used for forming an insulating resin layer (102) constituting a metal base circuit board (100). The said epoxy resin composition contains an epoxy resin and an alumina. The content of alumina is 75% by mass or more and 95% by mass or less with respect to 100% by mass of the total solid content of the epoxy resin composition.

Description

  The present invention relates to an epoxy resin composition, a carrier material with a resin layer, a metal base circuit board, and an electronic device.

2. Description of the Related Art Conventionally, an inverter device or a power semiconductor device configured by mounting an insulated gate bipolar transistor (IGBT) and a semiconductor element such as a diode, a resistor, and an electronic component such as a capacitor on a metal base circuit board is known. ing.
These power control devices are applied to various devices according to their withstand voltage and current capacity. In particular, from the viewpoint of environmental problems in recent years and the promotion of energy saving, the use of these power control devices for various electric machines is increasing year by year.
In particular, regarding an in-vehicle power control device, it is desired to install the power control device in an engine room along with downsizing and space saving. The engine room has a harsh environment such as a high temperature and a large temperature change, and a substrate having a large heat radiation area is required. For such applications, a metal base circuit board that is further excellent in heat dissipation has attracted attention.

  For example, Patent Document 1 discloses a semiconductor device in which a semiconductor element is mounted on a support such as a lead frame, and the support and a heat radiating plate connected to a heat sink are bonded with an insulating resin layer.

JP2011-216619A

  However, such an electronic device has not been sufficiently satisfactory in heat dissipation. For this reason, it may be difficult to transfer the heat of the electronic component to the outside. In this case, the durability of the electronic device is reduced.

According to the present invention,
Epoxy resin used for forming the insulating resin layer constituting a metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer A composition comprising:
Epoxy resin,
Alumina,
Including
An epoxy resin composition is provided in which the alumina content is 75% by mass or more and 95% by mass or less with respect to 100% by mass of the total solid content of the epoxy resin composition.

  According to this invention, since the content of the alumina is 75% by mass or more and 95% by mass or less, the contact area between the alumina particles is increased. As a result, the thermal conductivity of the insulating resin layer can be improved, and the heat dissipation of the electronic device can be improved. Therefore, the heat of the electronic component can be sufficiently transferred to the outside. Thereby, it can be set as a highly durable electronic device.

Moreover, according to the present invention,
A resin layer used for forming the insulating resin layer constituting a metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer. Carrier material with
Carrier material,
Provided on one surface of the carrier material, including an epoxy resin, alumina, and a B-stage resin layer;
With
A carrier material with a resin layer, in which the resin layer is formed of the epoxy resin composition described above, can be provided.

Furthermore, according to the present invention,
A metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer,
The said insulating resin layer can provide the metal base circuit board formed by the epoxy resin composition mentioned above.

Furthermore, according to the present invention,
A metal base circuit board as described above;
An electronic component provided on the metal base circuit board;
An electronic device comprising:

  ADVANTAGE OF THE INVENTION According to this invention, the epoxy resin composition which can implement | achieve a highly durable electronic device, the carrier material with a resin layer, a metal base circuit board, and a highly durable electronic device are provided.

  The above-described object and other objects, features, and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings.

It is sectional drawing of the metal base circuit board concerning one Embodiment of this invention. It is sectional drawing of the electronic device concerning one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same components are denoted by the same reference numerals, and detailed description thereof is appropriately omitted so as not to overlap. Moreover, the figure is a schematic diagram and does not necessarily match the actual dimensional ratio. In addition, unless otherwise specified, “to” represents the following.

First, the metal base circuit board 100 of this embodiment is demonstrated. FIG. 1 is a cross-sectional view of a metal base circuit board 100 according to an embodiment of the present invention.
The metal base circuit board 100 includes a metal substrate 101, an insulating resin layer 102 provided on the metal substrate 101, and a metal layer 103 provided on the insulating resin layer 102.
The insulating resin layer 102 is formed of the following epoxy resin composition. The said epoxy resin composition contains an epoxy resin and an alumina. The content of alumina is 75% by mass or more and 95% by mass or less with respect to 100% by mass of the total solid content of the epoxy resin composition. In the present embodiment, the total solid content of the epoxy resin composition is a solid content that remains when the epoxy resin composition is heat-cured, and for example, components that volatilize by heating such as a solvent are excluded. On the other hand, liquid components such as a liquid epoxy resin and a coupling agent are included in the total solid content because they are taken into the insulating resin layer 102 when heated and cured.

The metal substrate 101 is not particularly limited as long as it is a heat-dissipating metal substrate. For example, the metal substrate 101 is an aluminum substrate, a copper substrate, a stainless steel substrate, or the like, and an aluminum substrate is preferable.
Here, the aluminum substrate refers to a substrate containing aluminum, and includes a substrate formed of an aluminum alloy. Similarly, a copper substrate refers to a substrate containing copper, and includes a substrate formed of a copper alloy.
The thickness of the metal substrate 101 is, for example, not less than 100 μm and not more than 5000 μm. When the thickness of the metal substrate 101 is not less than the above lower limit value, the heat dissipation can be further improved. Further, when the thickness of the metal substrate 101 is equal to or less than the above upper limit value, workability such as bending of the metal base circuit board 100 can be improved.

