JP5650084B2 - Thermally conductive substrate and thermally conductive polyimide film - Google Patents

Description

  The present invention relates to a heat conductive substrate and a heat conductive polyimide film which have an insulating layer excellent in heat conductive characteristics and are suitably used for a heat radiating substrate, a circuit board, a copper foil with a heat conductive resin, and the like. .

  In recent years, there has been an increasing demand for downsizing and weight reduction of electronic devices typified by mobile phones, and accordingly, circuit boards advantageous for downsizing and weight reduction of devices have come to be widely used in the field of electronic technology. It is coming. Among them, a circuit board using a polyimide resin as an insulating layer has been widely used because of its good heat resistance and chemical resistance.

  By the way, with the recent miniaturization of electronic devices, the degree of circuit integration has increased, and in conjunction with the speeding up of information processing, heat dissipation means for heat generated in the device has attracted attention.

  In addition, with the growing awareness of environmental issues such as global warming, there is a strong demand for products with low environmental impact and energy saving. A typical example is the rapid spread of LED lighting in place of incandescent lamps, but in order to fully demonstrate the performance of LED lighting, it is important to efficiently release the heat generated during use. . Further, in SiC, which is a power semiconductor material used for in-vehicle applications, it is important to efficiently release heat generated during use in order to operate at a high temperature.

  Then, in order to provide the circuit board which was rich in workability and excellent in heat dissipation, about the polyimide film which comprises an insulating layer, examination which improves the thermal conductivity of the thickness direction is made | formed (patent document 1). Moreover, the polyimide film composite material which disperse | distributed the heat conductive filler to the polyimide induced | guided | derived from siloxane diamine is also proposed regarding the heat conductive polyimide film containing a heat conductive filler (patent document 2).

  However, the thermal conductivity in the thickness direction of the above-described conventional polyimide film is insufficient in performance as a heat radiating substrate and needs to be improved. In general, when a metal-clad laminate is produced by laminating a resin layer on a metal layer such as copper foil, an adhesive layer made of an epoxy adhesive or a thermoplastic resin is usually provided between the metal layer and the resin layer. There is a need. The interposition of the adhesive layer not only causes a further decrease in the heat dissipation generated in the metal layer, but also causes a decrease in various properties such as heat resistance and flexibility required for use as a practical substrate.

  In addition, in order to improve the thermal conductivity of the polyimide resin, a thermal conductivity in which a polyimide resin layer having a specific structural unit containing a thermally conductive filler and a polyimide resin layer having a glass transition temperature lower than that of the polyimide resin layer are laminated. A conductive polyimide film has been proposed (Patent Document 3).

  Although a substrate material and a film material in which a heat conductive filler is mixed with a polyimide resin are known in this way, when a heat-resistant polyimide resin is to be thermocompression-bonded with another member, it is performed under a high pressure condition. This is necessary, and there is a concern that it may cause a lack of wiring, damage to parts, and the like. In addition, when a thermally conductive filler is blended with siloxane polyimide, the above-mentioned conditions of high-temperature pressurization are relaxed, but sufficient heat resistance, particularly long-term heat resistance cannot be ensured, and heat dissipation used in a high-temperature environment. It is considered unsuitable for application as a main resin layer of a substrate.

  On the other hand, bis (3,4-dicarboxyphenyl) ether dianhydride and a specific structure are used for the purpose of improving the low temperature sticking property, low hygroscopicity, adhesive force during heating, and PCT resistance of polyimide resin used for an adhesive film. A method for producing a polyimide resin in which another acid anhydride and / or another diamine is reacted after reacting with other siloxane diamine has been proposed (for example, Patent Document 4). In addition, in order to safely and stably produce a high molecular weight polyimide resin having a silicone structure in the main chain, silicone-based diamine and silicone-based acid dianhydride are mixed in a specific molar ratio range, and heat dehydration condensation is performed. There has also been proposed a method for producing a polyimide resin in which an aromatic diamine is added to a reaction solution at a predetermined molar ratio and reacted until the molecular weight is controlled after the reaction is continued until no increase occurs (for example, Patent Document 5). However, the polyimide resins described in Patent Documents 4 and 5 are not considered at all for application to uses requiring thermal conductivity.

  Therefore, there is no need for an adhesive layer, it has practical adhesive strength between the insulating layer and the metal layer, ceramic substrate, Si substrate, and other base materials, and the thermal conductivity of the insulating layer, (long-term) heat resistance It has been desired to provide a heat conductive substrate excellent in heat resistance, and a heat conductive polyimide film that can give the above-mentioned characteristics to the heat conductive substrate and has thermocompression bonding properties in a relatively low temperature region.

JP 2006-274040 A JP 2006-169533 A International Publication WO 2009/110387 JP 2006-117945 A JP 2004-359874 A

  The present invention has a practical adhesive strength between an insulating layer and a metal layer, a ceramic substrate, a Si substrate, and other base materials, and has a thermal conductivity that is excellent in thermal conductivity and (long-term) heat resistance of the insulating layer. It is an object of the present invention to provide a substrate and a thermally conductive polyimide film having thermocompression bonding properties in a relatively low temperature region in addition to the characteristics.

  As a result of intensive studies to solve the above problems, the present inventors have found that an amino acid having a primary amino group in a polyimide resin after imidization containing a thermally conductive filler constituting a thermally conductive insulating layer. It has been found that when the compound is reacted, the heat resistance of the polyimide resin is remarkably improved, and the decrease in adhesive force is greatly improved even when used in a high temperature environment, and the present invention has been completed.

  That is, the thermally conductive substrate of the present invention is a thermally conductive substrate having a metal layer on one or both sides of an insulating layer having at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. The filler-containing polyimide resin layer has a heat conductive filler content of 5 to 80 wt% (% by weight; the same applies hereinafter), and the polyimide resin in the filler-containing polyimide resin layer has the following general formula: The ketone group in the polyimidesiloxane having the structural units represented by (1) and (2) reacts with an amino group of an amino compound having at least two primary amino groups as functional groups to form a C═N bond. A polyimide resin having a structure in which the polyimide siloxane is cross-linked by the amino compound. It is characterized in.

［式中、Ａｒは芳香族テトラカルボン酸無水物から誘導される４価の芳香族基、Ｒ_１はジアミノシロキサンから誘導される２価のジアミノシロキサン残基、Ｒ_２は芳香族ジアミン及び／又は脂肪族ジアミンから誘導される２価のジアミン残基をそれぞれ表し、Ａｒ及び／又はＲ_２中にはケトン基を含み、ｍ、ｎは各構成単位の存在モル比を示し、ｍは０．４〜１．０の範囲内、ｎは０〜０．６の範囲内である］

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, R ₂ is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R ₂ contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0, n is in the range of 0-0.6]

The thermally conductive polyimide film of the present invention is a thermally conductive polyimide film provided with a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin,
The content rate of the heat conductive filler in the said filler containing polyimide resin layer exists in the range of 5-80 wt%, and the polyimide resin in the said filler containing polyimide resin layer is represented by following General formula (1) and (2). The polyimide siloxane having a structural unit reacts with the amino group of an amino compound having at least two primary amino groups as functional groups to form a C═N bond with the ketone group in the polyimide siloxane having a structural unit. It is a polyimide resin having a structure crosslinked with the amino compound.

［式中、Ａｒは芳香族テトラカルボン酸無水物から誘導される４価の芳香族基、Ｒ_１はジアミノシロキサンから誘導される２価のジアミノシロキサン残基、Ｒ_２は芳香族ジアミン及び／又は脂肪族ジアミンから誘導される２価のジアミン残基をそれぞれ表し、Ａｒ及び／又はＲ_２中にはケトン基を含み、ｍ、ｎは各構成単位の存在モル比を示し、ｍは０．４〜１．０の範囲内、ｎは０〜０．６の範囲内である］

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, R ₂ is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R ₂ contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0, n is in the range of 0-0.6]

  Since the thermally conductive substrate and the thermally conductive polyimide film of the present invention are provided with a filler-containing polyimide resin layer containing a specific polyimide resin in the insulating layer, thermocompression bonding at a relatively low temperature is possible. The layer has excellent solder heat resistance, and even when repeatedly placed in a high temperature environment, it does not deteriorate the adhesive force with the metal wiring layer and has excellent heat conduction characteristics. Therefore, by using the heat conductive substrate and the heat conductive polyimide film of the present invention, the reliability of a circuit board, a heat dissipation board, a copper foil with a heat conductive resin, and the like used in a high temperature environment can be improved.

