JP3174026B2 - Metal-based multilayer circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal-based multi-layer circuit board having excellent noise shielding properties and withstand voltage and good heat dissipation.

[0002]

2. Description of the Related Art In recent years, circuit boards for mounting semiconductors have been required to be smaller in size, have higher mounting density, and have higher performance. In addition, miniaturization, higher performance, and higher power of semiconductor elements have been required. The problem is how to dissipate the heat generated from the semiconductor element. Therefore, mainly in the power supply field, a metal base circuit board formed by laminating a metal foil on a metal plate via an insulating layer and forming a circuit has been used because of its excellent heat dissipation. However, since the metal base circuit board has a structure in which a thin insulating layer is applied on a metal plate, there is a problem that noise is easily generated and a module is likely to malfunction.

For the purpose of shielding noise and increasing heat dissipation to achieve high-density mounting, for example, an upper layer circuit board having a circuit on both sides of the entire surface of a metal base circuit board or a part thereof is bonded with an adhesive. A metal-based multilayer circuit board is known in which heat-generating electronic components are mounted on the above-mentioned upper circuit board (Japanese Patent Laid-Open No. 5-327169). In such a metal-based multilayer circuit board, there is an adhesive layer made of a resin having poor heat conductivity between the metal plate and the upper layer board, and the heat dissipating property such as epoxy impregnated glass cloth as an insulating material is poor. Because of the use of the material, when mounting high heat-generating power electronic components on the upper circuit pattern, heat dissipation is insufficient, the temperature of the electronic components rises, and eventually malfunctions occur There was a problem. Means for Solving the Problems The inventors of the present invention have conducted various studies with a view to solving the above-described problems, and have studied a structure in which a circuit board is bonded to a metal plate via an insulating adhesive layer containing a metal oxide and / or a metal nitride. (Japanese Patent Application No. 7-87001).

[0004]

However, in the case of manufacturing the above-mentioned metal-based multilayer circuit board, a conventional method of preparing an upper-layer circuit board in advance and attaching it to a metal plate via an insulating adhesive layer is used. In some cases, the thickness of the upper substrate is so large that it lacks elasticity, so that a slight deformation acting on the upper substrate at the time of bonding causes a defect, resulting in a decrease in the withstand voltage between the circuits on both sides of the upper layer circuit, or insulation bonding. Air existing between the agent layer and the circuit pre-fabricated on the upper circuit board is entrained, causing the upper circuit board to swell slightly, or withstanding voltage characteristics between the circuit and the metal plate to decrease. For this reason, there is a problem that the yield is low and the productivity is poor.

An object of the present invention is to provide a metal-based multilayer circuit board having a structure in which a circuit board is bonded to a metal plate via an insulating adhesive layer containing a metal oxide and / or a metal nitride, in which the thermal resistance is further reduced. An object of the present invention is to provide a metal-based multilayer circuit board which is small, has excellent heat dissipation, and has excellent noise resistance and withstand voltage characteristics with high productivity.

[0006]

The present invention relates to a metal-based multilayer circuit board obtained by the above-mentioned manufacturing method, comprising:
Thermal conductivity of the insulating adhesive layer of 35 × 10 ^-4 cal / cm · sec.
It is 150 × 10 ^-4 cal / cm · sec · ° C or less and the thickness is 2
A metal-based multilayer circuit board having a thickness of 0 μm or more and 200 μm or less, and in particular, a thermal conductivity of a second insulating adhesive layer of 35 × 10 ⁻⁴ cal / cm · sec · ° C.
10 ⁻⁴ cal / cm · sec · ° C., thickness 40 μm or more 20
A metal-based multilayer circuit board having a thickness of 0 μm or less.

[0007] on a metal plate, set only a conductor circuit through the first insulating adhesive layer, to provide a circuit which is formed from the circuit conductor layer through the second insulating adhesive layer on the conductor circuit A metal-based multi-layer circuit board comprising: a first and a second insulating adhesive layers each having a thermal conductivity of 35 × 10 ⁻⁴ cal / cm · sec · ° C. or more and 150 × 10 ⁻⁴ cal; / cm · sec · ° C or less, and the thickness is respectively 20 μm or more and 200 μm or less, 40 μm or more and 20 μm or less.
A metal-based multilayer circuit board having a thickness of 0 μm or less.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. The present invention is a metal-based multilayer circuit board.
A metal base circuit board 4 having a conductor circuit 3 with an insulating adhesive layer 2 interposed therebetween, and a circuit conductor 6 on the conductor circuit 3 of the metal base circuit board 4 with a second insulating adhesive layer 5 interposed therebetween.
(Hereinafter, referred to as a first step). still,
In the following description, for the sake of simplicity, the case where the circuit conductor 6 is joined via the second insulating adhesive layer 5 so as to cover the entire surface of the conductor circuit 3 will be described. It may be joined so that the portion is exposed. Through this step, the metal base circuit board 4 has the structure shown in FIG. Further, the metal-based multilayer circuit board of the present invention includes a step of forming a via hole for electrically connecting the conductor circuit 3 and the circuit conductor layer 6 (hereinafter, a second step). The structure shown in FIG. 2 has a via hole 7 as illustrated in FIG. 5 through this step. Further, the metal-based multilayer circuit board of the present invention includes a step of forming a circuit on the circuit conductor layer 6 (hereinafter, a third step). After this step, the structure illustrated in FIG. 5 is illustrated in FIG. A metal-based multilayer circuit board 8 is formed. 3 and 4 are views showing a state in the course of manufacturing the metal-based multilayer circuit board of the present invention, and FIG. 3 shows a state in which an intermediate product having the structure shown in FIG. 2 immediately goes through a third step. FIG. 4 shows a state of the intermediate product obtained in FIG. 3 after a part of the second insulating adhesive layer has been cut by, for example, laser irradiation in the middle of the second step.

