JP2753764B2 - Substrate for mounting electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a board for mounting electronic components in which a heat sink and a ground circuit or a power supply circuit have low inductance.

(Prior art)

As shown in FIG.
A heat sink 8 mounted via an adhesive 98 in a recess 90 provided below the insulating base material 91; an electronic component mounting recess 70 provided above the heat sink 8; And a ground circuit 92 provided on the upper surface of the device. Note that the ground circuit 92 may be used as a power supply circuit. In the same figure, reference numeral 94 denotes a signal circuit, 95 denotes a through hole, and 96 denotes a conductor pin.

Also, the electronic component 7 mounted in the electronic component mounting recess 70 is provided.
And the ground circuit 92 are connected by a bonding wire 71. Thus, the ground electrode of the electronic component 7 is grounded via the bonding wire 71, the ground circuit 92 on the upper surface of the insulating base material, the through hole 95, and the conductor pin 96.

Further, a bonding wire 71 is connected between the signal circuit 94 and the electronic component 7.

[Problem to be solved]

However, in the conventional electronic component mounting board, since the ground circuit 92 is provided on the surface of the insulating base material, the space in which the signal circuit 94 is provided is limited. In particular, since the ground circuit and the power supply circuit need to be low inductance (magnetic induction coefficient) circuits, it is desired that the circuit pattern be as wide as possible.

When a resin-based insulating substrate such as a glass epoxy substrate is used as the insulating substrate 91, moisture may enter the sidewalls of the electronic component mounting recess 70 from outside the insulating substrate. This moisture has an adverse effect on the power supply circuit. Therefore, the above-mentioned recess is required to have moisture resistance.

In the conventional electronic component mounting board, heat generated from the electronic component 7 is radiated through the upper surface of the heat radiating plate 8. However, its heat dissipation is not sufficient. Especially,
In recent years, high-power electronic components have been used, and improvements in heat dissipation have been demanded.

In view of the above problems, the present invention can reduce the inductance of a grounding circuit or a power supply circuit, and can achieve moisture resistance,
It is an object of the present invention to provide an electronic component mounting board excellent in heat dissipation.

[Solutions to solve the problem]

The present invention relates to an insulating substrate having a through hole for forming an electronic component mounting recess, a conductive circuit and a through hole, and a heat radiating member joined to the entire back surface of the insulating substrate via an insulating adhesive layer. A conductive plating layer for a power supply circuit or a grounding circuit formed from the side wall of the through hole to the back side of the insulating base, and the heat sink is provided with the through hole. An electronic component mounting recess having a diameter larger than the through hole at a position corresponding to the electronic component, and an electronic component mounting recess formed by the through hole of the insulating base and the upper surface of the heat sink. It is on the mounting board.

In the present invention, it is most remarkable that the conductive plating layer is provided on the insulating base material from the side wall to the back surface of the through hole, and a heat sink is joined to the rear surface of the insulating base material. This is because the relief hole is provided.

The conductive plating layer is used as a power supply circuit or a ground circuit, and is formed from the side wall of the through hole to the back side of the insulating base as described above. The conductive plating layer is provided on the entire side wall of the through hole. The conductive plating layer on the back side is provided so as to communicate with, for example, a through hole for a power circuit or a ground circuit.

The relief hole provided in the heat sink is a hole having a diameter larger than that of the through hole at a position corresponding to the through hole. The relief hole is a hole for facilitating cleaning of the inside of the through-hole, and for facilitating the permeation of the solder for joining into the inner wall of the through-hole when the conductor pin is inserted from the insulating base material side into the through-hole. is there.

The electronic component mounting board is manufactured, for example, as follows. First, the through hole and the through hole are formed in an insulating base material. Then, panel plating (also called through-hole plating) is performed on the entire surface of the insulating base including the through-holes and the inner wall surfaces of the through-holes. Thereafter, a conductive circuit such as a ground circuit or a power supply circuit or a signal circuit is formed on the surface of the insulating base material by an ordinary method. At this time, a conductive plating layer for a ground circuit or a power supply circuit is formed.

