JPH07297518A - Mounting structure of electronic part - Google Patents

Abstract

PURPOSE:To improve reliability of a device and to improve mounting density by restraining thermal influence to a weak heat part without damaging heat dissipation of a heat generation part. CONSTITUTION:The title structure is a mounting structure of an electronic part 2 for mounting the electronic part 2 on front and rear sides of a printed wiring board 1. The printed wiring board 1 is formed as a composite printed wiring board which is formed by laminating and joining a metallic base substrate 1a including an aluminum base material 1b and a non-metallic base substrate 1f including a glass epoxy base material 1g. The electric part 2 is divided into a heat generating part 2a of a large heat generation amount and a weak heat part 2b which is easily affected by heat or has temperature characteristic. At least the heat generation part 2a is mounted on the side of the metallic base substrate 1a of the composite printed wiring board 5 and the weak heat part 2b is mounted on the side of the non-metallic base substrate 1f.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mounting structure for electronic parts.

[0002]

2. Description of the Related Art FIGS. 3 and 4 show a conventional mounting structure for electronic parts (first conventional example), in which an electronic part 2 is soldered to one surface side of a printed wiring board 1. It was implemented by.

The printed wiring board 1 uses a metal base substrate 1a excellent in heat dissipation in order to radiate heat from an electronic component 2 which generates a relatively large amount of heat. The metal base substrate 1a is the metal base substrate 1a. An insulating layer 1c is formed of an epoxy resin or the like on an aluminum base material 1b which is a base material, and a copper foil pattern 1d is formed on the insulating layer 1c by etching. In addition, the electronic component 2 is a heat-generating component 2 such as a power transistor or a triac that generates a relatively large amount of heat.
a and a heat-sensitive component such as an IC or a heat-sensitive component 2b that is weak against heat such as a transistor, a diode and a capacitor or has temperature characteristics. Such an electronic component 2 is a printed wiring. It is mounted on one side of the plate 1 on the side where the copper foil pattern 1d is formed.

FIG. 5 shows a mounting structure of an electronic component in a second conventional example disclosed in Japanese Patent Application Laid-Open No. 2-281790. A difference from the first conventional example is a printed wiring board. 1 is composed of a metal base substrate 1a and a resin wiring substrate 1f which is a non-metal base substrate, and electronic components 2 are mounted on those printed wiring substrates 1.

That is, the printed wiring board 1 has, in addition to the metal base substrate 1a in the first conventional example, a resin wiring substrate 1f which is a non-metal base substrate.
The heat generating component 2a having a relatively large heat generation amount is mounted on the one surface side which is the front surface side, and the non-heat generating component including the weak heat component 2b is mounted on the one surface side which is the surface side of the resin wiring board 1f. The metal base substrate 1a and the resin wiring substrate 1f are laterally arranged side by side on one surface side of the aluminum base plate 4 and electrically connected to each other by the lead wires 3, and further, the resin wiring substrate 1f is The terminal 1e for connecting to an external circuit is drawn out.

[0006]

However, in the mounting structure of the electronic component 2 shown in the first conventional example having such a structure, the heat generating component 2a and the weak heat component 2b are the metal base substrate excellent in heat dissipation. Since it is mounted on one surface side which is one surface side of 1a, although the heat dissipation effect of the heat generating component 2a having a relatively large heat generation amount such as a power transistor is good,
The heat is conducted to the entire surface of the printed wiring board 1 and is weak to heat.
There is a problem in that the weak heat component 2b such as C is affected, and in particular, the weak heat component 2b having a remarkable temperature characteristic with respect to heat may have variations in characteristics, which may lead to a decrease in reliability of the device. It was

Further, since the heat-generating component 2a and the weak-heat component 2b are mixedly mounted on one surface side of the printed wiring board 1, the influence of radiation heat from the heat-generating component 2a on the weak-heat component 2b is reduced. However, there is a problem in that it is necessary to increase the distance between the weak heat component 2b and the heat generating component 2a, which causes a decrease in the mounting density of the electronic components 2 and makes it difficult to reduce the size. Even when the electronic components 2 are mounted on both front and back surfaces of the printed wiring board 1, it is necessary to make the base material of the printed wiring board 1 have good thermal conductivity in order to dissipate heat from the heat generating components 2a. Since both the front and back surfaces of the wiring board 1 have substantially the same temperature due to the heat conduction of the heat-generating component 2a, there is a problem that the heat conduction of the heat-generating component 2a has an unavoidable effect on the weak heat component 2b.

In the mounting structure of the electronic component 2 shown in the second conventional example, the heat generating component 2a and the non-heat generating component including the weak heat component 2b are connected to the metal base substrate 1a and the resin wiring which is the non-metal base substrate. Although mounted separately on the board 1f, when the metal base board 1a and the resin wiring board 1f, which is a non-metal base board, are bonded to the one surface side of the aluminum base board 4, the heat generating parts 2a and Since the weak heat component 2b is mounted on the same surface side, in order to reduce the influence of the radiant heat from the heat generating component 2a, it is necessary to secure a sufficient distance between the weak heat component 2b and the heat generating component 2a. There was a problem that it was difficult to miniaturize.

