CN113710747A

CN113710747A - Insulating resin composition, cured insulating resin, laminate, and circuit board

Info

Publication number: CN113710747A
Application number: CN202080029640.9A
Authority: CN
Inventors: 熊谷良太; 八岛克宪; 木元裕纪; 山下幸彦
Original assignee: Denka Co Ltd
Current assignee: Denka Co Ltd
Priority date: 2019-08-27
Filing date: 2020-08-21
Publication date: 2021-11-26
Anticipated expiration: 2040-08-21
Also published as: JPWO2021039630A1; CN113710747B; WO2021039630A1

Abstract

An insulating resin composition comprising an epoxy resin, an amine-based curing agent and an inorganic fillerThe amine-based curing agent contains a first amine compound represented by the formula (A-1) and a second amine compound represented by the formula (A-2). [ wherein Y represents-NH ]₂or-NHR¹(R¹Is a group represented by the formula (Y-1), at least one of Y is-NHR¹。][ in the formula, R²Represents an alkyl group.]

Description

Insulating resin composition, cured insulating resin, laminate, and circuit board

Technical Field

The present invention relates to an insulating resin composition suitable for use in the production of a metal-base circuit board, and a cured product thereof. The present invention also relates to a laminate and a circuit board formed using the insulating resin composition.

Background

Various circuit boards have been put into practical use as circuit boards for mounting electronic and electric components such as semiconductor elements to form hybrid integrated circuits. Circuit substrates are classified into resin circuit substrates, ceramic circuit substrates, metal-base circuit substrates, and the like, based on the substrate material.

Although the resin circuit board is inexpensive, the heat conductivity of the board is low, and therefore, the resin circuit board is limited to applications that can use a small amount of power. Ceramic circuit boards are suitable for applications that can use large amounts of power because of the characteristics of ceramics, such as high electrical insulation properties and high heat resistance properties, but have the disadvantage of being expensive. On the other hand, the metal base circuit board has a property of being a compromise between both, and is suitable for general-purpose applications in which large electric power can be used, for example, applications such as an inverter for a refrigerator, an inverter for a commercial air conditioner, a power supply for an industrial robot arm, and a power supply for an automobile.

For example, patent document 1 discloses a method for obtaining a circuit board excellent in stress relaxation property, heat resistance, moisture resistance and heat dissipation property by using a composition for a circuit board containing a specific epoxy resin, a curing agent and an inorganic filler as essential components.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-266535

Disclosure of Invention

Problems to be solved by the invention

If a ceramic circuit board can be replaced with a metal base circuit board, improvement in productivity can be expected. However, metal-based circuit boards generally tend to have lower heat dissipation than ceramic circuit boards. In the field of industrial modules using ceramic circuit boards, high voltage may be applied under severe conditions, and high reliability under such conditions is required.

Accordingly, an object of the present invention is to provide an insulating resin composition capable of forming an insulating layer having excellent insulation reliability under conditions of high temperature, high humidity and high voltage application, and high thermal cycle resistance. Another object of the present invention is to provide a circuit board which has an insulating layer comprising a cured product of the insulating resin composition and is excellent in insulation reliability and heat cycle resistance under conditions of high temperature and high humidity and high voltage application.

Means for solving the problems

The present invention includes the following modes.

(1) An insulating resin composition containing an epoxy resin, an amine-based curing agent, and an inorganic filler, wherein the amine-based curing agent contains a first amine compound represented by formula (A-1) and a second amine compound represented by formula (A-2).

[ chemical formula 1]

[ in the formula (A-1), n¹Represents an integer of 0 to 4, X¹Represents an alkanediyl group, an oxygen atom or a sulfur atom. n is¹When it is 1 or more, there are plural X' s¹May be the same or different from each other.]

[ chemical formula 2]

[ in the formula (A-2), n²Represents an integer of 0 to 4, X²Represents an alkanediyl group, an oxygen atom or a sulfur atom, and Y represents-NH₂or-NHR¹(R¹Represents a group represented by the formula (Y-1). ). The plural Y's may be the same or different from each other. Wherein at least one of Y is-NHR¹。n²When it is 1 or more, there are plural X' s²May be the same or different from each other.]

[ chemical formula 3]

[ in the formula (Y-1), R²Represents an alkyl group.]

(2) The insulating resin composition according to (1), wherein X is¹And the above-mentioned X²Is a methanediyl group.

(3) The insulating resin composition according to (1) or (2), wherein the content of the first amine compound in the amine-based curing agent is 30 to 60% by mass, and the content of the second amine compound in the amine-based curing agent is 40 to 70% by mass.

