JP3424237B2 - Method for manufacturing surface metal insulated substrate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface metal insulating substrate having excellent heat conductivity, high heat dissipation, high insulation, and sufficient peel strength, and a method for producing the surface metal insulating substrate. Regarding

[0002]

2. Description of the Related Art Conventionally, as a substrate for a printed wiring board,
Resin substrates such as paper / phenolic resin laminates and glass / epoxy resin laminates have been widely used. However, with the recent trend toward higher performance, smaller size, and higher density of electronic devices, how to deal with the high density generation of heat generated by it has become a problem, so these conventional resin substrates are
It is impossible to deal with such a problem. That is,
These resin substrates have low thermal conductivity and poor heat dissipation, and especially in integrated circuits designed to carry large currents,
This is because the heat may damage the capacitors, transistors, and the like, and there is a drawback that the electrical characteristics change significantly before the damage.

In order to overcome such a drawback of the resin substrate, in recent years, a metal plate having good heat conductivity such as aluminum is used in place of the resin substrate, and an organic insulating layer such as epoxy resin is provided on the surface thereof. , A metal printed circuit board having a structure in which a copper foil or the like is attached on top of it to form a circuit has come to be used. However, in such a structure, since the resin layer having a low thermal conductivity still exists between the circuit and the metal plate, the high thermal conductivity of the metal plate cannot be fully utilized.

In view of the above, a method of forming the insulating layer provided on the surface of the metal substrate by thermal spraying of a ceramic such as alumina having good thermal conductivity has been considered. Further, although there are pores in the ceramic insulating layer formed by thermal spraying, in the technique disclosed in Japanese Patent Publication No. 57-39007 for the purpose of preventing the deterioration of withstand voltage and insulation characteristics during moisture absorption due to the pores. The ceramic insulating layer is impregnated with a prepolymer or a monomer to close the pores.

According to the above method in which the insulating layer is formed by thermal spraying of ceramic, the circuit layer and the metal plate are not completely blocked by the resin layer having a low thermal conductivity. The thermal conductivity is greatly improved. However, since adhesion between metal and ceramic is not good originally, in the case of an insulating substrate on which an insulating layer is formed by thermal spraying of ceramic, an electric circuit is formed by sticking a metal foil on the insulating layer. However, there is a problem with the adhesiveness at that time, and improvement of this point is desired.

Japanese Unexamined Patent Publication (Kokai) No. 58-140191 discloses a technique for smoothing the surface by placing a resin sheet on the plasma sprayed layer on the surface of a metal substrate and thermocompression bonding. However, with this technology, it is difficult to reduce the thickness of the resin sheet, so even if a ceramic is used for the insulating layer to increase heat dissipation, the resin layer with poor thermal conductivity is thick and sufficient heat dissipation is achieved. The problem remains that it is not effective. And the adhesion between the metal foil and the ceramic layer is still poor. Since the resin does not penetrate into the fine pores of the ceramic layer only by thermocompression bonding of the resin sheet, it is not possible to fill the pores of the ceramic and there is a problem that the insulating property is not so good. On the other hand, Japanese Patent Application Laid-Open No. 01-194491 discloses that a ceramic sprayed layer is formed on one surface of a copper foil, and a carbon fiber base material prepreg (CF) is formed between the sprayed layer and a metal substrate.
RP) is interposed between the metal substrate and the ceramic layer, and the copper foil is attached onto the metal substrate via the ceramic insulating layer.
However, the thermal conductivity of CFRP is 0.05 to 0.015.
(Unit cal / cm · s · ° C), which is better than 0.001 of glass fiber base material prepreg, but 0.0 of alumina.
It is inferior to 7 to 0.1, and since it is a prepreg, the thickness becomes 0.06 mm or more, and a sufficient effect cannot be obtained.

[0007]

Therefore, the present invention is
An object of the present invention is to provide a surface metal insulating substrate having improved adhesion to a metal without impairing the advantages of the ceramic insulating layer and a method for manufacturing the same.

[0008]

To solve Means for Solving the Problems] Such problems, this invention is directed to take the following, such as configuration. In addition, in the following, the metal material is gold.
It means a metal substrate or a metal foil.