The present invention has been made to solve the above problems, and an object of the present invention is to suppress the thermal influence on a weak heat component without impairing the heat radiation of the heat generating component,
An object of the present invention is to provide a mounting structure for electronic components, which can increase the reliability of the device and increase the mounting density to reduce the device size.

[0010]

In order to solve the above-mentioned problems, the present invention provides an electronic component 2 in which the electronic component 2 is mounted on both front and back surfaces of a printed wiring board 1 according to the present invention. In the mounting structure, the printed wiring board 1 is a composite printed wiring board 5 in which a metal base substrate 1a and a non-metal base substrate 1f are stacked and joined together, and the electronic component 2 is a heat-generating component 2a having a large heat generation amount and other components. The heat generating component 2a is mounted on the metal base substrate 1a side of the composite printed wiring board 5 and the weak heat component 2b is mounted on the non-metal base substrate 1f side. It is what

In the invention according to claim 2, the metal base substrate 1b of the metal base substrate 1a is an aluminum substrate.

Further, in the invention according to claim 3, on the metal base substrate 1a side of the printed wiring board 1,
It is characterized in that a terminal 1e for electrical connection with the outside is provided.

[0013]

As described above, according to the invention of claim 1, in the mounting structure of the electronic component 2 in which the electronic component 2 is mounted on both front and back surfaces of the printed wiring board 1, the printed wiring board 1 is Metal base substrate 1a and non-metal base substrate 1f
And an electronic component 2 are divided into a heat generating component 2a having a large heat generation amount and another weak heat component 2b, and at least the heat generating component 2 is formed.
Since a is mounted on the metal base substrate 1a side of the composite printed wiring board 5 and the weak heat component 2b is mounted on the non-metal base substrate 1f side, heat generated from the heat generating component 2a is directly radiated from the heat generating component 2a. The heat is radiated through the metal base substrate 1a and sufficient heat can be radiated, and the heat generating component 2a and the weak heat component 2b are combined by the composite printed wiring board 5.
It is separated into the front surface side and the back surface side, so that the influence of the radiant heat from the heat generating component 2a to the weak heat component 2b can be prevented. In addition, the influence of heat conduction from the heat generating component 2a to the weak heat component 2b is also
Since the non-metal base substrate 1f is interposed between them, it is suppressed to a small amount, and the thermal influence on the weak heat component 2b can be suppressed without impairing the heat radiation of the heat generating component 2a, and the reliability of the device can be improved. . Furthermore, since the thermal influence from the heat generating component 2a to the weak heat component 2b can be suppressed, the electronic components 2 can be mounted at high density, and the device can be downsized.

According to the second aspect of the invention, since the metal base material 1b of the metal base substrate 1a is an aluminum base material, the aluminum base material 1b is a metal base material 1b having excellent heat dissipation. Heat is radiated by the metal base substrate 1a provided with the heat generating component 2 through the metal base substrate 1a.
The heat dissipation of a increases.

Further, in the invention according to claim 3, on the metal base substrate 1a side of the printed wiring board 1,
Since the terminal 1e for electrical connection with the outside is provided, the heat generated from the heat-generating component 2a mounted on the metal base substrate 1a is also radiated through the terminal 1e, and the heat dissipation is further enhanced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a first embodiment of an electronic component mounting structure according to the present invention. In this electronic component mounting structure, electronic components 2 are soldered on both front and back surfaces of a printed wiring board 1. It is implemented by attachment.

The printed wiring board 1 is a metal base substrate 1a.
And a non-metal base substrate 1f are laminated and joined to form a composite printed wiring board 5. As an example of such a composite printed wiring board 5, a metal base substrate 1
For example, a is formed by forming an insulating layer 1c of an epoxy resin or the like on an aluminum base material 1b which is a metal base material excellent in heat dissipation, and forming a copper foil pattern 1d on one surface side by etching, and The non-metal base substrate 1f is configured, for example, by forming a copper foil pattern 1d on one surface side of a glass epoxy resin base material 1g by etching. Then, the two types of metal base substrate 1a and non-metal base substrate 1f are laminated and joined so that the other surface side thereof where the copper foil pattern 1d is not provided is brought into contact with each other, and also joined by the through hole 1h. The composite printed wiring board 5, which is the printed wiring board 1, is formed by connecting the copper foil patterns 1d and 1d on both the front and back surfaces of the two types of substrates thus formed.

In the composite printed wiring board 5 thus constructed, a heat-generating component 2a such as a power transistor is surface-mounted on the metal base substrate 1a side so as to come into contact with the metal base substrate 1a. On the board 1f side,
A heat-sensitive component such as an IC or a weak-heat component 2b such as a transistor, a diode or a capacitor which is weak against heat or has a remarkable temperature characteristic is mounted.

