JPH0442989A - Electronic component placing board and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a compact electronic component placing board having excellent heat dissipation, moisture resistance by providing heat dissipating upper and lower metal layers in an insulating base material, thermally connecting both via an inner viahole, and thermally connecting the lower metal layer to a heat dissipating metal layer provided on the rear surface side of the base material through a recess heat transfer part. CONSTITUTION:Two layers of heat dissipating upper and lower metal layers 1, 2 are isolated to be arranged in an insulating base material 3. A heat dissipating metal layer 45 is provided on the rear surface side of the material 3. The layer 1 is connected to a metal plated layer 41 of a recess 4, and the layer 1 is connected to the layer 2 via an inner viahole 5 formed with a metal plated layer 51. The layer 4 is connected to the layer 45 via a recess heat transfer part 6 formed with a metal plated layer 61.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a substrate for mounting electronic components that can efficiently dissipate heat generated from electronic components such as semiconductors.

[Prior Art] An electronic component mounting board has an electronic component such as a semiconductor mounted in a recess on the surface of an insulating base material, and a conductor circuit is formed on the surface of the insulating base material.

+ SN insulation base materials include those made of synthetic resin and those made of ceramics.The former synthetic resin insulation base material is cheaper, lighter, and easier to process than ceramic insulation base materials. It is excellent in terms of ease of use, etc.

However, the thermal conductivity of the 9 synthetic resin insulating base material is about 1/100 of that of the ceramic insulating base material, which is very low. Therefore, the 2-synthetic resin insulating base material is not suitable as a substrate for mounting a semiconductor element that generates high heat.

Therefore, electronic component mounting boards using heat sinks have been proposed to improve heat dissipation (for example, Japanese Patent Laid-Open No. 60
-136348). As shown in FIG. 5, this device has a
A metal heat sink 81 is provided. The electronic component 93 and the heat sink 81 are bonded by an adhesive 94, and the insulation 1[9o and the heat sink 81 are bonded by an adhesive 82.

Note that a conductor circuit is formed in the through hole 92 provided in the insulating base material 90 and its surroundings by a plating layer 91 of copper or the like. Further, the head of a lead pin 96 is inserted into the through hole 92 with the plating layer 91 interposed therebetween. Moreover, the code|symbol 98 is a bonding wire. Note that two figures are not shown.

The outer periphery of the electronic component 93 is sealed with resin to prevent moisture from entering.

Further, as shown in FIG. 6, a recess 97 is provided below the insulating base material 90, a heat sink 83 is placed in the recess 97, and an electronic component 93 is attached to the upper surface of the heat sink 83 using an adhesive 9.
A substrate for mounting electronic components bonded by 2 has also been proposed.

In manufacturing this board, first, a recess 97 is provided below the insulating base material 90, a heat sink 83 is placed therein via an adhesive 84, and the recesses 97 are pressed together.

Further, the electronic component mounting portion of the insulating base material 90 is cut from above to expose the upper surface of the heat sink 83. After that, a plating layer 91 is applied to the back surface of the through hole 92 and the heat sink 83. Then, the electronic component 93 is bonded onto the heat sink 83. Others are
This is the same as the case shown in FIG. 5 above.

[Problem to be solved]

However, in the case of the former substrate to which the heat sink 81 is bonded (FIG. 5), the area of the metal heat sink 81 is large, so the heat dissipation is excellent, but the heat sink 81 is
Since the adhesive 82 is interposed between 1 and the insulating base material 90, the airtightness is poor (.

Poor moisture resistance.

That is, moisture enters the electronic component 93 from between the adhesives 82 and the electronic component 9 deteriorates. Furthermore, the adhesive 82 bonding the heat sink 81 and the insulating base material 90 is
Since the difference in coefficient of thermal expansion with the heat sink 81 is large, the heat sink 81 is likely to peel off from the insulating base material 90 due to temperature cycles between high and low temperatures.

On the other hand, in the case of the latter substrate (FIG. 6) in which the heat sink 83 is disposed in the recess 97, the recess 97 is provided in the insulating base material 90 in advance as described above, and the heat sink 83 and the insulating base are It requires complicated and precise processing such as joining the heat sink 83 to the heat sink 90 and then cutting the electronic component mounting portion to expose the upper surface of the heat sink 83.

Moreover, this results in high costs. Furthermore, the area of the heat sink 83 must be larger than that of the electronic component 93.