[0009]   At least one is made of metal foil,
Good thermal conductivity with good insulation on each side by thermal spraying
Metal material 2 having an insulating layer made of ceramic
The insulating layers of each otherMade of adhesive insulationThrough the adhesive layer
Then crimpThe adhesive insulation on both sides.
The insulation layers impregnated with adhesive insulation materialTo do
By using, In addition, aboveNotePlace
In this case, it is useful to pre-impregnate the insulating layer with an insulating material.
In addition, remove the impregnated insulating material on the surface of the insulating layer.
It is also useful. In addition, the pressure of the insulating layer and the insulating resin layer
Adhesion is by thermocompression bonding in a vacuum atmosphere, or the resin layer has good heat
It is also useful to include a conductive filler in advance.

[0010]   At least one is made of metal foil,
Good thermal conductivity with good insulation on each side by thermal spraying
Insulation layer made of ceramic
Both insulation layers are each impregnated with adhesive insulation material.
Two metal materials are integrated by crimping the insulation layers of each other
I will let you.[Reference technology] 1 to 5 are out of the technical scope of the present invention,
Including technical contents that can be combined with the invention of
Showing technology . Figure 1, tableOf the surface metal insulating substrate
The process of obtaining one type is shown.

As shown in FIG. 1A, a metal substrate 1 made of aluminum is first coated with alumina, for example, 20 to 200.
Plasma spraying is performed at an output of kV to form the ceramic insulating layer 2. As the metal substrate, the above-mentioned aluminum plate is preferable from the viewpoint of corrosion resistance and heat conductivity, but depending on the application (mechanical strength, electromagnetic wave shielding property, etc.), plated steel plate, stainless steel plate, clad plate, copper plate, alloy plate (invar plate) , 42 alloy, etc.) can also be used, and other than these may be used. Ceramic spraying methods include flame spraying, arc spraying,
A plasma spraying method, a water plasma spraying method, a reduced pressure plasma spraying method and the like can be used, but the plasma spraying method is preferable in that the bonding force between the material and the sprayed powder is strong. Thermal spray powder is A
Inorganic substances having good thermal conductivity such as l ₂ O ₃ , ZrO ₂ , BeO, MgO, spinnel, mullite, SiC, AlN, and boron nitride can be used, and alumina (Al ₂
O ₃ ) is preferable, but other than these may be used. The particle size is preferably about 1 to 100 μm. The sprayed alumina layer has many pores, and the porosity is 5 to 15 vo.
It is about 1%. The thickness of the alumina layer is 30 to 300 μ
m, usually about 30 to 200 μm. This is because if it is thicker than that, cracks are likely to occur to cause deterioration of withstand voltage, and if it is thinner than that, insulation reliability is lowered. According to the low pressure plasma spraying method, it is possible to obtain a denser film that is thinner than the above.

The presence of water or the like in the pores significantly deteriorates the insulation properties such as withstand voltage. Therefore, it is preferable to seal the pores with an insulating material such as epoxy resin. Epoxy resin and polyimide resin are suitable for the insulating material used for sealing, but in addition to these, there are phenol resin, vinyl ester resin, unsaturated polyester resin, melamine resin, fluororesin, etc. Alkoxy chelates, low melting point glass and the like are included, but are not limited thereto. Since the insulating material to be sealed is required to have a good impregnation property into pores, a material having low viscosity and permeability is selected. In order to improve the impregnation property, it is preferable that the ceramic layer is surface-treated with a coupling agent. The impregnation is preferably performed by a vacuum impregnation method, and can be performed by a spray method, a dipping method, a coating method such as brush coating or roller coating, a doctor blade method, or a curtain coater method. In the vacuum impregnation method, the air in the pores of the ceramic insulating layer 2 is removed under vacuum. At the same time, it is useful to remove adhering water by heating and expel it. The insulating material is fully impregnated in a short time. If necessary, it may be heated to bring it to the B stage state (semi- cured ).

