JPH03218060A - Inverter - Google Patents

Abstract

PURPOSE:To form a very thin inverter for high power use by a method wherein inverter main circuits for high power use and driving circuits to make the circuits drive are formed on the same substrate. CONSTITUTION:Holes 2a, in which the surface of a metal substrate 1 is exposed, are provided in a thin insulating resin layer 2 sticked on the substrate 1 and power elements 5, which are used as main circuits of an inverter, are mounted on the substrate 1 exposed in the holes 2a via ceramic pieces 4. Moreover, a plurality of elements 6 for small signal use for making the main circuits drive are arranged on other regions. Thereby, the heat dissipation property of the elements 5 can be remarkably enhanced. Moreover, elements 6 for small signal use can be fixed on the same substrate. As a result, an inverter circuit where the main circuits for high power are integrated with driving circuits is obtained. Moreover, by connecting a conductor layer 3' provided on the peripheral end sides of the holes with spot facing parts 9 provided in the vicinity of the layer 3', self noise of the elements 5 in the main circuits can be suppressed at the time of switching.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an inverter in which a main circuit of an inverter and a drive circuit for driving the main circuit are constructed on the same substrate.
:m, and particularly relates to high-power inverter devices.

(Example) Conventional Technology Conventionally, power integrated circuits equipped with power semiconductor elements have often used a so-called heat sink (copper plate) in consideration of heat dissipation generated during operation. In this type of power integrated circuit, an alumina ceramic plate with a circuit pattern formed on one side and a thermally conductive layer made of copper on the other side is soldered to the heat sink (hereinafter referred to as a heat sink). There is a type that integrates both. As shown in Fig. 4, this type of power integrated circuit has a circuit pattern (52) made of highly conductive copper formed on the entire surface of an alumina ceramic substrate (51), and a pad portion (52') that is a part of the circuit pattern (52). ) is fixed with a brazing material to the power semiconductor element (53).By the way, the copper circuit pattern (52)
is formed by thermal spraying, plating, metallization, printing, and vapor deposition methods alone or in combination, or fixed by brazing a copper plate to form a popular circuit pattern (52).
is formed. The electrode of the semiconductor element (53) and the pad portion (52') constituting a part of the circuit pattern (52) are connected with a thin conductive metal wire (61), and the other surface of the alumina ceramic substrate (5l) is covered with the electrode. The heat conductive layer (54) made of deposited copper and the heat sink (55) were fixed together by a solder layer.

A plurality of alumina ceramic substrates (51) on which the above-mentioned power circuits are formed are fixedly mounted on the heat sink (55), and pad portions (52') formed on each alumina ceramic substrate (51) are fixedly mounted on the heat sink (55). A predetermined power circuit, for example, a part of the power of an inverter circuit, is connected using the above-mentioned thin wires and integrated into an integrated circuit, which is used as a power module IC. (8) Problems to be Solved by the Invention As shown in FIG. 4, in the power module IC, only the main circuit which is a part of the power of the inverter device is configured, so the effect of increasing the current is small. However, as mentioned above, in the power module shown in Fig. 4, only the main circuit of the inverter is formed, and the drive circuit that drives the main circuit is a separate external component, resulting in a large system. .

In addition, since the structure shown in Figure 4 uses a ceramic substrate, it is possible to form a pattern for a large inverter, but it is difficult to form a fine pattern for a small signal. It was impossible to form both circuits on the same substrate.

(2) Means for Solving the Problems The present invention has been made in view of the above-mentioned problems, and includes a metal substrate and a plurality of holes attached to the substrate and exposing the surface of the substrate. an insulating thin layer, a conductive path of a desired shape formed on the insulating thin layer, a ceramic piece with a low thermal resistance ratio fixed on the substrate exposed through the hole, and a conductive path fixed on the ceramic piece. It comprises a plurality of power elements serving as a main circuit of the connected power inverter and a plurality of small signal circuit elements serving as a drive circuit that drives the main circuit and is disposed on the substrate, and is arranged on the peripheral edge of the hole. The present invention is characterized in that an annular conductor layer is formed in the conductor layer, a counterbore portion exposing the substrate surface is formed near the conductor layer, and the conductor layer and the substrate exposed by the counterbore portion are connected.

(f) Function As described above, according to the present invention, a hole is provided in the thin insulating resin layer adhered to a metal substrate to expose the surface of the substrate, and an inverter is placed on the substrate exposed through the hole through a ceramic piece. By mounting a power element that serves as the main circuit of the device and arranging multiple /JX signal elements that drive the main circuit on other areas, the heat dissipation performance of the power element can be greatly improved. A small signal element can be fixed on top. As a result, it is possible to provide an inverter device that integrates a high-power main circuit and a drive circuit.