With this structure, the heat generated from the heat-generating component 2a directly dissipates heat from the heat-generating component 2a and the metal base substrate 1a provided with the aluminum base material 1b, which is a metal base material excellent in heat dissipation, is used. The heat is dissipated through the heat generating component 2a and the heat generating component 2a is sufficiently dissipated, and the heat generating component 2a and the weak heat component 2b are separated by the composite printed wiring board 5 into the front surface side and the back surface side thereof, and the heat generating component 2a is weakly heated. The influence of radiant heat on 2b can be prevented. Further, the influence of heat conduction from the heat-generating component 2a to the weak-heat component 2b is also suppressed to a small extent because the non-metal base substrate 1f is interposed between them, so that the heat-generating component 2a does not lose heat dissipation to the weak-heat component 2b. It is possible to improve the reliability of the apparatus by suppressing the thermal influence of the above and suppressing the variation in the characteristics of the weak heat component 2b due to heat. Furthermore, since the thermal influence from the heat generating component 2a to the weak heat component 2b can be suppressed, the electronic components 2 can be mounted at high density, and the device can be downsized. If all the electronic components 2 are surface-mounted, the device can be made thin.

FIG. 2 shows a second embodiment of the present invention. The difference from the first embodiment is that the metal base substrate 1a side is connected to the outside connected to the copper foil pattern 1d. The hybrid IC is configured by providing a plurality of terminals 1e for electrical connection, and the other configurations are similar to those of the first embodiment.

Because of the above-mentioned structure, the first
In addition to the effect of this embodiment, the heat from the heat generating component 2a mounted on the metal base substrate 1a is also radiated through the terminal 1e, and the heat radiating property of the heat generating component 2a is further improved.

In each of the above embodiments, an aluminum base material is used as the metal base base material 1b of the metal base substrate 1a.
Although the glass epoxy base material is exemplified as the non-metal base base material 1g, the present invention is not limited to this, and the base material of the metal base substrate is, for example, a metal base material such as an iron base base material. As the non-metal base material, any material such as a non-metal base material such as a polyimide glass base material may be used.

[0023]

As described above, according to the present invention, in the electronic component mounting structure in which the electronic component is mounted on both front and back surfaces of the printed wiring board, the printed wiring board is a metal base substrate. And a non-metal base substrate are laminated and joined to each other, and the electronic component is divided into a heat-generating component having a large heat generation amount and another weak heat component, and at least the heat-generating component is the composite printed wiring. Mounted on the metal base substrate side of the plate, the weak heat component is mounted on the non-metal base substrate side, so the heat generated from the heat generating component is directly radiated from the heat generating component and radiated through the metal base substrate. In addition to sufficient heat dissipation, the heat generating component and the low heat component are separated by the composite printed wiring board into the front side and the back side, and the influence of the radiant heat from the heat generating component to the weak heat component can be prevented. . Also, the influence of heat conduction from the heat-generating components to the weak-heat components is suppressed to a minimum because the non-metal base board is interposed between them, and the thermal influence on the weak-heat components is not impaired without damaging the heat dissipation of the heat-generating components. It is possible to suppress the variation in the characteristics of the weak heat component due to heat and improve the reliability of the device. Furthermore, since it is possible to suppress the thermal influence from the heat generating component to the weak heat component, high density mounting of electronic components becomes possible, and the size of the device can be reduced.

Further, in the invention of claim 2, since the metal base material of the metal base substrate is an aluminum base material, in addition to the effect of the invention of claim 1, an aluminum material excellent in heat dissipation is provided. The metal base substrate provided with the base material enhances heat dissipation of the heat-generating component through the metal base substrate.

Further, in the invention according to claim 3, since the terminal for electrical connection to the outside is provided on the metal base substrate side of the printed wiring board, the invention according to claim 1 or 2 is provided. In addition to the effects of the invention, the heat generated from the heat-generating component mounted on the metal base substrate is also radiated through the terminals, further improving the heat radiation performance.

[Brief description of drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is a perspective view of an essential part showing a second embodiment of the present invention.

FIG. 3 is a plan view showing a conventional electronic component mounting structure (first conventional example).

FIG. 4 is a side view of the above.

FIG. 5 is a perspective view showing another conventional mounting structure for electronic components (second conventional example).

[Explanation of symbols]

 1 Printed Wiring Board 1a Metal Base Substrate 1b Metal Base Substrate 1e Terminal 1f Non-metal Base Substrate 2 Electronic Components 2a Heat-generating Components 2b Weak-heat Components 5 Composite Printed Wiring Board

Claims (3)

[Claims] 1. In a mounting structure of an electronic component for mounting an electronic component on both front and back surfaces of a printed wiring board, the printed wiring board is a composite printed wiring board in which a metal base substrate and a non-metal base substrate are laminated and joined. At the same time, the electronic component is divided into a heat-generating component having a large heat generation amount and other weak heat components, and at least the heat-generating component is mounted on the metal base substrate side of the composite printed wiring board, and the weak heat component is a non-metal base. Electronic component mounting structure characterized by being mounted on the board side. 2. The mounting structure of an electronic component according to claim 1, wherein the metal base material of the metal base substrate is an aluminum base material. 3. The mounting structure for an electronic component according to claim 1, wherein a terminal for electrical connection to the outside is provided on the metal base substrate side of the printed wiring board.