Next, as shown in FIG. 1A, an insulating adhesive resin layer 4 made of epoxy resin or the like is formed on the surface of another metal material (metal foil such as copper foil) 3. It is preferable to mix an insulating filler having good thermal conductivity such as alumina in epoxy resin or the like in order to improve heat dissipation.
It is very good that the filler is filled at 50 vol% or more. As such a resin, generally, an epoxy resin, a polyimide resin, which has a good adhesion with a metal foil (metal substrate),
Phenol resin, butyral resin and the like can be used. As a coating method, a spray method, a coating method such as brush coating or roller coating, a doctor blade method, a curtain coater method, an extrusion (die coater) method, or the like can be used.
The thickness of the resin layer is preferably 1 to 100 μm, more preferably 1 to 30 μm. The resin layer is a film thinner than the resin-impregnated sheet (prepreg). After the formed resin layer is in the B stage state (in the case of thermosetting resin),
Insulating layer 2 of metal substrate (metal foil) 1 on which a ceramic insulating layer is formed, and metal foil (metal substrate) 3 on which a resin layer is formed
As shown in FIG. 1B, the resin layers 4 are laminated face to face and laminated by thermocompression bonding with a press or the like. Then,
As shown in (c), a surface metal insulating substrate is obtained. In this case, roll tow roll may be used for continuous treatment, but the present invention is not limited thereto.

In the above description, the case where the ceramic layer is formed on the metal substrate side and the resin layer is formed on the metal foil side has been mainly described, but conversely, the ceramic layer is formed on the metal foil side and the resin layer is formed on the metal substrate side. However, the result does not change and a good effect is obtained.
Further, both metal materials may be metal foils. Hereinafter, the case where the ceramic layer is formed on the metal foil side and the resin layer is formed on the metal base material side will be specifically described with reference to FIG.

As shown in FIG. 2A, first, alumina is plasma sprayed onto the metal foil (eg, copper foil) 3 at an output of 20 to 200 kV to form the ceramic insulating layer 2. Ceramic spraying methods include flame spraying, arc spraying,
A plasma spraying method, a water plasma spraying method, a reduced pressure plasma spraying method and the like can be used, but the plasma spraying method is preferable in that the bonding force between the material and the sprayed powder is strong. Thermal spray powder is A
Inorganic substances having good thermal conductivity such as l ₂ O ₃ , ZrO ₂ , BeO, MgO, spinnel, mullite, SiC, AlN, and boron nitride can be used, and alumina (Al ₂
O ₃ ) is preferable, but other than these may be used. The particle size is preferably about 1 to 100 μm. The sprayed alumina layer has many pores, and the porosity is 5 to 15 vo.
It is about 1%. The thickness of the alumina layer is 30 to 300 μ
m, usually about 30 to 200 μm. This is because if it is thicker than that, cracks are likely to occur to cause deterioration of withstand voltage, and if it is thinner than that, insulation reliability is lowered. According to the low pressure plasma spraying method, it is possible to obtain a denser film that is thinner than the above.

The pores are preferably sealed with an insulating material in order to improve the insulating property. Epoxy resin and polyimide resin are suitable for the insulating material used for sealing, but in addition to these, there are phenol resin, vinyl ester resin, unsaturated polyester resin, melamine resin, fluororesin, etc. Alkoxy chelates, low melting point glass and the like are included, but are not limited thereto. Since the insulating material to be sealed is required to have a good impregnation property into pores, a material having low viscosity and permeability is selected. Ceramic insulating layer 2 for better impregnation
It is good to surface-treat with a coupling agent. Impregnation is preferably performed by a vacuum impregnation method, a spray method,
Dipping method, coating method such as brush coating and roller coating,
A doctor blade method, a curtain coater method or the like can be used. In the vacuum impregnation method, the air in the pores of the ceramic insulating layer 2 is removed under vacuum. At the same time, it is useful to remove adhering water by heating and expel it. The insulating material is fully impregnated in a short time. If necessary, it may be heated to bring it to the B stage state (semi- cured ).

When the insulating material is impregnated, the impregnated insulating material on the surface of the ceramic insulating layer is preferably removed as follows. When a resin insulating material containing a sufficient amount of insulating filler having good thermal conductivity (for example, 50 vol%) is impregnated, the viscosity is too high to ensure a sufficient impregnation effect. However, in order to ensure a sufficient impregnation effect, if the insulating filler with good thermal conductivity is not contained or the content is small, intervene as a layer with poor thermal conductivity on the insulating surface to ensure sufficient heat dissipation. The impregnated insulating material on the surface of the insulating layer is removed because it may interfere.