In the first step of the present invention, an ordinary metal-based circuit board 4 is used. However, from the viewpoint of the withstand voltage characteristic of the obtained metal-based multilayer circuit board 8, the insulating adhesive constituting the metal-based circuit board 4 is used. It is preferable that the agent layer is sufficiently cured by heating. However, since the insulating adhesive layer of the metal-based circuit board becomes the first insulating adhesive layer 2 of the metal-based multilayer circuit board 8, the curing is insufficient and, for example, when a volatile substance is contained, This is because, when the second insulating adhesive layer 5 is cured after application, problems such as a blistering phenomenon and a decrease in the withstand voltage of the metal-based multilayer circuit board 8 may occur.

In the first step, the metal base circuit board 4
When the second insulating adhesive layer 5 applied thereon is in a semi-cured state, the circuit conductor layer 6 is attached using a hot press or a laminator, and the second insulating adhesive layer is cured. In the present invention, the second insulating adhesive layer 5 is inserted between the conductor circuits 3 so that the thickness of the conductor circuits 3 is 5 μm or more and 150 μm or less.
And the circuit conductor 6 can withstand voltage. This is because the metal base circuit board 4 having a thickness of the conductor circuit 3 of less than 5 μm is not readily available, and if it exceeds 150 μm, it is not always possible to obtain a metal base multilayer circuit board 8 having excellent withstand voltage.

In the present invention, the first, second, and third steps are employed to reduce the withstand voltage characteristic between circuits or between a circuit and a metal plate, which is a problem of the conventional method. It is intended to largely prevent the occurrence of blisters, and as a result, to improve the productivity. That is, in the present invention, rich in elasticity,
In addition, since metal foil that is not formed with a circuit is joined, the withstand voltage characteristics between circuits are not impaired, and swelling can be prevented.
Further, since the metal base circuit board, which has been previously insulated from the metal plate, is substantially used, the withstand voltage characteristics between the metal plate and the circuit are not impaired.

The second step in the present invention is an operation of forming a hole for a via hole by physically, chemically or mechanically removing a part of the circuit conductor layer 6 and the second insulating adhesive layer 5. Electrically connecting the conductor circuit 3 and the circuit conductor layer 6 by a combination of the above operation and the operation of filling at least the inner wall of the void formed by the above operation with a conductive material by a method such as plating or printing. It is. As a result of various studies, the inventors of the present invention open a predetermined position of the circuit conductor layer 6 by etching, irradiate the hole with a laser beam to remove the second insulating adhesive layer 5, and further perform plating. Thus, it has been found that the method of forming the via hole has high dimensional accuracy, so that the peripheral portion is not damaged and the method is high in productivity.

As a method of forming a hole for a via hole, a method using various laser beams such as an excimer laser, a CO2 laser, and a YAG laser can be used in addition to a machining method using a drill or the like. There is also a method of chemically removing the second insulating adhesive layer.

A method for covering or filling at least the inner wall portion of the via hole with a conductive substance and electrically connecting the conductive material to the via hole includes plating methods such as electroless plating, electrolytic plating, and direct plating; Alternatively, the above methods can be combined. Among these methods, the plating method is particularly preferable because it is inexpensive and has high productivity.

[0015] The plating material in the via hole is such that the electrical resistance between the conductor circuit 3 and the circuit conductor layer 6 does not increase, and breakage due to a difference in thermal expansion between the conductor circuit and the circuit conductor layer. Since it is unlikely to occur, it is preferable that they are of the same quality. As the material of the conductor circuit 3 and the circuit conductor, copper having small electric resistance is generally used, it is preferable that the plating in the via hole is copper plating.
The method of forming a via hole according to the present invention can be applied to a through hole.

The third step in the present invention is a step of forming a circuit on the circuit conductor layer bonded to the metal base circuit board in the first step, and according to a general circuit forming method such as etching. good. In the present invention, the first step only needs to be performed first, the order of the second and third steps does not need to be determined, and the second and third steps may be repeated as necessary. it can.