(4) The insulating resin composition as described in any one of (1) to (3), wherein-NHR in the amine-based curing agent¹Total number M of₂and-NH₂Total number M of₁Ratio of (M)₂/M₁) 0.05 to 0.30.

(5) The insulating resin composition according to any one of (1) to (4), wherein the ratio of the active hydrogen equivalent of the amine-based curing agent to the epoxy equivalent of the epoxy resin is 0.3 to 1.5.

(6) A cured insulating resin product of the insulating resin composition according to any one of (1) to (5).

(7) The insulating resin composition as described in (6), wherein the content of the inorganic filler is 35 to 80 vol%.

(8) The cured insulating resin according to (6) or (7), wherein the crosslinking density is 4.0X 10^-2～5.0×10^-1mol/cm³。

(9) The cured insulating resin product according to any one of (6) to (8), which has a storage elastic modulus at-40 ℃ of 100GPa or less.

(10) A laminate body, comprising: a metal plate; the cured insulating resin according to any one of (6) to (9) disposed on the metal plate; and a metal foil disposed on the cured insulating resin.

(11) A circuit board, comprising: a metal plate; the cured insulating resin according to any one of (6) to (9) disposed on the metal plate; and a circuit portion disposed on the cured insulating resin body.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, an insulating resin composition capable of forming an insulating layer having excellent insulation reliability and high heat cycle resistance under conditions of high temperature and high humidity and high voltage application can be provided. Further, according to the present invention, a circuit board having an insulating layer composed of a cured product of the insulating resin composition and having excellent insulation reliability and heat cycle resistance under conditions of high temperature, high humidity and high voltage application can be provided.

Drawings

FIG. 1 is a sectional view showing one embodiment of a laminate.

FIG. 2 is a cross-sectional view showing one embodiment of a circuit board.

Detailed Description

(insulating resin composition)

The insulating resin composition according to the present embodiment contains an epoxy resin, an amine-based curing agent, and an inorganic filler. In the present embodiment, the amine-based curing agent contains the first amine compound represented by the formula (A-1) and the second amine compound represented by the formula (A-2).

[ chemical formula 4]

In the formula (A-1), n¹Represents an integer of 0 to 4, X¹Represents an alkanediyl group, an oxygen atom or a sulfur atom. n is¹When it is 1 or more, there are plural X' s¹May be the same or different from each other.

[ chemical formula 5]

In the formula (A-2), n²Represents an integer of 0 to 4, X²Represents an alkanediyl group, an oxygen atom or a sulfur atom, and Y represents-NH₂or-NHR¹(R¹Represents a group represented by the formula (Y-1). ). The plural Y's may be the same or different from each other. Wherein at least one of Y is-NHR¹。n²When it is 1 or more, there are plural X' s²May be the same or different from each other.

[ chemical formula 6]

In the formula (Y-1), R²Represents an alkyl group.

The insulating resin composition according to the present embodiment can form an insulating resin cured product that can maintain excellent insulation reliability (for example, 200 hours or more) even under conditions of high temperature and high humidity (for example, 85 ℃ and 85% RH) and high voltage (for example, direct current 1200V) by combining the specific amine-based curing agent with the epoxy resin. Therefore, according to the insulating resin composition of the present embodiment, a circuit board having excellent insulation reliability and heat cycle resistance under conditions of high temperature and high humidity and high voltage application can be manufactured.

The reason why the above-mentioned effects can be obtained is not necessarily clear, but is considered to be because the use of the second amine compound can reduce the crosslink density of the cured product and introduce an alkyl group, thereby improving the flexibility of the cured product and enabling the formation of an insulating layer having excellent thermal cyclability.

The epoxy resin may be a resin curable by an amine-based curing agent. Examples of the epoxy resin include a bisphenol a type epoxy resin, a bisphenol S type epoxy resin, a bisphenol F type epoxy resin, a hydrogenated bisphenol a type epoxy resin, a polypropylene glycol type epoxy resin, a polytetramethylene glycol type epoxy resin, a naphthalene type epoxy resin, a phenylmethane type epoxy resin, a tetraphenolmethane type epoxy resin, a biphenyl type epoxy resin, an epoxy resin having a triazine ring, a bisphenol a alkylene oxide adduct type epoxy resin, a dicyclopentadiene type epoxy resin, a cresol Novolac type epoxy resin, a phenol Novolac type epoxy resin, and the like. The epoxy resin may be used alone or in combination of two or more.

From the viewpoint of heat resistance, the epoxy resin preferably contains at least one ring structure selected from the group consisting of a benzene ring structure, a naphthalene ring structure, and a triazine ring structure.

