JP6069834B2 - Resin sheet, metal foil with resin, resin cured product, metal substrate, LED substrate, and method for producing metal foil with resin - Google Patents

Description

  The present invention relates to a resin sheet, a resin-coated metal foil, a metal substrate, an LED substrate, and a method for producing a resin-coated metal foil.

With the progress of higher density and downsizing of electronic devices, heat dissipation of electronic components such as semiconductors has become a major issue. Therefore, a resin composition having high thermal conductivity and high electrical insulation has been required, and has been put to practical use as a heat conductive sealing material or a heat conductive adhesive.
In order to increase the heat dissipation of the epoxy resin composition, crystalline silica, alumina, aluminum nitride, etc. as inorganic fillers have higher thermal conductivity than fused silica normally used in epoxy resin compositions for sealing. Methods for adding substances have been reported in the past, but when a large amount of crystalline silica, alumina, aluminum nitride, etc. is added to obtain sufficient heat dissipation, molding such as flowability and curability of the epoxy resin composition In many cases, this results in a decrease in performance or a decrease in insulation reliability.

  In recent years, reports on attempts to increase the heat dissipation of the epoxy resin composition for sealing have come to be seen from the structural aspect of the resin in relation to the approach from the inorganic filler. For example, Patent Document 1 discloses a combination of a so-called mesogenic resin having a biphenyl skeleton and the like and a novolak resin such as catechol and resorcinol, and reducing the internal thermal resistance by increasing the orientation of the resin skeleton. It is disclosed that the heat dissipation of the composition can be enhanced.

  Patent Document 2 discloses an epoxy resin composition containing an epoxy resin exhibiting liquid crystallinity and alumina powder, and is said to have high thermal conductivity and excellent workability.

Japanese Patent No. 2874089 JP 2008-13759 A

However, novolak resins such as catechol and resorcinol described in Patent Document 1 are prone to gelation during resin synthesis, have a high softening point, and are difficult to produce an epoxy resin composition for sealing. There was a problem.
Moreover, in the epoxy resin composition described in Patent Document 2, sufficient electrical insulation properties may not be obtained.

  The present invention has been made in view of the above, a resin sheet that is capable of forming a cured resin having excellent thermal conductivity and excellent electrical insulation and is excellent in flexibility, and a resin-attached metal using the resin sheet It is an object of the present invention to provide a method for producing a foil, a metal substrate, an LED substrate, and a resin-coated metal foil.

The present invention includes the following aspects.
<1> An epoxy resin having a partial structure represented by the following general formula (I), a curing agent having a partial structure represented by at least one of the following general formulas (IIa) to (IId), and inorganic A resin sheet which is a semi-cured product of an epoxy resin composition containing a filler.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) and (IIIb). A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

<2> The inorganic filler has a peak value in each of a particle size distribution measured using a laser diffraction method of 0.01 μm to 1 μm, 1 μm to 10 μm, and 10 μm to 100 μm. And the resin sheet as described in said <1> in which the said inorganic filler which has a particle diameter of 10 micrometers or more and 100 micrometers or less contains boron nitride.

<3> The resin sheet according to <1> or <2>, further including an elastomer.

<4> Metal foil with resin provided with metal foil and the resin sheet of any one of said <1>-<3> arrange | positioned on the said metal foil.

<5> A metal support, a cured resin layer that is a cured product of the resin sheet according to any one of <1> to <3> disposed on the metal support, and the cured resin layer A metal substrate comprising a metal foil disposed on the substrate.

<6> A metal support, a cured resin layer that is a cured product of the resin sheet according to any one of <1> to <3> disposed on the metal support, and the cured resin layer An LED substrate comprising: a circuit layer made of a metal foil disposed on the LED layer; and an LED element disposed on the circuit layer.

<7> An epoxy resin that is disposed on the metal foil and has a partial structure represented by the following general formula (I), represented by at least one of the following general formulas (IIa) to (IId) And a semi-cured resin layer, which is a semi-cured product of an epoxy resin composition containing an inorganic filler.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

<8> At least one of a metal support, an epoxy resin disposed on the metal support and having a partial structure represented by the following general formula (I), and the following general formulas (IIa) to (IId) A metal substrate comprising a cured resin layer that is a cured product of a resin composition containing a curing agent having a partial structure represented by formula (1) and an inorganic filler, and a metal foil disposed on the cured resin layer.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

<9> Epoxy resin having a partial structure represented by the following general formula (I), a curing agent having a partial structure represented by at least one of the following general formulas (IIa) to (IId), and inorganic filling A resin-coated metal foil comprising: a step of applying a resin composition containing an agent on a metal foil to form a resin layer; and a B-stage forming step of heat-treating the resin layer to form a semi-cured resin layer Manufacturing method.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

  According to the present invention, a resin sheet that is capable of forming a cured resin having excellent thermal conductivity and excellent electrical insulation and has excellent flexibility, and a resin-coated metal foil, a metal substrate, an LED substrate, And the manufacturing method of metal foil with resin can be provided.

It is a graph which shows an example of the weight average molecular weight change of the phenol resin at the time of the synthesis | combination of the hardening | curing agent 1 concerning this embodiment. It is a graph which shows an example of the nucleus number change of the molecule | numerator of a phenol resin at the time of the synthesis | combination of the hardening | curing agent 1 concerning this embodiment. It is a figure which shows an example of the GPC chart of the phenol resin which is the hardening | curing agent 1 concerning this embodiment. It is a schematic sectional drawing which shows an example of the LED board concerning this embodiment. It is a perspective view which shows an example of the LED board concerning this embodiment. It is a schematic sectional drawing which shows an example of a structure of the power semiconductor device comprised using the resin sheet concerning this embodiment. It is a schematic sectional drawing which shows an example of a structure of the power semiconductor device comprised using the resin sheet concerning this embodiment. It is a schematic sectional drawing which shows an example of a structure of the power semiconductor device comprised using the resin sheet concerning this embodiment.

In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. It is.
Moreover, the numerical value range shown using "to" in this specification shows the range which includes the numerical value described before and behind "to" as a minimum value and a maximum value, respectively.
Furthermore, when referring to the amount of each component in the composition in the present specification, when there are a plurality of substances corresponding to each component in the composition, the plurality of the components present in the composition unless otherwise specified. Means the total amount of substances.

<Resin sheet>
The resin sheet of the present invention comprises (A) at least one epoxy resin having a partial structure represented by the following general formula (I) (hereinafter also referred to as “specific epoxy resin”), and (B) the following general formula. At least one curing agent having a partial structure represented by at least one of (IIa) to (IId) (hereinafter also referred to as “specific curing agent”), and (C) an inorganic filler. It is a semi-cured product of the contained epoxy resin composition.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) and (IIIb). A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

  The resin sheet of the present invention is a reaction product of (A) at least one epoxy resin having a structure represented by the following general formula (I), a dihydroxyarene and an aldehyde, and has a hydroxyl equivalent of 60 or more. It is also preferable that it is a semi-cured product of an epoxy resin composition containing at least one curing agent containing a phenol resin that is 130 or less and (C) an inorganic filler.

By configuring the epoxy resin composition (hereinafter also simply referred to as “resin composition”) to have the above-described structure, it is possible to achieve both excellent thermal conductivity and excellent electrical insulation, and a resin sheet having excellent flexibility. Can be configured. Moreover, the resin-attached metal foil with excellent flexibility can be obtained by arranging the resin sheet on the metal foil.
Below, each component which comprises an epoxy resin composition is demonstrated.

(A) Epoxy resin The epoxy resin constituting the epoxy resin composition is not particularly limited as long as it has a structure represented by the following general formula (I) and at least one epoxy group. Among these, a compound having a partial structure represented by the following general formula (I) and at least two epoxy groups is preferable.
When the epoxy resin has a partial structure represented by the general formula (I), it is possible to form a higher-order structure having a high order when a cured resin is obtained. Thereby, excellent thermal conductivity and high heat dissipation can be realized.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)

  The polyvalent epoxy resin represented by the general formula (I) has a feature that molecular orientation is easy. Such characteristics are advantageous for lowering the thermal resistance of the cured product of the epoxy resin composition, and as a result, the heat dissipation property of the cured product is enhanced and high heat dissipation is provided.

