JPH05218606A - Circuit device - Google Patents

Abstract

PURPOSE:To dissipate heat from a highly heat-generating component with good efficiency by providing the following: an insulating layer in which a window part has been formed; a two-layer conductive layer formed on the insulating layer; and the highly heat-generating component on a metal base material which has been exposed. CONSTITUTION:Window parts 44 which partly expose the surface of a metal base material 11 are formed in an insulating layer 12 which has been pasted on the metal base material 11. In addition, a conductive layer 34 which is composed of at least two layers is formed on the insulating layer 12. A highly heat-generating component (a semiconductor chip) 15 is arranged on the metal base material 11; it is connected to the conductive layer 34. As a result, the highly heat-generating component 15 is pasted directly on the metal base material 11, and a heat sink and the like are not required. Thereby, heat from the highly heat-generating component can be dissipated with good efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit device in which a circuit including a high heat generating component such as a power semiconductor chip is formed on a circuit board based on a metal base material.

[0002]

2. Description of the Related Art Conventionally, a power circuit device mounted with a power semiconductor chip often employs a so-called heat sink in consideration of dissipation of heat generated during its operation. The circuit device shown in FIGS. 8 and 9 is shown as an example of a system using such a heat sink.
As shown in FIGS. 8 and 9, a circuit device based on a metal base material on which high heat-generating components are mounted has a conductive layer 21 on a metal base material 11 such as copper or aluminum via an insulating layer 212.
What formed 3 is used. The insulating layer 212
An epoxy resin is used for this. Conductive layer 213
There is a method of forming a circuit in a pattern by etching a copper foil attached, or a method of forming the circuit by vacuum deposition, sputtering or the like.

A metal block 14 made of a copper material and serving as a heat sink is attached to a necessary portion of the conductive layer 213. A high heat-generating component 15 such as a power semiconductor chip is mounted on the metal block 14. When the high heat-generating component 15 is a semiconductor chip as described above, soldering is often used for bonding to the metal block 14. The size of the metal block 14 is about the same as that of the heat generating component 15 or several times, and the thickness thereof is 0.5 mm to 3 mm. An example power M is used as a power semiconductor chip.
Besides the OS-FET, there are power transistors, triacs, SCRs, diodes and the like. A gold wire, an aluminum wire, a copper wire, or the like is used as the bonding wire 16 for the high heat-generating component 15, and connects the chip and the conductive layer 213.

Next, the operation of the circuit example will be described with reference to FIG. As shown in FIG. 7, the circuit is a three-phase bridge circuit. The current i flows from one of the input terminals 18 of the circuit to the semiconductor chip 15 and through the output terminal 28 to a load (not shown). The current passing through the load returns to another output terminal 28,
The other input terminal 18 is passed through another semiconductor chip 15.
Flow to. The load in this case is the motor. The magnitude of the current depends on the load condition of the motor. The largest load is when the rotation of the motor seems to be locked. At this time, the current rapidly increases and the heat generation of the semiconductor chip 15 also rapidly increases. The heat generated by this heat is immediately transferred to the metal block 14
The temperature rise of the semiconductor chip 15 is suppressed. The heat transferred to the metal block 14 is radiated to the metal base material 11 via the insulating layer 212.

Further, in a circuit including such a high heat-generating component 15, the performance of the insulating layer 212 is large and small in radiating the heat generated from the high heat-generating component 15.
In the example shown here, the insulating layer 212 is mainly made of resin or ceramic, and its thermal conductivity is smaller than that of metal.

[0006]

As a problem of such a conventional example, it is possible to absorb momentary heat generation by increasing the temperature of the metal block 14, but the metal block 14 itself can be absorbed in a short time. The temperature will rise. After that, the heat radiation from the high heat generating component (semiconductor chip) 15
The heat conduction to the metal base material 11 via the insulating layer 212 is rate-determining. Therefore, it is necessary to devise how to improve the heat radiation through the insulating layer 212 in the case where the heat generation does not end instantly.

There are a plurality (six as an example) of the high heat-generating components 15 in the above conventional example, and all have the same amount of heat generation. However, in general, the calorific value may be different for each. In that case, the size of the metal block 14 should be changed respectively. However, in reality, there are many types of parts, and it is difficult to manage parts and support equipment, so it is not possible to make detailed correspondences. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide a circuit device in which heat is continuously generated and which is based on a metal base material having good heat dissipation.

[0008]

The present invention has the following means in order to achieve the above object.

Insulation provided with a metal base material and a window opening part which is stuck on the metal base material and partially exposes the surface of the metal base material, as described in claim 1. A layer, a conductive layer composed of at least two layers formed on the insulating layer, and a high heat-generating component arranged on the metal base material partially exposed at the window opening and connected to the conductive layer. It is characterized in that it is a circuit device provided with.