The insulating resin layer 102 is a layer for bonding the metal layer 103 to the metal substrate 101. The thickness of the insulating resin layer 102 is preferably 40 μm or more and 300 μm or less.
By setting the thickness of the insulating resin layer 102 to be equal to or less than the above upper limit value, heat from the electronic component can be easily transmitted to the metal substrate 101.
Further, by setting the thickness of the insulating resin layer 102 to be equal to or greater than the above lower limit, it is possible to sufficiently reduce the generation of thermal stress due to the difference in thermal expansion coefficient between the metal substrate 101 and the insulating resin layer 102 with the insulating resin layer 102. . Furthermore, the insulation of the metal base circuit board 100 is improved.

  The insulating resin layer 102 includes an epoxy resin (A), alumina (B), and, if necessary, a phenoxy resin (C), a curing agent (D), and a coupling agent (E). Is heat-cured. That is, the insulating resin layer 102 is in a C stage state including a thermosetting resin.

Here, the composition of the epoxy resin composition will be described.
An epoxy resin composition contains an epoxy resin (A), an alumina (B), a phenoxy resin (C), a hardening | curing agent (D), and a coupling agent (E) as needed.

The epoxy resin (A) preferably contains an epoxy resin (A1) having at least one of an aromatic ring structure and an alicyclic structure (alicyclic carbocyclic structure).
By using such an epoxy resin (A1), the glass transition temperature can be increased and the thermal conductivity of the insulating resin layer 102 can be improved.
Examples of the epoxy resin (A1) having an aromatic ring or alicyclic structure include, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol E type epoxy resin, bisphenol M type epoxy resin, Bisphenol type epoxy resins such as bisphenol P type epoxy resin and bisphenol Z type epoxy resin; Novolak type epoxy resins such as phenol novolac type epoxy resin, cresol novolac type epoxy resin, tetraphenol group ethane type novolac type epoxy resin; biphenyl type epoxy resin And arylalkylene type epoxy resins such as a phenol aralkyl type epoxy resin having a biphenylene skeleton; and epoxy resins such as a naphthalene type epoxy resin. One of these can be used alone, or two or more can be used in combination.

  In addition, naphthalene is used as an epoxy resin (A1) from the viewpoint of further increasing the glass transition temperature, suppressing the generation of voids in the insulating resin layer 102, further improving the thermal conductivity, and improving the dielectric breakdown voltage. Type epoxy resin is preferred. Here, the naphthalene type epoxy resin refers to one having a naphthalene ring skeleton and having two or more glycidyl groups. The content of the naphthalene type epoxy resin is preferably 20% by mass to 80% by mass, and more preferably 40% by mass to 60% by mass with respect to 100% by mass of the epoxy resin (A).

  As the naphthalene type epoxy resin, for example, any one of the following formulas (5) to (8) can be used. In the formula (6), m and n represent the number of substituents on the naphthalene ring, and each independently represents an integer of 1 to 7. In Formula (7), Me represents a methyl group, and l, m, and n are integers of 1 or more. However, l, m, and n are preferably 10 or less.

  In addition, as a compound of Formula (6), it is preferable to use any 1 or more types of the following.

  Moreover, as a naphthalene type epoxy resin, the naphthylene ether type epoxy resin represented by the following formula | equation (8) can also be used.

（上記式（８）において、ｎは１以上２０以下の整数であり、ｌは１以上２以下の整数であり、Ｒ_１はそれぞれ独立に水素原子、ベンジル基、アルキル基または下記式（９）で表される構造であり、Ｒ_２はそれぞれ独立に水素原子またはメチル基である。）

(In the above formula (8), n is an integer of 1 or more and 20 or less, l is an integer of 1 or more and 2 or less, and R ₁ is independently a hydrogen atom, a benzyl group, an alkyl group, or the following formula (9) And each R ₂ is independently a hydrogen atom or a methyl group.)

（上記式（９）において、Ａｒはそれぞれ独立にフェニレン基またはナフチレン基であり、Ｒ_２はそれぞれ独立に水素原子またはメチル基であり、ｍは１または２の整数である。）

(In the above formula (9), Ar is each independently a phenylene group or a naphthylene group, R ₂ is each independently a hydrogen atom or a methyl group, and m is an integer of 1 or 2.)

  Examples of the naphthylene ether type epoxy resin represented by the above formula (8) include those represented by the following formula (10).

（上記式（１０）において、ｎは１以上２０以下の整数であり、好ましくは１以上１０以下の整数であり、より好ましくは１以上３以下の整数である。Ｒはそれぞれ独立に水素原子または下記式（１１）で表される構造であり、好ましくは水素原子である。）

(In the above formula (10), n is an integer of 1 or more and 20 or less, preferably an integer of 1 or more and 10 or less, more preferably an integer of 1 or more and 3 or less. R is independently a hydrogen atom or (It is a structure represented by the following formula (11), preferably a hydrogen atom.)

（上記式（１１）において、ｍは１または２の整数である。）

(In the above formula (11), m is an integer of 1 or 2.)

    Examples of the naphthylene ether type epoxy resin represented by the above formula (10) include those represented by the following formulas (12) to (16).

  Although content of the epoxy resin (A) contained in an epoxy resin composition should just be suitably adjusted according to the objective, it is not specifically limited, 1 mass with respect to 100 mass% of total solids of an epoxy resin composition % To 23% by mass is preferable, and 2% to 15% by mass is more preferable. When the content of the epoxy resin (A) is not less than the above lower limit value, the handleability is improved and the insulating resin layer 102 can be easily formed. When the content of the epoxy resin (A) is not more than the above upper limit value, the strength and flame retardancy of the insulating resin layer 102 are further improved, and the thermal conductivity of the insulating resin layer 102 is further improved.