In addition to the epoxy resin having the partial structure represented by the general formula (I), the epoxy resin composition may include other epoxy resins other than the epoxy resin having the structure represented by (I). You may include in the range which does not impair an effect.
Other epoxy resins can be appropriately selected from generally used epoxy resins.

Examples of the other epoxy resins include phenol novolac type epoxy resins, orthocresol novolac type epoxy resins and other phenols, cresols, xylenol, resorcin, catechol, bisphenol A, bisphenol F and other phenols and / or α-naphthol, Epoxylated novolak resin obtained by condensation or cocondensation of naphthols such as β-naphthol and dihydroxynaphthalene with compounds having aldehyde groups such as formaldehyde, acetaldehyde, propionaldehyde, benzaldehyde, salicylaldehyde in the presence of an acidic catalyst. , Diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, bisphenol A / D, phenols and / or naphthols and dimeth Glycidyl obtained by reaction of polychlorinated acid such as epoxidized phenol / aralkyl resin, stilbene type epoxy resin, hydroquinone type epoxy resin, phthalic acid, dimer acid, etc., synthesized from xiparaxylene or bis (methoxymethyl) biphenyl with epichlorohydrin Ester-type epoxy resins, diaminodiphenylmethane, isocyanuric acid, and other polyamines and epichlorohydrin, glycidylamine-type epoxy resins, cyclopentadiene and phenols co-condensation resin dicyclopentadiene-type epoxy resins, hydroxynaphthalene and Epoxy compounds such as dihydroxy naphthalene dimer, triphenolmethane type epoxy resin, trimethylolpropane type epoxy resin, terpene modified epoxy Resins, linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peracids such as peracetic acid, alicyclic epoxy resins, sulfur atom-containing epoxy resins, and these epoxy resins based on silicone, acrylonitrile, butadiene, isoprene Examples thereof include epoxy resins modified with rubber, polyamide-based resins, and the like.
These may be used alone or in combination of two or more.

The content of the epoxy resin in the total solid content of the epoxy resin composition is not particularly limited, but from the viewpoint of thermal conductivity, electrical insulation, and flexibility of the resin sheet, 3 mass% or more and 10 mass% or less. It is preferable that it is 4 mass% or more and 7 mass% or less from a viewpoint of the physical property of the hardened | cured material mentioned later.
In addition, solid content in an epoxy resin composition means the residue which removed the volatile component from the component which comprises an epoxy resin composition.

(B) Curing Agent The epoxy resin composition is at least one curing agent (specific curing agent) having at least one partial structure represented by at least one of the following general formulas (IIa) to (IId). Including species. By combining a specific curing agent and a specific epoxy resin, excellent thermal conductivity can be achieved. Moreover, the said epoxy resin composition may further contain other hardening | curing agents other than a specific hardening | curing agent as needed.

(In the general formulas (IIa) to (IId), m and n are each independently a positive number and represent the number of repetitions of each repeating unit. Ar is any one of the following general formulas (IIIa) and (IIIb) A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)

The curing agent having a partial structure represented by at least one of the general formulas (IIa) to (IId) can be generated simultaneously by the production method described later, and the general formulas (IIa) to (IId) It can be produced as a mixture of compounds having at least two partial structures selected from:
That is, the specific curing agent is selected from the general formulas (IIa) to (IId) even if it contains a compound having only a partial structure represented by any one of the general formulas (IIa) to (IId). It may contain a compound having at least two kinds of partial structures.

In general formulas (IIa) to (IId), the substitution position of the hydroxyl group is not particularly limited as long as it is on the aromatic ring.
For each of the general formulas (IIa) to (IId), a plurality of Ars may be the same atomic group or may contain two or more kinds of atomic groups. The partial structures represented by the general formulas (IIa) to (IId) may be included as the main chain skeleton of the curing agent, or may be included as a part of the side chain. Furthermore, each repeating unit constituting the partial structure represented by any one of the general formulas (IIa) to (IId) may be included randomly or may be included regularly. However, it may be included in a block shape.

In the partial structure represented by any one of the general formulas (IIa) to (IId), Ar represents a group represented by any one of the above general formulas (IIIa) and (IIIb).
R ¹¹ and R ¹⁴ in the general formulas (IIIa) and (IIIb) are each independently a hydrogen atom or a hydroxyl group, but are preferably a hydroxyl group from the viewpoint of thermal conductivity. Further, the substitution positions of R ¹¹ and R ¹⁴ are not particularly limited.
R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Examples of the alkyl group having 1 to 8 carbon atoms in R ¹² and R ¹³ include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tertiary butyl group, a pentyl group, a hexyl group, and a heptyl group. Group and octyl group. In addition, the substitution positions of R ¹² and R ^{13 in} the general formulas (IIIa) and (IIIb) are not particularly limited.

Ar in the general formulas (IIa) to (IId) is a group derived from dihydroxybenzene (in the general formula (IIIa), R ¹¹ is a hydroxyl group from the viewpoint of achieving the effects of the present invention, particularly excellent thermal conductivity. , R ¹² and R ¹³ are a hydrogen atom), and a group derived from dihydroxynaphthalene (a group in which R ¹⁴ is a hydroxyl group in the general formula (IIIb)).
Here, the “group derived from dihydroxybenzene” means a divalent group formed by removing two hydrogen atoms from the aromatic ring portion of dihydroxybenzene, and the position at which the hydrogen atom is removed is not particularly limited. In addition, “group derived from dihydroxynaphthalene” has the same meaning.

  Moreover, from the viewpoint of productivity and fluidity of the epoxy resin composition, Ar is more preferably a group derived from dihydroxybenzene, and a group derived from 1,2-dihydroxybenzene (catechol) and 1, More preferably, it is at least one selected from the group consisting of groups derived from 3-dihydroxybenzene (resorcinol).

  Furthermore, from the viewpoint of particularly improving thermal conductivity, it is preferable that Ar contains at least a group derived from 1,3-dihydroxybenzene (resorcinol), and Ar is a group derived from 1,3-dihydroxybenzene (resorcinol). It is particularly preferable that the content rate of the structural unit containing is 60% by mass or more in the total mass of the partial structures represented by the general formulas (IIa) to (IId).

In the general formulas (IIa) to (IId), m and n are preferably m / n = 20/1 to 1/5, more preferably 20/1 to 5/1, from the viewpoint of fluidity. The ratio is preferably 20/1 to 10/1, and more preferably. Further, (m + n) is preferably 20 or less, more preferably 15 or less, and still more preferably 10 or less, from the viewpoint of fluidity.
The lower limit value of (m + n) is not particularly limited.

The specific curing agent having a partial structure represented by at least one of the general formulas (IIa) to (IId) is particularly at least one of Ar-substituted or unsubstituted dihydroxybenzene and substituted or unsubstituted dihydroxynaphthalene. In the case of one type, compared with a resin or the like obtained by simply converting these to a novolac, the synthesis is easy and a curing agent having a low softening point tends to be obtained. Therefore, there are advantages such as easy manufacture and handling of a resin composition containing such a resin.
In addition, the hardening | curing agent which has the partial structure represented by either of general formula (IIa)-(IId) is used as the fragment component by Field Desorption Ionization Mass-Spectrometry: Field desorption ionization mass spectrometry (FD-MS). The partial structure can be easily specified.

The molecular weight of the specific curing agent is not particularly limited. From the viewpoint of fluidity, the number average molecular weight is preferably 2000 or less, more preferably 1000 or less, and further preferably 350 or more and 1000 or less.
The weight average molecular weight is preferably 2000 or less, more preferably 1500 or less, and further preferably 400 or more and 1500 or less.
The number average molecular weight and the weight average molecular weight of the specific curing agent are measured by an ordinary method using GPC (gel permeation chromatography).

The hydroxyl equivalent of the specific curing agent is not particularly limited. From the viewpoint of the crosslinking density involved in heat resistance, the hydroxyl group equivalent of the specific curing agent is preferably 60 or more and 130 (g / eq) or less on average, and 65 or more and 120 (g / eq) or less. More preferably, it is 70 or more and 110 (g / eq) or less.
Moreover, the said epoxy resin composition may contain the monomer component mentioned later as a low molecular diluent in addition to a specific hardening | curing agent. It is preferable that the content rate of a monomer component is 40 mass% or less in the total mass of a hardening | curing agent. In this case, the hydroxyl group equivalent of the curing agent is preferably 60 to 80 (g / eq) on average.