In view of the problems of the prior art, the present invention provides heat dissipation,
The aim is to provide a circuit board equipped with electronic components that is highly moisture resistant and compact.

(Means for Solving the Problems) The present invention provides a substrate for mounting electronic components, in which a recess for mounting electronic components is provided in an insulating base material provided with a conductor circuit, and a metal plating layer is applied to the inner surface of the recess. The electronic component mounting board has two layers, an upper metal layer and a lower metal layer for heat dissipation, spaced apart from each other inside the insulating base material, and a heat dissipation metal layer on the back side of the insulating base material. The upper metal layer is connected to the metal plating layer in the recess, the upper metal layer and the lower metal layer are connected by an inner via hole provided with a metal plating layer, and the lower metal layer is connected to the metal plating layer in the recess. The patented component mounting board is characterized in that the heat dissipating metal layer and the heat dissipating metal layer are connected by a concave heat transfer portion provided with a metal plating layer.

The most noteworthy feature of the present invention (2) is that a -L metal layer for heat dissipation and a lower metal layer for heat dissipation are provided inside the insulating base material, and the two are thermally connected by an inner via hole. ．Also, the lower metal layer is the insulating base material ν(!?
Set on 11! The first and second parts are thermally connected to the heat dissipating metal layer by a concave heat transfer part.

The first metal layer is disposed on the inner surface of the insulating base material, that is, on the side closer to the recess.

Further, the lower metal layer is disposed inside the insulating base material J, and in a portion M near the back side thereof. Part 1 to Part 1 The upper metal layer and the lower metal layer are spaced apart from each other by j7.

The two-part metal layer and the lower metal layer are formed by copper foil provided on both lower surfaces of the copper-clad insulating base material, for example, by providing prepreg layers on the top and bottom of the copper-clad insulating base material,
From this, an upper metal layer and a lower metal layer are formed inside (
(See Figure 3C).

In addition, the upper metal layer and the lower metal layer are coated with two metal plates. Thermal connection via the inner via hole
The inner via hole 9 has a cylindrical shape, for example. Further, a large number of inner via holes are provided, for example, at an outer position of a recess for mounting an electronic component so as to surround the recess.

Further, the heat dissipation metal layer is placed on the back side of the insulating base material.

For example, applying a metal plating layer such as copper? , formed from this. The 1M heat dissipation metal layer and the lower metal layer marked -Y are thermally connected through the concave heat transfer portion ζ- provided with a metal coating layer. Further, the formation of the heat dissipating metal layer and the metal coating layer extending into the concave heat transfer portion can be performed simultaneously.

In addition, the concave heat transfer portion 9 may be provided with a large number of single cylindrical bodies, such as blind via holes.
(FIG. 4), or by forming an annular groove that is wider than the recess of the electronic component mounting board (FIG. 2).

Furthermore, the heat dissipation metal layer may be provided with a heat dissipation fin that is normally used for heat dissipation.

Furthermore, the present invention can be applied to various insulating base materials such as synthetic resins and ceramics. The above-mentioned method for manufacturing the board for mounting electronic components includes using a laminated plate having an upper metal layer and a lower metal layer on both upper and lower surfaces of an internal insulating base material, forming an inner via hole in the laminated plate, and forming an inner via hole in the laminated plate. A metal plating layer is formed in the via hole, and then a metal foil layer is heat-bonded to the upper F of the laminate via a blib 1/g layer, and then the electronic component reaches upward to the above-mentioned F part metal layer. Forming a recess for mounting by counterboring 1
-1. Manufacturing a board for mounting electronic components, characterized in that: (1) a concave heat transfer portion reaching the lower metal layer is formed below, and (2) a metal plating layer is formed on the concave portion and the concave heat transfer portion. There is a way.

In the above, a metal layer such as a copper foil layer is used as the upper metal layer, the lower metal layer, and the metal foil layer. Further, examples of the metal coating layer include copper plating, nickel metal, 7-gold metal, and the like.

In addition, the internal insulation base material is a glass epoxy resin substrate,
Glass] - There are riazine resin substrates, glass polyimide resin substrates, etc.

Further, as Brib 1/g, epoxy Brib I/Gtriazine Brib leg, polyimide prepreg, etc. are used.