When removing the impregnated insulating material on the surface of the ceramic insulating layer, for example, as shown in FIG. 4, the excess impregnated (resin) insulating material 20 on the ceramic insulating layer 2 is scraped off with a squeegee 21, and then, as shown in FIG. as seen in FIG. 5, removing while melting-containing Hitaze' coaming 20 in the recess 22a of the ceramic insulating layer surface with a sponge roller 22 containing a solvent which dissolves the impregnated insulating material 20. Thereafter, it may be cured to the extent necessary to free Hitaze' coaming of the heated ceramic insulating layer prior to bonding.

On the other hand, as shown in FIG. 2A, an insulating adhesive resin layer 4 made of epoxy resin or the like is formed on the surface of the metal substrate 1. As the metal substrate 1, the above-mentioned aluminum plate is preferable from the viewpoint of corrosion resistance and thermal conductivity, but depending on the application (mechanical strength, electromagnetic wave shielding property, etc.), plated steel plate, stainless steel plate, clad plate, copper plate, alloy plate ( Inver,
42 alloy, etc.) can also be used, and other than these may be used. It is preferable to mix an insulating filler having good thermal conductivity (metal-based filler or inorganic filler) such as alumina into epoxy resin or the like in order to improve heat dissipation. It is very good that the filler is filled at 50 vol% or more. As such a resin, in general, an epoxy resin, a polyimide resin, a phenol resin, a butyral resin, or the like, which has good adhesion to the metal substrate 1, can be used. As a coating method, a spray method, a coating method such as brush coating or roller coating, a doctor blade method, a curtain coater method, an extrusion (die coater) method, or the like can be used. The thickness of the resin layer 4 is preferably 1 to 100 μm, more preferably 1 to 30 μm. The resin layer 4 is a film thinner than the resin-impregnated sheet (prepreg). After the formed resin layer is in the B-stage state (in the case of thermosetting resin), the insulating layer 2 of the metal foil 3 on which the ceramic insulating layer is formed and the resin layer 4 of the metal substrate 1 on which the resin layer is formed. 2 are laminated facing each other as shown in FIG. 2B, and thermocompression bonded by a press or the like. Then, as shown in FIG. 2 (c),
A surface metal insulating substrate is obtained. In this case, roll tow roll may be used for continuous treatment, but the present invention is not limited thereto.

A series of steps for removing the impregnated insulating material on the surface of the ceramic insulating layer is shown in FIG.
First, as shown in FIG. 3 (a), the ceramic insulating layer 2 is formed on the metal foil 3, impregnated with an insulating material as shown in FIG. 3 (b), and then as shown in FIG. 3 (c). The insulating material 20 on the surface of the ceramic insulating layer 2 is removed. On the other hand, as shown in FIG. 3D, the adhesive resin layer 4 is formed on one surface of the metal substrate 1,
As shown in (e), the ceramic insulating layer 2 and the adhesive resin layer 4
Is pressure-bonded to complete the surface metal insulating substrate as shown in FIG. The insulating material 20 on the surface of the ceramic insulating layer
The not removed, it is not preferable because the crimp and the insulating material 20 is likely Do that thermally barrier layer in the state of FIG. 3 (b). The method of removing the impregnated insulating material on the surface of the ceramic insulating layer before pressure bonding is also effective when applied to the impregnated insulating material on the surface of the ceramic insulating layer formed on the metal substrate.

In the case of this technique , it is desirable that the insulating layer 2 and the resin layer 4 be bonded by thermocompression in a vacuum atmosphere. The thermocompression bonding method in the vacuum atmosphere is based on the ceramic insulating layer 2
It is particularly effective when the resin layer formed on one surface of the metal substrate 1 does not have been impregnated with the insulating material in advance and contains an insulating filler having good thermal conductivity. Of course, it may be applied to the case where the ceramic insulating layer 2 is impregnated with an insulating material in advance, or may be applied to the case where the ceramic insulating layer is formed on the metal substrate side.

As shown in FIG. 2B, the insulating layer 2 and the resin layer 4 are superposed on each other, and the inside of the vacuum press is evacuated to about 1 to 10 Torr while being lightly pressed by the hot plate. This allows
The air in the pores of the ceramic insulating layer is removed. Then, the hot plate is heated to a temperature at which the adhesive resin layer is re-melted, and pressure is applied in this state, and the hot plate temperature is further raised and kept for a certain period of time. Even if the adhesive resin layer contains a large amount of filler, it melts and easily penetrates into every corner of the deflated ceramic insulating layer to cure.