The manufacturing method of the hardening | curing agent (specific hardening | curing agent) which has the partial structure represented by at least 1 among general formula (IIa)-(IId) is not specifically limited. For example, the following method using an intramolecular ring closure reaction by autoxidation of dihydroxyarenes can be used. That is, for example, phenols containing 20 mol% to 90 mol% catechol (1,2-dihydroxybenzene, a compound in which R ¹¹ is a hydroxyl group and R ¹² and R ¹³ are hydrogen in the general formula (IIIa)), and the like, It can be produced by reacting an aldehyde with an acid catalyst such as oxalic acid in the same manner as a general novolak resin.

  The reaction conditions can be appropriately selected according to the structure of the specific curing agent. For example, when formaldehyde is used as the aldehyde, the reaction is performed under reflux conditions around 100 ° C. This refluxing reaction is performed for 1 to 8 hours, and then the temperature is raised to 120 ° C. to 180 ° C. while removing water in the reaction system by a conventional method. The atmosphere at this time is preferably an oxidizing atmosphere (for example, in an air stream). Then, by continuing this state for 2 to 24 hours, a compound having a partial structure represented by the general formula (IIa) or (IIb) is generated in the system, and a desired curing agent can be obtained.

  Further, in the intramolecular ring closure reaction by autooxidation of the above-mentioned dihydroxyarenes, by using resorcinol, catechol and aldehydes in the same manner, at least one of general formulas (IIa) to (IId) A mixture of compounds having the partial structure represented is produced. Furthermore, resorcinol and aldehydes are similarly reacted to produce a mixture of compounds having a partial structure represented by at least one of general formulas (IIa), (IIc) and (IId). Furthermore, by reacting hydroquinone, catechol and aldehydes in the same manner, a mixture of compounds having a partial structure represented by at least one of general formulas (IIa) and (IIb) is generated.

  When the specific curing agent is viewed from another viewpoint, it is a phenol resin composition obtained by reacting dihydroxyarenes and aldehydes in the presence of an acidic catalyst, and the hydroxyl group equivalent is a theoretical hydroxyl group equivalent of a novolak resin of dihydroxyarenes (60 It is a phenolic resin composition that is larger than before and after. By using such a phenol resin composition as a curing agent, it is considered that the effect of assisting the orientation of the epoxy resin and, as a result, enhancing the heat dissipation of the epoxy resin composition can be obtained. The reason why the hydroxyl group equivalent becomes larger than the theoretical value is considered to be because dihydroxyarenes undergo an intramolecular ring-closing reaction during the reaction and include a phenol resin having a partial structure such as the above general formulas (IIa) to (IId). .

Dihydroxyarenes used for the production of the specific curing agent include monocyclic dihydroxyarenes such as catechol, resorcinol, and hydroquinone, and 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, and 1,4-dihydroxynaphthalene. And polycyclic dihydroxyarenes such as dihydroxynaphthalenes. These may be used alone or in combination of two or more.
Examples of aldehydes include aldehydes usually used for phenol resin synthesis, such as formaldehyde, acetaldehyde, benzaldehyde, salicylaldehyde, and the like. These may be used alone or in combination of two or more.

These dihydroxyarenes and aldehydes are preferably reacted in the presence of an acid catalyst using 0.3 to 0.9 moles of aldehydes per mole of dihydroxyarenes. More preferably, aldehydes are used in an amount of 0.4 mol to 0.8 mol.
By using 0.3 mol or more of aldehydes, the content of dibenzoxanthene derivatives can be increased, and the amount of unreacted dihydroxyarenes can be suppressed and the amount of resin produced can be increased. . Further, when the aldehydes are 0.9 mol or less, gelation in the reaction system is suppressed and the reaction tends to be easily controlled.

Examples of acids used as the acid catalyst include oxalic acid, acetic acid, p-toluenesulfonic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, and organic acids such as methanesulfonic acid, and inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid. Can be mentioned. These acids may be used alone or in combination of two or more.
The amount of the acid catalyst used is preferably, for example, 0.0001 mol to 0.1 mol with respect to 1 mol of the dihydroxyarene used. More preferably, 0.001 to 0.05 mol is used. When the amount of the acid catalyst used is 0.0001 mol or more, the process of performing intramolecular dehydration and ring closure at 120 to 180 ° C. tends to be short. If the amount is 0.1 mol or less, the catalyst removal step tends to be easier, and application to a system that dislikes ionic impurities in semiconductor applications and the like is facilitated.

  The said epoxy resin composition may further contain other hardening | curing agents other than a specific hardening | curing agent in the range which does not impair the effect of this invention. The other curing agent can be appropriately selected from curing agents generally used for sealing and adhesive epoxy resin compositions. Specific examples of other curing agents include phenols such as phenol, cresol, resorcin, catechol, bisphenol A, bisphenol F, phenylphenol, and aminophenol; naphthols such as α-naphthol, β-naphthol, and dihydroxynaphthalene. A novolak type phenol obtained by condensing or co-condensing at least one selected from the group consisting of phenols and naphthols with a compound having an aldehyde group such as formaldehyde, benzaldehyde, and salicylaldehyde under an acidic catalyst Resin; dicyclopentadiene type phenol novolac resin synthesized by copolymerization with at least one selected from the group consisting of phenols and naphthols and cyclopentadiene, and dicyclopentadi Examples thereof include dicyclopentadiene-type phenol resins such as ene-type naphthol novolak resins; terpene-modified phenol resins; triphenolmethane-type phenol resins.

  The content rate of the other hardening | curing agent contained in the said epoxy resin composition is not restrict | limited especially unless the effect of this invention is impaired, It selects suitably.

  The said epoxy resin composition may contain the monomer which is a phenolic compound which comprises a specific hardening | curing agent. Although there is no restriction | limiting in particular as a content ratio (henceforth a "monomer content ratio") of the monomer which is a phenolic compound which comprises a specific hardening | curing agent, It is preferable that it is 5-80 mass%, and 15-60. More preferably, it is 20 mass%, and it is still more preferable that it is 20-50 mass%.

  When the monomer content ratio is 20% by mass or more, an increase in the viscosity of the phenol resin is suppressed, and the adhesion of the inorganic filler is further improved. Moreover, by being 50 mass% or less, a higher-order higher-order structure is formed by the crosslinking reaction in the case of hardening, and the outstanding heat conductivity and heat resistance can be achieved.

  Examples of the phenolic compound monomer constituting the specific curing agent include resorcinol, catechol, and hydroquinone, and it is preferable that at least resorcinol is included as a monomer.

(C) Inorganic filler The said epoxy resin composition contains at least 1 sort (s) of an inorganic filler. The inorganic filler can be appropriately selected from inorganic fillers usually used in the technical field. Specific examples include non-conductive materials such as alumina, aluminum nitride, boron nitride, silicon nitride, silicon oxide, magnesium oxide, aluminum hydroxide, and barium sulfate. Examples of the conductive material include gold, silver, nickel, and copper. These can be used alone or in a mixture of two or more.

The inorganic filler may be an inorganic filler having a particle size distribution having a single peak, or may be a combination of a plurality of types of inorganic fillers having different particle size distributions. Among these, from the viewpoint of thermal conductivity, it is preferable to combine three or more types of inorganic fillers each showing a different particle size distribution, and a combination of three or more types of inorganic fillers each showing a different particle size distribution. It is more preferable that the inorganic filler having the largest particle diameter is boron nitride.
When the inorganic filler is, for example, a combination of three types of inorganic fillers each having a different particle size distribution, the particle size distribution of the inorganic filler contained in the epoxy resin composition is that of the three types of inorganic fillers. It has at least three peaks corresponding to each. Moreover, the peak area of each peak is according to the content rate of each inorganic filler.

  When the inorganic filler is a combination of a plurality of types of alumina particles and boron nitride, the mixing ratio is appropriately selected according to the number of alumina particle groups to be combined, the average particle diameter of each alumina particle group, and the like. be able to.