[Thermal conductive substrate]
The heat conductive substrate of one embodiment of the present invention has at least one filler-containing polyimide resin layer in which a heat conductive filler is dispersed in a polyimide resin. The insulating layer only needs to have at least one filler-containing polyimide resin layer. The insulating layer has a metal layer on one side or both sides. The filler-containing polyimide resin layer contains a thermally conductive filler in the following specific polyimide resin. The polyimide resin constituting the filler-containing polyimide resin layer has a cross-linked structure by a C═N bond with an amino compound. A resin layer having an insulating layer with a filler-containing polyimide resin layer in which the crosslinking formation rate (degree of curing) of this crosslinked structure is controlled can be such that the resin layer has adhesiveness. For example, as a copper foil with a resin, that is, as a copper foil with a heat conductive resin, it can be used by being bonded to another base material.

[Insulation layer]
The insulating layer only needs to have at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. In addition to the filler-containing polyimide resin layer, another polyimide resin layer laminated thereon May be provided. In this case, the polyimide resin constituting the filler-containing polyimide resin layer and the polyimide resin constituting the other polyimide resin layer in the insulating layer may be the same type of polyimide resin or different types of polyimide resins. The kind of polyimide resin in the case of using different types of polyimide resins as other polyimide resin layers other than the filler-containing polyimide resin layer is not particularly limited. However, from the viewpoint of enhancing the heat dissipation characteristics of the thermally conductive substrate, it is preferable that the entire insulating layer is formed of a filler-containing polyimide resin layer. In this case, the filler-containing polyimide resin layer is not limited to a single layer, and may be a laminate of a plurality of layers.

[Thermal conductive filler]
The content ratio of the thermally conductive filler in the filler-containing polyimide resin layer needs to be in the range of 5 to 80 wt%, and preferably in the range of 10 to 60 wt%. If the content of the heat conductive filler is less than 5 wt%, the heat dissipation characteristics when the electronic component such as a circuit board is not sufficient, and if it exceeds 80 wt%, the bending resistance and the bending resistance decrease significantly. In addition, the strength of the polyimide resin layer also decreases.

  As the thermally conductive filler, a highly thermally conductive filler is preferable, and specifically, for example, aluminum, copper, nickel, silica, diamond, alumina, magnesia, beryllia, boron nitride, aluminum nitride, silicon nitride, silicon carbide, etc. Can be mentioned. Among these, at least one filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, and magnesia is preferable. Since the polyimide resin layer acts as an insulating layer, the filler blended in the polyimide resin layer is suitable from that viewpoint. The filler shape is not particularly limited, and may be, for example, a plate shape (including a flake shape), a spherical shape, a needle shape, or a rod shape. Moreover, considering the balance with characteristics such as thermal conductivity by increasing the content of the thermal conductive filler, fillers having different shapes (for example, plate-like and spherical, plate-like and needle-like) can be used in combination. .

  From the viewpoint of improving the thermal conductivity by uniformly dispersing the filler in the thickness direction of the polyimide resin layer, the size of the thermally conductive filler is preferably in the range of, for example, an average particle diameter of 0.5 to 10 μm. More preferably, it is in the range of 0.8 to 5 μm. If the average particle size of the thermally conductive filler is less than 0.5 μm, the thermal conductivity inside each filler is reduced, and as a result, the thermal conductivity of the polyimide resin layer is not improved and the particles are aggregated. It tends to occur and it may be difficult to disperse uniformly. On the other hand, when it exceeds 10 μm, the filling rate into the polyimide resin layer is lowered, and the polyimide resin layer tends to be brittle at the filler interface.

[Polyimide resin and polyimide siloxane]
The polyimide resin for forming the filler-containing polyimide resin layer contains at least a ketone group in the group Ar and / or the group R ₂ in the polyimide siloxane having the structural units represented by the general formulas (1) and (2). By reacting an amino compound having two primary amino groups as functional groups to form a C═N bond, the polyimide siloxane has a structure crosslinked with the amino compound. The group Ar in the general formulas (1) and (2) is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, and the group R ₁ is a divalent diaminosiloxane derived from a diaminosiloxane. The radical R ₂ is a divalent diamine residue derived from an aromatic diamine and / or an aliphatic diamine. The abundance of the structural unit represented by the formula (1) in the resin is in the range of 40 mol% to 100 mol%, preferably in the range of 80 mol% to 100 mol%.

In a preferred embodiment of the thermally conductive substrate of the present invention, the general formulas (1) and (2) contain a functional group that enables hydrogen bonding (hereinafter referred to as “hydrogen bond-forming group”). it can. Here, examples of the “hydrogen bond-forming group” include —NHCO—. By including such a hydrogen bond-forming group, a hydrogen bond is generated between adjacent polyimide siloxane chains, and the ketone groups that are the reaction points of the crosslinking reaction with the amino compound can be brought close to each other. The reaction is accelerated and the heating time until sufficient heat resistance is generated can be shortened. The hydrogen bond forming group may be contained in either one of the general formulas (1) and (2), or may be contained in both. In addition, the hydrogen bond-forming group may be contained in either the acid anhydride component represented by the group Ar or the diamine component represented by the group R ₁ or R _2. It is preferably contained in the group R ₂ in 2). The molar ratio of hydrogen bond-forming groups to all diamines is in the range of more than 0 and less than or equal to 1.3, more preferably more than 0 and less than 0 in order to efficiently form hydrogen bonds between the main chains of adjacent polyimidesiloxanes. .5 or less, and most preferably 0.02 or more and 0.5 or less.

The general formula (1), in the polyimide siloxanes having a structural unit represented by (2), during the group Ar and / or groups R _2, include a ketone group, the ketone group is, for reaction with the amino compound Involved. In this case, it is only necessary that the amino group of the amino compound reacts with at least a part of the ketone group in the group Ar and / or the group R ₂ in the polyimidesiloxane to form a C═N bond. The crosslinking formation rate (degree of curing) of the polyimide resin may not be a state in which the curing of the polyimide resin by the crosslinking formation is completed, and may be a level that can ensure practically sufficient heat resistance. That is, the polyimide resin may be in a cured state where the crosslinking reaction has been completed, or may be in a semi-cured state in which room for crosslinking is left. By keeping the cured state in a semi-cured state, the resin layer can be provided with adhesiveness and can be made suitable for the use of the resin-coated copper foil. Whether or not the cross-linked polyimide resin has practically sufficient heat resistance can be determined using, for example, viscosity as an index.

In addition, if the filler content is constant, the filler-containing polyimide resin layer has relatively high adhesion when the polyimide resin has a low cross-linking formation rate, and relatively high adhesion when the polyimide resin has a high cross-linking formation rate. Tend to be low. Therefore, it is also possible to judge the crosslink formation rate of the polyimide resin using, for example, peel strength (bonding surface adhesion strength) with the copper foil after thermocompression bonding as an index. More specifically, after producing a heat conductive substrate having a metal layer on one side, a rolled copper foil (surface roughness Ra = 0.7 μm) having a thickness of 18 μm is formed on the polyimide resin layer of the heat conductive substrate. And is pressed under the conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours. Then, a 180 ° peel test is performed in accordance with “copper foil peel strength (peel strength)” shown in Examples below, and the peel strength between the rolled copper foil and the polyimide resin layer is measured. At this time, for example, when the filler content is 80 wt% and the peel strength is 0.4 [kN / m] or more, it is set as a semi-cured state in which the crosslinking is not completed (a state in which room for crosslinking is left), A case where the filler content is 5 wt% and the peel strength is 0.4 [kN / m] or less can be determined as a cured state in which the crosslinking is completed. The “cured state in which the cross-linking has been completed” is a state in which the cross-linking rate is 100% (a state in which the ketone group in the group Ar and / or the group R ₂ in the polyimidesiloxane completely forms a C═N bond). ), And means a state in which the crosslinking reaction does not proceed any more even when the heat treatment is performed under the pressing conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours.

  In the structural units represented by the general formulas (1) and (2), examples of the aromatic tetracarboxylic acid for forming the group Ar containing a ketone group include 3,3 represented by the following formula (3): Mention may be made of ', 4,4'-benzophenonetetracarboxylic dianhydride (BTDA).

  In addition, in the structural units represented by the general formulas (1) and (2), examples of the aromatic tetracarboxylic acid used as a raw material for forming the group Ar include, in addition to those having the ketone group, for example, 3, 3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA), pyromellitic dianhydride (PMDA) Etc. can be used. These can be used alone or in combination of two or more.

In addition, examples of the group R ₁ in the structural unit represented by the general formula (1) include a diaminosiloxane residue derived from a diaminosiloxane represented by the following formula (4).