[Operations and Effects] In the electronic component mounting board of the present invention, when the mounted electronic component generates heat, this heat is transferred from the metal plating layer formed on the inner surface of the recess for electronic component mounting to the upper metal layer for heat dissipation. communicated. Then, the nuclear heat is transferred from the metal plating layer of the inner via hole to the lower metal layer for heat dissipation, and further transferred to the heat dissipation metal layer on the back side through the metal plating layer of the concave heat transfer part such as the blind via hole. . That is, the in-server via hole and the concave heat transfer portion serve as a heat vibrator.

Next, the heat transferred to this heat dissipation metal layer is m1Ti′
Heat is radiated into the atmosphere from the i side. Since this heat dissipation metal layer is provided on the back side of the insulating base material, it has a large area. Therefore, heat is efficiently radiated from the heat-radiating gold WAM.

Further, 1. The inside of the recess mentioned above is coated with a metal plating layer, and furthermore, the inner via ball, the recessed heat transfer portion, and the heat dissipation metal layer are all formed of a metal layer such as a metal plating layer.

Therefore, there is no resin adhesive between the inside of the recess and the back side of the insulating base material as in the prior art, and therefore, moisture does not infiltrate into the recess from the back side of the insulating base material. Note that, after mounting the electronic components as described above, the recess side is sealed with resin to prevent moisture from entering.

In addition, as mentioned above, the metal plating layer inside the recess is connected to the upper metal layer, inner via hole, lower metal layer, recessed heat transfer part, and heat dissipation metal layer, so there is no electrical continuity between them. It is planned.

Therefore, these metal layers can also be used as a power supply circuit or a ground circuit.

Further, in the second invention, unlike the conventional method, a heat sink is not used, so that the thickness of the entire electronic component mounting board can be suppressed to the thickness of the insulating base material.

It is thin and compact.

Therefore, according to the present invention, it is possible to provide a compact electronic component mounting board that has excellent heat dissipation properties and moisture resistance.

Moreover, according to the above manufacturing method, it is possible to easily manufacture the excellent electronic component mounting substrate as described above.

〔Example〕

First Embodiment An electronic component mounting board according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3F.

As shown in FIGS. 1 and 2, the substrate for mounting electronic components of this example has a recess 4 for mounting electronic components in an insulating base material 3 provided with a conductor circuit 440, and an inner surface of the recess 4. A metal plating layer 41 is applied to the surface. Inside the insulating base material 3, two layers, an upper metal layer 1 for heat radiation and a lower metal layer 2 for heat radiation, are arranged spaced apart from each other.

Furthermore, a heat dissipating metal layer 45 is provided on the back side of the insulating base material 3. Further, the upper metal layer 1 is connected to the metal plating layer 41 of the recess 4, and the upper metal layer 1 and the lower metal layer 2
is an inner via hole 5 coated with a metal plating layer 51.
connected by. Further, the lower metal layer 2 and the heat dissipating metal layer 45 are connected by a concave heat transfer portion 6 provided with a metal plating layer 61.

Further, the concave heat transfer portion 6 is formed by an annular groove as shown in FIG. In addition, in Figures 1 and 2,
Reference numeral 92 is a through hole for inserting a conductor pin.

Next, regarding the manufacturing method of the above-mentioned electronic component mounting board, the third
This will be explained using Figures A to 3F.

First, as shown in FIG. 3A, a copper-clad laminate 30 is prepared. In the copper-clad laminate 30, the tp and Vi layers on the upper surface form the upper metal layer 1 according to the present invention, and the copper foil layer on the lower surface forms the lower metal layer 2.

Further, an internal insulating base material 31 made of a glass epoxy substrate is provided between the upper metal layer 1 and the lower metal layer 2.

Next, as shown in FIG. 3B, inner via holes 5 are bored in the copper-clad laminate 30. Then, a metal plating layer 51 is formed inside the inner via hole 5. Further, the upper and lower surfaces are etched to form land metal layers 13 and 23 for through holes 92, which will be described later.

Next, as shown in FIG. 3C, a copper foil layer 44. A heat dissipating metal layer 45 is provided.

The heat dissipation metal layer 45 is made of copper foil.

Then, as shown in FIG. 3D, these are pressed under pressure to form a laminate 301. As a result, the inside of the inner via hole 5 is also filled with the prepreg 33. In addition, the insulating base material 3 in the laminate 301 is the internal insulating base material 3
1 and upper and lower prepregs 3333.

Thereafter, as shown in FIG. 3E, a counterbore is formed above the laminated plate 301 to provide a recess 4 for mounting the eleventh child component. The recess 4 penetrates the upper metal layer 1 and reaches the inner insulating base 31 . Also.