  Here, the particle size D50 of the inorganic filler (preferably alumina) is measured using a laser diffraction method, and when the volume cumulative particle size distribution curve is drawn from the small particle size side, the particle size at which the volume cumulative is 50%. Corresponding to The particle size distribution measurement using the laser diffraction method can be performed using a laser diffraction scattering particle size distribution measuring apparatus (for example, trade name: LS230, manufactured by Beckman Coulter, Inc.).

Of the three types of inorganic fillers, the first inorganic filler group preferably has a particle diameter D50 corresponding to 50% cumulative from the small particle size side of the volume cumulative particle size distribution of 10 μm or more and 100 μm or less. From the viewpoint of thermal conductivity and electrical insulation, it is preferably 20 μm or more and 90 μm or less, and from the viewpoint of maintaining the flatness of the sheet, it is more preferably 30 μm or more and 80 μm or less.
Further, the boron nitride content of the first inorganic filler group in the total mass of the inorganic filler contained in the epoxy resin composition is preferably 50% by volume or more and 80% by volume or less, From the viewpoint of electrical insulation, it is more preferably 60% by volume or more and 70% by volume or less.

Of the three types of inorganic fillers, the second inorganic filler group may have a particle diameter D50 corresponding to 50% cumulative from the small particle size side of the volume cumulative particle size distribution of 1 μm or more and less than 10 μm. preferable. From the viewpoint of thermal conductivity and electrical insulation, it is preferably 2 μm or more and 6 μm or less, and from the viewpoint of reducing voids in the sheet, it is more preferably 2.5 μm or more and 5 μm or less.
The content of the second inorganic filler group in the total volume of the inorganic filler contained in the epoxy resin composition is preferably 15% by volume or more and 30% by volume or less, and has a thermal conductivity and electrical insulation properties. From a viewpoint, it is more preferable that it is 18 volume% or more and 27 volume% or less, and it is still more preferable that it is 18.5 volume% or more and 25 volume% or less.

Further, among the three types of inorganic fillers, the third inorganic filler group preferably has a particle diameter D50 corresponding to 50% cumulative from the small particle diameter side of the weight cumulative particle size distribution is less than 1 μm. From the viewpoints of thermal conductivity and electrical insulation, it is preferably 0.1 μm or more and 0.8 μm or less, and from the viewpoint of reducing voids in the sheet, it is more preferably 0.2 μm or more and 0.6 μm or less.
The content of the third inorganic filler group in the total volume of the inorganic filler contained in the epoxy resin composition is preferably 1% by mass or more and 25% by mass or less, and has a thermal conductivity and electrical insulation properties. From the viewpoint, it is more preferably 5% by mass or more and 20% by mass or less, and further preferably 10% by mass or more and 18% by mass or less.

The alumina used as the inorganic filler in the present invention is not particularly limited in crystal structure and the like as long as it has the particle size distribution described above, and α-alumina, β-alumina, γ-alumina, δ-alumina, θ -Alumina or the like may be used, but at least one of the second and third inorganic filler groups is preferably an alumina group, and at least one of the second and third inorganic filler groups is α-alumina is more preferable, and these are more preferably composed of α-alumina only from the viewpoint of thermal conductivity.
The second and third inorganic filler groups are more preferably alumina made of α-alumina single crystal particles from the viewpoint of thermal conductivity.

  The alumina used for the second and third inorganic filler groups can be appropriately selected from commercially available ones. Also, the alumina powder that becomes transition alumina by heat treatment or heat treatment is fired in an atmosphere gas containing hydrogen chloride (see, for example, JP-A-6-191833, JP-A-6-191836, etc.). ).

There is no restriction | limiting in particular in the content rate of the inorganic filler (preferably alumina) contained in the said epoxy resin composition. The solid content constituting the epoxy resin composition can be 80% by mass or more and 95% by mass or less, and from the viewpoint of thermal conductivity, electrical insulation, and sheet flexibility, 82% by mass or more and 90% by mass or less. It is more preferable that
In addition, solid content in an epoxy resin composition means the residue which removed the volatile component from the component which comprises an epoxy resin composition.

(D) Elastomer The epoxy resin composition preferably contains at least one elastomer. By including an elastomer, the flexibility of the resin sheet can be increased and the excessive fluidity of the resin during crimping can be suppressed.
There is no restriction | limiting in particular as a kind of elastomer, A conventionally well-known elastomer can be used according to heat resistance or availability. Among these, from the viewpoint of viscosity characteristics, an elastomer having a weight average molecular weight of 10,000 to 300,000 is preferable, an elastomer of 30,000 to 200,000 is more preferable, and an elastomer of 50,000 to 100,000 is preferable. More preferably.
The weight average molecular weight of the elastomer is measured by a usual method using GPC.

In addition, the elastomer is preferably an acrylic elastomer from the viewpoint of compatibility with the epoxy resin, and is an acrylic elastomer that is a methyl methacrylate / butyl acrylate / ethyl acrylate / glycidyl methacrylate copolymer. More preferred.
Further, an acrylic elastomer that does not contain a nitrile rubber component as a copolymer component is also preferable. By not including the nitrile rubber component in the copolymerizable component, electrical reliability can be further improved.

The elastomer preferably contains an acrylic elastomer having a weight average molecular weight of 10,000 or more and 300,000 or less, and an acrylic having a weight average molecular weight of 30,000 or more and 200,000 or less, from the viewpoint of the flexibility and flowability of the resin sheet. More preferably, a system elastomer is included.
Furthermore, the content of the acrylic elastomer having a weight average molecular weight of 50,000 or more and 100,000 or less contained in the elastomer is preferably 70% by mass or more in the total mass of the elastomer contained in the epoxy resin composition, More preferably, it is 90 mass% or more.

  When the epoxy resin composition contains an elastomer having a predetermined weight average molecular weight, the melt viscosity of the semi-cured resin sheet can be prevented from becoming too low even if the epoxy resin composition contains a specific epoxy resin and a specific curing agent. . Thereby, even when high stress (press etc.) is applied before gelatinization, an excessive flow property can be suppressed.

  There is no restriction | limiting in particular in the content rate of the elastomer contained in the said epoxy resin composition. The content of the elastomer can be 0.1% by mass or more and 2.0% by mass or less in the solid content constituting the epoxy resin composition. From the viewpoint of thermal conductivity and sheet flexibility, 0.3% It is more preferable that the content is not less than 1.5% by mass.

The epoxy resin composition preferably contains at least one curing accelerator in addition to the essential components. By including a curing accelerator, the gel time can be easily adjusted to a desired range.
As the curing accelerator, a commonly used curing accelerator can be used without particular limitation. Examples of curing accelerators include, for example, 1,8-diaza-bicyclo [5.4.0] undec-7-ene, 1,5-diaza-bicyclo [4.3.0] nonene, 5, 6 -Cycloamidine compounds such as dibutylamino-1,8-diaza-bicyclo [5.4.0] undec-7-ene, and maleic anhydride, 1,4-benzoquinone, 2,5-toluquinone 1,4-naphthoquinone, 2,3-dimethylbenzoquinone, 2,6-dimethylbenzoquinone, 2,3-dimethoxy-5-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, phenyl A compound having intramolecular polarization formed by adding a quinone compound such as -1,4-benzoquinone, a compound having a π bond such as diazophenylmethane or phenol resin; benzyldimethyl Tertiary amine compounds such as min, triethanolamine, dimethylaminoethanol, tris (dimethylaminomethyl) phenol and their derivatives; 2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl Imidazole compounds such as 2-phenylimidazole and their derivatives; organic phosphines such as tributylphosphine, methyldiphenylphosphine, triphenylphosphine, tris (4-methylphenyl) phosphine, diphenylphosphine, phenylphosphine, etc. Organophosphorus compounds such as maleic acid, quinone compounds, diazophenylmethane, phenolic resins and other compounds having an intramolecular polarization formed by adding a compound having a π bond; Le phosphonium tetraphenylborate, triphenylphosphine tetraphenylborate, 2-ethyl-4-methylimidazole tetraphenyl borate, etc. tetraphenyl boron salts and derivatives thereof such as N- methylmorpholine tetraphenylborate and the like. These may be used alone or in combination of two or more. From the viewpoint of reliability and moldability, an organophosphorus compound is preferred.