The amine-based curing agent is a curing agent having an amino group and capable of curing an epoxy resin. In the present embodiment, the amine-based curing agent contains the first amine compound represented by the formula (A-1) and the second amine compound represented by the formula (A-2).

In the formula (A-1), n¹Is 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

In the formula (A-1), X¹Is an alkanediyl group, an oxygen atom or a sulfur atom, and is preferably an alkanediyl group. The number of carbon atoms of the alkanediyl group is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1.

X's present in plural¹May be the same or different from each other, and is preferably the same.

In the formula (A-2), n²Is 0 to 4, preferably 0 to 2, and more preferably 0 or 1.

In the formula (A-2), X²Is an alkanediyl group, an oxygen atom or a sulfur atom, and is preferably an alkanediyl group. The number of carbon atoms of the alkanediyl group is preferably 1 to 5, more preferably 1 to 3, and still more preferably 1.

X's present in plural²May be the same or different from each other, and is preferably the same.

X²Can be with X¹The same groups. In such an embodiment, the production of the amine-based curing agent becomes easy.

In the formula (A-2), Y is-NH₂or-NHR¹. Y's may be the same or different and at least one of Y's is-NHR¹。

In one preferred embodiment, the amine-based curing agent may include: a part of Y being-NH₂The other part is-NHR¹The amine compound (A-2-1); and Y is all-NHR¹The amine compound (A-2-2) of (1).

In the formula (A-2), R¹Is a group represented by the formula (Y-1). In the formula (Y-1), R²The alkyl group is preferably an alkyl group having 1 to 8 carbon atoms, and more preferably an alkyl group having 3 to 5 carbon atoms. R²The alkyl group (b) may be linear, branched or cyclic, and is preferably linear from the viewpoint of further improving flexibility of the cured product.

-NHR in amine-based curing agent¹Total number M of₂Relative to-NH₂Total number M of₁Ratio of (M)₂/M₁) For example, 0.05 or more, preferably 0.08 or more, and more preferably 0.10 or more. This provides a cured product having more excellent insulation reliability under high temperature and high humidity. In addition, the above ratio (M)₂/M₁) For example, 0.30 or less, preferably 0.25 or less, and more preferably 0.20 or less. This tends to further improve the insulation properties of the cured product. I.e. ratio (M)₂/M₁) For example, the concentration of the metal oxide may be 0.05 to 0.30, 0.08 to 0.30, 0.10 to 0.30, 0.05 to 0.25, 0.08 to 0.25, 0.10 to 0.25, 0.05 to 0.20, 0.08 to 0.20, or 0.10 to 0.20.

The content of the first amine compound in the amine-based curing agent may be, for example, 15 mass% or more, preferably 30 mass% or more, and more preferably 40 mass% or more, from the viewpoint of further improving the insulating properties of the cured product. In addition, from the viewpoint of obtaining a cured product having more excellent insulation reliability under high temperature and high humidity, the content of the first amine compound in the amine-based curing agent may be, for example, 75 mass% or less, preferably 60 mass% or less, and more preferably 55 mass% or less. That is, the content of the first amine compound in the amine-based curing agent may be, for example, 15 to 75 mass%, 30 to 75 mass%, 40 to 75 mass%, 15 to 60 mass%, 30 to 60 mass%, 40 to 60 mass%, 15 to 55 mass%, 30 to 55 mass%, or 40 to 55 mass%.

The content of the second amine compound in the amine-based curing agent may be, for example, 30 mass% or more, preferably 40 mass% or more, and more preferably 45 mass% or more, from the viewpoint of obtaining a cured product having more excellent insulation reliability under high temperature and high humidity. In addition, the content of the second amine compound in the amine-based curing agent may be, for example, 80 mass% or less, preferably 70 mass% or less, and more preferably 55 mass% or less, from the viewpoint of further improving the insulating properties of the cured product. That is, the content of the second amine compound in the amine-based curing agent may be, for example, 30 to 80 mass%, 40 to 80 mass%, 45 to 80 mass%, 30 to 70 mass%, 40 to 70 mass%, 45 to 70 mass%, 30 to 55 mass%, 40 to 55 mass%, or 45 to 55 mass%.

The amine-based curing agent may further contain an amine-based curing agent other than the first amine compound and the second amine compound, but it is preferable that the first amine compound and the second amine compound are main components. Specifically, the total content of the first amine compound and the second amine compound in the amine-based curing agent is, for example, 50 mass% or more, preferably 70 mass% or more, more preferably 90 mass% or more, and may be 95 mass% or more, 99 mass% or more, or 100 mass%.