Below the laminated plate 301, a concave heat transfer portion 6 is formed outwardly from the inner via hole 5 by counterboring. Furthermore, a through hole 92 is bored.

Thereafter, as shown in FIG. 3F, by applying a copper metal plating layer to the entire surface of the laminate 301, the metal plating layer 4 is applied inside the recess 4, inside the concave heat transfer part 6, and inside the through hole 92.
1,61.921 is formed. Then, 9
The copper foil layer 44 on the front side is etched to form a conductor circuit 440.
form.

Through this process, the electronic component mounting board shown in FIG. 1 is obtained.

In the electronic component mounting board of this example, the heat generated by the electronic component (not shown) mounted in the recess 4 is transferred to the metal plating layer 41 of the recess 4. ”Partial metal layer 1. Inner via hole 5
metal plating layer 51. Lower metal! 2. The heat dissipating metal layer 45 is emitted through the metal coating layer 61 of the concave heat transfer section 6. Since the heat dissipation metal layer 45 is widely formed on the back side of the electronic component mounting board, it has excellent heat dissipation properties.

Moreover, the inside of the recess 4 is coated with a metal plating layer 41,
Inner via hole 5. Concave heat transfer part 6 heat dissipation metal layer 45
are all metal layers. Therefore, moisture does not enter into the recess 4 from the back side of the insulating base material. Note that the recess 4 side is sealed with resin to prevent moisture after electronic components are mounted.

Further, the metal plating layer 41 in the recess is the L part gold rjA layer 1.
Inner via hole 5. Lower metal layer 2. Concave heat transfer part 6
．． All of the metal layers 45 and 45 are connected by metal (, -), and electrical continuity is obtained between them. Therefore, these metal layers can also be used as a power supply circuit or a ground circuit.

Moreover, according to the above manufacturing method j, the electronic component mounting board can be easily manufactured.

In addition, there is no need to use a large-area heat sink like in the past, so the entire board for mounting electronic components can be placed in a compact space.
becomes −.

Second Embodiment The electronic component mounting board of this example is as shown in Figure 4 (
A concave heat transfer section 65 consisting of two cylindrical blind via holes instead of the concave heat transfer section 6 of the annular groove in the first embodiment.
The other features are the same as those in the first embodiment.

According to this example, effects similar to those of the first example can be obtained.

[Brief explanation of drawings]

Figures 1 to 3F show the electronic component mounting board of the first embodiment; Figure 1 is a sectional view thereof; Figure 2 is a partially cutaway back view;
Figures 3A and 1 to 3F are manufacturing steps. Figure 4 is a cross-sectional view of the electronic component mounting board of the second embodiment, and Figures 5 and 6 are cross-sectional views of the conventional electronic component mounting board. be. Figure 1 I. 3゜31゜4゜41゜45゜5゜Top metal layer. Bottom metal layer insulation base material internal insulation irrigation prepreg. Recess 61... Metal plating layer. , heat dissipation metal layer, inner via hole 65, , concave heat transfer section. Figure 2 Figure 2 Construction drawing Figure 4 Figure Construction drawing Figure 5

Claims (2)

[Claims] (1) A board for mounting an electronic component, which has a recess for mounting an electronic component on an insulating base material provided with a conductor circuit, and a metal plating layer is applied to the inner surface of the recess. has two layers, an upper metal layer and a lower metal layer for heat dissipation, spaced apart from each other inside the insulating base material, and has a heat dissipation metal layer on the back side of the insulating base material. The metal layer is connected to the metal plating layer in the recess, the upper metal layer and the lower metal layer are connected by an inner via hole provided with a metal plating layer, and the lower metal layer and the heat dissipation metal layer are connected to the metal plating layer. A board for mounting electronic components, characterized by being connected by a concave heat transfer portion coated with a plating layer. (2) Using a laminated plate having an upper metal layer and a lower metal layer on both upper and lower surfaces of an internal insulating base material, an inner via hole is bored in the laminated plate, and a metal plating layer is formed in the inner via hole. Next, a metal foil layer is heat-bonded to the top and bottom of the laminate via a prepreg layer, and then a recess for mounting electronic components that reaches the upper metal layer is formed by counterbore processing, and a recess for mounting an electronic component is formed in the lower part by counterboring. 1. A method of manufacturing a substrate for mounting electronic components, comprising forming a concave heat transfer portion reaching a metal layer, and then forming a metal plating layer on the concave portion and the concave heat transfer portion.