  Although the content rate of the hardening accelerator in the said epoxy resin composition will not be restrict | limited especially if the quantity in which a hardening acceleration effect is achieved, 0.1-10 mass% is preferable with respect to an epoxy resin. There exists a tendency which is excellent in curability in a short time that the content rate of a hardening accelerator is 0.1 mass% or more. Moreover, when the content rate of a hardening accelerator is 10 mass% or less, there exists a tendency for it to suppress that a cure rate becomes too quick and to obtain a favorable hardened | cured material.

The epoxy resin composition preferably contains at least one coupling agent. Thereby, the adhesiveness of the resin component which consists of an epoxy resin and a hardening | curing agent, and an inorganic filler can be improved.
Examples of the coupling agent include silane coupling agents such as epoxy silane, mercapto silane, amino silane, alkyl silane, ureido silane, and vinyl silane, titanium compounds, aluminum chelates, and aluminum / zirconium compounds. These may be used alone or in combination of two or more.

  Commercially available silane coupling agents can be used normally, but considering the compatibility with epoxy resins and curing agents and reducing heat conduction loss at the interface between the resin layer and the inorganic filler, It is preferable to use a silane coupling agent having an epoxy group, an amino group, a mercapto group, a ureido group, or a hydroxyl group.

Specifically, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3 , 4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3-amino Examples thereof include propyltrimethoxysilane, 3-phenylaminopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptotriethoxysilane, 3-ureidopropyltriethoxysilane, etc., and trade name: SC- 6000KS It may also be mentioned, such as typified by a silane coupling agent oligomer (manufactured by Hitachi Chemical Coated Sand Co., Ltd.) to.
These silane coupling agents can be used alone or in combination of two or more.

  The content of the coupling agent in the epoxy resin composition is preferably 0.05% by mass to 5% by mass and more preferably 0.1% by mass to 2.5% by mass with respect to the inorganic filler. When the content of the coupling agent is 0.05% by mass or more, moisture resistance tends to be further improved. Moreover, there exists a tendency for thermal conductivity to improve more that the content rate of a coupling agent is 5 mass% or less.

  The epoxy resin composition can contain a dispersant. Any dispersant can be used without particular limitation as long as it is effective for dispersing the inorganic filler. As the dispersant, for example, Ajinomoto Finetech Co., Ltd., trade name: Ajisper series ("Ajisper" is a registered trademark), Enomoto Kasei Co., Ltd., trade name: HIPLAAD series ("HIPLAAD" is a registered trademark), Kao Product name: Homogenol series ("Homogenol" is a registered trademark), etc. These dispersants can be used alone or in combination of two or more.

The resin sheet of this invention consists of a semi-hardened material of the said epoxy resin composition, and has a sheet-like shape.
The resin sheet of the present invention includes, for example, a process for forming a resin film by applying and drying the epoxy resin composition on a release film, and a process for heat-treating the resin film to a B-stage state. Can be manufactured.
The resin sheet of the present invention is formed by heat-treating the epoxy resin composition, thereby being excellent in thermal conductivity and electrical insulation, and excellent in flexibility and usable time as a resin sheet.

Specifically, for example, a resin film can be obtained by applying and drying a varnish-like epoxy resin composition to which a solvent such as methyl ethyl ketone or cyclohexanenon is added on a release film such as a PET film. .
Application | coating can be implemented by a well-known method. Specific examples of the coating method include comma coating, die coating, lip coating, and gravure coating. As a coating method for forming a resin layer with a predetermined thickness, a comma coating method in which an object to be coated is passed between gaps, a die coating method in which a resin varnish whose flow rate is adjusted from a nozzle, or the like can be applied. . For example, when the thickness of the resin layer before drying is 50 μm to 300 μm, it is preferable to use a comma coating method.

Since the resin layer after coating has hardly progressed the curing reaction, it has flexibility, but it has poor flexibility as a sheet, and in the state where the PET film as a support is removed, the sheet is not self-supporting, It is difficult to handle. Therefore, in the present invention, the resin composition is B-staged by heat treatment described below.
In the present invention, the conditions for heat-treating the obtained resin film are not particularly limited as long as the epoxy resin composition can be semi-cured to the B stage state, and should be appropriately selected according to the configuration of the epoxy resin composition. Can do. In the present invention, the heat treatment is preferably performed by a heat treatment method selected from a hot vacuum press and a hot roll laminate. As a result, voids in the resin layer generated during coating can be reduced, and a flat resin sheet can be efficiently produced.

  The thickness of the resin sheet can be appropriately selected depending on the purpose, and can be, for example, 50 μm or more and 200 μm or less. From the viewpoint of thermal conductivity, electrical insulation, and sheet flexibility, 60 μm or more and 150 μm or less. It is preferable that It can also be produced by hot pressing while laminating two or more resin films.

<Metal foil with resin>
The metal foil with resin of this invention is equipped with metal foil and the semi-hardened resin layer which is a semi-hardened body of the said epoxy resin composition arrange | positioned on the said metal foil. By having a semi-cured resin layer derived from the epoxy resin composition, the thermal conductivity, electrical insulation, and flexibility are excellent.
The semi-cured resin layer is obtained by heat-treating the resin composition so as to be in a B-stage state.

The metal foil is not particularly limited, such as a gold foil, a copper foil, and an aluminum foil, but a copper foil is generally used.
The thickness of the metal foil can be, for example, 1 μm or more and 210 μm or less. In particular, the thickness is preferably 10 μm or more and 150 μm or less, and more preferably 18 μm or more and 105 μm or less. By using such a metal foil, the flexibility is further improved.
Also, nickel, nickel-phosphorus alloy, nickel-tin alloy, nickel-iron alloy, lead, lead-tin alloy, etc. are used as the intermediate layer as the metal foil, and a copper layer of 0.5 μm to 15 μm and 10 μm to 300 μm on both sides. It is also possible to use a three-layer composite foil provided with a copper layer, or a two-layer composite foil obtained by combining aluminum and copper foil.

  The resin-coated metal foil forms a resin layer (resin film) by applying and drying the resin composition on the metal foil, and heat-treats the resin layer so as to be in a B-stage state (semi-cured state). Can be manufactured.

The production conditions of the resin-coated metal foil are not particularly limited, but in the resin layer after drying, the organic solvent used in the resin varnish is volatilized by 80% by mass or more from the viewpoint of electrical insulation and appearance during the production of the metal substrate. Preferably it is. The drying temperature is about 80 ° C. to 180 ° C., and the drying time can be determined in consideration of the gelling time of the varnish, and is not particularly limited. The application amount of the resin varnish is preferably applied so that the thickness of the resin layer after drying is 50 μm to 200 μm, and more preferably 60 μm to 150 μm.
The resin layer forming method and heat treatment conditions are as described above.

<Metal substrate>
The metal substrate of the present invention comprises a metal support, a cured resin layer that is a cured product of the epoxy resin composition disposed on the metal support, and a metal foil disposed on the cured resin layer. Prepare. The metal substrate of the present invention is that the cured resin layer disposed between the metal support and the metal foil is formed by heat treatment so that the epoxy resin composition is in a cured state, Excellent adhesion, thermal conductivity, and electrical insulation.

  The material and thickness of the metal support are appropriately selected according to the purpose. Specifically, for example, it is preferable to use a metal such as aluminum or iron and set the thickness to 0.5 mm or more and 5 mm or less from the viewpoint of workability.

  Moreover, the metal foil arrange | positioned on a cured resin layer is synonymous with the metal foil in the said metal foil with resin, and its preferable aspect is also the same.

  The metal substrate of this invention can be manufactured as follows, for example. On the metal support such as aluminum, the epoxy resin composition is applied and dried in the same manner as described above to form a resin layer. Further, a metal foil is disposed on the resin layer, and this is heated and pressurized. It can manufacture by processing and hardening | curing a resin layer. Alternatively, the metal foil with resin may be laminated on a metal support so that the resin layer faces the metal support, and then heated and pressurized to cure the resin layer. it can.