Examples of the amine-based curing agent other than the first amine compound and the second amine compound include ethylenediamine, diethylenetriamine, hexamethylenediamine, m-phenylenediamine, diaminodiphenylsulfone, pentaethylenediamine, and diethyleneglycol dipropylamine.

From the viewpoint of obtaining a cured product having more excellent insulation reliability under high temperature and high humidity, the content of the amine-based curing agent is preferably such that the ratio of the active hydrogen equivalent of the amine-based curing agent to the epoxy equivalent of the epoxy resin falls within the following range. The ratio of the active hydrogen equivalent of the amine-based curing agent to the epoxy equivalent of the epoxy resin may be, for example, 0.2 or more, preferably 0.3 or more, and more preferably 0.5 or more. The ratio of the active hydrogen equivalent of the amine-based curing agent to the epoxy equivalent of the epoxy resin may be, for example, 1.8 or less, preferably 1.5 or less, and more preferably 1.2 or less. That is, the ratio of the active hydrogen equivalent of the amine-based curing agent to the epoxy equivalent of the epoxy resin may be, for example, 0.2 to 1.8, 0.3 to 1.8, 0.5 to 1.8, 0.2 to 1.5, 0.3 to 1.5, 0.5 to 1.5, 0.2 to 1.2, 0.3 to 1.2, or 0.5 to 1.2.

The inorganic filler is not particularly limited, and known inorganic fillers used in applications requiring insulation properties and thermal conductivity can be used without particular limitation. The inorganic filler material may also be referred to as an inorganic filler.

Examples of the inorganic filler include inorganic fillers composed of boron nitride, aluminum oxide, magnesium oxide, aluminum nitride, silicon oxide, zinc oxide, and the like.

The shape of the inorganic filler is not particularly limited, and may be a scale shape, a particle shape, an aggregate thereof, or the like, and is preferably a particle shape.

The inorganic filler may be blended in the insulating resin composition so that the content of the insulating resin cured product falls within a predetermined range. From the viewpoint of further improving the thermal conductivity, the content of the inorganic filler in the insulating resin cured body is preferably 35 vol% or more, and more preferably 40 vol% or more. The content of the inorganic filler in the insulating resin cured product is preferably 80 vol% or less, more preferably 75 vol% or less, from the viewpoint of improving the coatability of the insulating resin composition and suppressing formation of voids during curing. That is, the content of the inorganic filler in the insulating resin cured body may be 35 to 80 vol%, 35 to 75 vol%, 40 to 80 vol%, or 40 to 75 vol%. The volume of the inorganic filler can be determined by dividing the mass of the inorganic filler by the true specific gravity of the inorganic filler. The content of the inorganic filler in the insulating resin cured product represents a ratio of a volume of the inorganic filler to a total volume of the insulating resin cured product.

The insulating resin composition may further contain other components than those described above. The insulating resin composition may further contain, for example, a curing accelerator, an antitarnish agent, a surfactant, a coupling agent, a coloring agent, a viscosity modifier, an antioxidant, an ion scavenger, and the like, as required.

The content of other components is preferably 5% by mass or less, more preferably 2% by mass or less, and may be 0% by mass, based on the total amount of the insulating resin composition.

(insulating resin cured product)

The insulating resin cured product according to the present embodiment is a cured product of the insulating resin composition described above. The cured insulating resin can form an insulating layer having excellent insulating reliability and high heat cycle resistance under conditions of high temperature, high humidity and high voltage application.

The crosslinking density of the insulating resin cured product is preferably 4.0X 10^-2mol/cm³Above, more preferably 6.0 × 10^- ²mol/cm³The above. This further improves the strength of the cured product, and further suppresses the occurrence of cracks in the heat cycle test, thereby enabling the formation of an insulating layer having more excellent heat cycle resistance. The cured insulating resin preferably has a crosslinking density of 5.0X 10^-1mol/cm³Hereinafter, 3.0 × 10 is more preferable^-1mol/cm³The following. This further improves the flexibility of the cured product, and enables the formation of an insulating layer having more excellent stress relaxation properties. The crosslinking density can be appropriately adjusted by: adjusting-NHR in amine-based curing agent¹Total number M of₂Relative to-NH₂Total number M of₁Ratio of (M)₂/M₁) (ii) a Or adjusting the molecular weight and the number of functional groups of the epoxy resin.

In the present specification, the crosslinking density of the insulating resin cured product is a value calculated by the following method.

< method for measuring crosslink Density >

(1) Preparation of measurement sample

After the insulating resin composition was defoamed in a vacuum, the resin composition was poured into a silicone resin mold having a thickness of 1mm, and cured under curing conditions of 50 ℃ for 3 hours and then 160 ℃ for 6 hours to obtain an insulating resin cured product. The obtained cured insulating resin was cut with a diamond cutter to obtain a plate-shaped measurement sample of 1mm × 3mm × 40 mm.