Alumina (B) is a mixed system of three components (large particle size, medium particle size, small particle size) having different average particle sizes, the large particle size component is spherical, and the medium particle size component and small particle size component are A polyhedral shape is preferred.
More specifically, the alumina (B) belongs to the first particle size range in which the average particle diameter is 5.0 μm or more and 50 μm or less, preferably 5.0 μm or more and 25 μm or less, and the circularity is 0.80 or more and 1 0.02 or less, preferably 0.85 or more and 0.95 or less of the large particle size alumina, the average particle size belongs to the second particle size range of 1.0 μm or more and less than 5.0 μm, and the circularity is 0.00. A medium particle size alumina that is 50 or more and 0.90 or less, preferably 0.70 or more and 0.80 or less, a third particle size range in which the average particle size is 0.1 μm or more and less than 1.0 μm, and the circularity Is preferably a mixture with small particle size alumina having a particle size of 0.50 to 0.90, preferably 0.70 to 0.80.
Here, the particle diameter can be measured by dispersing alumina in water by ultrasonic treatment for 1 minute using a laser diffraction particle size distribution analyzer SALD-7000.

As a result, the medium particle size component is filled in the gap between the large particle size components, and the small particle size component is filled in the gap between the medium particle size components, so that the alumina filling property is improved and the contact area between the alumina particles is increased. Can be made larger. As a result, the thermal conductivity of the insulating resin layer 102 can be further improved. Furthermore, the solder heat resistance, flex resistance, and insulation of the insulating resin layer 102 can be further improved.
Further, by using such alumina (B), the adhesion between the insulating resin layer 102 and the metal substrate 101 can be further improved.
Due to these synergistic effects, the insulation reliability of the metal base circuit board 100 can be further enhanced.

  The content of alumina (B) contained in the epoxy resin composition is 75% by mass or more and 95% by mass or less, and more preferably 80% by mass or more with respect to 100% by mass of the total solid content of the epoxy resin composition. 90% by mass or less. By making the content of alumina (B) as high as 75% by mass or more and 95% by mass or less, the contact area between the alumina particles is increased. As a result, the thermal conductivity of the insulating resin layer 102 can be improved, and the heat dissipation of the electronic device 1 can be improved. Therefore, the heat of the electronic component 11 can be sufficiently transferred to the outside. Thereby, it can be set as the electronic device 1 with high durability.

  The content of alumina belonging to the first particle size range is preferably 65% by mass or more and 85% by mass or less with respect to the total 100% by mass of alumina (B), and the content of alumina belonging to the second particle size range The amount is preferably 10% by mass or more and 20% by mass or less, and the content of alumina belonging to the third particle size range is preferably 5% by mass or more and 18% by mass or less.

The epoxy resin composition preferably further contains a phenoxy resin (C). By including the phenoxy resin (C), the bending resistance of the insulating resin layer 102 can be improved. Therefore, it is possible to suppress a decrease in handling properties of the insulating resin layer 102 due to a high filling of alumina (B).
Further, by including the phenoxy resin (C), the elastic modulus of the insulating resin layer 102 can be reduced, and in this case, the stress relaxation force of the metal base circuit board 100 can be improved. For example, when the electronic device 1 is manufactured, defects such as cracks may occur at or near the solder joint where the electronic component 11 and the metal base circuit board 100 are joined, even under rapid heating / cooling environments. Will be suppressed. Thus, the heat cycle characteristic of the metal base circuit board 100 can be improved.
Further, when the phenoxy resin (C) is contained, the fluidity at the time of pressing is reduced due to an increase in viscosity, and generation of voids or the like in the obtained insulating resin layer 102 can be suppressed, or the obtained insulating resin layer 102 The thickness can be adjusted more easily, and the uniformity of the thickness of the insulating resin layer 102 can be improved. In addition, the adhesion between the insulating resin layer 102 and the metal substrate 101 can be improved. Due to these synergistic effects, the insulation reliability of the metal base circuit board 100 can be further enhanced.

  Examples of the phenoxy resin (C) include a phenoxy resin having a bisphenol skeleton, a phenoxy resin having a naphthalene skeleton, a phenoxy resin having an anthracene skeleton, and a phenoxy resin having a biphenyl skeleton. A phenoxy resin having a structure having a plurality of these skeletons can also be used.

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

The weight average molecular weight of the phenoxy resin (C) is not particularly limited, but is preferably 4.0 × 10 ⁴ or more and 8.0 × 10 ⁴ or less.
In addition, the weight average molecular weight of phenoxy resin (C) is a value in terms of polystyrene measured by gel permeation chromatography (GPC).

  The content of the phenoxy resin (C) is, for example, preferably 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more and 10% by mass or less with respect to 100% by mass of the total solid content of the epoxy resin composition. .