  The conditions of the heating / pressurizing treatment for curing the resin layer are appropriately selected according to the configuration of the epoxy resin composition. For example, the heating temperature is preferably 80 ° C. to 250 ° C., the pressure is preferably 0.5 MPa to 8.0 MPa, the heating temperature is 130 ° C. to 230 ° C., and the pressure is 1.5 MPa to 5.0 MPa. More preferred.

<LED board>
The LED substrate 100 of the present invention includes a metal support 14 and a cured resin layer 12 that is a cured product of the epoxy resin composition disposed on the metal support, as schematically shown in FIGS. The circuit layer 10 which consists of metal foil arrange | positioned on the said cured resin layer 12, and the LED element 20 arrange | positioned on the said circuit layer are provided.
By forming the cured resin layer having excellent adhesion, thermal conductivity, and electrical insulation on the metal support, it is possible to efficiently dissipate heat released from the LED element.

The LED substrate of the present invention includes, for example, a step of forming a circuit layer by processing a metal foil on the metal substrate obtained as described above, a step of arranging an LED element on the formed circuit layer, It can manufacture with the manufacturing method containing.
A commonly used method such as photolithography can be applied to the process of processing the metal foil on the metal substrate. Moreover, the method generally used can also be used without a restriction | limiting especially about the process of arrange | positioning an LED element on a circuit layer.
Details of each step are as described above.

6 to 8 show configuration examples of a power semiconductor device configured using a cured resin layer that is a cured product of the epoxy resin composition.
In FIG. 6, a power semiconductor chip 110 is laminated with a copper plate 104 arranged via a solder layer 112, a cured resin layer 102, and a heat dissipation base 106 arranged on a water-cooled jacket 120 via a grease layer 108. 2 is a schematic cross-sectional view showing a configuration example of a power semiconductor device 200 configured as described above. FIG. Since the heating element including the power semiconductor chip 110 is in contact with the heat radiating member via the cured resin layer 102, heat is efficiently radiated. The heat dissipation base 106 can be configured using copper or aluminum having high thermal conductivity. Examples of the power semiconductor chip include an IGBT (Insulated Gate Bipolar Transistor) and a thyristor.

  FIG. 7 is a schematic cross-sectional view showing a configuration example of a power semiconductor device 300 configured by disposing cooling members on both surfaces of the power semiconductor chip 110. In the power semiconductor device 300, the cooling member disposed on the upper surface of the power semiconductor chip 110 includes the two layers of copper plates 104. With such a configuration, generation of chip cracks and solder cracks can be more effectively suppressed. In FIG. 7, the cured resin layer 102 and the water cooling jacket 120 are disposed via the grease layer 108, but the cured resin layer 102 and the water cooling jacket 120 may be disposed so as to be in direct contact with each other.

  FIG. 8 is a schematic cross-sectional view showing a configuration example of a power semiconductor device 400 configured by disposing cooling members on both surfaces of the power semiconductor chip 110. In the power semiconductor device 400, the cooling members disposed on both surfaces of the power semiconductor chip 110 are each configured to include one layer of the copper plate 104. In FIG. 8, the cured resin layer 102 and the water cooling jacket 120 are disposed via the grease layer 108, but the cured resin layer 102 and the water cooling jacket 120 may be disposed so as to be in direct contact with each other.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

(Synthesis of curing agent 1)
Put 627 g of resorcinol, 33 g of catechol, 316.2 g of 37% formalin, 15 g of oxalic acid, and 300 g of water in a 3 L separable flask equipped with a stirrer, a cooler, and a thermometer. Warm up. The mixture was refluxed at around 104 ° C., and the reaction was continued at the reflux temperature for 4 hours. Thereafter, the temperature in the flask was raised to 170 ° C. while distilling off water. The reaction was continued for 8 hours while maintaining 170 ° C. After the reaction, concentration was performed under reduced pressure for 20 minutes to remove water and the like in the system, and a phenol resin as the target curing agent 1 was obtained.
Moreover, when the structure was confirmed by FD-MS about the obtained hardening | curing agent 1, presence of all the partial structures represented by general formula (IIa)-(IId) has been confirmed.

The change of the weight average molecular weight at the time of the synthesis | combination of the hardening | curing agent 1 was shown in FIG. 1, and the change of the content rate of a monomer, a dimer, a trimer, and a tetramer or more was shown in FIG. The GPC chart of the obtained phenol resin is shown in FIG.
Since catechol and resorcinol are used, it is thought that the mixture of the phenol resin which has the partial structure represented by general formula (IIa)-(IId) was obtained.
Note that, under the above reaction conditions, a compound having a partial structure represented by the general formula (IIa) is formed first, and this is further subjected to a dehydration reaction. It is considered that a compound having a partial structure is generated.

In addition, about the hardening | curing agent obtained above, the physical-property value was measured as follows.
The number average molecular weight (Mn) and the weight average molecular weight (Mw) are measured using Hitachi, Ltd. high performance liquid chromatography, trade name: L6000 and Shimadzu Corporation data analyzer, trade name: C-R4A. It was. As the GPC column for analysis, trade names: G2000HXL and G3000HXL manufactured by Tosoh Corporation were used. The sample concentration was 0.2% by mass, tetrahydrofuran was used as the mobile phase, and the measurement was performed at a flow rate of 1.0 ml / min. A calibration curve was prepared using a polystyrene standard sample, and the number average molecular weight and the like were calculated using the polystyrene conversion value.

The hydroxyl equivalent was measured by acetyl chloride-potassium hydroxide titration method. The determination of the titration end point was performed by potentiometric titration rather than coloration with an indicator because the solution color was dark. Specifically, the hydroxyl group of the measurement resin is acetylated in a pyridine solution, the excess reagent is decomposed with water, and the resulting acetic acid is titrated with a potassium hydroxide / methanol solution.
The physical property values of the curing agent 1 are shown below.

Curing agent 1: a mixture of compounds having a partial structure represented by at least one of the general formulas (IIa) to (IId), wherein Ar is R ¹¹ = hydroxyl group in the general formula (IIIa) , R ¹² = R ¹³ = a group derived from 1,2-dihydroxybenzene (catechol), which is a hydrogen atom, and a group derived from 1,3-dihydroxybenzene (resorcinol), and a monomer component as a low molecular diluent It was a phenol resin containing a curing agent (hydroxyl equivalent 62 g / eq, number average molecular weight 422, weight average molecular weight 564) containing 35% (resorcinol).

Below, the material and its abbreviation which were used for preparation of the resin sheet in a present Example are shown.
(First inorganic filler)
FS-3: Boron nitride (manufactured by Mizushima Alloy Iron Co., Ltd., trade name: FS-3, volume average particle size 67 μm)
-HP-40: Boron nitride (manufactured by Mizushima Alloy Iron Co., Ltd., trade name: HP-40, volume average particle size 42 μm)
-PTX-25: Boron nitride (made by Momentive Performance Materials, trade name: PTX-25, volume average particle shape 25 μm)
(Second inorganic filler)
AA-3: Aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-3, volume average particle diameter 3 μm)
(Third inorganic filler)
AA-04: Aluminum oxide (manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-04, volume average particle size 0.4 μm)

(Curing agent)
Curing agent 1: Novolac resin produced by the above method (synthesis of curing agent 1).
TPM: triphenylmethane type novolak resin (manufactured by Nippon Kayaku Co., Ltd., trade name: Kayahard TPM (“Kayahard” is a registered trademark), hydroxyl group equivalent 103 g / eq)
PN: phenol novolac resin (Maywa Kasei Co., Ltd., trade name: H-100, hydroxyl group equivalent 105 g / eq)

(Epoxy resin monomer)
PNAP: triphenylmethane type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., trade name: EPPN-502H (“EPPN” is a registered trademark), polyfunctional epoxy resin, epoxy equivalent 168 g / eq)
BIS (A + F): A mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin (manufactured by Nippon Steel Chemical Co., Ltd., trade name: ZX-1059, bifunctional liquid epoxy resin, epoxy equivalent 170 g / eq)
BP: biphenyl type epoxy resin mixture (Mitsubishi Chemical Corporation, trade name: YL6121H, epoxy equivalent 172 g / eq)

(Elastomer 1)
AR-122-4: Acrylic resin (manufactured by Hitachi Chemical Co., Ltd., trade name: REB122-4)