(2) Measurement of storage elastic modulus

A dynamic viscoelasticity measuring apparatus (T) was used for the measurement sample&A Instruments, "RSA 3", measured temperature T by DMA method (JIS K0129 (2005))₁(K) Storage modulus of elasticity. Note that, the temperature T₁The glass transition temperature of the resin component constituting the cured insulating resin body is +30 (K). The measurement was carried out at a frequency of 10Hz and a temperature rise rate of 10 ℃/min in a temperature range of-50 ℃ to +250 ℃.

(3) Calculation of crosslink Density

From the measurement results, the crosslinking density (mol/cm) was calculated by the following formula³). The gas constant was 8.31429J/(mol. K).

Cross-linking density ═ storage elastic modulus/(3 × gas constant × T)₁)

The storage elastic modulus of the insulating resin cured product at-40 ℃ is preferably 100GPa or less, and more preferably 50GPa or less. This tends to further improve the thermal cyclability. The lower limit of the storage elastic modulus at-40 ℃ of the insulating resin cured product is not particularly limited.

In the present specification, the storage elastic modulus of the insulating resin cured body represents a value measured by the following method.

< method for measuring storage elastic modulus >

(1) Preparation of measurement sample

The insulating resin cured product was cut into a plate-like size of 1mm × 3mm × 40mm to prepare a measurement sample.

(2) Measurement of storage elastic modulus

The storage elastic modulus was measured at a frequency of 10Hz and a temperature rise rate of 10 ℃/min in a temperature range of-50 ℃ to +250 ℃ using a dynamic viscoelastometer ("RSA 3" manufactured by T & A Instruments).

The method for producing the insulating resin cured product is not particularly limited. For example, the insulating resin cured product can be produced by curing an insulating resin composition by heat treatment. The heat treatment may be performed in one stage or two stages. By performing the heat treatment in two stages, an insulating resin cured body can be formed via the semi-cured body of the insulating resin composition.

When the heat treatment is performed in one stage, the temperature of the heat treatment may be, for example, 40 to 220 ℃, preferably 70 to 180 ℃, and the time of the heat treatment may be, for example, 0.5 to 48 hours, preferably 1 to 6 hours.

When the heat treatment is carried out in two stages, the temperature of the heat treatment in the 1 st stage may be, for example, 40 to 150 ℃, preferably 50 to 100 ℃, and the time of the heat treatment may be, for example, 0.2 to 8 hours, preferably 0.5 to 5 hours. The temperature of the heat treatment in the 2 nd stage may be, for example, 70 to 220 ℃, preferably 120 to 180 ℃, and the time of the heat treatment may be, for example, 0.5 to 9 hours, preferably 1 to 6 hours.

An insulating resin cured product having a predetermined shape can be obtained by heat-treating an insulating resin composition or a prepreg thereof while maintaining the insulating resin composition or the prepreg in a predetermined shape. For example, a layer-shaped cured insulating resin body can be formed on a metal plate by coating an insulating resin composition on the metal plate, laminating a metal foil as necessary, and curing the laminate.

(laminated body)

The laminate according to the present embodiment includes: a metal plate; an insulating resin cured body disposed on the metal plate; and a metal foil disposed on the cured insulating resin. In the laminate according to the present embodiment, the metal plate and the metal foil may be separated by the cured insulating resin, and the cured insulating resin may function as an insulating layer.

The metal material constituting the metal plate is not particularly limited, and examples thereof include aluminum, aluminum alloys, copper alloys, iron alloys such as stainless steel, and the like. The metal plate may be made of one metal material, or may be made of two or more metal materials. The metal plate may have a single-layer structure or a multilayer structure.

The thickness of the metal plate is not particularly limited, and may be, for example, 0.5 to 3.0mm from the viewpoint of being applied to the production of a circuit board.

The metal material constituting the metal foil is not particularly limited, and examples thereof include copper, aluminum, and nickel. The metal foil may be made of one metal material or two or more metal materials. The metal foil may have a single-layer structure or a multilayer structure.

The thickness of the metal foil is not particularly limited, and may be, for example, 0.009 to 1.0mm from the viewpoint of being suitable for manufacturing a circuit board.

The thickness of the insulating resin cured product is not particularly limited, and may be, for example, 0.05 to 0.30mm from the viewpoint of being suitable for use in manufacturing a circuit board.