FIG. 6 exemplifies a metal-based multilayer circuit board 8 of the present invention having a multilayer structure as a whole, and its structure is as follows. That is, the metal-based multilayer circuit board 8 of the present invention is provided on the metal-based circuit board 4 on which the conductor circuit 3 is formed on the metal plate 1 via the first insulating adhesive layer 2. An outer layer circuit formed from the circuit conductor layer 6 is laminated and integrated via the layer 5, and the outer layer circuit and the conductor circuit 3 are integrated.
Are electrically connected by via holes 7. Although not shown, an electronic element may be mounted on the outer layer circuit as necessary, or may be connected to another component by wire bonding or the like. or,
The conductor circuit 3 and the outer layer circuit need only be laminated on at least a part of at least one main surface of the metal plate 1, and a plurality of circuit boards may be laminated on the outer layer circuit.

The thermal conductivity of the first insulating adhesive layer 2 is 35 ×
10 ^-4 cal / cm-sec-C or higher 150 x 10 ^-4 cal / cm-sec-C
Or less, and the thickness is not less than 20 μm and not more than 200 μm.
It is as follows. If the thermal conductivity is less than 35 × 10 ⁻⁴ cal / cm · sec · ° C., the thermal resistance of the metal-based multilayer circuit board 8 increases, and the desired good heat dissipation may not be obtained. . Further, those exceeding 150 × 10 ⁻⁴ cal / cm · sec · ° C. are difficult to obtain industrially. However, in order to use the first insulating adhesive layer 2 having a thermal conductivity in the above range and to surely obtain the metal-based multilayer substrate 8 having good heat dissipation, the first insulating adhesive layer 2 2 has a thickness of not less than 20 μm and not more than 200 μm. If the thickness exceeds 200 μm, good heat dissipation cannot be achieved,
If the thickness is less than 20 μm, the withstand voltage decreases, which is not preferable.

The first insulating adhesive layer 2 comprises a metal oxide and / or
Alternatively, it is composed of a metal nitride and a resin. Metal oxides and metal nitrides are preferably excellent in heat conductivity and electrically insulating. Aluminum oxide, silicon oxide, beryllium oxide, and magnesium oxide are used as metal oxides, and boron nitride and nitride are used as metal nitrides. Silicon and aluminum nitride are selected, and these can be used alone or in combination of two or more. In particular, among the above-mentioned metal oxides, aluminum oxide can easily obtain an insulating adhesive layer having good electric insulation and thermal conductivity, and can be easily obtained at a low cost. Of the metal nitrides, boron nitride is preferred because it has excellent electrical insulation and thermal conductivity, and has a small dielectric constant.

The total amount of the metal oxide and the metal nitride is 45
It is at least 85% by volume and preferably at least 48% by volume. If it is less than 45% by volume, the thermal conductivity of the first insulating adhesive layer 2 is reduced to 35 × 10 ⁻⁴ cal / cm · s.
It is not easy to increase the temperature to ec · ° C. or higher. As a result, a metal-based multilayer circuit board having excellent heat dissipation properties cannot be obtained.
On the other hand, when the content exceeds 85% by volume, bubbles are easily entrained in mixing with the resin, and as a result, the metal-based multilayer circuit board 8 having excellent withstand voltage may not be obtained.
In order to obtain a metal-based multilayer circuit board excellent in heat dissipation and voltage resistance with good reproducibility, the range of 48% by volume to 80% by volume is preferable.

The resin constituting the first insulating adhesive layer 2 contains the metal oxide and / or the metal nitride described above, but is in a hardened state and is in contact with the metal plate 1 and the conductor circuit 3. Those that have excellent bonding strength and do not impair withstand voltage characteristics and the like are selected. As such a resin, various engineering plastics other than epoxy resin, phenol resin, and polyimide resin can be used alone or in combination of two or more. Among them, epoxy resin is preferable because of its excellent bonding strength between metals. . In particular, among the epoxy resins, bisphenol A-type epoxy resins and bisphenol F-type epoxy resins, which have high fluidity and are excellent in mixing properties with the above-mentioned metal oxides and metal nitrides, are more preferable resins.

The thermal conductivity of the second insulating adhesive layer 5 is 35
× 10 ^-4 cal / cm ・ sec ・ ℃ or more 150 × 10 ^-4 cal / cm ・ sec ・
° C or less, and the thickness is 40 µm or more and 200 µ
m or less. Thermal conductivity 35 × 10 ^-4 cal / cm · sec · ° C
If the value is less than 1, the thermal resistance of the metal-based multilayer circuit board 8 increases, and the desired good heat dissipation property may not be obtained, or exceeds 150 × 10 ⁻⁴ cal / cm · sec · ° C. Is difficult to obtain industrially. If the thickness of the second insulating adhesive layer 5 is less than 40 μm, the withstand voltage may decrease, and if it exceeds 200 μm, the heat dissipation may decrease. By limiting the thermal conductivity and the thickness of the second insulating adhesive layer 5, the characteristic that the metal-based multilayer circuit board 8 is excellent in the withstand voltage and the heat dissipation is the same as that of the first insulating adhesive layer 2. When the thermal conductivity is 35 × 10 ⁻⁴ cal / cm · sec · ° C. or more and 150 × 10 ⁻⁴ cal / cm · sec · ° C. or less and the thickness is 20 μm or more and 200 μm or less,
It is particularly preferred because it is achieved.

