JPH06196877A - Board for mounting of electronic component and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide a board, for mounting of an electronic component, wherein, when a heat sink is bonded, a high thermal load is not exerted, the bonding force of both is strong and an excellent high-density mounting operation is performed and to provide its manufacturing method. CONSTITUTION:This board is provided with an insulating substrate 9, with an opening part 90 formed in the insulating substrate 9, with a heat sink 7 bonded so as to cover one end of the opening part 90 and with a recessed part 900, for mounting of an electronic component, which is formed of the heat sink 7 and the opening part 90. The side face 70 of the heat sink 7 is bonded to the insulating substrate 9 by a synthetic resin 1. The synthetic resin 1 is a resin which is hardened at, e.g. 100 to 150 deg.C, and it is an insulating resin. A bonding operation by the synthetic resin may be executed partially.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a board for mounting electronic parts which is highly densely mounted and has excellent airtightness, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as an electronic component mounting substrate, as shown in FIGS. 11 to 13, for example, an insulating substrate 9, an opening 90 provided in the insulating substrate 9, and one end of the opening 90 are covered. Some have a metal heat sink 7 adhered as described above, and a recess 900 for mounting an electronic component formed by the heat sink 7 and the opening 90.

The heat sink 7 is adhesively fixed to the insulating substrate 9 by an adhesive sheet 65. Further, in order to reinforce the adhesive fixation between the insulating substrate 9 and the heat sink 7, a pad 51 is formed near the adhesive sheet 65, and the pad 51 and the side surface 70 of the heat sink 7 are joined by solder 60.

As shown in FIG. 13, the electronic component 3 is mounted in the recess 900, and is electrically connected to the wiring pattern 59 of the insulating substrate 9 by the wire 30. The electronic component mounting board has lead pins 50 inserted into through holes formed in the insulating substrate 9 in order to achieve electrical continuity with other electronic components. After the electronic component 3 is mounted, the electronic component sealing resin 690 having excellent moisture resistance is filled around the electronic component 3 in the recess 900. Further, its surface is sealed by a metal cap 69.

[0005]

However, at the time of soldering, a high heat of about 260 ° C. is applied to the electronic component mounting board in order to pass through the reflow furnace. Therefore, a high heat load is applied to the insulating substrate 9. Also, when cooling the electronic component mounting board after soldering in the reflow furnace,
Due to the difference in thermal expansion between the insulating substrate 9 and the solder 60, a crack 600 may occur in the solder 60 as shown in FIG. When cracks occur in this way, the bonding force between the insulating substrate 9 and the heat sink 7 decreases.

Further, in order to strengthen the solder joint, it is necessary to widely provide the metal-plated pad 51 as shown in FIG. 12, but the existence of the pad 51 makes the wiring pattern or the lead pin 50 high density. Cannot be implemented. In view of the above conventional problems, the present invention provides an electronic component mounting substrate and a method for manufacturing the same, in which a high heat load is not applied to the insulating substrate during the heat sink bonding, the bonding force between the two is strong, and the high density mounting is excellent. It is the one we are trying to provide.

[0007]

According to the present invention, an insulating substrate, an opening provided in the insulating substrate, a heat sink bonded to cover one end of the opening, and an electron formed by the heat sink and the opening are provided. In an electronic component mounting substrate having a recess for mounting a component, the side surface of the heat sink and the insulating substrate are bonded by a synthetic resin.

In the present invention, the above synthetic resin is preferably one which is cured by heating at 100 to 150 ° C., for example. Examples of such synthetic resin include insulating resins such as epoxy resin, polyimide resin, and triazine resin. Among them, it is preferable to use a resin for encapsulating electronic components, such as an epoxy resin, which is particularly excellent in moisture resistance.

When the temperature is lower than 100 ° C., it is difficult to cure the synthetic resin, and when the temperature exceeds 150 ° C., the insulating substrate,
The heat load on the lead pins increases. The opening is larger than the shape of the electronic component and smaller than the shape of the heat sink.

It is also possible to form a step portion having the same shape as the outer shape of the heat sink at the peripheral portion of the opening, and mount the heat sink inside the step portion. As a result, the peripheral portion of the heat sink and the insulating substrate can be bonded together with a small amount of synthetic resin. Further, the heat sink can be more firmly fixed to the insulating substrate in the step portion.

Between the side surface of the heat sink and the insulating substrate, the entire circumference is bonded with a synthetic resin (FIGS. 2 and 3).
Alternatively, they may be partially bonded with a synthetic resin (FIGS. 8 and 9). In this case, it is preferable to cover at least the surface of the electronic component mounting substrate including the side surface of the heat sink with the sealing resin. As a result, it is possible to prevent moisture from entering the recess for mounting electronic components.

As a method of manufacturing a substrate for mounting electronic parts according to the present invention, an insulating substrate, an opening provided in the insulating substrate, a heat sink adhered to cover one end of the opening, and a heat sink And a method for manufacturing an electronic component mounting substrate having a recess for mounting an electronic component formed by the opening, wherein the heat sink is fixed to the insulating substrate in advance, and then the side surface of the heat sink and the insulating substrate are separated from each other. There is a method for manufacturing an electronic component mounting substrate, which is characterized in that is bonded with a synthetic resin.