Examples of the curing agent (D) (curing catalyst) include organic metals such as zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III). Salt: Dicyandiamide, diethylenetriamine, triethylenetetramine, metaxylylenediamine, diaminodiphenylmethane, diaminodiethyldiphenylmethane, metaphenylenediamine, diaminodiphenylsulfone, isophoronediamine, norbornenediamine, triethylamine, tributylamine, diazabicyclo [2,2,2] Amine-based curing agents such as octane; 2-phenyl-imidazole, 2-phenyl-4-methylimidazole, 2-ethyl-4-methylimidazole, 2-ethyl-4 Imidazole-based curing agents such as ethylimidazole, 2-phenyl-4-methyl-5-hydroxyimidazole, 2-phenyl-4,5-dihydroxyimidazole; triphenylphosphine, tri-p-tolylphosphine, tetraphenylphosphonium tetraphenyl Organophosphorus compounds such as borate, triphenylphosphine / triphenylborane, 1,2-bis- (diphenylphosphino) ethane; phenolic compounds such as phenol, bisphenol A, nonylphenol; acetic acid, benzoic acid, salicylic acid, paratoluenesulfonic acid Organic acids, etc., or a mixture thereof. As a hardening | curing agent (D), 1 type including these derivatives can also be used independently, and 2 or more types including these derivatives can also be used together.
Among these, an amine-based curing agent and an imidazole-based curing agent are preferable in that a cured product having excellent adhesiveness, reacting at a relatively low temperature, and excellent heat resistance can be obtained.

  The content of the curing catalyst 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 epoxy resin composition.

  Furthermore, the epoxy resin composition may include a coupling agent (E). The coupling agent (E) can improve the wettability of the interface between the epoxy resin (A) and the alumina (B).

As the coupling agent (E), any of those usually used can be used. Specifically, an epoxy silane coupling agent, a cationic silane coupling agent, an aminosilane coupling agent, a titanate coupling agent, and a silicone oil type. It is preferable to use one or more coupling agents selected from coupling agents.
The addition amount of the coupling agent (E) depends on the specific surface area of the alumina (B) and is not particularly limited, but is preferably 0.05 parts by mass or more and 3 parts by mass or less with respect to 100 parts by mass of the alumina (B). Particularly preferred is 0.1 to 2 parts by mass.

  The epoxy resin composition can contain an antioxidant, a leveling agent and the like as long as the effects of the present invention are not impaired.

Next, the physical properties of the epoxy resin composition will be described.
The epoxy resin composition of the present embodiment preferably has the following viscosity behavior. When the epoxy resin composition is heated from 60 ° C. to a molten state at a rate of temperature increase of 3 ° C./min and a frequency of 1 Hz using a dynamic viscoelasticity measuring device, the melt viscosity initially decreases and the minimum melt viscosity And the minimum melt viscosity is in the range of 1 × 10 ³ Pa · s to 1 × 10 ⁵ Pa · s.
When the minimum melt viscosity is not less than the above lower limit, the epoxy resin (A) and the alumina (B) are separated, and only the epoxy resin (A) can be prevented from flowing, and a more uniform insulating resin layer 102 Can be obtained.
Further, when the minimum melt viscosity is not more than the above upper limit value, the wettability of the epoxy resin composition to the metal substrate 101 can be improved, and the adhesion between the insulating resin layer 102 and the metal substrate 101 can be further improved.
These synergistic effects can further improve the heat dissipation and dielectric breakdown voltage of the metal base circuit board 100. Furthermore, the heat cycle characteristics of the metal base circuit board 100 can be further improved.

The epoxy resin composition of the present embodiment preferably has a temperature at which the minimum melt viscosity is reached in the range of 60 ° C. or higher and 100 ° C. or lower.
Moreover, the epoxy resin composition of this embodiment has a flow rate of preferably 15% or more, more preferably less than 60%. The flow rate can be measured by the following procedure. First, 5-7 sheets of metal foil having a resin layer formed of the epoxy resin composition of the present embodiment are cut into a predetermined size (50 mm × 50 mm), and the weight is measured. Next, after pressing for 5 minutes between hot plates maintained at an internal temperature of 175 ° C., it is cooled, the resin that has flowed out is carefully dropped, and the weight is measured again. The flow rate can be obtained by the following formula (I).
Flow rate (%) = (weight before measurement−weight after measurement) / (weight before measurement−weight of metal foil) (I)
With such a viscosity behavior, when the epoxy resin composition is heated and cured to form the insulating resin layer 102, air can be prevented from entering the epoxy resin composition, and in the epoxy resin composition. The dissolved gas can be discharged to the outside sufficiently. As a result, generation of bubbles in the insulating resin layer 102 can be suppressed, and heat can be reliably transmitted from the insulating resin layer 102 to the metal substrate 101. Moreover, the insulation reliability of the metal base circuit board 100 can be improved by suppressing the generation of bubbles. In addition, the adhesion between the insulating resin layer 102 and the metal substrate 101 can be improved.
These synergistic effects can further improve the heat dissipation of the metal base circuit board 100, and as a result, the heat cycle characteristics of the metal base circuit board 100 can be further improved.

  In order to realize an epoxy resin composition having such a viscosity behavior, for example, the type and amount of the above-described epoxy resin (A), the type and amount of alumina (B), the type and amount of phenoxy resin (C), and the like. May be adjusted as appropriate. In particular, by using a resin having good fluidity such as a naphthalene type epoxy resin, the above-mentioned viscosity characteristics can be easily obtained.