The second insulating adhesive layer 5 has a total content of the metal oxide and the metal nitride of 45% by volume to 85% by volume, preferably 48% by volume to 80% by volume, and the balance of resin. It can be obtained by using. Particularly, preferable results are obtained when the metal oxide is aluminum oxide and the metal nitride is boron nitride. The amount, type, and type of resin of the metal oxide and / or metal nitride contained in the second insulating adhesive layer 5 are the same as those in the first insulating adhesive layer 2. That is, metal oxides and metal nitrides have excellent thermal conductivity, and are preferably electrically insulating.
Examples of the metal oxide include aluminum oxide, silicon oxide, beryllium oxide, and magnesium oxide, and examples of the metal nitride include boron nitride, silicon nitride, and aluminum nitride. These may be used alone or in combination of two or more. Can be. In particular, aluminum oxide as a metal oxide is preferable because it can easily obtain an insulating adhesive layer having good electric insulation and thermal conductivity, and is easily available at a low cost. Boron nitride is preferable because it has excellent electrical insulation and thermal conductivity, and further has a small dielectric constant.

The resin constituting the second insulating adhesive layer 5 contains the above-mentioned metal oxide and / or metal nitride and is bonded to the conductor circuit 3 and the circuit conductor layer 6 in a cured state. Those that have excellent power and do not impair the characteristics of the metal-based multilayer circuit board 8 are selected. As such a resin, various engineering plastics other than an epoxy resin, a phenol resin, and a polyimide resin can be used alone or in combination of two or more. Among them, the epoxy resin is preferable because of its excellent bonding strength between metals. . In particular, among epoxy resins, bisphenol A type epoxy resin having high fluidity and excellent mixing with inorganic filler,
Bisphenol F type epoxy resins are more preferred resins.

The total amount of the metal oxide and metal nitride in the second insulating adhesive layer 5 is at least 45 vol% and at most 85 vol%, preferably at least 48 vol% and at most 80 vol%. If the content is less than 45% by volume, it is not easy to make the thermal conductivity of the second insulating adhesive layer 5 equal to or higher than 35 × 10 ⁻⁴ cal / cm · sec · ° C. Only the multilayer circuit board 8 can be obtained. On the other hand, when the content exceeds 85% by volume, bubbles are easily entrained in mixing with the resin, and as a result, the metal-based multilayer circuit board 8 having excellent withstand voltage may not be obtained. When the content is 48% by volume or more and 80% by volume or less, a metal-based multilayer circuit board excellent in heat dissipation and withstand voltage can be obtained with good reproducibility.

The material of the conductor circuit 3 and the circuit conductor layer 6 is copper,
Any of aluminum, nickel, iron, tin, silver, and titanium, or an alloy containing these metals and a clad foil using each metal and / or alloy can be used. The method of manufacturing the foil at this time may be an electrolytic method or a rolling method. The foil may be plated with a metal such as Ni plating, Ni + Au plating, or solder plating. In view of the adhesiveness to the insulating adhesive layer 5, it is more preferable that the surface of the circuit conductor layer 6 be roughened in advance by etching, plating, or the like. The thickness of the circuit conductor layer 6 is not particularly limited, but is generally 500 μm or less.

In the present invention, the metal plate 1 is made of a metal having good thermal conductivity, such as aluminum and aluminum alloys, copper and copper alloys, iron and iron alloys, copper / iron-nickel alloys, and aluminum / iron-nickel alloys. Composite material of two layers, such as alloys, or 3 such as copper / iron-nickel alloy / copper, aluminum / iron-nickel alloy / aluminum
Layer composites and the like can be used. The thickness of the metal plate 1 is not particularly limited, but is 0.5 mm to 3.0 m.
m is generally used.

Hereinafter, the present invention will be described more specifically based on examples.

[Example 1] 53 pieces of boron nitride (GP, manufactured by Denki Kagaku Kogyo KK) were placed on an aluminum plate of 510 mm x 510 mm x 1.5 mm.
A bisphenol F type epoxy resin (manufactured by Yuka Shell Co., Ltd .; Epicoat 807) containing a volume% is used as an insulating adhesive, an amine-based curing agent is added, and the mixture is applied to a thickness of 200 μm, and the thickness is 35 μm. Copper foil was laminated by a lamination method. Next, after forming a shield pattern on the copper foil, an amine-based curing agent was added to the insulating adhesive on the copper foil, and applied to a thickness of 200 μm,
Further, a copper foil having a thickness of 35 μm was adhered by a laminating method and cured by heating. Next, a round hole having a diameter of 0.5 mm was drilled in a predetermined portion of the outer layer copper foil by a drill, and after cutting to the second insulating adhesive layer, copper plating was performed to form a via hole. A desired circuit was formed on the surface by etching to obtain a metal-based multilayer circuit board. For this metal-based multilayer circuit board, the thermal resistance, the withstand voltage, the operation stability of the electronic element, and the productivity were measured by the following methods.
The results were good as described in Table 1. In addition, a heat-cured body of a disc having a diameter of 10 mm and a thickness of 1 mm was separately prepared from an insulating adhesive, and used as a test piece for measuring thermal conductivity by a laser method.