[0013]

In the electronic component mounting substrate of the present invention, the side surface of the heat sink and the insulating substrate are bonded by the synthetic resin. And this synthetic resin for adhesion is
For example, it can be cured at a low temperature of about 100 to 150 ° C., and does not require a high temperature of about 260 ° C. as in the case of soldering. Therefore, the heat load on the insulating substrate and lead pins is small.

Further, the synthetic resin directly adheres to the insulating substrate, and the difference in thermal expansion between the two is extremely small as compared with the case of solder joining. Therefore, unlike the case of soldering, there is no possibility of cracks. Therefore, the insulating substrate and the heat sink are firmly joined.

Further, since the synthetic resin is directly adhered to the insulating substrate, it is not necessary to form a metal plating pad for joining a heat sink on the insulating substrate as in the conventional case.
Therefore, the conventional pad formation area is not necessary, and the wiring pattern and the through holes can be mounted at a high density because of the increased area.

Further, according to the above manufacturing method, the excellent electronic component mounting board as described above can be easily manufactured. According to the present invention, it is possible to provide a substrate for mounting electronic components, which does not apply a high heat load to an insulating substrate at the time of joining a heat sink, has a strong joint between the two, and is excellent in high-density mounting, and a manufacturing method thereof.

[0017]

EXAMPLE 1 An example according to the present invention will be described with reference to FIGS. The electronic component mounting substrate of this example includes an insulating substrate 9 and
An opening 90 provided in the insulating substrate 9, a heat sink 7 adhered so as to cover one end of the opening 90, and a recess 900 for mounting an electronic component formed by the heat sink 7 and the opening 90. Have.

The opening 90 is larger than the shape of the electronic component to be mounted and smaller than the shape of the heat sink 7. The heat sink 7 is adhesively fixed by the adhesive sheet 65.

The side surface 70 of the heat sink 7 and the upper surface of the insulating substrate 9 are bonded by the synthetic resin 1. The synthetic resin 1 is cured by heating at 100 to 150 ° C. for 3 to 5 hours. The synthetic resin 1 is an insulating resin, and uses an epoxy (Sumitomo Bakelite) resin for encapsulating electronic components, which is excellent in moisture resistance.

A wiring pattern 59 is formed on the lower surface of the electronic component mounting board. Further, as shown in FIGS. 2 and 3, a through hole 95 is formed in the insulating substrate 9, and a lead pin 50 is inserted in the through hole 95. The electronic component mounting board is a lead pin 5
It is a face-down type in which 0 is projected to the opening side of the recess 900 for mounting electronic components.

Next, a method of manufacturing the electronic component mounting substrate of this example will be described. First, as shown in FIG.
The insulating substrate 9 and the heat sink 7 are prepared, and the opening 90 and the wiring pattern 59 are formed in the insulating substrate 9. next,
As shown in FIG. 4B, the heat sink 7 is attached to one end of the opening 90 by thermocompression bonding using the adhesive sheet 65.
To fix. The conditions for thermocompression bonding are 100 to 150 ° C, 3
~ 5 hours.

Next, as shown in FIG. 4C, the insulating substrate 9 and the side surface of the heat sink 7 are bonded with the synthetic resin 1. After that, lead pins are inserted into the through holes of the insulating substrate (not shown). As a result, the electronic component mounting board is obtained. Others are the same as the conventional example.

Next, the function and effect of this example will be described.
The electronic component mounting substrate of this example is the side surface 7 of the heat sink 7.
0 and the insulating substrate 9 are bonded by the synthetic resin 1. The adhesive synthetic resin is, for example, about 10
It can be cured at a low temperature of 0 to 150 ° C, and does not require a high temperature of about 260 ° C as in the case of soldering. Therefore, the thermal load on the insulating substrate 9, the wiring pattern 59, and the lead pins 50 is small.

Further, the synthetic resin 1 is directly adhered to the insulating substrate 9, and the difference in thermal expansion between the two is extremely small as compared with the case of solder joining. Therefore, unlike the case of solder joining, no cracks are generated and the moisture resistance is excellent. Further, since the synthetic resin 1 is directly adhered to the insulating substrate 9, it is not necessary to form a metal plating pad for joining a heat sink on the insulating substrate 9 as in the conventional case. Therefore, the pad formation area becomes unnecessary, and the wiring pattern and the lead pins 50 can be mounted at a high density because of the increased area.

Embodiment 2 As shown in FIG. 5, the electronic component mounting substrate of this embodiment has a stepped portion 91 having the same shape as that of the heat sink 7 formed above the opening 90 in the insulating substrate 9. Bottom surface 9 of step 91
A heat sink 7 is attached to the sheet 10 via an adhesive sheet 65. Further, between the side surface 70 of the heat sink 7 and the upper surface of the insulating substrate 9, the synthetic resin 1 is used as in the first embodiment.
Are glued by. Others are the same as in the first embodiment.