［ここで、Ｒ_３及びＲ_４は、それぞれ、酸素原子を含有していてもよい２価の有機基を示し、Ｒ_５〜Ｒ_８は、それぞれ炭素数１〜６の炭化水素基を示し、平均繰り返し数であるｍ_１は、１〜２０である］

[Wherein R ₃ and R ₄ each represent a divalent organic group that may contain an oxygen atom, R _{5 to} R ₈ each represent a hydrocarbon group having 1 to 6 carbon atoms, M ₁ that is the average number of repetitions is ₁ to 20]

In particular, as the group R ₁ , R ₃ and R ₄ in the formula (4) are each a divalent hydrocarbon group, and R _{5 to} R ₈ are each 1 to 1 carbon atoms in order to impart solubility of the polyimide. 6 having a mean repeating number of m ₁ of 5 to 15 is preferable.

  The above-mentioned diaminosiloxane residue is a group having a siloxane bond (Si-O-Si) obtained by removing an amino group from diaminosiloxane. By increasing the ratio of this siloxane bond, a plasticizer can be added. Sufficient flexibility is imparted to the insulating layer. Moreover, since many polar groups are contained in the plasticizer, as an advantage of not containing the plasticizer, a polyimide resin using a polyimide siloxane having structural units represented by the general formulas (1) and (2) The amount of polar groups contained therein can be suppressed. For this reason, in this invention, the value of m in Formula (1) shall be 0.4 or more, Preferably it is 0.8 or more. If the value of m is less than 0.4, the effect of suppressing warpage cannot be obtained sufficiently. In addition, it is considered that increasing the siloxane bond also has an effect of reducing curing shrinkage due to a decrease in the imide bond site of polyimidesiloxane. For this reason, the value of n in the formula (2) is set to 0 to 0.6, preferably 0 to 0.2.

Thus, by introducing the siloxane skeleton into the polyimide using the diaminosiloxane represented by the above general formula (4), the resulting polyimidesiloxane is given fluidity at the time of thermocompression bonding and adhered to a metal layer or the like. Can be improved. As specific examples of the diaminosiloxane represented by the general formula (4), diaminosiloxanes represented by the following formulas (5) to (9) are preferable. Among these, the formula (5) or (6) is preferable. Aliphatic diaminosiloxanes are more preferred. These diaminosiloxanes can be blended in combination of two or more. Moreover, when mix | blending in combination of 2 or more types of diaminosiloxane, 90 weight part or more of aliphatic diaminosiloxane represented by Formula (5) or (6) may be mix | blended with respect to 100 weight part of all diaminosiloxanes. preferable. In the equation (4) to Formula (9), _{m 1} is an average repeating number is in the range of 1 to 20, preferably in the range of 5-15. When m ₁ is less than 1, the flexibility is lowered, and when it exceeds 20, the adhesion with the metal layer is lowered.

In the structural unit represented by the general formula (2), as a group R ₂ containing a ketone group (a divalent diamine residue derived from an aromatic diamine and / or an aliphatic diamine), for example, the following formula (10 ) And (11). These can be used alone or in combination of two or more.

［ここで、Ｒ_９は独立に炭素数１〜６の１価の炭化水素基又はアルコキシ基を示し、ＸはＣＯを示し、ｎ_１は独立に０〜４の整数を示す］

[Wherein R ₉ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, X represents CO, and n ₁ independently represents an integer of 0 to 4]

Examples of the aromatic diamine for forming the group R ₂ represented by the above formulas (10) and (11) include 4,4′-bis (3-aminophenoxy) benzophenone (BABP), 1,3- Bis [4- (3-aminophenoxy) benzoyl] benzene (BABB) and the like can be mentioned.

In the structural unit represented by the general formula (2), as a diamine compound that is a raw material for forming the group R ₂ having a hydrogen bond-forming group, for example, when the hydrogen bond-forming group is a —NHCO— group May include dihydrazide compounds. Specific examples of the dihydrazide compound include dodecanedioic acid dihydrazide and adipic acid dihydrazide which are aliphatic dihydrazides, and isophthalic acid dihydrazide which is an aromatic dihydrazide. Among these, dodecanedioic acid dihydrazide and adipic acid dihydrazide which are aliphatic dihydrazides are preferable.

Further, in the structural unit represented by the general formula (2), as another aromatic diamine which is a raw material for forming the group R ₂ , for example, 2,2-bis (4-aminophenoxyphenyl) propane ( BAPP), 2,2′-divinyl-4,4′-diaminobiphenyl (VAB), 2,2′-dimethyl-4,4′-diaminobiphenyl (m-TB), 2,2′-diethyl-4, 4′-diaminobiphenyl, 2,2 ′, 6,6′-tetramethyl-4,4′-diaminobiphenyl, 2,2′-diphenyl-4,4′-diaminobiphenyl, 9,9-bis (4- And aminophenyl) fluorene. These aromatic diamines can be used alone or in combination of two or more.

  As for the above-mentioned acid anhydride and diamine, which are the raw materials for polyimide siloxane, only one kind thereof may be used or two or more kinds may be used in combination. In addition, acid anhydrides and diamines other than those described above can be used in combination.

[Synthesis of polyimide siloxane]
The polyimidesiloxane having the structural units represented by the general formulas (1) and (2) is obtained by reacting the aromatic tetracarboxylic acid anhydride with diaminosiloxane and aromatic diamine and / or aliphatic diamine in a solvent, It can be produced by producing a polyamic acid, which is a precursor resin, and then ring-closing with heating. For example, it is a polyimide precursor by dissolving an acid anhydride component and a diamine component in an approximately equimolar amount in an organic solvent and stirring and polymerizing at a temperature in the range of 0 to 100 ° C. for 30 minutes to 24 hours. A polyamic acid is obtained. In the reaction, the reaction components are dissolved so that the precursor to be produced is in the range of 5 to 30% by weight, preferably in the range of 10 to 20% by weight in the organic solvent.

  Examples of the organic solvent used for the polymerization reaction include N, N-dimethylformamide, N, N-dimethylacetamide (DMAC), N-methyl-2-pyrrolidone, 2-butanone, dimethyl sulfoxide, dimethyl sulfate, cyclohexanone, and dioxane. , Tetrahydrofuran, diglyme, triglyme and the like. Two or more of these solvents can be used in combination, and further, aromatic hydrocarbons such as xylene and toluene can be used in combination.

  The synthesized precursor is usually advantageously used as a reaction solvent solution, but can be concentrated, diluted, or replaced with another organic solvent if necessary. Moreover, since a precursor is generally excellent in solvent solubility, it is advantageously used. The method for imidizing the precursor is not particularly limited, and for example, heat treatment in which heating is performed in the solvent at a temperature within the range of 80 to 300 ° C. for 1 to 24 hours is suitably employed.

  When preparing the polyimidesiloxane having the structural units represented by the general formulas (1) and (2), the blending ratio of the acid anhydride component and the diamine component as raw materials is not particularly limited. From the standpoint that the terminal substituent of polyimide siloxane is an amino group, that is, the acid anhydride group is sealed with diamine and the polarity of the polyimide resin is suppressed, the acid anhydride component: diamine component has a molar ratio of 1. 000: 1.001 to 1.0: 1.2 is preferable.

Moreover, the polyimidesiloxane which has a structural unit represented by the said Formula (1) and (2) is obtained by reaction with aromatic tetracarboxylic anhydride, diaminosiloxane, aromatic diamine, and / or aliphatic diamine. When it is used as an insulating layer, it has an imide structure, and a completely imidized structure is most preferable in order to suppress copper diffusion. However, a part of the polyimide may be amic acid. The imidation ratio was measured at about 1015 cm ⁻¹ by measuring the infrared absorption spectrum of the polyimide thin film by a single reflection ATR method using a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). Based on the absorbance of C═O stretching derived from an imide group of 1780 cm ⁻¹ , based on the benzene ring absorber.

  When the polyimidesiloxane obtained as described above has a hydrogen bond-forming group in the molecular structure, hydrogen bonding occurs between the main chains of adjacent polyimidesiloxanes even at room temperature. For example, when the hydrogen bond forming group contained in the polyimide siloxane is an —NHCO— group, a hydrogen bond is generated between the NH group of one adjacent polyimide siloxane chain and the CO group of the other polyimide siloxane chain. . As a result, many polyimide siloxane chains can be brought close to a certain degree of orientation, and the adjacent polyimide siloxane chains can be brought close to each other as a reaction point for a crosslinking reaction with an amino compound. By forming such hydrogen bonds, the imine crosslinking reaction can be promoted.

[Amino compound]
In the present invention, as an amino compound having at least two primary amino groups as functional groups, which are reacted with the ketone group of the polyimidesiloxane having the structural units represented by the above formulas (1) and (2), , (I) aromatic diamine, (II) diaminosiloxane, (III) aliphatic amine, (IV) dihydrazide compound, and the like.