Next, physical properties of the insulating resin layer 102 will be described.
The insulating resin layer 102 has high thermal conductivity. Specifically, the thermal conductivity in the thickness direction of the insulating resin layer 102 measured by a laser flash method is preferably 3.0 W / (m · k) or more, and is preferably 5.0 W / (m · k). More preferably.
Thereby, the heat from the electronic component 11 can be easily transmitted to the metal substrate 101 through the insulating resin layer 102.

In addition, the insulating resin layer 102 has increased rigidity and can reduce the warpage of the insulating resin layer 102. As a result, positional displacement of the electronic component with respect to the circuit board can be suppressed, and connection reliability between the electronic component and the circuit board can be improved. From the viewpoint that it can be further increased, the glass transition temperature is preferably 100 ° C. or higher and 150 ° C. or lower. The glass transition temperature of the insulating resin layer 102 can be measured as follows based on JIS C 6481.
Using a dynamic viscoelasticity measuring device (DMA Instruments' DMA / 983) under a nitrogen atmosphere (200 ml / min), a tensile load was applied, and a frequency of 1 Hz and a temperature of −50 ° C. to 300 ° C. The range is measured at a temperature rising rate of 5 ° C./min, and the glass transition temperature Tg is obtained from the peak position of tan δ.

Further, the elastic modulus (storage elastic modulus) E ′ of 25 ° C. of the insulating resin layer 102 increases the rigidity and can reduce the warp of the insulating resin layer 102. As a result, it is possible to suppress the displacement of the electronic component with respect to the circuit board, From the viewpoint of further enhancing the connection reliability between the electronic component and the circuit board, it is preferably 30 GPa or more and 70 GPa or less.
In addition, the said storage elastic modulus is measured with the dynamic viscoelasticity measuring apparatus.
The storage elastic modulus E ′ is a storage elastic modulus of 25 ° C. when a tensile load is applied to the insulating resin layer 102 and measured at −50 ° C. to 300 ° C. at a frequency of 1 Hz and a heating rate of 5 to 10 ° C./min. Value.

The metal base circuit board 100 as described above can be manufactured as follows.
First, the metal substrate 101 is prepared.
Thereafter, a B-stage resin layer made of the epoxy resin composition described above is provided on the metal substrate 101. At this time, a resin layer may be formed on the metal substrate 101 by applying the resin composition described above to the metal substrate 101, or a resin layer is formed on the carrier material to produce a carrier material with a resin layer. Then, the resin layer may be formed on the metal substrate 101 by laminating the carrier material with the resin layer on the metal substrate 101.
At this time, the thickness of the resin layer in the B stage state is, for example, not less than 40 μm and not more than 300 μm.

Hereinafter, a method for producing a carrier material with a resin layer and laminating the carrier material with a resin layer on the metal substrate 101 will be described. First, a resin layer is formed on a carrier material to obtain a carrier material with a resin layer.
The carrier material is, for example, a resin film such as a polyethylene terephthalate film; a metal foil such as a copper foil. The thickness of the carrier material is, for example, 10 to 500 μm.

  Next, the carrier material with a resin layer is laminated on the metal substrate 101 such that the surface on the resin layer side of the carrier material with the resin layer is in contact with the surface of the metal substrate 101. Thereafter, the insulating resin layer 102 is formed by pressurizing and heat-curing the resin layer using a press or the like.

Next, the carrier material is removed from the insulating resin layer 102, and the metal layer 103 is formed on the exposed surface of the insulating resin layer 102. When the carrier material is a metal foil, the carrier material may be used as the metal layer 103 as it is.
The metal layer 103 is made of, for example, copper, aluminum, nickel, iron, tin, or the like, and may include two or more kinds. The thickness of the metal layer 103 is, for example, 10 μm or more and 500 μm or less. Note that another layer such as an adhesive layer may be interposed between the insulating resin layer 102 and the metal layer 103.
Thereafter, the insulating resin layer 102 is formed by post-curing the resin layer.
Next, if necessary, a circuit is formed by etching the metal layer 103 into a predetermined pattern, and the metal base circuit board 100 is obtained. In this embodiment, the metal base circuit board 100 includes a state before the metal layer 103 is processed.
In the case of a multilayer, after forming a circuit on the metal base circuit board 100, an insulating sheet is further laminated, and a circuit is formed by etching in the same manner as described above, whereby the multilayer metal base circuit board 100 can be obtained. The insulating sheet is preferably formed of the same epoxy resin composition as that used for the insulating resin layer 102 from the viewpoint of further improving the thermal conductivity of the electronic device 1.
Alternatively, a solder resist may be formed on the outermost layer, and the connection electrode portion may be exposed so that the electronic component 11 can be mounted by exposure and development.

Next, the electronic device 1 of this embodiment will be described. FIG. 2 is a cross-sectional view of the electronic device 1 according to the embodiment of the present invention.
The electronic device 1 includes a metal base circuit board 100 and an electronic component 11 provided on the metal base circuit board 100. The insulating resin layer 102 is formed by the epoxy resin composition described above.

In this embodiment, the electronic device 1 is a semiconductor device, for example, a power semiconductor device, LED lighting, or an inverter device.
Here, the inverter device electrically generates AC power from DC power (has a function of reverse conversion). In addition, the power semiconductor device is characterized by higher withstand voltage, higher current, higher speed and higher frequency than ordinary semiconductor elements, generally called power devices, rectifier diodes, power transistors, Examples include a power MOSFET, an insulated gate bipolar transistor (IGBT), a thyristor, a gate turn-off thyristor (GTO), and a triac.
The electronic component 11 is a semiconductor element such as an insulated gate bipolar transistor or a diode, or various heating elements such as a resistor or a capacitor. The metal base circuit board 100 functions as a heat spreader.
The electronic component 11 is joined to the support base 12 via the solder 15.