<Method of Measuring Thermal Resistance> A multilayered portion or a conductor circuit portion of a metal-based multilayer circuit board is cut into a size of 40 mm × 30 mm to obtain a test piece.
Etch the test piece and measure 10m near its center
An mx14 mm pad portion is formed, and a transistor (2SC2233; TO220 type; manufactured by Toshiba Corporation) is soldered to this portion. The transistor is operated while the back surface of the substrate is cooled to room temperature, and the temperature of the substrate and the back side of the transistor sandwiching only the first and second insulating adhesive layers or only the first insulating adhesive layer are measured. The thermal resistance is calculated from the temperature difference and the power consumption (collector loss) of the transistor (refer to the Denka HITT plate catalog).

<Measurement Method of Withstand Voltage> The conductor circuit arranged on the first insulating adhesive layer of the metal-based multilayer circuit board is used as a solid pattern, and the circuit conductor or the conductor circuit on the second insulating adhesive layer is used. To etch φ2
3 × 3 0 mm circular patterns were formed at 10 mm intervals. The circular pattern located at the center was electrically connected to the conductor circuit by a via hole. With respect to the metal-based multilayer circuit board, the withstand voltage between the central circular pattern and the other circular patterns was measured by the step-up method defined in JIS C 2110.

<Method for Evaluating Operation Stability of Power Electronic Device> p-mos-FET (2SK2174S) manufactured by Hitachi, Ltd.
Was fabricated on a circuit conductor or a conductor circuit at three intervals of 2 mm, and the module was continuously operated for 96 hours at 100 ° C. while consuming 10 W per element, and evaluated for malfunction. I do. If no malfunction occurs, the power consumption is further increased by 10 W and the evaluation is performed again.
Thereafter, similarly, the power consumption is increased, and the operation stability of the power electronic element is evaluated based on the power consumption when a malfunction occurs.

<Evaluation Method of Productivity> Evaluation was made based on the time required to manufacture 10,000 metal-based multilayer circuit boards having a business card size (90 mm × 55 mm).

[0033]

[Table 1]

[ Reference Example 1 ] Aluminum oxide (shown by Showa Denko KK: A
-42-2) containing 54% by volume (manufactured by Toray Dow Corning Silicone Co., Ltd .; SE1880)
The thermal resistance, the withstand voltage, the operation stability of the electronic element, and the productivity were measured by the same method for the metal-based multilayer circuit board obtained by performing the same operation as in Example 1 except that the above method was used. The results were good as described in Table 1.

[ Reference Example 2 ] Aluminum oxide (shown by Showa Denko KK: A
Bisphenol A type epoxy resin containing 54% by volume (Epicoat 82, manufactured by Yuka Shell Co., Ltd.)
Except for using 8), the thermal resistance, the withstand voltage, the operation stability of the electronic element, and the productivity were measured for the metal-based multilayer circuit board obtained by performing the same operation as in Example 1. The results were good, as described in Table 1.

Reference Example 3 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Bisphenol A type epoxy resin containing 54% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was used as an insulating adhesive, and an amine-based curing agent was added.
m, and a copper foil having a thickness of 5 μm was adhered by a lamination method and cured by heating. Next, after etching this copper foil to form a shield pattern, an amine-based curing agent was added to the above-mentioned insulating adhesive on the copper foil, and applied so as to have a thickness of 200 μm. Were laminated by a laminating method and then cured by heating. Next, a predetermined portion of the outer layer copper foil is etched by φ
A 0.5 mm round hole was formed, and a laser beam was applied to the hole to cut a part of the second insulating adhesive layer, followed by copper plating to form a via hole. Next, a desired circuit was formed by etching the outer layer copper foil, thereby obtaining a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were as described in Table 1.
It was good.

REFERENCE EXAMPLE 4 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Bisphenol A type epoxy resin containing 54% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was used as an insulating adhesive, and an amine-based curing agent was added.
m, and a copper foil having a thickness of 150 μm was adhered by a lamination method and cured by heating. Next, after this copper foil is etched to form a shield pattern, an amine-based curing agent is added to the above-mentioned insulating adhesive on the copper foil, and applied so as to have a thickness of 200 μm. The foils were laminated by a laminating method and cured by heating. Next, a circular hole having a diameter of 0.5 mm is formed in a predetermined portion of the outer layer copper foil by etching, a laser beam is applied to the hole, and a portion of the second insulating adhesive layer is cut, and then copper plating is performed. Via holes were formed. Furthermore,
The desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 1.