Thereafter, a heat sink is bonded to the back surface of the insulating base via an insulating adhesive layer such as an adhesive sheet or prepreg. Thus, a recess for mounting an electronic component is formed by the through hole of the insulating base material and the heat sink. In addition, it is preferable that the insulating adhesive layer has a portion corresponding to the through hole and the through hole previously opened.

As the metal plating layer for the conductive plating layer,
Copper, nickel, nickel-metal, or the like is used. The thickness of the conductive plating layer is preferably set to 10 to 40 μm.

[Action and effect]

In the present invention, the conductive plating layer is provided on the side wall and the back surface side of the through hole in the insulating base material. Therefore, the conductive plating layer is first formed with a wide area on the side wall of the through hole, and is formed as an arbitrary wide pattern on the back side of the insulating base material. Therefore, the conductive plating layer can be a circuit with low inductance.

Further, since the wall surface of the through hole is covered with the conductive plating layer, there is no possibility that moisture may enter the electronic component mounting recess through the insulating base material.

Further, the heat radiating plate is disposed on the entire back surface of the insulating base material. Therefore, the electronic component mounting board of the present invention is also excellent in heat dissipation. In addition, the above-mentioned relief hole communicating with the through-hole is provided in the heat sink, and the diameter of the relief hole is made larger than the diameter of the through-hole, so that the inspection of the pin connection is easy, and the short-circuit between the pin and the heat sink is shorted. Can be prevented.

As described above, according to the present invention, the inductance of the grounding circuit and the power supply circuit can be reduced, and the moisture resistance,
An electronic component mounting board excellent in heat dissipation can be provided.

〔Example〕

First Embodiment An electronic component mounting board according to an embodiment of the present invention will be described.
This will be described with reference to FIGS.

As shown in FIG. 1, the electronic component mounting board 1 of this embodiment has a through hole 13 for forming an electronic component mounting recess 130.
Base material 10 having a signal circuit 18 and a through hole 15
And a heat radiating plate 2 joined to the entire back surface (lower side) of the insulating base material 10 via an insulating adhesive layer 3. Then, the insulating base material 10 is inserted into the insulating base material 10 from the side wall of the through hole 13.
Conductive plating layer 16 for the ground circuit formed on the back side of
Having.

In addition, the radiator plate 2 has a relief hole having a diameter larger than that of the through hole 15 at a position corresponding to the through hole 15.
With 21. The through hole 13 of the insulating base material 10 and the upper surface of the heat sink 2 form an electronic component mounting recess 130.

As shown in FIGS. 1 and 2, the side wall of the through hole 13 has a square shape, and the side wall is covered with a side wall conductive plating layer 161. On the back side of the insulating base material, a back side conductive plating layer 162 is provided.
It is formed to extend between 61 and the through hole 15 for the ground circuit.

Further, a solder resist 19 is provided on the backside conductive plating layer 162 on the backside of the insulating base material 10. Further, the side wall conductive plating layer 161 of the through hole 13, a part of the upper surface of the heat sink forming the lower surface of the recess 130, and the signal circuit 18.
The gold plating layer 4 is formed on each surface of the through hole 15 via a nickel layer.

The insulating adhesive layer 3 has an opening 31 having a diameter larger than the opening diameter of the through hole 13. Further, it has an opening 32 which is larger than the through hole 15 and is similar to the escape hole 21 of the heat sink 2.

In the above description, a glass cloth epoxy resin substrate was used as the insulating base material 10, and a copper plate having a thickness of 0.5 mm was used as the heat sink.
The insulating adhesive layer is made of prepreg material and has a thickness of about 0.1 mm.
And The conductive plating layer was formed of copper to a thickness of 25 μm. The diameter of the through hole was 0.6 mm, and the diameter of the clearance hole of the heat sink 2 was 1.6 mm.

Further, as shown in FIG. 3, the electronic component 50 is mounted in the electronic component mounting recess 130 on the electronic component mounting board 1 configured as described above. Then, bonding wires 51 and 52 are connected between the electronic component 50 and the conductive plating layer 16 and between the electronic component 50 and the signal circuit 18. The head of the conductor pin 56 is inserted into the through hole 15 from the recess 130 side.

 Next, the operation and effect will be described.