(I) Aromatic diamine:
Examples of the aromatic diamine include those represented by the following formulas (12) and (13).

［ここで、Ｒ_１０は独立に炭素数１〜６の１価の炭化水素基又はアルコキシ基を示し、Ｚは単結合又は炭素数１〜１５の２価の炭化水素基、Ｏ、Ｓ、ＣＯ、ＳＯ、ＳＯ_２、ＮＨ若しくはＣＯＮＨから選ばれる２価の基を示し、ｎ_２は独立に０〜４の整数を示す］

[Wherein R ₁₀ independently represents a monovalent hydrocarbon group or alkoxy group having 1 to 6 carbon atoms, and Z represents a single bond or a divalent hydrocarbon group having 1 to 15 carbon atoms, O, S, CO , SO, SO ₂ , NH or CONH represents a divalent group, and n ₂ independently represents an integer of 0 to 4]

  Examples of such aromatic diamines include 4,4′-diaminodiphenyl ether, 2′-methoxy-4,4′-diaminobenzanilide, 1,4-bis (4-aminophenoxy) benzene, 1,3- Bis (4-aminophenoxy) benzene, 2,2′-bis [4- (4-aminophenoxy) phenyl] propane, 2,2′-dimethyl-4,4′-diaminobiphenyl, 3,3′-dihydroxy- Preferred examples include 4,4′-diaminobiphenyl, 4,4′-diaminobenzanilide, bisaniline fluorene and the like.

  Further, other examples of the aromatic diamine include 2,2-bis- [4- (3-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3 -Aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy)] biphenyl, bis [4- (3-aminophenoxy) biphenyl, bis [1- (4-aminophenoxy)] biphenyl, bis [1- (3-Aminophenoxy)] biphenyl, bis [4- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] ether Bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy)] benzophenone, bis 4- (3-aminophenoxy)] benzophenone, bis [4,4 ′-(4-aminophenoxy)] benzanilide, bis [4,4 ′-(3-aminophenoxy)] benzanilide, 9,9-bis [4 -(4-aminophenoxy) phenyl] fluorene, 9,9-bis [4- (3-aminophenoxy) phenyl] fluorene, 2,2-bis- [4- (4-aminophenoxy) phenyl] hexafluoropropane, 2,2-bis- [4- (3-aminophenoxy) phenyl] hexafluoropropane, 4,4′-methylenedi-o-toluidine, 4,4′-methylenedi-2,6-xylidine, 4,4′- Methylene-2,6-diethylaniline, 4,4′-diaminodiphenylpropane, 3,3′-diaminodiphenylpropane, 4,4′-diamino Diphenylethane, 3,3′-diaminodiphenylethane, 4,4′-diaminodiphenylmethane, 3,3′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfide, 3,3′-diaminodiphenyl sulfide, 4,4 ′ -Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, benzidine, 3,3'-diaminobiphenyl, 3,3 '-Dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxybenzidine, 4,4' '-diamino-p-terphenyl, 3,3' '-diamino-p-terphenyl, m-phenylenediamine , P-phenylenediamine, 2,6-diaminopyridy 1,4-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4 ′-[1,4-phenylenebis (1-methylethylidene)] bisaniline, 4, 4 ′-[1,3-phenylenebis (1-methylethylidene)] bisaniline, bis (p-aminocyclohexyl) methane, bis (p-β-amino-t-butylphenyl) ether, bis (p-β-methyl) -Δ-aminopentyl) benzene, p-bis (2-methyl-4-aminopentyl) benzene, p-bis (1,1-dimethyl-5-aminopentyl) benzene, 1,5-diaminonaphthalene, 2,6 -Diaminonaphthalene, 2,4-bis (β-amino-t-butyl) toluene, 2,4-diaminotoluene, m-xylene-2,5-diamine, p-xylene-2,5-di Examples include amines, m-xylylenediamine, p-xylylenediamine, 2,6-diaminopyridine, 2,5-diaminopyridine, 2,5-diamino-1,3,4-oxadiazole, piperazine and the like. it can.

  The above aromatic diamines may be used alone or in combination of two or more.

(II) Diaminosiloxane:
As diaminosiloxane, diaminosiloxane represented by the following general formula (14) or an oligomer thereof is preferably exemplified.

（ここで、Ｒ_１１及びＲ_１２は２価の炭化水素基を示し、Ｒ_１３〜Ｒ_１６は炭素数１〜６の炭化水素基を示し、ｍ_１は１〜２０の数、好ましくは１〜１０の数を示す。）

(Here, R ₁₁ and R ₁₂ represent a divalent hydrocarbon group, R _{13 to} R ₁₆ represent a hydrocarbon group having 1 to 6 carbon atoms, and m ₁ represents a number of ₁ to 20, preferably 1 to 1. Indicates a number of 10.)

  Examples of such diaminosiloxanes include diaminopropyltetramethyldisiloxane and diaminosiloxanes represented by the above general formulas (5) to (9).

  The above diaminosiloxanes may be used alone or in combination of two or more.

(III) Aliphatic amines:
Examples of the aliphatic amine include 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 2-methyl-1,5-diaminopentane, 1,7-diaminoheptane, and 1,8. -Diaminooctane, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1,9-diaminononane, 1,10-diaminodecane, 1,11-diaminoundecane, 1,12- Diaminoalkanes such as diaminododecane, 4,4′-methylenebiscyclohexylamine, tris (2-aminoethyl) amine, N, N′-bis (2-aminoethyl) -1,3-propanediamine, bis (3 -Aminopropyl) ethylenediamine, 1,4-bis (3-aminopropyl) piperazine, diethylenetriamine, N-methyl-2,2'-dia Nodiethylamine, 3,3′-diaminodipropylamine, amines containing nitrogen atoms such as N, N-bis (3-aminopropyl) methylamine, bis (3-aminopropyl) ether, 1,2-bis Amines containing oxygen atoms such as (2-aminoethoxy) ethane, 3,9-bis (3-aminopropyl) -2,4,8,10-tetraoxaspiro [5.5] -undecane, Examples include amines having a sulfur atom such as 2'-thiobis (ethylamine).

  These aliphatic amines may be used alone or in combination of two or more.

(IV) Dihydrazide compound:
Examples of the dihydrazide compound include those represented by the following general formula (15).

In the general formula (15), examples of R ₁₇ include a single bond, an aliphatic group, and an aromatic group. What is preferable as R ₁₇ is described with reference to examples of dihydrazide compounds. For example, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, pimelic acid dihydrazide, suberic acid dihydrazide, azelaic acid dihydrazide, sebacic acid dihydrazide dihydrazide, maleic acid dihydrazide Diglycolic acid dihydrazide, tartaric acid dihydrazide, malic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, terephthalic acid dihydrazide, 2,6-naphthoic acid dihydrazide, 4,4-bisbenzenedihydrazide, 1,4-naphthoic acid dihydrazide, 2 , 6-pyridinedihydrazide, itaconic acid dihydrazide and the like.

  The above dihydrazide compounds may be used alone or in combination of two or more.

  Of the amino compounds having at least two primary amino groups as functional groups as described above, dihydrazide compounds are most preferable. When a dihydrazide compound is used, the curing time due to cross-linking formation of the polyimide resin can be shortened as compared with the case where another amino compound is used. This is because the product obtained by reacting the primary amino group of the dihydrazide compound with the ketone group has a semicarbazone-like molecular structure, and forms a dimer structure by hydrogen bonding between NHs between molecules. Because the stability of the product is improved, the equilibrium of the reaction is biased toward the product side, and the reverse reaction in the direction of generating the ketone group of the polyimidesiloxane that is the raw material and the amino group of the dihydrazide compound is less likely to occur. It is considered a thing.

  In addition, amino compounds such as (I) aromatic diamine, (II) diaminosiloxane, (III) aliphatic amine, and (IV) dihydrazide compound are, for example, combinations of (I) and (II), (I) and ( It can also be used in combination of two or more types across categories, such as combinations with (III), combinations of (I), (II) and (III), and combinations of (I) to (IV). In particular, by combining the amino compound of (I), (II) or (III) and the dihydrazide compound of (IV) at a predetermined blending ratio, taking advantage of the properties of the amino compound of (I) to (III) It is expected to obtain an effect of shortening the curing time depending on the blending ratio of the dihydrazide compound (IV).

  Further, from the viewpoint of making the network structure formed by crosslinking of the amino compound more dense, the amino compound used in the present invention has a molecular weight (weight average molecular weight when the amino compound is an oligomer) of 5,000 or less. It is preferably 90 to 2,000, more preferably 100 to 1,500. Among these, amino compounds having a molecular weight of 100 to 1,000 are particularly preferable. When the molecular weight of the amino compound is less than 90, one amino group of the amino compound only forms a C = N bond with the ketone group of the polyimide siloxane, and the remaining amino group is sterically bulky so that it remains. The amino group tends to be difficult to bond C═N.