Furthermore, by connecting the conductor layer provided around the peripheral edge of the hole and the counterbore portion provided in the vicinity of the conductor layer, self-noise during switching of the power element of the main circuit can be suppressed.

(f) Examples The present invention will be explained in detail below based on the examples shown in FIGS. 1 and 2.

FIG. 1 is a plan view showing an inverter device of the present invention,
Figure 2 is a sectional view taken along line II in Figure 1. As shown in FIGS. 1 and 2, the inverter device of the present invention includes a metal substrate (1) and a plurality of holes (2) attached on the surface of the substrate.
a), a conductive path (3) of a desired shape formed on the insulating thin layer (2), and a conductive path (3) of a desired shape formed on the insulating thin layer (2), and fixed on the substrate (1) exposed by the hole (2a). a ceramic piece (4), and a hole (2a) surrounding the ceramic piece (4).
A conductor layer (3゛) formed on the insulating thin layer (2) at the peripheral edge of , a counterbore (9) provided near the conductor layer (3'), and a ceramic piece (4) It consists of a power element (5) fixed on the guide path (3) and a plurality of small signal elements (6) fixed on the guide path (3).

A copper substrate with a thickness of 2 to 5 cm is used as the metal substrate (1). The surface of the copper substrate is coated with a nickel plating film (1a) by electroless plating to increase copper oxidation and mechanical strength.
) is coated.

For example, epoxy or polyimide resin is used as the insulating thin layer (2) that is adhered to the entire surface of the substrate (1), and a plurality of holes (2a) are provided at predetermined positions. The holes (2a) are formed in advance by means such as pressing before being attached to the substrate (1). When the thin insulating layer (2) is pasted onto the substrate (1), only the surface of the substrate (1) is exposed through the plurality of holes (2a). The hole (
2a) is provided so as to be placed approximately at the center of the substrate (1). In this embodiment, since a three-phase inverter is used, six holes (2a) are formed.

A conductive path (3) of a desired shape made of copper foil is formed on the insulating thin layer (2). By the way, copper foil and insulating thin layer (2
) are integrated in advance with an adhesive, and when the thin insulating layer (2) is pasted onto the substrate (1), the copper foil is also pasted at the same time. As is clear from FIG. 1, the conductive path (3) includes a power conductive path (3a) and a small signal conductive path (3b). The power conductive path (3a) is the hole (2a)
The extended substrate (1) is formed to extend between
A power pad (3C) to which a power lead terminal is fixed is formed on the peripheral edge of the power pad (3C). On the other hand, the small signal conductive path (3b) is placed between the substrates and the power conductive path (3a).
1) is formed in the regions at both ends of the power pad (3C
), a conductive path (3b) is extended to form a small signal pad (3d). In addition, the conductive path for power (
3a) In this embodiment, a copper plate (7) whose surface is plated with Ni is fixed on top of the plate (7) in order to handle a large current.

Furthermore, the conductive path (3b) for small signals formed in this embodiment has a fine pattern of 30 to 100 μ class.

By the way, a conductor layer 3') is formed on the insulating thin layer (2) at the peripheral end of the hole (2a) so as to surround a ceramic/gloss piece (4) to be described later. This conductor layer (3゛) is a conductive path (3゛).
) is made of the same material, copper foil, and is formed in the same process. In addition, this conductor layer (3゛) becomes essential in the manufacturing process, and in the present invention, the conductor layer (3゛) is essential in the manufacturing process.
3)).

Since the insulating thin layer (2) and the copper foil forming the guiding path (3) are integrated in advance as described above, the hole (2a) is formed in the integrated material and the substrate (1) is formed. It is very difficult to apply a resist film on only the substrate (1) exposed through the hole (2a) when etching the copper foil. When applying a resist film on (1), it is necessary to overlap the area around the hole (2a).As a result, when forming the conductive path (3) by etching, the area surrounding the hole (2a) A conductor layer (3') is formed.A conductor layer (3') is also formed.
The top is plated to protect the surface.

On the other hand, a counterbore (9) is provided near the conductor layer (3) to expose the surface of the substrate (1).
) exposed by the substrate (1) and the aforementioned conductor layer (3
') are electrically connected using a connecting means such as an aluminum wire. According to this structure, the conductor layer (3') and the substrate (1) are grounded, and the self-noise generated from the power element (5), which will be described later, is surrounded by the conductor layer (3'). It is possible to significantly suppress the adverse effects caused by other circuit elements, especially small signal type elements.

A power element (5) is mounted on the substrate (1) exposed through the above-mentioned hole (2a) via a ceramic piece (4) having a small thermal resistance ratio.