In the electronic component mounting board of the present embodiment, as shown in FIG. 1, a conductive plating layer 16 is formed between the side wall of the through hole 13 in the insulating base material 10 and the back side. Therefore, the conductive plating layer 16 can occupy a large area on the side wall of the through hole 13 and on the back side of the insulating base material 10. Therefore,
The conductive plating layer 16 can be a low inductance circuit.

The through-hole 13 has a wall surface formed by the conductive plating layer.
Since it is covered with 16, the recess 130
Moisture does not penetrate through the insulating base material. Therefore, it has excellent moisture resistance.

Further, since the heat radiating plate 2 is provided on the entire back surface of the insulating base material 10, the heat generated by the electronic components can be efficiently dissipated.

Second Embodiment A method of manufacturing the electronic component mounting board shown in the first embodiment will be described with reference to FIGS. 4A to 4E.

First, as shown in FIG. 4A, a copper-clad glass cloth epoxy resin substrate as an insulating base material 10 is prepared. Copper foils 11, 11 are formed on the upper and lower surfaces of the insulating base material 10, respectively. Next, as shown in FIG. 4B, a through hole 13 for forming the recess is formed in the insulating base material 10.
And a large number of through holes 15 are formed.

Then, as shown in FIG. 4C, the entire surface of the insulating base material 10, that is, the through holes 13, the through holes 15, and the upper and lower surfaces of the insulating base material are subjected to panel plating by two-step plating of electroless plating and electrolytic plating. Form a copper plating layer.

Then, the photoresist, etching,
Solder resist printing is performed, and as shown in FIG. 4D, a conductive plating layer 16 is formed on the side wall and the back side of the through hole 13 in the insulating base material 10. At the same time, the signal circuit 18 is formed. Further, the back side conductive plating layer 16 on the back side of the insulating base material 10.
A solder resist film 19 is formed on the surface of 2, the surface of the signal circuit 18, and the like.

On the other hand, separately from the insulating base material 10, a heat sink 2 and a sheet-like insulating adhesive layer 3 are prepared as shown in FIG. 4E.
The heat sink 2 has a relief hole 21 having a diameter larger than that of the through hole 15 of the insulating base material 10. The relief holes 21 are provided in large numbers at positions corresponding to the through holes 15. The insulating adhesive layer 3 has an opening 31 having the same diameter as the through hole 13 of the insulating base material.
And an opening 32 having the same shape as the escape hole 21 of the heat sink 2.

Thereafter, the heat radiating plate 2 is laminated on the back surface of the insulating base material 10 shown in FIG. 4D via the insulating adhesive layer 3, and these are heat-pressed. Further, after that, a nickel plating is applied, and then a gold plating layer 4 is applied. As a result, the electronic component mounting board 1 (FIG. 1) in which the above three members are integrally fixed is obtained.

According to this embodiment, the electronic component mounting board 1 can be easily manufactured.

In the above embodiment, the example in which the conductive plating layer 16 is used as a ground circuit has been described. However, it is needless to say that the conductive plating layer 16 can be used as a power supply circuit instead of the ground circuit.

[Brief description of the drawings]

1 to 3 show an electronic component mounting board according to the first embodiment. FIG. 1 is a cross-sectional view, FIG. 2 is a rear view thereof, and FIG. Figure,
FIGS. 4A to 4E are manufacturing process diagrams of the second embodiment, and FIGS.
The figure is a sectional view of a conventional electronic component mounting substrate. DESCRIPTION OF SYMBOLS 1 ... Electronic component mounting board, 10 ... Insulating base material, 13 ... Through hole, 130 ... Electronic component mounting recess, 15 ... Through hole, 16 ... Conducting plating layer, 2 ... Heat sink , 21 ... escape hole, 3 ... insulating adhesive layer, 4 ... gold plating layer,

Claims (1)

(57) [Claims] An insulating base material having a through hole for forming an electronic component mounting recess, a conductive circuit and a through hole, and an insulating adhesive layer bonded to the entire back surface of the insulating base material. A conductive plate layer for a power supply circuit or a ground circuit formed from the side wall of the through hole to the back surface side of the insulating base material; An electronic device characterized in that an escape hole having a diameter larger than that of a through hole is provided at a position corresponding to the hole, and a recess for mounting an electronic component is formed by the through hole of the insulating base and the upper surface of the heat sink. Component mounting board.