[Production of filler-containing polyimide resin]
The filler-containing polyimide resin is obtained by mixing and uniformly dispersing a heat conductive filler in a resin solution containing polyimide siloxane having the structural units represented by the general formulas (1) and (2). It is produced by adding an amino compound having a primary amino group as a functional group and subjecting a polyimide siloxane ketone group to a condensation reaction of the amino compound primary amino group. By this condensation reaction, a cross-linked structure is formed in the polyimide siloxane and cured to a cured product. In this case, the added amount of the amino compound is 0.004 mol to 1.5 mol, preferably 0.005 mol to 1.2 mol, more preferably 0.001 mol to 1.2 mol in total for the primary amino group with respect to 1 mol of the ketone group. The amount is 0.03 mol to 0.9 mol, particularly preferably 0.04 mol to 0.5 mol. The addition amount of the amino compound in which the primary amino group is less than 0.004 mol in total with respect to 1 mol of the ketone group is not sufficient for crosslinking of the polyimide siloxane with the amino compound. Solder heat resistance tends to be difficult to develop in a cured product after curing a resin composition containing a filler, and when the added amount of the amino compound exceeds 1.5 mol, the unreacted amino compound acts as a thermoplastic agent. However, the cured product tends to reduce solder heat resistance or to reduce long-term heat resistance at high temperatures.

The conditions for the condensation reaction are not particularly limited as long as the ketone group in the polyimidesiloxane and the primary amino group of the amino compound react to form an imine bond (C═N bond). Depending on the type of amino compound, for example, when an aliphatic amine is used, it can be condensed with a ketone group in polyimide siloxane even at room temperature, but it is preferable to promote the condensation reaction by heating. When an aliphatic amine is used, it is preferable to perform heat condensation within a range of 60 to 200 ° C., for example. When an aromatic amine is used, heat condensation is performed within a range of 120 to 220 ° C., for example. preferable. The temperature of the heat condensation is, for example, 120 for the purpose of releasing water generated by the condensation out of the system or simplifying the condensation step when the heat condensation reaction is subsequently performed after the synthesis of the polyimidesiloxane. Within the range of -220 degreeC is preferable, and the inside of the range of 140-200 degreeC is more preferable. The reaction time varies depending on the heat treatment temperature, but can be, for example, in the range of 3 minutes to 30 hours. Here, when it is desired to obtain a high crosslinking rate, it is preferable that the reaction time is, for example, more than 1 hour to about 24 hours in the above temperature range, and when it is desired to keep the crosslinking rate low, the above temperature range. The reaction time is preferably in the range of 3 to 60 minutes, for example, and more preferably in the range of 5 to 30 minutes. The end point of the condensation reaction is derived from the ketone group in polyimidesiloxane near 1670 cm ⁻¹ by measuring the infrared absorption spectrum using, for example, a Fourier transform infrared spectrophotometer (commercial product: FT / IR620 manufactured by JASCO Corporation). It can be confirmed by the decrease or disappearance of the absorption peak and the appearance of an absorption peak derived from an imine group near 1635 cm ⁻¹ , or by using a Raman spectrophotometer (commercial product: NRS-3100 manufactured by JASCO Corporation). By measuring the spectrum, it can be confirmed by the appearance of a peak derived from an imine group in the vicinity of 1567 cm ⁻¹ .

  The polyimide resin solution containing the above heat conductive filler is prepared, for example, by adding a predetermined amount of each of the heat conductive filler and the amino compound for cross-linking to a polyimide resin solution containing a solvent, and dispersing with a stirrer or the like. And a method of adding an amino compound for cross-linking after adding a diamine and an acid anhydride to form a polyimide resin solution while dispersing a thermally conductive filler in a solvent. preferable. Examples of the solvent include N, N-dimethylacetamide, n-methylpyrrolidinone, 2-butanone, diglyme, xylene, and the like, and these can be used alone or in combination of two or more.

In a preferred embodiment, the heat condensation of the ketone group of the polyimide siloxane and the primary amino group of the amino compound is, for example,
(A) Subsequent to the synthesis (imidization) of polyimide siloxane, adding an amino compound and a thermally conductive filler and heating,
(B) An excess amount of an amino compound is charged in advance as a diamine component, and after the synthesis (imidation) of polyimide siloxane, a thermally conductive filler is added, and then the remaining amino acid not involved in imidization (or amidation) Heating the polyimide siloxane with the compound, or
(C) heating after processing the composition of polyimide siloxane to which an amino compound and a thermally conductive filler are added into a predetermined shape (for example, after being applied to an arbitrary base material or after being formed into a film),
Etc.

  In the case of (b) above, the excess amino compound is consumed in the reaction of sealing the acid anhydride group as a terminal substituent during the production of polyimidesiloxane, and the molecular weight of the resulting polyimidesiloxane may be extremely reduced. Therefore, it tends to be difficult to obtain sufficient heat resistance in the cured product. Therefore, when an excess amount of an amino compound is charged in advance [the above (b)], it is preferably used as long as the effects of the present invention are not impaired. In order to effectively react at least two primary amino groups in an amino compound with a ketone group to form a C═N bond, the amino compound is synthesized from polyimide siloxane as in (a) or (c) above. It is preferable to add after completing (imidization). In the case of the above (c), the heat condensation can also be performed by, for example, a heat treatment after forming a composition in which an amino compound and polyimide siloxane are mixed on a support substrate.

[Metal layer]
Examples of the metal layer in the thermally conductive substrate of the present invention include conductive metal foils such as copper, aluminum, iron, silver, palladium, nickel, chromium, molybdenum, tungsten, zinc, and alloys thereof. Among them, copper foil or alloy copper foil or aluminum foil containing 90% or more of copper is preferably used. Although the preferable thickness range of a metal layer can be set according to the use of a heat conductive board | substrate, when using as board | substrate materials, such as an electronic device and a lighting device, it is preferable to set it as the range of 5-2000 micrometers, for example. If the thickness of the metal layer is less than 5 μm, problems such as wrinkles may occur during conveyance in the manufacturing process. Conversely, if the thickness exceeds 2000 μm, workability may be reduced.

  Further, the conductive metal foil used as the metal layer has a surface roughness (Ra) of the surface to be bonded to the insulating layer of, for example, 0.05 in order to achieve both the adhesion to the insulating layer and the fine circuit processability. It is preferable to be within a range of ˜1.0 μm. If the surface roughness (Ra) of the surface that adheres to the insulating layer is less than 0.05 μm, the metal layer and the insulating layer may be easily peeled off depending on the use of the thermally conductive substrate, while the surface of the surface that adheres to the insulating layer. When the roughness (Ra) exceeds 1.0 μm, the adhesion between the metal layer and the insulating layer becomes good due to the anchor effect due to the roughening, but there is a concern that the wiring shape may deteriorate when the metal layer is processed by wiring. .

[Method for producing thermally conductive substrate]
Next, an example of a method for producing a heat conductive substrate (metal-clad laminate) will be described. The thermally conductive substrate is a coating of a polyimide resin containing filler that is uniformly dispersed in polyimide siloxane and then mixed with an amino compound. A filler-containing polyimide resin layer is formed by heating the coating film and reacting the amino group of the amino compound with at least a part of the ketone group in polyimidesiloxane to form a C = N bond. Can be manufactured by a method including. In this case, the filler-containing polyimide resin layer may be further laminated on the filler-containing polyimide resin layer by the same method, or another polyimide resin layer may be laminated. Here, as a metal base material, metal foils, such as above-mentioned copper foil used as the conductor layer of a thermal radiation board | substrate or a circuit board, can be used. In addition, as described above, the filler-containing polyimide resin layer may be in a cured state in which cross-linking is completed or in a semi-cured state in which cross-linking is not completed.

  Application of the filler-containing polyimide resin solution on the metal substrate can be performed by a known method, for example, appropriately selected from a barcode method, a gravure coating method, a roll coating method, a die coating method, and the like. Can do.

  In order to explain the present invention more clearly, a thermally conductive substrate (single-sided metal thermally conductive substrate) having a metal layer on one side of an insulating layer and a thermally conductive substrate (double-sided metal having a metal layer on both sides of the insulating layer) Production examples are shown separately for the thermally conductive substrate. Here, a case where the insulating layer is constituted by only one filler-containing polyimide resin layer will be described as an example.