[0010]

Insulation provided with a metal base material and a window opening part which is attached to the metal base material and partially exposes the surface of the metal base material, as described in claim 1. A layer, a conductive layer composed of at least two layers formed on the insulating layer, and a high heat-generating component fixedly connected to the metal base material partially exposed at the window opening part and connected to the conductive layer. By using the circuit device having the above, the high heat generating component (semiconductor chip) can be directly attached onto the metal base material, and the heat radiation from the high heat generating component (semiconductor chip) is efficiently performed. When there are a plurality of high heat generating components (semiconductor chips) as in the embodiment, only the high heat generating components (semiconductor chips) having the same potential are directly attached to the metal base material.
Also, when mounting multiple high heat-generating components (semiconductor chips) that generate different amounts of heat, if the high heat-generating components (semiconductor chips) with the highest heat generation are directly attached to the metal substrate, heat can be dissipated more efficiently. Can be done.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the circuit device of the present invention will be described in detail below with reference to FIG. In FIG. 5, 11 is a metal base material having good thermal conductivity such as copper or aluminum.
The first insulating layer 12 is formed on the metal base 11.
The first insulating layer 12 is, for example, epoxy resin or glass fiber impregnated with epoxy resin, and is formed by a coating method such as a roll coater or a flow coater, a screen printing method, or a sheet-like prepreg attaching method. At the time of forming the first insulating layer 12, the window opening portion 44 partially having no insulating layer is formed.

A first conductive layer 34 made of copper or the like is formed on the first insulating layer 12. The method of forming the first conductive layer 34 includes a method of sticking a copper foil punched in a pattern, a method of sticking a copper foil on the entire surface and forming a pattern by etching, or a method of forming a pattern on a stainless plate or the like. There is a method of performing electrolytic copper plating of a pattern like No. 5 and transferring or pasting it onto the first insulating layer 12. As the first conductive layer 34, an arbitrary layer having a thickness of about 0.03 mm to about 3 mm can be manufactured by the above method. Among them, the thin copper is formed by the above-mentioned etching or electroplating method and transferring.

The embodiment shown in FIGS. 5, 1 and 2 is shown in FIG.
2 is an embodiment of the present invention in the circuit of FIG. In this circuit, the six power MOS-FETs 15 generate heat evenly. In FIG. 5, the metal substrate 1 partially exposed at the window opening portion 44 having no insulating layer
1 has three power MOS-FETs mounted on it, and one power MOS on each first conductive layer 34.
Implement the FET. The patterns are designed so that the separated first conductive layers 34 have the same area. In terms of expression applicable to a general circuit, each area of the first conductive layer is changed according to the heat generation amount of the heat generating component.

Thereafter, a resin is applied between the patterns of the first conductive layer 34 and at the end portions of the substrate, that is, in the portion 19 without the copper foil in FIG. 5, so as to eliminate the surface step as much as possible. The resin material is the same epoxy resin as the first insulating layer 12. A dispenser or a screen printing method is used for coating.
In this way, a state having almost no step is formed, and the second insulating layer 22 is formed thereon as shown in FIG. The forming method is a screen printing method, and the material is an epoxy resin.

When the second insulating layer 22 is printed, the window openings 54, 64, 74, 84 having no insulating layer that partially exposes the metal substrate 11 or the first conductive layer 34. To form. Of these window opening parts 54, 64, 74, 84, 54 and 64 are windows to which the high heat generating component (semiconductor chip) 15 is attached, 74 is a window to which an external lead terminal is attached, and 84 is wire bonding of the semiconductor chip. For windows. In the window opening portions 54, 64, 74 and 84 of FIG. 1 in which the second insulating layer 22 is formed on the substrate of FIG. 5, the metal base material 11 or the first conductive layer 34 is partially exposed. Becomes

A second conductive layer 13 shown in FIG. 2 is formed on the second insulating layer 22. The formation method is the first conductive layer 3
The method is the same as that of 4, and a method of sticking a punched copper foil in a pattern, a method of forming a pattern by sticking a copper foil on the entire surface and etching, or electrolytic copper plating of a desired pattern on a stainless plate or the like Then, a method of transferring and pasting onto the second insulating layer 12 or a semi-additive method can be used.

An example of forming the second conductive layer by the semi-additive method is shown in FIG. In FIG. 4A, the surface of the second insulating layer 22 is roughened by, for example, liquid honing, and the entire surface of the second insulating layer 22 is electroless plated. In the figure, 23 is electroless plating (copper) and has a thickness of 0.5 μm to 1 μm. The electroless plating 23 is also formed on the window opening portions 54, 64, 74, 84 of the second insulating layer 22. Plating resist 1 on electroless plating 23
11 is printed to form a wiring pattern. Then, the second conductive layer 33 is formed by electrolytic copper plating.

After that, the plating resist 111 is removed and the copper on the plating surface is etched for a short time, whereby the exposed electroless copper plating 23 is dissolved. Thus, at the same time as the formation of the second conductive layer 33, the first conductive layer and the second conductive layer 3 are formed through the window opening of the second insulating layer 22.
A junction of 3 is also formed.