(Additive)
TPP: Triphenylphosphine (Wako Pure Chemical Industries, Ltd.)
PAM: 3-phenylaminopropyltrimethoxysilane (silane coupling agent, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KBM-573)

(Organic solvent)
MEK: Methyl ethyl ketone (Wako Pure Chemical Industries, Ltd., 1st grade)
CHN: cyclohexanone (Wako Pure Chemical Industries, Ltd., grade 1)

(Support)
PET film: manufactured by Teijin DuPont Films, Ltd., trade name: A31, thickness 50 μm
Copper foil: Furukawa Electric Co., Ltd., thickness 80 μm, GTS grade Aluminum foil: Sumitomo Light Metal Industries, Ltd., thickness 20 μm

[Example 1]
(Preparation of resin sheet)
42.99 parts of aluminum oxide mixture (AA-3: AA-04; volume-based mixing ratio 2.4: 1) and 46.13 parts of boron nitride (HP-40) (volume-based mixing ratio with respect to AA-04: 6. 6), 0.09 part of a silane coupling agent (PAM), 8.29 parts (solid content 50%) of a CHN solution of (curing agent 1) as a curing agent for epoxy resin, and 46.02 parts of (CHN) And 0.97 parts of (AR-122-4) were mixed and confirmed to be uniform, and then 5.6 parts of (PNAP) and 5.6 parts of {BIS (A + F)}, ( (TPP) 0.13 part was further added and mixed, and then ball milling was performed for 20 to 40 hours to obtain a resin layer forming coating solution as a resin composition.

  The obtained coating solution for forming a resin layer was obtained by using a comma coater (manufactured by Hirano Techseed Co., Ltd., “Comma Coater” is a registered trademark), and a PET (polyethylene terephthalate) film (thickness 50 μm, one side of which was release-treated) Teijin DuPont Films Co., Ltd., trade name: A31) is used as a support, coated on the release surface to a thickness of about 150 μm, dried in a box oven at 100 ° C. for 5 minutes, and on a PET film. A stage A resin sheet was formed.

  Two A-stage sheets on which the resin layers obtained above were formed were stacked so that the resin layers face each other, and a hot press apparatus (hot plate temperature 150 ° C., pressure 10 MPa, treatment time 1 minute) was used. Then, heat-pressing and bonding were performed to obtain a B-stage resin sheet having a thickness of 198 μm.

(Preparation of cured resin sheet laminate)
The PET film was peeled from both sides of the sheet obtained above, and a copper foil (Furukawa Electric Co., Ltd., trade name: GTS grade) with a thickness of 80 μm was laminated on both sides, followed by pressing (pressing process) Conditions: hot plate temperature 165 ° C., degree of vacuum ≦ 1 kPa, pressure 10 MPa, treatment time 3 minutes). By heating in a box type oven at 160 ° C. for 0.5 hour and 190 ° C. for 2 hours, a cured C-stage resin sheet laminate 1 having copper foil on both sides was obtained.

[Example 2]
In the same manner as in Example 1, except that 7.84 parts of (PNAP), 3.36 parts of {BIS (A + F)}, and 7.23 parts of curing agent 1 were used in Example 1, B stage The cured resin sheet laminate 2 in the C stage state in which the copper sheet was provided on both sides of the resin sheet in the state was obtained.

[Example 3]
In Example 1, {BIS (A + F)} was not added, 11.2 parts of (PNAP) and 7.23 parts of (curing agent 1) were used. The resin sheet laminate cured product 3 in the C-stage state in which the resin sheet in the stage state and the copper foils were provided on both surfaces was obtained.

[Example 4]
In Example 1, except that 46.04 parts of boron nitride (FS-3) was added instead of (HP-40), the resin sheet in the B stage state and copper foil on both sides were the same as in Example 1. Each provided C-stage resin sheet laminate cured product 4 was obtained.

[Example 5]
27.59 parts of aluminum oxide mixture (AA-3: AA-04; volume-based mixing ratio 2.4: 1) and 29.60 parts of boron nitride (HP-40) (volume-based mixing ratio with respect to AA-04: 6. 6), 0.06 part of a silane coupling agent (PAM), 8.27 parts (solid content 50%) of (curing agent 1) as a curing agent for epoxy resin, and 22.54 parts of (CHN) And 5.6 parts of (PNAP), 5.6 parts of {BIS (A + F)}, and 0.13 part of (TPP) were added as epoxy resin monomers. Except for the above, in the same manner as in Example 1, a C-stage resin sheet laminate cured product 6 in which a B-stage resin sheet and copper foils were provided on both surfaces were obtained.

[Example 6]
34.26 parts of aluminum oxide mixture (AA-3: AA-04; volume-based mixing ratio 2.4: 1) and 36.76 parts of boron nitride (HP-40) (volume-based mixing ratio with respect to AA-04: 6. 6), 0.07 part of silane coupling agent (PAM), 8.29 parts (solid content 50%) of CHN solution of curing agent 1 as a curing agent for epoxy resin, and 27.50 parts of (CHN) After mixing and confirming that it was uniform, 5.6 parts of (PNAP), 5.6 parts of {BIS (A + F)}, and 0.13 part of (TPP) were added and mixed as epoxy resin monomers In the same manner as in Example 1, a B-stage resin sheet and a C-stage resin sheet cured product 6 in which copper foils were provided on both surfaces were obtained.

[Comparative Example 1]
52.42 parts of aluminum oxide mixture (AA-3: AA-04; volume-based mixing ratio 2.4: 1) and 56.25 parts of boron nitride (HP-40) (volume-based mixing ratio with respect to AA-04: 6. 6), 0.11 part of silane coupling agent (PAM), 8.28 parts (solid content 50%) of CHN solution of curing agent 1 as a curing agent for epoxy resin, and 33.98 parts of (CHN) After mixing and confirming that it was uniform, (PNAP) 5.61 parts, {BIS (A + F)} 5.61 parts, and (TPP) 0.13 parts were further added as epoxy resin monomers. In the same manner as in Example 1, a B-stage resin sheet and a C-stage resin sheet laminate C1 in which copper foils were provided on both surfaces were obtained.

[Comparative Example 2]
In Example 1, except that 56.25 parts of boron nitride (PTX-25) was added instead of (HP-40), the resin sheet in the B stage state and copper foil on both sides were the same as in Example 1. The provided C-stage resin sheet laminate cured product C2 was obtained.

[Comparative Example 3]
In Example 1, 4.7 parts of (TPM), 3.8 parts of (PNAP), 3.8 parts of {BIS (A + F)}, and 27.03 parts of (CHN) were added instead of curing agent 1. In the same manner as in Example 1 except for the above, a B-stage resin sheet and a C-stage resin sheet cured product C3 in which copper foils were provided on both surfaces were obtained.

[Comparative Example 4]
In Example 1, 4.7 parts of (PN), 3.8 parts of (PNAP), 3.8 parts of {BIS (A + F)}, and 27.0 parts of (CHN) were added instead of curing agent 1. In the same manner as in Example 1 except for the above, a B-stage resin sheet and a C-stage resin sheet cured product C4 in which copper foil was provided on both surfaces were obtained.

[Comparative Example 5]
In Example 1, 6.6 parts of (curing agent 1), 8.9 parts of {BIS (A + F)}, and 28.0 parts of (CHN) were added in the same manner as in Example 1, except that B A resin sheet laminate cured product C5 in a C-stage state in which a resin sheet in a stage state and copper foils were provided on both surfaces was obtained.

[Comparative Example 6]
In Example 1, except that 6.5 parts of (curing agent 1), 9.0 parts of (biphenyl type epoxy resin), and 28.4 parts of (CHN) were added, A resin sheet laminate cured product C6 in a C-stage state in which a resin sheet in a stage state and copper foils were provided on both sides was obtained.

[Comparative Example 7]
In Example 1, except that (AR-122-4) was not added, a B-stage resin sheet and a C-stage resin sheet laminate provided with copper foil on both surfaces were the same as in Example 1. Each cured product C7 was obtained.