The laminate preferably has a 90-degree peel strength of the metal foil at 85 ℃ of 2N/cm or more, more preferably 4N/cm or more. In such a laminate, adhesion between the metal foil and the cured insulating resin is easily maintained sufficiently even under conditions of high temperature and high humidity and application of a dc voltage, and thus a circuit board having excellent heat cycle resistance can be obtained from the laminate. The peel strength can be measured by the method described above.

The method for producing the laminate is not particularly limited. For example, the laminate can be produced by a method including the steps of: a step of coating an insulating resin composition on a metal plate and curing or semi-curing the resin composition; and a step of bonding a metal foil to the cured or semi-cured insulating resin composition (i.e., the insulating resin cured body or the semi-cured body). The method may further include a step of curing the prepreg of the insulating resin composition. The metal foil can be joined by a method such as a roll lamination method or a lamination pressing method.

The laminate may be produced by a method including the steps of: a step of coating an insulating resin composition on a metal foil and curing or semi-curing the resin composition; and a step of bonding a metal plate to the cured or semi-cured insulating resin composition (i.e., the insulating resin cured body or the semi-cured body). The method may further include a step of curing the prepreg of the insulating resin composition.

Fig. 1 is a sectional view showing a preferred embodiment of the laminate. The laminate 10 shown in fig. 1 includes: a metal plate 1; a metal foil 3; and an insulating layer 2 made of an insulating resin cured body interposed between the metal plate 1 and the metal foil 3. By processing the metal foil 3 of the laminate 10 into a predetermined pattern, a circuit board can be easily formed.

(Circuit Board)

The circuit board according to the present embodiment includes: a metal plate; an insulating resin cured body disposed on the metal plate; and a circuit portion disposed on the cured insulating resin body. In the circuit board according to the present embodiment, the metal plate and the circuit portion may be separated by the cured insulating resin, and the cured insulating resin may function as an insulating layer.

The metal plate may be exemplified by the same metal plates as those in the above-described laminated body.

The circuit portion may be made of a metal material. As the metal material constituting the circuit portion, the same material as the metal material constituting the metal foil described above can be exemplified. The circuit portion may be obtained by processing the metal foil into a predetermined pattern.

The thickness of the circuit portion is not particularly limited, and may be, for example, 0.035 to 0.5mm from the viewpoint of the amount of current and the heat dissipation.

The thickness of the insulating resin cured product is not particularly limited, and may be, for example, 0.07 to 0.2mm from the viewpoint of insulation and heat dissipation.

The method for manufacturing the circuit board is not particularly limited. For example, the circuit board can be manufactured by a method including a step of processing the metal foil of the laminate into a predetermined pattern. The method of processing (etching) the metal foil is not particularly limited, and conventionally known methods may be applied.

Fig. 2 is a sectional view showing a suitable one embodiment of the circuit substrate. The circuit board 20 shown in FIG. 2 includes a metal plate 1; a circuit section 4; and an insulating layer 2 made of an insulating resin cured body interposed between the metal plate 1 and the circuit portion 4. The circuit board 20 may be obtained by processing the metal foil 3 of the laminate 10 into the circuit portion 4, for example.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

Examples

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

< example 1>

(amine curing agent)

As the amine-based curing agent, an amine-based curing agent (1) containing 37 mass% of an amine compound represented by the following formula (A-1-1), 17 mass% of an amine compound represented by the following formula (A-1-2), 32 mass% of an amine compound represented by the following formula (A-2-1) and 12 mass% of an amine compound represented by the following formula (A-2-2) was prepared. These amine compounds can be synthesized by known methods.

[ chemical formula 7]

(preparation of insulating resin composition)

35.9 parts by volume of a bisphenol A epoxy resin (EXA850CRP, manufactured by Mitsubishi chemical corporation, and shown as "epoxy resin (1)") and 14.07 parts by volume of the amine-based curing agent (1) were mixed by stirring at 25 ℃. Subsequently, 50.0 parts by volume of a boron nitride filler (manufactured by Denka, having an average particle diameter of 60 μm, and shown as "inorganic filler (1)") and a curing accelerator (2E4MZ, manufactured by Sizhou chemical industry Co., Ltd., specific gravity of 0.975 g/cm)³)0.2 part by volume, and stirring and mixing for 15 minutes by a planetary mixerThus, an insulating resin composition was obtained.

(production of Circuit Board)

The insulating resin composition was applied to a film made of polyethylene terephthalate (PET) having a thickness of 0.05mm so that the cured thickness became 0.20mm, and the film was heated at 100 ℃ for 15 minutes to prepare a sheet in a B-stage (semi-cured) state.