FIGS. 4B and 4C are cross-sectional views showing a method of further performing partial plating 43 such as gold plating on the land portion for bonding on the above. Plating resist 111
4B in a state before the removal is performed, the plating resist 121 is printed again, leaving a portion where plating is desired,
Electroplating 43 is performed on the window exposed portion. When the electroplating 43 is gold plating, nickel plating is performed accurately, and then gold plating is performed again. After that, the plating resists 111 and 121 are removed and the copper on the plating surface is etched for a short time to expose the exposed electroless copper plating 23.
Will dissolve. Therefore, the final structure as shown in FIG. 4C can be obtained, and a circuit board having the partial plating 43 and the second conductive layer 33 connected to the first conductive layer 34 can be formed. it can. Even when the second conductive layer is formed by another method, after the formation of the second conductive layer, the land portion of the bonding to which the semiconductor chip or the like is bonded is subjected to partial plating such as gold plating.

FIG. 6 is a sectional view showing a state in which the semiconductor chip 15 is bonded on the metal base material 11. Wire bonding is performed between the semiconductor chip 15 and the bonding land portion of the first conductive layer 34 or the second conductive layer 13. In FIG. 6, wire bonding is performed between the semiconductor chip 15 and the second conductive layer 13 by the bonding wire 16. On the other hand, FIG. 3 is a sectional view showing a state in which the semiconductor chip 15 is bonded on the first conductive layer 34. Thus, it is not necessary to provide a metal such as a heat sink between the semiconductor chip 15 and the first conductive layer 34. The wire bonding is performed starting from the bonding point on the side of the semiconductor chip 15 and ending at the bonding point of the first conductive layer 34 or the second conductive layer 13. Normal semiconductor chip 1
After mounting 5, the area 5 is sealed with a silicone resin 17. This is intended to ensure reliability by protecting the chip.

As an alternative method of connection between the first conductive layer and the second conductive layer, a partial window opening of the first conductive layer and a bonding land portion of the second conductive layer are formed. An electroplated portion such as gold plating can be used to form a circuit device connected by wire bonding.

[0022]

The following effects can be obtained by using the above-described structure.

Insulation provided with a metal base material and a window opening part which is attached to the metal base material and partially exposes the surface of the metal base material, as shown in claim 1. A layer, a conductive layer composed of at least two layers formed on the insulating layer, and a high heat-generating component arranged on the metal base material partially exposed at the window opening and connected to the conductive layer. By using the circuit device equipped with the high heat generating component (semiconductor chip), the heat generating component (semiconductor chip) can be directly attached onto the metal base material, and a heat sink or the like is not required.
The heat is efficiently dissipated. Further, when mounting a plurality of high heat-generating components (semiconductor chips) having different heat generation amounts, the high heat-generating component (semiconductor chip) having the largest heat generation amount can be directly adhered to the metal base material for efficient heat dissipation. ..

[Brief description of drawings]

FIG. 1 is a perspective view at a stage where a second insulating layer is formed in the process of forming the circuit device according to the first embodiment of the present invention.

FIG. 2 is a perspective view at a stage where a second conductive layer is formed in a process in the middle of forming the circuit device according to the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view showing a semiconductor chip mounting portion mounted on the first conductive layer in the embodiment showing the semiconductor chip mounting portion of the present invention.

FIG. 4A is a cross-sectional view of a step in which a second conductive layer is formed in the process of forming a circuit device according to another embodiment of the present invention, and FIG. 4B is a step of forming a partial plating. Cross section,
FIG. 3C is a partially enlarged cross-sectional view of the completed metal base-based circuit device.

FIG. 5 is a perspective view at a stage where a first conductive layer is formed in a process in the middle of forming the circuit device according to the first embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view showing a semiconductor chip mounting portion mounted on a metal substrate in an example showing the semiconductor chip mounting portion of the present invention.

FIG. 7 is a circuit diagram for explaining an example.

FIG. 8 is a perspective view showing a conventional circuit device.

FIG. 9 is a cross-sectional view showing a semiconductor chip mounting portion in a conventional circuit device.

[Explanation of symbols]

 11 Metal Base Material 12 First Insulating Layer 13 Second Conductive Layer 14 Metal Block 15 High Heat-generating Component (Semiconductor Chip) 16 Bonding Wire 22 Second Insulating Layer 34 First Conductive Layer 44 First Insulating Layer Window Window portion 54 Second window layer of insulating layer 64 Window window portion of second insulating layer 74 Window window portion of second insulating layer 84 Window window portion of second insulating layer

Claims (1)

[Claims] 1. A metal base material, an insulating layer provided on the metal base material and provided with a window opening part for partially exposing the surface of the metal base material, and formed on the insulating layer. And a high heat-generating component connected to the conductive layer, the conductive layer being composed of at least two layers and disposed on the metal base material that is partially exposed in the window opening. ..