When the obtained surface metal insulating substrate has a structure in which the thermal expansion coefficient is gradually changed, that is, metal substrate / filler-containing ultra-thin resin layer / ceramic layer / metal foil, the ceramic layer is cracked even in the heat cycle test. It doesn't mean that The coefficient of thermal expansion of the resin layer can be appropriately adjusted by the amount of filler added. Further, since the resin containing the filler is sufficiently impregnated and filled in the ceramic insulating layer, the insulating property, particularly the breakdown voltage characteristic is good. This is a very useful method because it is not necessary to take special assisting measures such as application of ultrasonic waves. In this case, it is not necessary to impregnate the ceramic insulating layer with the insulating material in advance. Therefore, it is possible to omit the step of impregnating the insulating layer with the insulating material and the step of removing the impregnated insulating agent on the surface of the insulating layer, which makes it possible to manufacture at low cost with simple equipment, and to process in a relatively short time. There is little waste.

When the ceramic insulating layer is formed on the metal foil side, cracks are less likely to occur in the ceramic insulating layer in the heat cycle test and reliability tends to be higher than when the ceramic insulating layer is formed on the metal substrate side. To be [Detailed Description of the Invention] Next, among the surface metal insulating substrates according to the present invention,
The manufacturing process of the two types will be described in detail with reference to FIG.

In this type, ceramic insulating layers 12 and 14 are formed on one surface of two metal materials (at least one of which is a metal foil) 11 and 13 by thermal spraying in the same manner as described above. Then, as shown in FIG. 6A, the insulating layers 12 and 14 of the two metal materials 11 and 13 are sandwiched by an insulating adhesive layer 15 between them as shown in FIG. 6B. By laminating, a surface metal insulating substrate is obtained as shown in FIG. 6 (c). This adhesive layer may be a sheet or a film, and is not limited to the one shown in the figure, and may be formed by applying an adhesive to one or both ceramic insulating layer surfaces by a general method. . When crimped, the adhesive impregnates the pores of the ceramic layer, thereby sealing the ceramic layer. Like this type,
When the insulating layers are joined together, the ceramics are joined together (the effect of joining the same materials) and the effect of the unevenness of the surface of the sprayed layer provides excellent adhesion. In addition,
By setting the amount of the adhesive material layer to an appropriate amount so as to fill the pores, the thickness of the adhesive material layer existing between both insulating layers becomes extremely thin, and heat dissipation can be improved. Also in this case, the adhesive may be organic or inorganic and is not particularly limited. However, similar to the above, it is preferable to select a material having physical properties that allow good penetration into the pores. The pressure-bonding step is not particularly limited, but it is preferable that the pores are easily impregnated with an adhesive material formed by vacuum forming or the like. Specific examples of the material of the adhesive layer include a resin sheet, a resin film or a resin coating layer made of the same material as the resin layer 4 of FIG.

Next, the manufacturing process of another type of the surface metal insulating substrate according to the present invention will be described in detail with reference to FIG. Also in this type, as shown in FIG. 7A, two metal materials (at least one is a metal foil)
Ceramic insulating layers 12 and 14 are formed on one surface of 11 and 13 by thermal spraying in the same manner as described above. And FIG.
As shown in (b), the ceramic insulating layers 12 and 14 are impregnated with an insulating adhesive material (adhesive insulating material). Then,
By bonding the insulating layers 12 and 14 of the two metal materials 11 and 13 to each other by pressure bonding, a surface metal insulating substrate can be obtained as shown in FIG. 7C. As the adhesive material, a resin material similar to the resin layer 4 in FIG. 1 is exemplified. The metal materials 11 and 13 may be impregnated with different adhesives. The impregnation method is a general spray method, brush coating method, roller coating method,
There are dipping method, doctor blade method, curtain coater method, etc., but the vacuum impregnation method is preferable.

In FIGS. 6 and 7, when the insulating material is impregnated, it is preferable to remove the impregnated insulating material on the surface of the ceramic insulating layer, as described above. In order to improve the adhesion of the ceramic layer, it is preferable that the surface of the metal material is subjected to a physical or chemical surface roughening treatment prior to the ceramic spraying. A sandblast method is used as the physical surface roughening treatment, and an etching method is used as the chemical surface roughening treatment. However, the following method is also preferably carried out.