As the ceramic piece (4) having a low thermal resistance ratio, there are materials such as aluminum nitride, boron nitride, and beryllia, but in this embodiment, aluminum nitride, which is the most common material, is used. FIG. 3 is a sectional view showing the ceramic piece 4〉, and a conductor layer (4a) to which a copper plate is fixed via oxidized steel is formed on the upper and lower surfaces thereof.

Therefore, it becomes possible to fix it onto the substrate (1) by soldering. Further, it goes without saying that the power element <5) fixed on the ceramic piece (4) is also fixedly mounted by solder. In addition, the above-mentioned ceramic piece (4
Although not shown, a nickel plating film is formed on the surface of the conductor layer (4a) formed on the upper and lower surfaces of the conductor layer (4a). The power element (5) fixed on the ceramic piece (4) and the power conductive path (3a) are connected by bonding using aluminum wires, and a bridge connection is made to form the main circuit of the inverter. In this embodiment, since the ceramic piece (4) is independent by the hole (2a), the ceramic piece <4) and the power conductive path (3a) are used to form the bridge circuit that constitutes the main circuit described above. ) can be connected to form the main circuit of the inharter.

As described above, the conductor layer (4a) is formed on the upper and lower surfaces of the ceramic piece (4).
) fixed on the power element (5>, for example, the connector of a power transistor becomes common with the conductor layer (4a), and connects the conductor layer (4a) and the power conductive path (3a) with a wire etc. By doing so, the main circuit of the power inverter can be constructed.The conductor layer (4a) and the power conductive path (3a) are connected by bonding with aluminum wire, but at this time, a nickel plating film is coated on the surface of each. There is no problem because it is formed.

On the other hand, on the small signal conductive path (3b) formed on the insulating thin layer (2), there are a plurality of small signal elements that do not generate heat, such as transistors, chip resistors, chip capacitors, and die capacitors. (6) is installed, and constitutes a drive circuit and a protection circuit that drive the main circuit of the inverter.

According to the present invention, a hole is provided in a thin insulating resin layer adhered to a metal substrate to expose the surface of the substrate, and an inverter is installed on the substrate exposed through the hole via a ceramic piece having a low thermal resistance ratio. By mounting a power element serving as a main circuit and arranging a plurality of small signal elements for driving the main circuit on other areas, the heat dissipation performance of the power element can be greatly improved. Furthermore, since small signal elements can be fixed on the same substrate, it is possible to provide an inverter device that integrates a high power main circuit and a drive circuit. Further, a conductor layer (3') is provided around the peripheral edge of the hole (2a), that is, surrounding the power element (5), and the conductor layer (3') is provided so as to surround the power element (5).
) and the substrate (1) exposed by the counterbore (9), it is possible to suppress self-noise during switching of the power element (5).

(G) Effects of the Invention As detailed above, according to the present invention, it is possible to form a high-power inverter main circuit and a drive circuit for driving the circuit on the same base plate, resulting in extremely A thin high-power inverter device can be provided.

Further, since only the power element is fixed on the ceramic piece used in the present invention, it is possible to form a fine pattern for small signals on the same substrate at low cost.

Further, according to the present invention, since the self-noise of the power element can be suppressed, as a result, the peripheral small-signal circuit elements can operate stably, and an inverter device with excellent characteristics can be realized.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line II in Fig. 1, Fig. 3 is a sectional view showing a ceramic piece used in this embodiment, and Fig. 4 is a conventional example. FIG. (1)...metal substrate, (2)...insulating thin layer, (
2a)...hole, ku3)...conducting path, (3')...
...Conductor layer, 4)...Ceramic piece, 5)
...power element, (6) small signal element, (9) ... counterbore part.

Claims (6)

[Claims] (1) A metal substrate, an insulating thin layer attached to the substrate and provided with a plurality of holes that expose the surface of the substrate, and a conductive path of a desired shape formed on the insulating thin layer and exposed through the holes. a ceramic piece having a low thermal resistance ratio fixed on the substrate, a plurality of power elements fixed on the ceramic piece and connected to the conductive path and forming a main circuit of a power inverter, and driving the main circuit; a plurality of small signal circuit elements disposed above and serving as a drive circuit, a ring-shaped conductor layer is formed on the peripheral edge of the hole, and a counterbore portion exposing the substrate surface near the conductor layer. and connecting the conductive layer and the substrate exposed by the counterbore. (2) The inverter device according to claim 1, wherein a copper substrate is used as the metal substrate. (3) an aluminum nitride piece as the ceramic piece;
2. The inverter device according to claim 1, wherein boron nitride pieces, silicon carbide pieces, or beryllia pieces are used. (4) The inverter device according to claim 1, wherein copper foil is used as the conductive path. (5) The inverter device according to claim 1, wherein the power elements are bridge-connected. (6) The inverter device according to claim 1, wherein conductor layers are provided on both sides of the ceramic piece.