Example 2 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Using bisphenol A type epoxy resin containing 56% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent,
m, and a copper foil having a thickness of 35 μm was laminated by a laminating method and cured by heating. next,
After the copper foil was etched to form a shield pattern, a bisphenol A type epoxy resin (manufactured by Yuka Shell Co., Ltd .; Epicoat 828) containing 54% by volume of aluminum oxide was used as an insulating adhesive on the copper foil. An amine-based curing agent was added, and the mixture was applied so as to have a thickness of 250 μm, and a copper foil having a thickness of 35 μm was adhered by a lamination method and cured by heating. Next, a circular hole having a diameter of 0.5 mm is formed in a predetermined portion of the outer layer copper foil by etching, a laser beam is applied to the hole, and a portion of the second insulating adhesive layer is cut, and then copper plating is performed. Via holes were formed. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 1.

Example 3 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Bisphenol A type epoxy resin containing 56% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was used as an insulating adhesive, and an amine-based curing agent was added thereto.
, And a copper foil having a thickness of 35 μm was adhered by a laminating method and cured by heating. Next, after the copper foil was etched to form a shield pattern, a bisphenol A type epoxy resin (manufactured by Yuka Shell Co .; Epicoat 828) containing 54% by volume of aluminum oxide was insulated on the copper foil. An amine-based curing agent was added thereto, and applied so as to have a thickness of 250 μm. A copper foil having a thickness of 35 μm was laminated by a laminating method and cured by heating. Next, a circular hole having a diameter of 0.5 mm is formed in a predetermined portion of the outer layer copper foil by etching, a laser beam is applied to the hole, and a portion of the second insulating adhesive layer is cut, and then copper plating is performed. Via holes were formed. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 1.

Example 4 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Using bisphenol A type epoxy resin containing 56% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent,
m, and a copper foil having a thickness of 35 μm was laminated by a laminating method and cured by heating. next,
After the copper foil was etched to form a shield pattern, the above-mentioned insulating adhesive was applied to the copper foil so as to have a thickness of 200 μm by adding an amine-based curing agent, and further a copper foil having a thickness of 35 μm was formed. They were laminated by a lamination method and cured by heating. Next, a predetermined portion of the outer layer copper foil is etched to form a round hole of φ0.5 mm, a laser beam is applied to the hole, and a part of the second insulating adhesive layer is cut.
Copper plating was performed to form via holes. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good, as described in Table 1.

Example 5 Aluminum oxide (A-42 manufactured by Showa Denko KK) was placed on a 510 mm × 510 mm × 1.5 mm aluminum plate.
Using bisphenol A type epoxy resin containing 56% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent,
m, and a copper foil having a thickness of 35 μm was laminated by a laminating method and cured by heating. next,
After the copper foil is etched to form a shield pattern, the above-mentioned insulating adhesive is applied on the copper foil so as to have a thickness of 40 μm by adding an amine-based curing agent to a thickness of 35 μm.
m copper foils were laminated by a laminating method and heat-cured. Next, a predetermined portion of the outer layer copper foil was etched to obtain φ0.
A 5 mm round hole was made, and a laser beam was applied to the hole to cut a part of the second insulating adhesive layer, followed by copper plating to form a via hole. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good and are described in Table 1.

Example 6 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Using bisphenol F type epoxy resin containing 80% by volume (Epicoat 807 manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent,
m, and a copper foil having a thickness of 35 μm was laminated by a lamination method. Next, after the copper foil is etched to form a shield pattern, the above-mentioned insulating adhesive is applied on the copper foil so as to have a thickness of 200 μm by adding an amine-based curing agent, and the copper foil having a thickness of 35 μm is formed. Were laminated by a laminating method and cured by heating. Next, a predetermined hole in the outer layer copper foil was drilled into a round hole of φ0.5 mm, cut to the depth of the second insulating adhesive layer, and then plated with copper to form a via hole. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. About this metal-based multilayer circuit board,
The thermal resistance, the withstand voltage, the operation stability of the electronic device, and the productivity were measured. The results were good as described in Table 1.

Reference Example 5 Silicon nitride (manufactured by Denki Kagaku Kogyo Kogyo KK; SN-) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Using bisphenol F type epoxy resin containing 48 volume% of 9) (Eicoat 807 manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent, and adding 200 μm
And a copper foil having a thickness of 35 μm was laminated by a lamination method. Next, after the copper foil was etched to form a shield pattern, aluminum oxide (A-42-2, manufactured by Showa Denko KK) was applied on the copper foil for 5 hours.
A bisphenol F type epoxy resin containing 6% by volume was used as an insulating adhesive, and an amine-based curing agent was added.
m, and a copper foil having a thickness of 35 μm was laminated by a laminating method and cured by heating. next,
After drilling a round hole of φ0.5 mm by drilling a predetermined portion of the outer copper foil and cutting it to the second insulating adhesive layer,
Copper plating was performed to form via holes. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 1.