Subsequently, the produced sheet was peeled from the PET film, placed on a copper plate having a thickness of 2.0mm, and a copper Foil (GTS-MP, manufactured by Furukawa Circuit Foil Co., Ltd.) having a thickness of 0.035mm was disposed thereon. While applying a surface pressure of 100kgf/cm by a press²The resultant was cured by heating at 180 ℃ for 180 minutes to obtain a laminate.

Next, the copper foil is etched using a sulfuric acid-hydrogen peroxide mixed solution as an etching solution after masking a predetermined position with a resist. The resist was removed, and the substrate was washed and dried to obtain a circuit board having a circular electrode with a diameter of 20mm formed of a copper foil.

< example 2>

A circuit board was obtained in the same manner as in example 1, except that a naphthalene-based epoxy resin (HP4032D, manufactured by DIC corporation, and shown as "epoxy resin (2)" in the table) was used instead of the bisphenol a-based epoxy resin, and the blending amounts of the respective components were changed as shown in table 1.

< example 3>

As the amine-based curing agent, an amine-based curing agent (2) containing 50 mass% of the amine compound represented by the formula (A-1-1), 18 mass% of the amine compound represented by the formula (A-1-2), 30 mass% of the amine compound represented by the formula (A-2-2), and 2 mass% of another amine compound was prepared.

A circuit board was obtained in the same manner as in example 1, except that the amine-based curing agent (2) was used instead of the amine-based curing agent (1) and the amount of each component was changed as shown in table 1.

< examples 4 to 6>

A circuit board was obtained in the same manner as in example 1, except that the blending amount of each component was changed as shown in table 1 or table 2.

< example 7>

A circuit board was obtained in the same manner as in example 1, except that a boron nitride filler (manufactured by Denka corporation, having an average particle diameter of 40 μm, and shown as "inorganic filler (2)" in the table) was used instead of the inorganic filler (1), and the blending amounts of the respective components were changed as shown in table 2.

< comparative example 1>

A circuit board was obtained in the same manner as in example 1, except that diaminodiphenyl sulfone (DDS) was used as the curing agent instead of the amine-based curing agent (1) and the amounts of the respective components were changed as shown in table 2.

< comparative example 2>

A circuit board was obtained in the same manner as in example 1, except that methylenedianiline (diaminodiphenylmethane, DDM) was used as the curing agent instead of the amine-based curing agent (1) and the blending amounts of the respective components were changed as shown in table 2.

< comparative example 3>

A circuit board was obtained in the same manner as in example 1 except that a Novolac type phenol resin (VH-4150, manufactured by DIC corporation) was used as the curing agent in place of the amine-based curing agent (1) and the amounts of the components to be blended were changed as shown in table 2.

The examples and comparative examples were evaluated by the following methods. The results are shown in tables 1 and 2.

[ evaluation of thermal conductivity ]

The sheets in the B-stage (semi-cured) state obtained by the above method were stacked, and pressure heat-molded to produce a thermal conductive sheet having a length of 10mm, a width of 10mm, and a thickness of 0.5mm, and thermal diffusivity α was measured by a laser flash method to evaluate thermal conductivity λ according to the following formula.

λ＝α×Cp×ρ

The specific heat Cp was calculated from DSC measurement.

The specific gravity ρ of the thermal conductive sheet was calculated by the following equation, by measuring the weight of the sheet in air and the weight of the sheet in distilled water at 25 ℃ and 1013hPa using a specific gravity measurement kit AD-1653 (trade name) available from a & D.

ρ＝A/(A-B)×(ρ0-d)+d

(wherein A represents the mass of the thermal conductive sheet in air, B represents the mass of the thermal conductive sheet in distilled water,. rho.0 represents the density of distilled water, and d represents the density of air.)

The results are shown in tables 1 and 2. The thermal conductivity is preferably 8W/mK or more.

[ evaluation of insulation ]

The insulation strength of the circuit board obtained by the above method was measured based on JIS C6481 using TOS 8650 (trade name) manufactured by jerusalem electronics industries co. The results are shown in tables 1 and 2. When the thermal conductive sheet is 0.20mm, the insulation strength is preferably 8kV or more (40kV/mm or more).