<Single-sided metal thermal conductive substrate>
First, a metal foil such as a copper foil constituting the metal layer of the thermally conductive substrate is prepared. On this metal foil, a polyimide resin solution containing a heat conductive filler and an amino compound is applied, and dried at a temperature of, for example, 120 ° C. or less to remove a certain amount of solvent. Thereafter, it is further heat-treated at a high temperature to cause a crosslinking reaction with an amino compound. Thereby, it can be set as the heat conductive board | substrate which has a metal layer on the single side | surface of a filler containing polyimide resin layer. Here, the heat treatment time for forming a cross-link with the amino compound can be set according to the target cross-link formation rate. When a single-sided metal thermal conductive substrate is used as a resin-coated copper foil, the crosslink formation rate is lowered on the assumption that, for example, a metal foil, a ceramic substrate, or another material member will be bonded to the filler-containing polyimide resin layer later. Therefore, the heat treatment time in that case is preferably in the range of 3 to 60 minutes, and more preferably in the range of 5 to 30 minutes, in the above temperature range.

<Double-sided metal thermal conductive substrate>
The double-sided metal thermally conductive substrate can be produced by thermocompression bonding a metal foil to the filler-containing polyimide resin layer of the single-sided metal thermally conductive substrate obtained by the above method. The conditions for thermocompression bonding of the metal foil are preferably, for example, a heating temperature in the range of 120 to 180 ° C., a pressure in the range of 2 to 4 MPa, and a pressing time in the range of 0.1 to 24 hours.

[Action]
The reaction between the ketone group of the polyimidesiloxane having the structural units represented by the general formulas (1) and (2) and the primary amino group of the amino compound is a dehydration condensation reaction, and the carbon of the ketone group in the polyimidesiloxane As a result of the atom and the nitrogen atom of the primary amino group forming a C═N bond, it is considered that the chain polyimidesiloxane is crosslinked with an amino compound to form a network polymer. Normally, polyimidesiloxane is difficult to cause intermolecular interaction, so it is difficult to control the orientation of polyimidesiloxane. However, when a cross-linked structure occurs, not only the apparent high molecular weight of polyimidesiloxane but also the polyimidesiloxane molecules Since it becomes possible to restrain to some extent, it is considered that the heat resistance of the polyimide resin is improved and extremely excellent solder heat resistance is obtained. In addition, the vicinity of the nitrogen atom in the C = N bond becomes three-dimensionally bulky, thereby reducing the nucleophilic ability of the copper atom to the polar group contained in the polyimide resin, thereby leading to the copper insulating layer from the copper wiring. It is thought that the effect of suppressing the decrease in the adhesive strength when used in a high temperature environment can be obtained. For these reasons, the amino compound used in the present invention needs to have at least two amino groups, and the number of amino groups is preferably 2 to 5, more preferably 2 to 3. In addition, in an amino compound having three or more amino groups, the cross-linked structure after the two amino groups form a C═N bond becomes three-dimensionally bulky, so that the remaining unreacted amino group is a ketone group. It is particularly preferable that the number of amino groups is 2. Furthermore, as described above, it is most preferable to use a dihydrazide compound as the amino compound from the viewpoint of shortening the curing time by the crosslinking formation of the polyimide resin.

  And the heat conductive board | substrate of this Embodiment has adjusted content of a heat conductive filler in the appropriate range in addition to the crosslinked structure by an amino compound. As a result, the insulating layer has sufficient heat resistance, the metal layer and the insulating layer can be bonded at a relatively low temperature without interposing an adhesive layer, and has excellent thermal conductivity. Accordingly, the thermally conductive substrate of the present embodiment can be widely used industrially as a substrate material for electronic devices and lighting devices that require high heat dissipation, such as a heat dissipation substrate for power semiconductor mounting. It is particularly suitable for use in applications such as a heat dissipation board and a circuit board typified by a flexible board.

  In addition, when the polyimide siloxane contains a hydrogen bond forming group, a hydrogen bond is generated between adjacent polyimide siloxane chains prior to the crosslinking reaction, and the ketone groups that are the reaction points of the crosslinking reaction with the amino compound are brought closer to each other. be able to. As a result, the crosslinking reaction by the amino compound is promoted, and the heating time for forming the crosslinking can be shortened.

[Thermal conductive polyimide film]
The thermally conductive polyimide film of the present embodiment is a thermally conductive polyimide film provided with a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin. The content rate of the heat conductive filler in this filler containing polyimide resin layer exists in the range of 5-80 wt%, and the polyimide resin in the said filler containing polyimide resin layer is the structure represented by the said General formula (1) and (2). The polyimide siloxane is an amino compound by reacting the ketone group in the polyimide siloxane having a unit with an amino group of an amino compound having at least two primary amino groups as functional groups to form a C = N bond. It has the structure bridge | crosslinked by. The polyimide resin may be in a cured state where the crosslinking reaction has been completed, or in a semi-cured state in which room for crosslinking is left. Here, the filler-containing polyimide resin layer has the same configuration as the filler-containing polyimide resin layer constituting a part or all of the insulating layer in the thermally conductive substrate. What was demonstrated in said heat conductive board | substrate can be used for the polyimide resin and heat conductive filler which comprise the filler containing polyimide resin layer of this Embodiment.

  The entirety of the thermally conductive polyimide film of the present embodiment may be constituted by a filler-containing polyimide resin layer, and other than the filler-containing polyimide resin layer, other than the insulating layer of the thermally conductive substrate, Although the polyimide resin layer may be provided, it is preferable that the whole is formed of the filler-containing polyimide resin layer from the viewpoint of enhancing the heat dissipation characteristics. In this case, the filler-containing polyimide resin layer is not limited to a single layer, and may be a laminate of a plurality of layers. Thus, the thermally conductive polyimide film of the present embodiment has the same structure and physical properties as the insulating layer of the thermally conductive substrate, except that it is not bonded to the metal layer. And a heat conductive polyimide film is producible by removing the metal layer by etching, for example after producing the said heat conductive board | substrate. Alternatively, a coating solution in which an amino compound having a primary amino group is mixed with a polyimide resin solution after imidization containing a thermally conductive filler is applied to an arbitrary substrate, dried, and then peeled off from the substrate. It can also be set as a heat conductive polyimide film. In this case, it may be peeled off from the base material after it is heated on the base material to complete the crosslinking reaction, or it is peeled off from the base material in a state prior to curing just dried, and then heated to depend on the cross-linking reaction. Curing may be completed.

  The thermally conductive polyimide film of the present embodiment has practical adhesion strength to a metal foil (metal plate), a ceramic substrate, a Si substrate, etc., and is excellent in thermal conductivity. This thermally conductive polyimide film can be bonded to a metal foil (metal plate), a ceramic substrate, a Si substrate or the like without an adhesive layer. That is, the heat conductive polyimide film has a property that can be directly bonded to a bonding target base material such as a metal foil (metal plate) or a ceramic substrate on one or both sides without requiring an adhesive layer. Yes. Therefore, the thermally conductive polyimide film of the present embodiment is a film suitable for being used by being laminated on a base material such as a metal layer or a ceramic layer in applications such as a heat dissipation board or a circuit board.

  Since the other structure and effect of the heat conductive polyimide film of this Embodiment are the same as that of the insulating layer in the said heat conductive board | substrate, description is abbreviate | omitted.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples, various measurements and evaluations are as follows unless otherwise specified.

[Copper foil peel strength (peel strength)]
The copper foil layer of the thermally conductive substrate was pattern-etched into a long rectangle having a width of 1.0 mm and a length of 180 mm, and a test piece was cut out to a width of 20 mm and a length of 200 mm so that the pattern was in the center, and IPC-TM- A 180 ° peeling test was conducted by 650.2.19 (manufactured by Toyo Seiki).

[Thickness direction thermal conductivity (λzTC)]
A thermally conductive polyimide film was cut into a size of 20 mm × 20 mm, subjected to platinum deposition and blackening treatment, and then the thermal diffusivity in the thickness direction by a laser flash method (Xenon Flash Analyzer LFA 447 Nanoflash, manufactured by NETZSCH), DSC The specific heat and the density by the underwater substitution method were measured, and the thermal conductivity (W / m · K) was calculated based on these results. In addition, the heat conductive polyimide film produced and used the sample of thickness 100 micrometers at the time of a measurement.

[Withstand voltage]
The thermally conductive polyimide film was cut into a size of 5 cm × 5 cm, and the withstand voltage was measured in insulating oil by a step-up method using a TOS 5101 apparatus manufactured by KIKUSUI based on JIS C2110. The voltage was stepped up in steps of 0.2 kV, held at each voltage for 20 seconds, a leakage current of 8.5 mA, and the value immediately before the broken voltage was the initial withstand voltage. The size of the electrode is 2 cmφ.