Reference Example 6 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Using bisphenol F type epoxy resin containing 56% by volume (Epicoat 807 manufactured by Yuka Shell Co., Ltd.) as an insulating adhesive, adding an amine-based curing agent,
m, and a copper foil having a thickness of 35 μm was laminated by a lamination method. Next, after etching the copper foil to form a shield pattern, a bisphenol F type epoxy resin containing 48% by volume of silicon nitride (manufactured by Denki Kagaku Kogyo Co., Ltd .; SN-9) is coated on the copper foil with an insulating adhesive. An amine-based curing agent was added, and the mixture was applied so as to have a thickness of 200 μm, and a copper foil having a thickness of 35 μm was adhered by a lamination method and cured by heating. Next, a predetermined hole of the outer layer copper foil was drilled into a round hole having a diameter of 0.5 mm and cut to a portion of the second insulating adhesive layer, and then plated with copper to form a via hole. Further, a desired circuit was formed by etching the outer layer copper foil to obtain a metal-based multilayer circuit board. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 1.

Comparative Example 1 A glass epoxy resin circuit board having a base material having a thickness of 60 μm and a desired circuit having a thickness of 35 μm on both sides of the base material was prepared as follows.
After a through hole having a diameter of 0.5 mm was formed in a predetermined place by a drill, copper plating was performed to form a via hole. Further, a desired circuit was formed by etching the copper foil on both sides. Next, a glass epoxy prepreg having a thickness of 100 mm was formed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
μm, and the glass epoxy resin circuit board was placed and cured by heating to produce a metal-based multilayer circuit board. For this metal-based multilayer circuit board, the thermal resistance, the withstand voltage, the operation stability of the electronic element, and the productivity were measured in the same manner as in Example 1. As a result, the thermal resistance is 3.
At 8 ° C./W, the operation stability of the power electronic device was 20 W, which was poor.

Comparative Example 2 A desired circuit made of a copper foil having a thickness of 35 μm was provided on both sides.
Glass epoxy resin circuit board made of glass epoxy resin having a thickness of 60 μm (Matsushita Electric Works, Ltd .; R-17)
66) is prepared, and φ0.5m
After opening a through hole of m, copper plating was performed to form a via hole. Further, a desired circuit was formed by etching the copper foil on both sides. Next, 510 mm × 510 mm × 1.
A bisphenol F type epoxy resin (manufactured by Yuka Shell Co .; Epicoat 807) containing 57% by volume of silicon nitride (manufactured by Denki Kagaku Kogyo Co., Ltd .; SN-9) was used as an insulating adhesive on a 5 mm aluminum plate. An amine-based curing agent was added thereto, applied so as to have a thickness of 200 μm, laminated with the glass epoxy resin circuit board by a laminating method, and cured by heating to produce a metal-based multilayer circuit board. With respect to the metal-based multilayer circuit board, thermal resistance, withstand voltage, operation stability of electronic elements, and productivity were measured.
As a result, as shown in Table 1, the thermal resistance, the withstand voltage and the operation stability of the electronic element were good, but the productivity was low and the product was poor.

Example 7 On an aluminum plate of 510 mm × 510 mm × 1.5 mm, 53 boron nitride (GP, manufactured by Denki Kagaku Kogyo KK) were placed.
A bisphenol A-type epoxy resin (manufactured by Yuka Shell Co., Ltd .; Epicoat 828) containing a volume% is used as an insulating adhesive, an amine-based curing agent is added, and the mixture is applied to a thickness of 200 μm to form a coating having a thickness of 35 μm. Copper foil was laminated by a lamination method. Next, after the inner layer circuit is formed on the copper foil, the above-mentioned insulating adhesive is added to only a predetermined portion of the copper foil so as to have an amine-based curing agent, and is applied so as to have a thickness of 200 μm. The copper foil was laminated by a lamination method and cured by heating. Next, a circular hole having a diameter of 0.5 mm was drilled at a predetermined position of the outer layer copper foil having a copper foil immediately below, and after cutting to the second insulating adhesive layer, copper plating was performed to form a via hole. A desired outer layer circuit was formed on the surface by etching to obtain a metal-based multilayer circuit board in which a part of the inner layer circuit was exposed. With respect to the metal-based multilayer circuit board, thermal resistance, withstand voltage, operation stability of electronic elements, and productivity were measured. The results were good as described in Table 2.

[0048]

[Table 2]

[ Reference Example 7 ] Aluminum oxide (shown by Showa Denko KK: A
-42-2) containing 54% by volume (manufactured by Toray Dow Corning Silicone Co., Ltd .; SE1880)
Except for the use of the same, a metal-based multilayer circuit board with a part of the inner layer circuit obtained by performing the same operation as in Example 13 was used, and the thermal resistance, the withstand voltage, the operation stability of the electronic element, and the productivity Was measured in the same manner. The results were good as described in Table 2.