(Measurement method of thermal conductivity)
The thermal conductivity was obtained from the product of the actually measured density, specific heat and thermal diffusivity, respectively, according to the thermal conduction equation.
First, a method for measuring the thermal diffusivity is shown below. Only the copper was etched away from the obtained copper foil-clad resin sheet cured product using a sodium persulfate solution to obtain a sheet-shaped resin cured product. The thermal diffusivity of the obtained cured resin was measured by a flash method using a product name: Nanoflash LFA447 manufactured by NETZSCH.
Similarly, the density was determined by the Archimedes method using a cured sheet from which the copper foil was removed. Furthermore, specific heat was calculated | required by the difference of the input calorie | heat amount by a differential thermal analyzer (DSC) (The product made by Parkin Elmer, brand name: Pyris 1 type). As measurement conditions, measurement was performed in a nitrogen atmosphere at 5 ° C./min with alumina as a reference.

(Dielectric breakdown voltage measurement method)
Copper was removed by etching using a sodium persulfate solution from the resin sheet cured product in which the copper foil was provided on both surfaces in the C-stage state obtained above to obtain a sheet-shaped resin cured product. The dielectric strength of the obtained cured resin under alternating current was measured using a product name: YST-243-100RHO manufactured by Yamayo Tester Co., Ltd. The measurement conditions were a measurement temperature of 23 ° C. ± 2 ° C., a pressure increase rate of 1 kV / second, and measurement was performed in the atmosphere.

(Measurement method of shear bond strength)
The PET film was peeled off from both surfaces of the resin sheet in the B-stage state, a metal plate was bonded, and the tensile shear bond strength was measured according to JIS K 6850. Specifically, two 100 mm × 25 mm × 3 mm copper plates were alternately stacked and bonded and cured on a 12.5 mm × 25 mm × 0.2 mm resin sheet. Measurement was performed by pulling this with a test speed of 1 mm / min, measurement temperatures of 23 ° C. and 175 ° C., manufactured by Shimadzu Corporation, trade name: AGC-100 type.
Adhesion and curing were performed as follows. After vacuum hot pressing (hot plate temperature 165 ° C., degree of vacuum ≦ 1 kPa, pressure 10 MPa, treatment time 3 minutes), in a box-type oven at 140 ° C. for 2 hours, 165 ° C. for 2 hours, and 190 ° C. for 2 hours Performed by time step cure.

(Inorganic filler particle size)
0.5 g of a varnish-like resin composition is dispersed in 50 g of methanol, and an appropriate amount is introduced into a laser diffraction / scattering particle size distribution measuring device (trade name: LS230, manufactured by Beckman Coulter, Inc.), and an inorganic filler in the resin composition The particle size distribution was measured.

(Flexibility of resin sheet)
The flexibility of the resin sheet was evaluated as follows.
The prepared resin sheet was cut out to a length of 100 mm and a width of 10 mm, and the PET film on the surface was removed to make a sample for evaluation. A sample is placed on a jig made of aluminum and rounded in 20 mm increments of 20 mm to 140 mm, and the minimum diameter that can be bent without breaking at 25 ° C is measured. Consistency was evaluated.

~Evaluation criteria~
A: The minimum radius was 20 mm.
B: The minimum radius was 40 mm or 60 mm, which was a practical limit.
C: The minimum radius was 80 mm or more.

Table 1 shows the evaluation results of the above examples and comparative examples.
In Table 1, “-” indicates that it is not contained.
From Table 1, it can be seen that the cured product of the resin sheet of the present invention exhibits excellent thermal conductivity and excellent electrical insulation. Moreover, it turns out that the flexibility of a resin sheet is excellent.

DESCRIPTION OF SYMBOLS 10 Circuit layer 12, 102 Cured resin layer 14 Metal support 20 LED element 100 LED board 104 Copper plate 106 Radiation base 108 Grease layer 110 Power semiconductor chip 112 Solder layer 120 Water cooling jacket 200, 300, 400 Power semiconductor device

Claims (9)

An epoxy resin having a partial structure represented by the following general formula (I);
A curing agent having a partial structure represented by at least one of the following general formulas (IIa) to (IId);
An inorganic filler;
Acrylic elastomers,
Contain,
In the particle size distribution measured using a laser diffraction method, the inorganic filler has a peak value in each of 0.01 μm or more and less than 1 μm, 1 μm or more and less than 10 μm, and 30 μm or more and 80 μm or less, A B-stage resin sheet, which is a semi-cured product of an epoxy resin composition in which the inorganic filler having a particle size of 30 μm or more and 80 μm or less contains boron nitride .

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)





(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any of the following general formulas (IIIa) and (IIIb). Or a single group.)


(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.) Metal foil and a resin coated metal foil and a resin sheet according to claim 1 disposed on the metal foil. A metal support, a metal substrate having a cured resin layer is a cured product of the resin sheet as described, and a metallic foil disposed on the cured resin layer to claim 1 disposed on the metal support. A metal support, a curing resin layer is a cured product of the resin sheet of claim 1 disposed on the metal support, and a circuit layer made of disposed metal foil on the cured resin layer, wherein An LED board comprising: an LED element disposed on a circuit layer. A cured product of the resin sheet according to claim 1 . Metal foil,
An epoxy resin disposed on the metal foil and having a partial structure represented by the following general formula (I), and a curing having a partial structure represented by at least one of the following general formulas (IIa) to (IId) Agent , inorganic filler, and acrylic elastomer, and the inorganic filler has a particle size distribution measured using a laser diffraction method of 0.01 μm or more and less than 1 μm, 1 μm or more and less than 10 μm, and 30 μm. A semi-cured resin layer in a B stage state, which is a semi-cured product of an epoxy resin composition in which the inorganic filler having a peak value in each of the above 80 μm or less and having a particle size of 30 μm or more and 80 μm or less includes boron nitride A metal foil with resin.


(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)








(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)


(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.) A metal support;
An epoxy resin disposed on the metal support and having a partial structure represented by the following general formula (I), having a partial structure represented by at least one of the following general formulas (IIa) to (IId) The inorganic filler contains a curing agent , an inorganic filler, and an acrylic elastomer, and the inorganic filler has a particle size distribution measured using a laser diffraction method of 0.01 μm or more and less than 1 μm, 1 μm or more and less than 10 μm, and A cured resin layer which is a cured product of a resin composition in which the inorganic filler having a peak value in each of 30 μm or more and 80 μm or less and having a particle diameter of 30 μm or more and 80 μm or less includes boron nitride ;
And a metal foil disposed on the cured resin layer.


(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)








(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)

(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.) An epoxy resin having a partial structure represented by the following general formula (I), a curing agent having a partial structure represented by at least one of the following general formulas (IIa) to (IId) , an inorganic filler, and an acrylic In the particle size distribution measured using a laser diffraction method, the inorganic filler has a peak at 0.01 μm or more and less than 1 μm, 1 μm or more and less than 10 μm, and 30 μm or more and 80 μm or less. A step of forming a resin layer by applying a resin composition containing a boron nitride containing an inorganic filler having a particle diameter of 30 μm or more and 80 μm or less on a metal foil;
A B-stage process for heat-treating the resin layer to form a semi-cured resin layer;
The manufacturing method of the metal foil with resin containing.

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)






(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any one of the following general formulas (IIIa) or (IIIb) A group represented by one is shown.)


(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.) An epoxy resin having a partial structure represented by the following general formula (I);
A curing agent having a partial structure represented by at least one of the following general formulas (IIa) to (IId);
An inorganic filler;
Acrylic elastomers,
In the particle size distribution measured using a laser diffraction method, the inorganic filler has a peak value of 0.01 μm or more and less than 1 μm, 1 μm or more and less than 10 μm, and 30 μm or more and 80 μm or less. A cured product of an epoxy resin composition , wherein the inorganic filler having a particle size of 30 μm to 80 μm contains boron nitride .

(In general formula (I), n represents an average value and represents a real number included in 1 to 10.)





(In the general formulas (IIa) to (IId), m and n are each independently a positive number, indicating the number of repeating units, and Ar is any of the following general formulas (IIIa) and (IIIb). Or a single group.)


(In the general formulas (IIIa) and (IIIb), R ¹¹ and R ¹⁴ each independently represent a hydrogen atom or a hydroxyl group. R ¹² and R ¹³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. Is shown.)