[Measurement of weight average molecular weight (Mw)]
The weight average molecular weight was measured by a gel permeation chromatograph (manufactured by Tosoh Corporation, using HLC-8220GPC). Polystyrene was used as a standard substance, and N, N-dimethylacetamide was used as a developing solvent.

[Method for evaluating solder heat resistance (drying)]
Circuit processing is performed by patterning the copper foil layer of the thermally conductive substrate into a predetermined shape, soaking in a solder bath at each temperature up to 300 ° C. for 10 seconds, observing the adhesive state, foaming, blistering, peeling, etc. The presence or absence of defects was confirmed. For the heat resistance, the upper limit temperature at which no defects occur was defined as solder heat resistance. For example, “300 ° C.” means that no defect is observed when evaluated in a solder bath at 300 ° C.

[Measurement method of curl]
CCL curl (maximum warpage):
Cut the metal / resin laminate into a size of 50 mm x 50 mm, leave it for 24 hours in a constant temperature and humidity environment (23 ± 3 ° C, 50 ± 5% RH), and then measure the amount of warping at the four corners using a caliper. Carried out. At this time, when warping toward the resin surface side or the metal side, the CCL maximum warpage amount was determined at the place where the warpage amount was the largest. The case where the absolute amount of the maximum warpage amount was 5 mm or less was judged as “good” (good), and the case where it was 5 mm or more was judged as “poor” (bad).

The abbreviations used in the examples represent the following compounds.
BTDA: 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride BPDA: 3,3 ′, 4,4′-diphenyltetracarboxylic dianhydride BAPP: 2,2-bis (4-aminophenoxy) Phenyl) propane DAPE: 4,4′-diaminodiphenyl ether m-TB: 2,2′-dimethyl-4,4′-diaminobiphenyl

PSX: diaminosiloxane represented by the following general formula (the number average value of m ₁ is in the range of 1 to 20, and the weight average molecular weight is 740)

N-12: Dodecanedioic acid dihydrazide having the following structural formula

NMP: N-methyl-2-pyrrolidone DMAc: N, N-dimethylacetamide

Synthesis example 1
In a 1000 ml separable flask, 71.850 g PSX (0.0971 mol), 7.474 g BAPP (0.0182 mol), 1.568 g N-12 (0.0061 mol), 39.109 g BTDA. (0.1214 mol) 168 g of N-methyl-2-pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C., heated and stirred for 20 hours to obtain a polyimide solution a having completed imidization. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution a was 90,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80%.

[Example 1]
63.88 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, and 2.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 38.4 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned alumina-containing polyimide solution and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating and drying at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 10 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained.

  In order to evaluate the characteristics of the insulating layer in the obtained heat conductive substrate, the copper foil was removed by etching to produce a heat conductive polyimide film (F1), and the withstand voltage and the heat conductivity were evaluated. These results are shown in Table 1. Further, the heat conductive substrate was processed into a predetermined pattern, and the adhesive strength, solder heat resistance and curl were measured. These results are shown in Table 2. “Applied surface adhesive strength” in Table 2 means the adhesive strength between the coated film and the metal layer at the boundary between the copper foil when the polyimide solution is applied onto the rolled copper foil. “Adhesion strength” means the adhesion strength when the metal layer is later pressure-bonded to the surface side of the coating film when the polyimide solution is applied onto the rolled copper foil (the same applies in Table 4).

[Example 2]
47.99 g of polyimide solution a obtained in Synthesis Example 1 was weighed, and 17.28 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 28.81 g of solvent NMP was weighed in another container, 0.82 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above polyimide solution containing alumina and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating and drying at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 3]
47.88 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, 17.24 g of aluminum nitride (average particle size 1.1 μm, manufactured by Tokuyama) was added, and mixed with a centrifugal stirrer until uniform. Subsequently, 15.6 g of solvent NMP was weighed into another container, 0.82 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the polyimide solution containing the above aluminum nitride and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating and drying at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of aluminum nitride which is a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Synthesis example 2
In a 1000 ml separable flask, 71.30 g PSX (0.0964 mol), 9.89 g BAPP (0.0241 mol), 38.66 g BTDA (0.120 mol), 168 g N-methyl-2 -Pyrrolidone and 112 g of xylene were charged and mixed well at room temperature for 1 hour to obtain a polyamic acid solution. This polyamic acid solution was heated to 190 ° C. and heated and stirred for 20 hours to obtain a polyimide solution b in which imidization was completed. The weight average molecular weight (Mw) of the polyimide resin in the obtained polyimide solution b was 122,000. At this time, the mol% of the diaminosiloxane component relative to the total diamine component is 80% (m value = 0.8). In addition, "m value" means the presence molar ratio of the structural unit represented by the said General formula (1) contained in the obtained polyimide resin.

[Example 4]
400.24 g of the polyimide solution b obtained in Synthesis Example 2 was weighed, and 16.34 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 97.4 g of solvent NMP was weighed into another container, 4.2 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the polyimide solution containing the alumina and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating and drying at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 2 hours to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and a heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 10 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Example 5]
400 g of the polyimide solution b obtained in Synthesis Example 2 was weighed, and 147.0 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added until uniform. Mix with a centrifugal stirrer. Subsequently, 97.3 g of solvent NMP was weighed into another container, 4.2 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the polyimide solution containing the alumina and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating and drying at 80 ° C. for 30 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 2 hours to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and a heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 50 wt%. Subsequently, a rolled copper foil having a thickness of 18 μm is placed on the polyimide insulating layer of the thermally conductive substrate, pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours, and the thermal conductivity having a metal layer on both sides. A substrate was obtained. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

Synthesis example 3
To 255 g of DMAc in a 500 ml separable flask equipped with a stirrer, 28.9050 g of BAPP was added with stirring under a nitrogen stream and dissolved, and then 15.0281 g of PMDA was added while maintaining stirring. After 10 minutes, 1.0669 g of BPDA was added. Thereafter, stirring was continued at room temperature for 4 hours to carry out a polymerization reaction to obtain a viscous polyamic acid solution c to be a polyimide precursor.

[Comparative Example 1]
78.7 g of the polyamic acid solution c obtained in Synthesis Example 3 was weighed, and 1.3 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. Was mixed with a centrifugal stirrer until. Subsequently, 15.7 g of the solvent DMAc was added and mixed with a centrifugal stirrer until it became uniform again to obtain a polyamic acid solution containing 10 wt% of a heat conductive filler. Next, this polyamic acid solution was applied onto a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and dried by heating at 120 ° C. to remove the solvent. Then, it heated up in steps over 20 minutes in the temperature range of 130-340 degreeC, and produced the heat conductive board | substrate which has a metal layer on one side. Subsequently, a rolled copper foil having a thickness of 18 μm was superposed on the polyimide insulating layer of this thermally conductive substrate, and thermocompression bonding was attempted at 160 ° C. using a vacuum press. However, since it could not be bonded at 160 ° C., it was heated at 160 ° C. and 270 ° C. for 30 minutes, then heated to a temperature of 360 ° C. at a surface pressure of 19.1 MPa, and subjected to thermocompression bonding under a press time of 25 minutes. A thermally conductive substrate having metal layers on both sides was obtained. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 2]
69.6 g of the polyamic acid solution c obtained in Synthesis Example 3 was weighed, and 10.4 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added to be uniform. Was mixed with a centrifugal stirrer until. Subsequently, 13.9 g of solvent DMAc was added and mixed with a centrifugal stirrer until it became uniform again to obtain a polyamic acid solution containing 50 wt% of a heat conductive filler. Next, a heat conductive substrate was obtained in the same manner as in Comparative Example 1. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Synthesis Example 4]
To 255 g of DMAc in a 500 ml separable flask equipped with a stirrer, 20.7283 g of m-TB was added with stirring under a nitrogen stream and dissolved, and then 11.5380 g of PMDA was added while maintaining stirring. In addition, after 10 minutes, 12.7337 g of BPDA was added. Thereafter, the polymerization reaction was continued for 4 hours at room temperature to obtain a viscous solution of the polyamic acid solution d serving as a polyimide precursor.

[Comparative Example 3]
In place of the polyamic acid solution c of Comparative Example 1, the polyamic acid solution d obtained in Synthesis Example 4 was used in the same manner as in Comparative Example 1, and thermocompression bonding was attempted. A heat conductive substrate of Comparative Example 3 was obtained by thermocompression bonding with a press temperature of 360 ° C. at 380 ° C. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 4]
In place of the polyamic acid solution c of Comparative Example 2, the polyamic acid solution d obtained in Synthesis Example 4 was used in the same manner as in Comparative Example 2, and thermocompression bonding was attempted. A heat conductive substrate of Comparative Example 4 was obtained by thermocompression bonding with a press temperature of 360 ° C. at 380 ° C. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[Comparative Example 5]
A double-sided metal laminate of Comparative Example 5 was obtained in the same manner as in Example 1 except that the alumina of Example 1 was not added. Subsequently, evaluation was performed in the same manner as in Example 1. The results are shown in Tables 1 and 2.