Reference Example 8 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on an aluminum plate of 510 mm × 510 mm × 1.5 mm.
Bisphenol A type epoxy resin containing 54% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was used as an insulating adhesive, and an amine-based curing agent was added.
m, and a copper foil having a thickness of 5 μm was adhered by a lamination method and cured by heating. Next, after the copper foil is etched to form an inner layer circuit, the above-mentioned insulating adhesive is added to only a predetermined portion thereof with an amine-based curing agent and applied to a thickness of 200 μm. After laminating a copper foil having a thickness of 5 μm by a laminating method, it was cured by heating. Next, a predetermined hole of the outer copper foil having a copper foil immediately below is drilled into a circular hole of φ0.5 mm by etching, a laser beam is applied to the hole, and the insulating layer on the second insulating adhesive layer is cut. Then, copper plating was performed to form via holes. Next, a desired outer layer circuit was formed by etching the outer layer copper foil, and a metal-based multilayer circuit board in which a part of the inner layer circuit was exposed was obtained. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 2.

Reference Example 9 Aluminum oxide (A-42, manufactured by Showa Denko KK) was placed on a 510 mm × 510 mm × 1.5 mm aluminum plate.
Bisphenol A type epoxy resin containing 54% by volume (Epicoat 828, manufactured by Yuka Shell Co., Ltd.) was used as an insulating adhesive, and an amine-based curing agent was added.
m, and a copper foil having a thickness of 150 μm was adhered by a lamination method and cured by heating. Next, after etching this copper foil to form an inner layer circuit,
The above-mentioned insulating adhesive is added to only a predetermined portion thereon with an amine-based curing agent and applied so as to have a thickness of 200 μm.
After laminating a copper foil having a thickness of 150 μm by a lamination method, it was cured by heating. Next, a predetermined hole of the outer copper foil having a copper foil immediately below is drilled into a circular hole of φ0.5 mm by etching, a laser beam is applied to the hole, and the insulating layer on the second insulating adhesive layer is cut. , Copper plating,
Via holes were formed. Further, a desired outer layer circuit was formed by etching the outer layer copper foil, and a metal-based multilayer circuit board in which a part of the inner layer circuit was exposed was obtained. This metal-based multilayer circuit board was measured for thermal resistance, withstand voltage, operation stability of electronic elements, and productivity. The results were good as described in Table 2.

[0052]

According to the present invention, in a metal-based multilayer circuit board having a structure in which a circuit board is joined to a metal plate via an insulating adhesive containing a metal oxide and / or a metal nitride, the thermal resistance is further reduced. A metal-based multilayer circuit board that is small, has excellent heat dissipation, and has excellent noise resistance and voltage resistance can be provided with high productivity.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a metal-based circuit board used for a metal-based multilayer circuit board of the present invention.

FIG. 2 is a view showing an example of a metal-based circuit board after a first step (1) in the manufacturing method of the present invention.

FIG. 3 is a view of an example showing a middle of a step (2) in the manufacturing method of the present invention, showing a state in which only a circuit conductor layer is opened.

FIG. 4 is a view of an example showing the middle of the step (2) in the manufacturing method of the present invention, showing a state in which the circuit conductor layer and the second insulating adhesive layer are opened.

FIG. 5 is a view of an example showing a state after the step (2) in the manufacturing method of the present invention, in which a via hole is formed.

FIG. 6 is an example of a view after the step (3) in the manufacturing method of the present invention, which is an example of the metal-based multilayer circuit board of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 metal plate 2 first insulating adhesive layer 3 conductive circuit 4 metal-based circuit board 5 second insulating adhesive layer 6 circuit conductive layer 7 via hole 8 metal-based multilayer circuit board

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-216391 (JP, A) JP-A-60-171791 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/46 H05K 1/05

Claims (3)

(57) [Claims] (1) A conductive circuit is formed on a metal plate via a first insulating adhesive layer. A conductive circuit is formed on the metal base circuit board via a second insulating adhesive layer. Joining the circuit conductor layer; (2) forming a via hole for electrically connecting the conductor circuit and the circuit conductor layer; (3) forming a circuit in the circuit conductor layer; Wherein the first insulating adhesive layer has a thermal conductivity of 35 × 10 ⁻⁴ cal / cm · sec · ° C. or more. Fifteen
0 × 10 ⁻⁴ cal / cm · sec · ° C. or less, thickness 20 μm
A metal-based multilayer circuit board having a thickness of 200 μm or less. 2. The thermal conductivity of the second insulating adhesive layer is 35 × 1.
^{0 -4 cal / cm · sec ·} ℃ than ^{150 × 10 -4 cal / cm ·} sec · ℃ or less, according to claim 1, wherein the thickness is equal to or is 40μm or more 200μm or less metal base multilayer circuit substrate. To 3. A metal plate, set only a conductor circuit through the first insulating adhesive layer, the circuit formed from the circuit conductor layer through the second insulating adhesive layer on the conductor circuit A metal-based multi-layer circuit board provided , wherein the first and second insulating adhesive layers both have a thermal conductivity of 35 × 10 ⁻⁴ cal / cm · sec · ° C. or more and 150 × 10 ^{−. 4} cal / cm · sec · ° C or less, and the thickness is 20 μm or more and 200 μm or less and 40 μm or more, respectively.
A metal-based multilayer circuit board having a thickness of 0 μm or less.