The support base 12 is one on which the electronic component 11 is mounted. In the present embodiment, the support base 12 includes a lead frame 121 and an insulating sheet 122.
The lead frame 121 includes a die pad part 121A, an inner lead (not shown) connected to the die pad part 121A, and an outer lead (not shown) connected to the inner lead. The lead frame 121 supports the electronic component 11 with a die pad portion 121A. The die pad portion 121 </ b> A is electrically connected to the electronic component 11 through the solder 15. The lead frame 121 may be a conductive member, but is made of a metal such as Cu, for example.

The insulating sheet 122 is for insulating the metal layer 103 from the lead frame 121. The insulating sheet 122 is made of a resin material.
For example, the insulating sheet 122 includes a resin having a carboxyl group that is a resin component and a thermally conductive filler.
Examples of the resin having a carboxyl group include a carboxyl group-containing poly (meth) acrylate polymer compound (so-called acrylic rubber) containing one or both of butyl acrylate and ethyl acrylate as a main raw material component.
Further, as the heat conductive filler, boron nitride, alumina or the like can be used.
It is preferable that content of a heat conductive filler is 50-60 volume% with respect to the whole insulating sheet 122, and a resin component is 40-50 volume%.
In the present embodiment, the insulating sheet 122 has a larger planar shape than the die pad portion 121 </ b> A of the lead frame 121, and the electronic component 11, the support base 12, the metal layer 103, the insulating resin layer 102, and the metal substrate 101 are laminated. When the electronic device 1 is viewed in plan along the direction, it protrudes from the outer peripheral edge of the die pad portion 121A.
The insulating sheet 122 is preferably formed of the same epoxy resin composition as that used for the insulating resin layer 102 described above from the viewpoint of further improving the thermal conductivity of the electronic device 1.

The metal layer 103 is disposed between the insulating resin layer 102 and the insulating sheet 122 and is in direct contact with the insulating resin layer 102.
The metal layer 103 transfers heat from the electronic component 11 to the metal substrate 101. The metal layer 103 is made of metal such as Cu, for example. The metal layer 103 is a plate-like member and has almost the same size as the insulating sheet 122.

The electronic device 1 as described above can be manufactured as follows.
First, the metal base circuit board 100 is prepared.
Next, the insulating sheet 122 and the lead frame 121 are disposed on the metal layer 103. Thereafter, the die pad part 121 </ b> A of the lead frame 121 and the electronic component 11 are joined via the solder 15. Thereafter, the electronic component 11 is sealed with the sealing material 16.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope that can achieve the object of the present invention are included in the present invention.
For example, in the above-described embodiment, the support base 12 includes the lead frame 121 and the insulating sheet 122, but is not limited thereto. For example, a ceramic substrate may be used instead of the support base 12 and the metal layer 103. In this case, the insulating resin layer 102 bonds the ceramic substrate and the metal substrate 101.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to these. In addition, in an Example, unless otherwise specified, a part represents a mass part. Moreover, each thickness is represented by the average film thickness.

Example 1
(1) Preparation of resin varnish Phenoxy resin having bisphenol F skeleton and bisphenol A skeleton (Mitsubishi Chemical Corporation, 4275, weight average molecular weight 6.0 × 10 ⁴ , ratio of bisphenol F skeleton to bisphenol A skeleton = 75: 25) 3.9 parts by mass, bisphenol F type epoxy resin (DIC, 830S, epoxy equivalent 170) 3.0 parts by mass, naphthalene type epoxy resin (DIC, HP-6000, epoxy equivalent 250: in chemical formula (10) , R are all hydrogen atoms, a mixture of a component where n = 1 and a component where n = 2) 3.0 parts by mass, 0.3 parts by mass of dicyandiamide (manufactured by Degussa), γ-glycidoxypropyltri Methoxysilane (manufactured by Shin-Etsu Silicone, KBM-403) 1.3 parts by mass, spherical alumina (average particle size 22 μm, circularity: .91, Nippon Steel & Sumikin Materials Co., Ltd., AX-25) 67.3 parts by mass, polyhedral alumina (average particle size 4 μm, circularity: 0.75, Nippon Light Metal Co., Ltd., LS-210) 13.2 parts by mass , 8.0 parts by mass of polyhedral alumina (average particle size 0.7 μm, circularity: 0.71, Nippon Light Metal Co., Ltd., LS-250) was dissolved and mixed in cyclohexanone and stirred using a high-speed stirring device. A varnish-like epoxy resin composition having a solid content of 86% by mass was obtained.
(2) Preparation of metal foil with resin As a metal foil, a copper foil having a thickness of 70 μm (GTSMP, manufactured by Furukawa Circuit Foil Co., Ltd.) was used, and a varnish-like epoxy resin composition was applied to the roughened surface of the copper foil with a comma coater. This was applied and dried by heating at 100 ° C. for 3 minutes and 150 ° C. for 3 minutes to obtain a resin-coated copper foil having a resin thickness of 80 μm.
(3) Fabrication of metal base circuit board The above-mentioned copper foil with resin and an aluminum plate having a thickness of 1 mm are bonded together, and pressed by a vacuum press at a press pressure of 100 kg / cm ² at 80 ° C. for 30 minutes and 180 ° C. for 60 minutes. A metal base circuit board (insulating resin layer thickness: 80 μm) was obtained.
In addition, the measuring method of the characteristic shown in Table 1 is as follows. The same applies to examples and comparative examples described later.