In this example, the heat sink 7 has a step 9
It is installed in 1. Therefore, as shown in Figure 5,
The side surface 70 of the heat sink 7 and the insulating substrate 9 can be bonded with a small amount of synthetic resin 1. Further, the heat sink 7 can be more firmly fixed to the insulating substrate 9. In addition, the same effect as that of the first embodiment can be obtained.

Example 3 The electronic component mounting substrate of this example is a multilayer substrate in which insulating substrates 98 and 99 are laminated as shown in FIG. Insulating substrate 9
An opening 90 is formed in the insulating substrate 9
8 has a step portion 91 for inserting the heat sink 7. The insulating substrate 98 and the insulating substrate 99 are adhered by a prepreg. An inner layer circuit 995 is formed on the surface of the insulating substrate 99 between the insulating substrate 99 and the insulating substrate 98. Others are the same as those in the second embodiment. Also in this example, the same effect as in Example 2 can be obtained.

Embodiment 4 As shown in FIG. 7, the electronic component mounting substrate of this embodiment has a step 911 larger than the heat sink 7 formed above the opening 90 of the insulating substrate 9. The heat sink 7 is inserted in the step 911. The side surface 70 of the heat sink 7 and the step 911 of the insulating substrate 9 are bonded by the synthetic resin 1. Others are the same as those in the second embodiment.
Also in this example, the same effect as in Example 2 can be obtained. Further, in this example, the heat sink 7 can be inserted and attached within the thickness of the insulating substrate 9.

Embodiment 5 As shown in FIGS. 8 to 10, the electronic component mounting substrate of this embodiment is such that the space between the side surface 70 of the heat sink 7 and the insulating substrate 9 is
The synthetic resin 1 is partially adhered to the side surface 70 at four points near the center of each side. As shown in FIG. 10, the electronic component 3 is mounted in the recess 900, and the electronic component 3 is mounted.
And the wiring pattern 59 are electrically connected by the wire 30. The surface of the electronic component mounting substrate including the side surface 70 of the heat sink 7 is covered with the sealing resin 8.
Others are the same as in the first embodiment.

In this example, the electronic component 3 is placed in the recess 900.
After mounting, the entire surface of the insulating substrate is covered with the sealing resin 8. Therefore, it is possible to prevent moisture from entering the recess 900. In addition, the same effect as that of the first embodiment can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an electronic component mounting board according to a first embodiment.

FIG. 2 is a perspective view of the electronic component mounting board according to the first embodiment.

FIG. 3 is a plan view of the electronic component mounting board according to the first embodiment.

FIG. 4 is an explanatory view showing a manufacturing process of the electronic component mounting substrate of the first embodiment.

FIG. 5 is a cross-sectional view of an electronic component mounting board according to a second embodiment.

FIG. 6 is a sectional view of an electronic component mounting board according to a third embodiment.

FIG. 7 is a cross-sectional view of an electronic component mounting board according to a fourth embodiment.

FIG. 8 is a plan view of an electronic component mounting board according to a fifth embodiment.

9 is a sectional view taken along the line AA of FIG.

FIG. 10 is a cross-sectional view of an electronic component mounting substrate covered with a sealing resin according to a fifth embodiment.

FIG. 11 is a cross-sectional view of a conventional electronic component mounting substrate.

FIG. 12 is a plan view of a conventional electronic component mounting board.

FIG. 13 is an enlarged cross-sectional view of a main part of an electronic component mounting board, showing the problems of the conventional example.

[Explanation of symbols]

 1. ． ． Synthetic resin, 3. ． ． Electronic components, 59. ． ． Wiring pattern, 65. ． ． Adhesive sheet, 7. ． ． Heat sink, 70. ． ． Side, 8. ． ． Sealing resin, 9, 98, 99. ． ． Insulating substrate, 90. ． ． Opening, 900. ． ． Recess, 91, 92. ． ． Step, 95. ． ． Through hole,

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location // H05K 1/02 F 7047-4E 1/18 M 7128-4E

Claims (3)

[Claims] 1. An insulating substrate, an opening provided in the insulating substrate, a heat sink adhered to cover one end of the opening, and a recess for mounting an electronic component formed by the heat sink and the opening. An electronic component mounting substrate having: a side surface of the heat sink and an insulating substrate are bonded by a synthetic resin. 2. The electronic component mounting substrate according to claim 1, wherein the side surface of the heat sink and the insulating substrate are partially bonded by a synthetic resin. 3. An insulating substrate, an opening provided in the insulating substrate, a heat sink adhered to cover one end of the opening, and a recess for mounting an electronic component formed by the heat sink and the opening. In a method of manufacturing an electronic component mounting board having: an electronic component mounting method, wherein the heat sink is fixed to an insulating substrate in advance, and then a side surface of the heat sink is bonded to the insulating substrate with a synthetic resin. Substrate manufacturing method.