That is, if the surface roughness of the metal material is too large, the bonding surface of the ceramic layer is affected by this and becomes uneven, which makes it difficult to form a fine printed board. According to the method described below, the roughness of the surface of the metal material for increasing the adhesion with the ceramic is reduced, and the adhesion does not decrease. In this method, the surface area of the surface of the metal material is expanded by a mechanical method such as sandblasting, and then the surface of the metal material is activated by a chemical method such as plasma etching to strengthen the binding force.
This will be described in detail. First, the surface of the metal material is polished by a mechanical method. Mechanical polishing methods include, for example, sandblasting, liquid honing, and the like. Then, it is polished by a chemical method. Examples of the chemical polishing method include plasma etching, etching with a NaOH solution of about 20% by weight, etching with a phosphoric acid solution of about 90% by weight, chromic acid treatment, and oxidation treatment. However, the mechanical method and the chemical method are not limited to the above. Depending on the case, either the mechanical method or the chemical method may be used. However, in this case, the surface roughness (ten-point average roughness R
It is important to polish so that z) is in the range of 1 to 20 μm.

For reference, the surface of an aluminum plate having a thickness of 3 mm was sandblasted with # 320 (Rz
4.6 μm), and then plasma-etching the surface thereof, and immediately using alumina having a particle size of 10 to 30 μm by plasma spraying (spraying condition 30 kw) to a thickness of 100 μm.
A ceramic insulating layer of μm was formed. ..Roughening method A.
For comparison, in Method A, the sandblast treatment of # 320 was performed with a roughness of Rz 24.6 μm, and otherwise the same as in Method A. ..Roughening method B.

When the surface roughness of the ceramic insulating layer thus formed is measured, it is as follows, and there is a clear difference. Surface roughening method A Surface roughening method B Center average roughness Ra 2.9 5.1 Ten-point average roughness Rz 17.0 48.3 Maximum roughness Rmax 23.8 55.2

[0031]

[Action] Even without least one is a metal foil, one of one side are thermal spraying by insulation good good thermal conductivity of the adhesive resin to the other one surface together with the insulating layer of ceramic is formed two metal materials layers are formed, Then, as be integrated by crimping each other of the insulating layer and the resin layer, the heat resistance is low, a high withstand voltage, moreover, the peel strength is sufficient.

[0032] Even without least one is a metal foil, a metal material 2 Like insulation is an insulating layer is formed of a ceramic of good good thermal conductivity by the respective thermal spraying on one side, another insulating layer crimp through the contact adhesive layer comprising an adhesive insulating material and impregnated with the adhesive insulating material on both sides of the insulating layer
The insulating layers impregnated with the adhesive insulating material are joined together, or at least one of them is made of metal foil, and an insulating layer made of ceramic with good insulation and good thermal conductivity is formed on each side by the thermal spraying method. And two insulating layers are each impregnated with an adhesive insulating material.
Insulate each other by crimping or insulating them .
Then , the thermal resistance is low, the withstand voltage is high, and the peel strength is sufficient.

Further, since the surface metal insulating substrate of the present invention has the metal foil on the surface, there is an advantage that the circuit can be easily and inexpensively formed by the processing by the so-called subtract method.

[0034]

EXAMPLES describe real施例below, the scope of the invention is not limited thereto. Examples 1 to 5 are technical examples of the present invention.
This is a reference technique out of the range , and Examples 6 and 7
3 is a specific example of the invention of FIG.

Example 1 An aluminum plate (thickness: 2 mm) is used as a metal substrate, and an alumina layer of about 70 μm is formed on the aluminum plate by plasma spraying.
The epoxy resin (Toto Kasei) was impregnated by vacuum impregnation (1 to 10 Torr, about 1 hour). After impregnation, wipe off the resin on the alumina surface. A resin layer having a thickness of about 10 μm was formed on the surface of the copper foil 35 μm (Mitsui Metals Co., Ltd.) with a roll coater, and dried to be in a B stage state. Then, both are thermocompression bonded by a molding press. In this case, the conditions are 180 ℃ x 80 minutes, 40kg / cm ²
Met.