1. Characteristics of Epoxy Resin Composition (1) Viscosity Characteristics Using a rheometer MCR301 manufactured by Anton Paar Japan, the temperature was increased from 60 ° C. to 160 ° C. at a rate of temperature increase of 3 ° C./min and a frequency of 1 Hz. From the obtained viscosity profile, the minimum melt viscosity and the temperature at which the minimum melt viscosity was reached were determined.
(2) Flow rate After the obtained metal foil with resin is cut to 50 mm x 50 mm, 5 sheets are laminated and sandwiched between hot plates maintained at an internal temperature of 175 ° C, and the pressure is 50 kg / cm ² for 5 minutes. After pressing, it was cooled. Thereafter, the resin that flowed out was cut off, and the flow rate was calculated according to the above-described calculation formula (I).
2. Characteristics of Alumina (3) Circularity Circularity was measured using a flow type particle image analyzer “FPIA-3000” manufactured by Sysmex. A measurement sample was prepared by adding an appropriate amount of a surfactant to 50 to 100 ml of distilled water, adding 10 to 20 mg of alumina particles thereto, and then dispersing the mixture with an ultrasonic disperser for 1 minute. The circularity of the flow type particle image analyzer “FPIA-3000” analyzes the circumference of one particle projection image and the circumference of a circle corresponding to the area of the particle projection image. The average value per 20000 is automatically calculated.
Circularity = (perimeter of circle corresponding to area of particle projection image) / (perimeter of particle projection image)
3. Characteristics of Metal Base Circuit Board (4) Thermal Conductivity Copper foil and aluminum plate were peeled from the metal base circuit board to obtain an insulating resin layer. And the heat conductivity of the thickness direction of the insulating resin layer was measured. Specifically, 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 according to JIS-K-6911. The thermal conductivity was calculated using the following formula. The unit of thermal conductivity is W / m · K. Thermal conductivity [W / m · K] = α [mm ² / s] × Cp [J / kg · K] × ρ [g / cm ³ ]
(5) Peel strength After cutting the metal base circuit board to 100 mm × 25 mm with a grinder saw, a sample was prepared by leaving only 100 mm × 10 mm of copper foil at the center by etching, and the copper foil and insulating resin layer at 23 ° C. Peel strength was measured. The peel strength measurement was performed according to JIS C 6481.
(6) Solder heat resistance After a metal base circuit board was cut into a 50 mm × 50 mm grinder saw, a sample in which only 1/2 of the copper foil was left by etching was prepared and evaluated in accordance with JIS C 6481. The evaluation was performed by immersing in a solder bath at 260 ° C. for 30 seconds and then checking for abnormal appearance.
Evaluation criteria ○: No abnormality
×: Abnormal (there is an overall swollen part)
(7) Moisture-absorbing solder heat resistance A metal base circuit board was cut to 50 mm x 50 mm with a grinder saw, and then half-etched according to JIS C 6481 to prepare a sample. After processing for 2 hours in a 121 ° C. pressure cooker, the copper foil surface was floated down in a 260 ° C. solder bath, and the presence or absence of appearance abnormality after 30 seconds was examined.
Evaluation criteria ○: No abnormality
×: Swelled (there is a swelled area as a whole)
(8) Tg (glass transition temperature)
Based on JIS C 6481, it measured as follows.
The copper foil and the aluminum plate were peeled from the metal base circuit board to obtain an insulating resin layer. A tensile load was applied under a nitrogen atmosphere (200 ml / min) using a dynamic viscoelasticity measuring apparatus (DMA / 983 manufactured by TA Instruments Inc.), and a frequency of 1 Hz, −50 ° C. to 300 ° C. The glass transition temperature Tg was obtained from the peak position of tan δ.
(9) Storage elastic modulus (E ')
The copper foil and the aluminum plate were peeled from the metal base circuit board to obtain an insulating resin layer. Then, the insulating resin layer was cut to obtain an 8 × 20 mm test piece. Using a dynamic viscoelasticity measuring device, measurement was performed in a temperature range of −50 ° C. to 300 ° C. with a tensile mode, a frequency of 1 Hz, and a temperature rising rate of 5 ° C./min. And the storage elastic modulus of 25 degreeC was obtained.
(10) Dielectric breakdown voltage After the metal base circuit board was cut to 100 mm × 100 mm with a grinder saw, the copper foil was removed by etching to prepare a sample. Using a withstand voltage tester (MODEL7473, manufactured by EXTECH Electronics), the electrode was brought into contact with the insulating resin layer and the aluminum plate, and an AC voltage was applied to both electrodes so that the voltage increased at a rate of 0.5 kV / sec. Applied. The voltage at which the insulating resin layer of the metal base circuit board was broken was defined as the breakdown voltage.
(11) Flame retardance evaluation It evaluated according to UL specification UL94V (A).