  In Table 1, the content of the curing agent means weight percent with respect to the solid content of the polyimide resin, and the filler content means weight percent of filler with respect to the entire thermally conductive polyimide film from which the copper foil has been removed by etching.

  From Table 1, the heat conductive board | substrate of Examples 1-5 which contains a heat conductive filler in the polyimide resin which forms an insulating layer is the comparative example 5 which formed the insulating layer with the polyimide resin which does not contain a heat conductive filler. It can be seen that the thermal conductivity is greatly improved as compared with the metal-clad laminate. Moreover, from Table 2, the thermal conductive polyimide films of Examples 1 to 5 using a polyimide resin having a structure in which polyimide siloxane is crosslinked by an amino compound are Comparative Examples 1 to 5 using a polyimide resin having no crosslinked structure. Compared with the heat conductive polyimide film No. 4, the press workability was good, and practically sufficient adhesiveness was obtained by pressing at a low temperature. In addition, about withstand voltage property and heat resistance, Example 1-5 and Comparative Examples 1-5 had a practically sufficient characteristic. The heat conductive substrates of Examples 1 to 5 were small in curling and excellent in usability.

[Example 6]
63.89 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, and 86.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned alumina-containing polyimide solution and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 60 minutes to form an insulating layer in which a thermally conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 79 wt%.

  In order to evaluate the characteristics of the insulating layer in the obtained heat conductive substrate, the copper foil was removed by etching to produce a heat conductive polyimide film (F6), and the withstand voltage and the heat conductivity were evaluated. Further, the thermally conductive substrate was cut into a 5 cm square size, and the curl was measured. These results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resins was measured, it was 0.5. [KN / m] or more.

[Example 7]
63.89 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, and 53.69 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned alumina-containing polyimide solution and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 70 wt%. Subsequently, evaluation was performed in the same manner as in Example 6. The results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm 180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.6 was obtained. [KN / m] or more.

[Example 8]
In Example 7, in place of heating at 120 ° C. for 5 minutes and 160 ° C. over 10 minutes, except that heating was performed at 120 ° C. for 5 minutes and 160 ° C. over 60 minutes, as in Example 7, A thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 6. The results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm 180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.6 was obtained. [KN / m] or more.

[Example 9]
63.89 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, and 2.56 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned alumina-containing polyimide solution and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina which is a heat conductive filler in this insulating layer is 10 wt%. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.7 [KN / m] or more.

[Example 10]
In Example 9, in place of heating at 120 ° C. for 5 minutes and 160 ° C. over 10 minutes, except that heating was performed at 120 ° C. for 5 minutes and 160 ° C. over 60 minutes, as in Example 9, A thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 6. The results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.7 [KN / m] or more.

[Example 11]
63.89 g of the polyimide solution a obtained in Synthesis Example 1 was weighed, and 23.01 g of alumina (average particle size 1.5 μm, manufactured by Sumitomo Chemical Co., Ltd., trade name: AA-1.5) was added uniformly. It mixed with the centrifugal stirrer until it became. Subsequently, 35.06 g of solvent NMP was weighed in another container, 1.096 g of N-12 was added, and the mixture was stirred until N-12 was dissolved. This N-12 NMP solution was put into the above-mentioned alumina-containing polyimide solution and mixed with a centrifugal stirrer until it became uniform again to obtain a polyimide solution containing a thermally conductive filler. This polyimide solution was applied on a rolled copper foil (Ra = 0.7 μm) having a thickness of 18 μm so that the thickness after curing was 25 μm, and the solvent was removed by heating at 80 ° C. for 15 minutes. Thereafter, heating is performed at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes to form an insulating layer in which a heat conductive filler is dispersed in polyimide resin on the rolled copper foil, and heat conduction having a metal layer on one side. A conductive substrate was produced. The content of alumina as a heat conductive filler in this insulating layer is 50 wt%. Subsequently, evaluation was performed in the same manner as in Example 6. The results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.7 [KN / m] or more.

[Example 12]
In Example 11, instead of heating at 120 ° C. for 5 minutes and at 160 ° C. for 10 minutes, except for heating at 120 ° C. for 5 minutes and 160 ° C. for 60 minutes, the same as in Example 11, A thermally conductive substrate having a metal layer on one side was produced. Subsequently, evaluation was performed in the same manner as in Example 6. The results are shown in Table 3. Moreover, about the rolled copper foil thermocompression-bonded to the polyimide resin layer of the heat conductive board | substrate which has a metal layer on this single side | surface, when 1 mm180 degree peel strength (crimp surface adhesive strength) between metal / resin was measured, 0.7 [KN / m] or more.

[Example 13]
A rolled copper foil having a thickness of 18 μm is placed on a polyimide insulating layer of a heat conductive substrate having a metal layer on one side produced in Example 7, and pressed under conditions of a temperature of 160 ° C., a pressure of 2 MPa, and a time of 2 hours. A thermally conductive substrate having a metal layer was obtained. The obtained heat conductive substrate was processed into a predetermined pattern, and adhesive strength, solder heat resistance and curl were measured. The results are shown in Table 4.

  From Table 3, the single-sided metal thermally conductive substrates of Examples 6 to 12 containing a thermally conductive filler in the polyimide resin forming the insulating layer have high thermal conductivity, little curling, and excellent usability. It was. Moreover, from Table 4, the double-sided metal thermally conductive substrate of Example 13 had good press workability, and practically sufficient adhesiveness was obtained by pressing at a low temperature. In addition, the single-sided or double-sided metal thermally conductive substrates of Examples 6 to 13 had practically sufficient characteristics with respect to voltage resistance and heat resistance.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment, A various deformation | transformation is possible.

Claims (8)

In a thermally conductive substrate having a metal layer on one or both sides of an insulating layer having at least one filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin, the thermally conductive filler of the filler-containing polyimide resin layer The content rate of 5 to 80 wt%, and the polyimide resin in the filler-containing polyimide resin layer is represented by the following general formulas (1) and (2):

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, R ₂ is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R ₂ contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0, n is in the range of 0-0.6]
The polyimide group having the amino group reacts with the amino group of the amino compound having at least two primary amino groups as functional groups to form a C═N bond, so that the polyimide siloxane has the amino group. A thermally conductive substrate, which is a polyimide resin having a structure crosslinked with a compound.   The thermally conductive substrate according to claim 1, wherein the amino compound is a dihydrazide compound.   The thermally conductive substrate according to claim 1 or 2, wherein the thermally conductive filler is at least one filler selected from silica, alumina, aluminum nitride, boron nitride, silicon nitride, and magnesia.   The thermally conductive substrate according to any one of claims 1 to 3, wherein the thermally conductive filler is a spherical alumina having an average particle diameter in the range of 0.5 to 10 µm.   The thermally conductive substrate according to claim 1, wherein the polyimidesiloxane has a functional group that enables hydrogen bonding. A step of applying a solution of a filler-containing polyimide resin in which the polyimide siloxane, the thermally conductive filler, and the amino compound are mixed onto a metal base material to be the metal layer and drying to form a coating film;
Heating the coating film, and reacting an amino group of the amino compound with at least a part of the ketone group in the polyimidesiloxane to form a C = N bond to form a filler-containing polyimide resin layer;
The thermally conductive substrate according to claim 1, which is produced by a method comprising:   The thermally conductive substrate according to claim 6, wherein the filler-containing polyimide resin layer is in a semi-cured state. A thermally conductive polyimide film comprising a filler-containing polyimide resin layer in which a thermally conductive filler is dispersed in a polyimide resin,
The content rate of the heat conductive filler in the said filler containing polyimide resin layer exists in the range of 5-80 wt%, and the polyimide resin in the said filler containing polyimide resin layer is represented by following General formula (1) and (2). Unit:

[Wherein Ar is a tetravalent aromatic group derived from an aromatic tetracarboxylic anhydride, R ₁ is a divalent diaminosiloxane residue derived from diaminosiloxane, R ₂ is an aromatic diamine and / or Each represents a divalent diamine residue derived from an aliphatic diamine, Ar and / or R ₂ contains a ketone group, m and n represent the molar ratio of each constituent unit, and m is 0.4 In the range of -1.0, n is in the range of 0-0.6]
The polyimide group having the amino group reacts with the amino group of the amino compound having at least two primary amino groups as functional groups to form a C═N bond, so that the polyimide siloxane has the amino group. A thermally conductive polyimide film, which is a polyimide resin having a structure crosslinked with a compound.