Example 2-Alumina filler (particle size: 0.1 to 5 μm, manufactured by Showa Denko KK) was mixed with the epoxy resin applied to the surface of the copper foil at a ratio of 85% by weight. Others were the same as in Example 1. -Example 3-Alumina is plasma sprayed to a thickness of about 70 μm on a copper foil (manufactured by Mitsui Kinzoku Co., Ltd.) having a thickness of 35 μm, and this ceramic insulating layer is vacuum impregnated (1 to 10 Torr, about 1 hour) with an epoxy resin. Impregnated. After impregnation, wipe off the resin on the surface of the alumina, and put the epoxy resin on the aluminum plate (thickness 2 mm) to about 10 μm.
Was applied and dried to obtain a B-stage state. Then, both were thermocompression bonded by a molding press. The condition is 180
C. × 80 minutes, 40 kg / cm ² .

Furthermore, as shown in FIGS. 4 and 5, Example 4 is shown in which a surface metal insulating substrate is obtained by removing the impregnated resin (insulating material) with a squeegee and a sponge roller. -Example 4-A ceramic insulating layer having a thickness of 100 μm was formed by performing plasma spraying (at 30 kV) on an uneven surface (mat surface) side of a copper foil having a thickness of 35 μm (3EC manufactured by Mitsui Kinzoku Co., Ltd.) using 10 to 30 μm of alumina. Was formed.

Vacuum impregnation (10 Tor)
r, about 10 hours). afterwards,
It was dried at 100 ° C. for 20 minutes. Unnecessary resin on the surface of the insulating layer where the resin was gelled was scraped off with a squeegee, and then the resin in the recess was removed with a sponge roller containing methyl ethyl ketone. Then, it was cured at 180 ° C. for 1 hour.

On the other hand, an epoxy adhesive containing 65 vol% of alumina filler was printed on a 3 mm thick aluminum plate by screen printing to a thickness of 30 μm. After the solvent was scattered, it was dried at 150 ° C. for 20 minutes. A copper foil having a ceramic insulating layer formed thereon and an aluminum plate coated with an adhesive layer were thermocompression bonded by a press to obtain a surface metal insulating substrate. Press condition is 80
kg / cm ² , 180 ° C., 1 hour. The withstand voltage of this surface metal insulating substrate was 6.34 kV. The thermal resistance was 0.47 ° C / W.

Further, Example 5 will be shown in which the surface metal insulating substrate is obtained by performing the pressure bonding in a vacuum atmosphere. -Example 5- Plasma spraying was performed by using alumina of 5 to 25 m on the uneven surface (matt surface) side of a copper foil (3EC manufactured by Mitsui Kinzoku Co., Ltd.) having a thickness of 35 m to form a ceramic insulating layer having a thickness of 100 m.

On the other hand, an alumina plate (thickness: about 0.5 to 3 mm) and an alumina filler (average particle size: about 5 to 30 μm)
Was added by a screen printing method to a paste-like epoxy adhesive having a thickness of 10 to 20 μm. After printing, the solvent was scattered and then dried at 150 ° C. for about 3 to 5 minutes to obtain a B stage state. The ceramic insulating layer forming surface and the adhesive material layer forming surface were faced to each other and overlapped, and set in a vacuum press. The temperature in the vacuum press is evacuated to about 1 to 10 Torr while being lightly pressed by the hot plate, and then the hot plate is heated to remelt the adhesive at a temperature of 150 to 1
Raise to about 60 ° C and pressurize (40-70
kg / cm ² ), the temperature was further raised to 180 ° C., and the temperature was kept for 30 to 40 minutes to cure and integrate the adhesive material to obtain a surface metal insulating substrate.

-Comparative Example 1- Instead of applying the resin on the surface of the copper foil, an epoxy resin sheet (thickness 40 µm) was attached. The thickness of the alumina sprayed layer was set to 50 μm, the sealing with the resin was stopped, the moisture in the alumina sprayed layer was removed by drying after the spraying, and then immediately molding was performed for integration. Others are the same as those in the first embodiment.

-Comparative Example 2-100 μm glass epoxy prepreg, 35 μm copper foil,
Metal board (made by Matsushita Electric Works) that is made of 2mm aluminum plate
Was used as a comparative example. Table 1 shows the results of testing the performances of the surface metal insulating substrates of Examples 1 to 3 and Comparative Examples 1 and 2 for performance comparison.