[ storage elastic modulus and crosslink Density of insulating resin cured product ]

The insulating resin composition was degassed in vacuum and then cured under curing conditions of 50 ℃ for 3 hours +160 ℃ for 6 hours to obtain an insulating resin cured product. The obtained cured insulating resin was cut with a diamond cutter to obtain a plate-shaped measurement sample of 1mm × 3mm × 40 mm. A dynamic viscoelasticity measuring apparatus (T) was used for the measurement sample&A Instruments, "RSA 3", measured the storage modulus of elasticity at a temperature of T1(K) by the DMA method (JIS K0129 (2005)). The temperature T1 is the glass transition temperature of the resin component constituting the cured insulating resin +30(K), and the storage elastic modulus is measured in a temperature range of-50 ℃ to +250 ℃ under the conditions of a frequency of 10Hz and a temperature rise rate of 10 ℃/min. From the measurement results, the crosslinking density (mol/cm) was calculated by the following formula³)。

Crosslinking density ═ storage elastic modulus/(3X gas constant X T1)

[ evaluation of reliability based on high-temperature high-pressure bias Test (THB) ]

A high-temperature high-voltage bias Test (THB) was carried out under test conditions in which a DC voltage of 1200V was applied between the metal foil and the metal plate in an environment of 85 ℃ and 85% humidity. The durability time was 350 hours or longer and evaluated as A, and the durability time was less than 200 hours and evaluated as C.

[ evaluation of Heat cycle resistance ]

A lead-tin eutectic solder was used to mount 6 chip resistors having a chip size of 2.0mm × 1.25mm on a circuit board, and a thermal cycle test was performed 500 times with 1 cycle of-40 ℃ for 7 minutes to +125 ℃ for 7 minutes. After the test, the cross section of the joint between the solder and the component was observed with a microscope at 50 magnifications to examine the crack occurrence state. The same test was conducted 3 times, and the number of cracks in 18 (6 × 3) connecting portions was determined and evaluated.

[ Table 1]

[ Table 2]

Industrial applicability

According to the present invention, an insulating layer having excellent insulating reliability under conditions of high temperature, high humidity and high voltage application and high heat cycle resistance can be formed. Further, according to the present invention, a circuit board including the insulating layer and having excellent insulation reliability and heat cycle resistance under conditions of high temperature, high humidity and high voltage application can be obtained. Therefore, the present invention can be suitably used in the semiconductor field and the like.

Description of the reference numerals

1 … metal plate, 2 … insulating layer, 3 … metal foil, 4 … circuit part, 10 … laminated body, 20 … circuit board.

Claims

1. An insulating resin composition comprising an epoxy resin, an amine-based curing agent, and an inorganic filler,

the amine-based curing agent comprises a first amine compound represented by the formula (A-1) and a second amine compound represented by the formula (A-2),

in the formula (A-1), n¹Represents an integer of 0 to 4, X¹Represents an alkanediyl group, an oxygen atom or a sulfur atom; n is¹When it is 1 or more, there are plural X' s¹May be the same or different from each other;

in the formula (A-2), n²Represents an integer of 0 to 4, X²Represents an alkanediyl group, an oxygen atom or a sulfur atom, and Y represents-NH₂or-NHR¹(R¹A group represented by the formula (Y-1); y's in plural may be the same or different from each other; wherein at least one of Y is-NHR¹；n²When it is 1 or more, there are plural X' s²May be the same or different from each other;

in the formula (Y-1), R²Represents an alkyl group.

2. The insulating resin composition according to claim 1, wherein X is¹And said X²Is a methanediyl group.

3. The insulating resin composition according to claim 1 or 2, wherein the content of the first amine compound in the amine-based curing agent is 30 to 60% by mass,

the content of the second amine compound in the amine-based curing agent is 40 to 70 mass%.

4. The insulating resin composition according to any one of claims 1 to 3, wherein-NHR in the amine-based curing agent¹Total number M of₂and-NH₂Total number M of₁Ratio of (M)₂/M₁) 0.05 to 0.3.

5. The insulating resin composition according to any one of claims 1 to 4, wherein a ratio of active hydrogen equivalent of the amine-based curing agent to epoxy equivalent of the epoxy resin is 0.3 to 1.5.

6. An insulating resin cured product of the insulating resin composition according to any one of claims 1 to 5.

7. The cured insulating resin according to claim 6, wherein the content of the inorganic filler is 35 to 80 vol%.

8. The insulating resin cured product according to claim 6 or 7, wherein the crosslinking density is 4.0X 10^-2～5.0×10^-1mol/cm³。

9. The cured insulating resin according to any one of claims 6 to 8, which has a storage elastic modulus at-40 ℃ of 100GPa or less.

10. A laminate body, comprising:

a metal plate;

the cured insulating resin according to any one of claims 6 to 9 disposed on the metal plate; and

and a metal foil disposed on the cured insulating resin.

11. A circuit board, comprising:

a metal plate;

the cured insulating resin according to any one of claims 6 to 9 disposed on the metal plate; and the combination of (a) and (b),

and a circuit section disposed on the cured insulating resin body.