(12) Heat cycle test The electronic device shown in FIG. 2 was manufactured using the obtained epoxy resin composition. However, no sealing material was provided.
An insulating sheet 122 and a lead frame 121 made of Cu were disposed on the metal base circuit board. As the insulating sheet 122, Fuko TM sheet HF manufactured by Furukawa Electric was used. Thereafter, the die pad portion 121A of the lead frame 121 and the electronic component 11 were joined via the solder 15 (material Sn-3.0Ag-0.5Cu).
As described above, three electronic devices were prepared and a heat cycle test was performed. The heat cycle test was performed 3000 times with one cycle of −40 ° C. for 5 minutes to + 125 ° C. for 5 minutes. After the heat cycle test, the crack rate of the solder portion was observed with a microscope.
A case in which even one of the three electronic devices has a crack rate of 100% is regarded as defective (x), and all three electronic devices have a crack rate of less than 100% as good (O). Judged.
Here, the crack rate of the solder portion refers to the crack progress rate of the solder portion of the component joint portion. The ratio is 100% when the crack progresses and the connection with the substrate is completely disconnected.

(Examples 2 to 5, Comparative Examples 1 and 2)
In Examples 2 to 5 and Comparative Examples 1 and 2, except that the composition of the resin varnish was changed to that shown in Table 1, in the same manner as in Example 1, a varnish-like epoxy resin composition, a resin-coated copper foil, Metal base circuit boards and electronic devices were fabricated and evaluated.

The metal base circuit boards obtained in the examples all had high peel strength, and were excellent in solder heat resistance and flame retardancy. Moreover, it had sufficient dielectric breakdown voltage value and high thermal conductivity. Moreover, the favorable result was obtained also about the heat cycle property in an electronic device.
Therefore, it was found that a highly durable electronic device can be obtained by using the epoxy resin composition and the metal base circuit board according to the present invention.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2013-216115 for which it applied on October 17, 2013, and takes in those the indications of all here.

Claims (15)

Epoxy resin used for forming the insulating resin layer constituting a metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer A composition comprising:
Epoxy resin,
Alumina,
Including
The epoxy resin composition whose content of the said alumina is 75 to 95 mass% with respect to 100 mass% of the total solid of the said epoxy resin composition. The epoxy resin composition according to claim 1,
The alumina is
Large particles having an average particle size in the first particle size range of 5.0 μm or more and 50 μm or less in a weight-based particle size distribution measured by a laser diffraction / scattering particle size distribution measurement method and a circularity of 0.80 or more and 1.0 or less Diameter alumina,
The average particle size in the weight-based particle size distribution measured by the laser diffraction / scattering particle size distribution measurement method belongs to the second particle size range of 1.0 μm or more and less than 5.0 μm, and the circularity is 0.50 or more and 0.90 or less. Medium particle size alumina;
The average particle size in the weight-based particle size distribution by the laser diffraction / scattering particle size distribution measurement method belongs to the third particle size range of 0.1 μm or more and less than 1.0 μm, and the circularity is 0.50 or more and 0.90 or less. Small particle size alumina,
An epoxy resin composition which is a mixture of The epoxy resin composition according to claim 1 or 2,
Using a dynamic viscoelasticity measuring device, when the epoxy resin composition was heated from 60 ° C. to a molten state at a temperature rising rate of 3 ° C./min and a frequency of 1 Hz,
Initially melt viscosity decreases, has the property of further increasing after reaching the minimum melt viscosity, and
An epoxy resin composition having a minimum melt viscosity of 1 × 10 ³ Pa · s to 1 × 10 ⁵ Pa · s. In the epoxy resin composition according to claim 3,
The epoxy resin composition whose temperature which reaches | attains the said minimum melt viscosity exists in the range of 60 to 100 degreeC. In the epoxy resin composition according to any one of claims 1 to 4,
An epoxy resin composition having a flow rate of 15% or more. In the epoxy resin composition according to any one of claims 1 to 5,
The epoxy resin is an epoxy resin composition comprising a naphthalene type epoxy resin having a naphthalene ring skeleton and having two or more glycidyl groups. In the epoxy resin composition according to any one of claims 1 to 6,
An epoxy resin composition further comprising a phenoxy resin. In the epoxy resin composition according to any one of claims 1 to 7,
An epoxy resin composition further comprising a curing agent. A resin layer used for forming the insulating resin layer constituting a metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer. Carrier material with
Carrier material,
Provided on one surface of the carrier material, including an epoxy resin, alumina, and a B-stage resin layer;
With
The carrier material with a resin layer in which the said resin layer is formed with the epoxy resin composition as described in any one of Claims 1 thru | or 8. In the carrier material with a resin layer according to claim 9,
A carrier material with a resin layer, wherein the carrier material is a resin film or a metal foil. The carrier material with a resin layer according to claim 9 or 10,
A carrier material with a resin layer, wherein the resin layer in the B-stage state has a thickness of 300 μm or less. A metal base circuit board comprising a metal substrate, an insulating resin layer provided on the metal substrate, and a metal layer provided on the insulating resin layer,
The said insulating resin layer is a metal base circuit board formed by the epoxy resin composition as described in any one of Claims 1 thru | or 8. The metal base circuit board according to claim 12,
The metal base circuit board is an aluminum board. The metal base circuit board according to claim 12 or 13,
A metal base circuit board having a thermal conductivity in the thickness direction of the insulating resin layer of 3 W / (m · k) or more as measured by a laser flash method. A metal base circuit board according to any one of claims 12 to 14,
Electronic components provided on the metal base circuit board;
An electronic device comprising:

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