[0044]

[Table 1]

-Example 6- One surface of an aluminum plate (thickness: 2 mm) is finely roughened by sandblasting and etching. (Roughening) Alumina layers of about 40 μm each are plasma-sprayed on the roughened surfaces of the surface-treated aluminum plate and the electrolytic copper foil (one side roughened). The particle size of alumina is about 1 to 10 μm. A surface metal insulating substrate was obtained by sandwiching a sheet of about 15 μm epoxy resin between them and thermocompression bonding with a vacuum forming machine. The conditions are a vacuum of 1 to 5 Torr, a pressure of 60 kg / cm, and a temperature of 180 ° C. for 120 minutes.

-Example 7-After forming an alumina layer, thermosetting polyimide resin was vacuum impregnated (vacuum impregnation was about 1 to 5 Torr for about 1 hour), excess resin on the surface was removed with a squeegee and a roller, and a B-stage condition was obtained. And then press-bond with a molding machine (condition: 40
(kg / cm, temperature 190 ° C. × 120 minutes), the same as Example 1.

-Comparative Example 3-Alumina layer of about 80 µm was plasma sprayed only on the electrolytic copper foil, vacuum impregnated in the same manner as in Example 3, excess resin on the surface was removed, and the aluminum plate was pressure-bonded. Example 4
Same as. -Comparative Example 4- 60 μm of glass epoxy prepreg was put in between and pressure-bonded. Otherwise the same as Comparative Example 3.

The evaluation results are shown in Table 2. The evaluation items are withstand voltage, heat resistance, and peel strength, and the measuring method conforms to JIS.

[0049]

[Table 2]

From the data in Tables 1 and 2, it is clear that the surface metal insulating substrates of the examples are sufficiently satisfactory in terms of thermal resistance characteristics, pressure resistance characteristics and peel strength.

[0051]

Since the present invention is constructed as described above, it provides a metal substrate having a high degree of heat dissipation, which is not obtained by the conventional metal substrate, and which is excellent in insulating property and has good adhesion. can do. In the method for producing a surface metal insulating substrate according to the present invention, since the metal foil is used for at least one of both metal materials, as in the conventional method, the metal foil may be stretched through complicated steps such as paste application and plating later. You don't have to. Therefore, the surface metal insulating substrate can be easily manufactured at low cost. And, the heat dissipation property thereof is comparable to that of the ceramic sprayed layer alone.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of a manufacturing process of a surface metal insulating substrate .

FIG. 2 is a schematic cross-sectional view illustrating another example.

FIG. 3 is a schematic cross-sectional view illustrating another example.

FIG. 4 is a schematic cross-sectional view illustrating a step of removing the impregnated insulating material on the surface of the insulating layer.

FIG. 5 is a schematic cross-sectional view illustrating a step of removing the impregnated insulating material on the surface of the insulating layer.

FIG. 6 is a schematic cross-sectional view explaining an example of a manufacturing process according to an embodiment of the present invention .

FIG. 7 is a schematic cross-sectional view illustrating an example of a manufacturing process according to another embodiment .

[Explanation of symbols] 1, 11 Metal substrate 2, 12, 14 Ceramic insulation layer 3,13 Metal foil 4 Adhesive resin layer 15 Adhesive layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-50985 (JP, A) JP-A-1-157589 (JP, A) JP-A-3-214793 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01B 17/56-17 / 66,19 / 00 H05K 1/05

Claims (2)

(57) [Claims] 1. Two metal materials, at least one of which is made of a metal foil, and one surface of which is provided with an insulating layer of ceramic having good insulation and good thermal conductivity by thermal spraying. crimp through an adhesive layer comprising an adhesive insulating material and impregnated with the adhesive insulating material on both sides of the insulating layer
And a method for manufacturing a surface metal insulating substrate in which the insulating layers impregnated with the adhesive insulating material are joined together to be integrated. 2. At least one of them is made of metal foil, and an insulating layer made of ceramic having good insulation and good thermal conductivity is formed on one surface of each by a thermal spraying method, and both insulating layers are made of adhesive insulation. A method for manufacturing a surface metal insulating substrate, wherein two metal materials impregnated with a material are integrated by pressure bonding their insulating layers.