JPH0430497A - Printed wiring board unit - Google Patents

Abstract

PURPOSE:To make a printed wiring board unit small in size by a method wherein a heat dissipating block is provided only to a position correspondent to a semiconductor component, and I/O sections are provided to the surface of an insulating board on which the heat dissipating block is bonded. CONSTITUTION:I/O pins 46 used for electrically connecting a semiconductor module 48 with a printed wiring board can be arranged not only on the periphery of the insulating board 32 but also on the comparatively inside part of the board 32. Therefore, pads or the like used for electrically connecting the module 48 with the wiring board 44 are not required to be provided outside the component mounting area of the module 48, so that the board 44 can be made small in size. The thickness of a printed wiring board unit conforms to that of the module 48, so that it can be formed thinner than usual. A heat dissipating block 42 is provided only to a part of the board 32 where semiconductor component is provided, so that a base is small in area, and when the block 42 is bonded to the board 32, air bubbles are hardly induced in adhesive agent and a printed wiring board can be prevented from deteriorating in heat dissipating property due to the air bubbles concerned.

Description

[Detailed Description of the Invention] Summary Regarding a printed wiring board unit in which a semiconductor module with heat generating components is further mounted on a printed wiring board, for the purpose of downsizing the printed wiring board unit, a semiconductor module is mounted on one side of an insulating board. A heat dissipation system in which a semiconductor component is mounted, a multilayer wiring thin film is formed, a cap is attached to collectively seal the semiconductor component and the multilayer wiring thin film, and a plurality of heat dissipation protrusions are formed on one surface of the base part. In a printed wiring board unit in which a semiconductor module configured by bonding the base portion of the block to the other surface of the insulating substrate is mounted on a printed wiring board, a heat dissipation block bonded to the insulating substrate; A plurality of I/O parts are provided only at positions corresponding to the semiconductor components and electrically connect the semiconductor module and the printed wiring board, and a plurality of I/O parts are provided on the other surface of the insulating substrate, and the printed wiring board A punching portion is formed through which a heat radiation block bonded to the insulating substrate can pass, and the semiconductor module is mounted on a printed wiring board with the heat radiation block passing through the punching portion.

INDUSTRIAL APPLICATION FIELD The present invention relates to a printed wiring board unit formed by mounting a semiconductor module on which a heat generating component is mounted on a printed wiring board.

In vertical mounting of printed wiring boards such as communication equipment, multiple electronic components such as IC5LSI are mounted on the printed wiring board to form a printed wiring board unit (electronic circuit package), and multiple printed wiring board units is inserted along a guide rail provided on the shelf and plug-in connected to a back wiring board via a connector, thereby configuring an electronic device such as a communication device. In these electronic devices, due to the demand for miniaturization, semiconductor components such as IC5LS■ are being mounted in high density, and the heat generated by the semiconductor components increases the temperature inside the electronic device.
It is necessary to suppress this temperature rise. There is a demand for miniaturization of printed wiring board units in which semiconductor modules mounted with heat-generating components such as LSIs are mounted on printed wiring boards without reducing heat dissipation efficiency.

Prior Art FIG. 5 is a perspective view of a conventional example in which a semiconductor module prototyped by the present inventors is mounted on a printed wiring board, and FIG. 6 is an exploded sectional view of the semiconductor module portion of FIG. 5. The printed wiring board unit 2 is configured by mounting four semiconductor modules 6 on a printed wiring board 4, and plugs this printed wiring board unit 2 into a back wiring board (not shown) via one or more connectors 8. The electronic device is configured by making the in-connection.

The semiconductor module 6 is constructed as shown in FIG. That is, a multilayer wiring thin film 12 in which copper and polyimide are alternately laminated is formed on a ceramic substrate 10, an LSI pair chip 14 is bonded on the ceramic substrate 10 with a bonding adhesive, and a chip component 16 is bonded on the multilayer wiring thin film 12. The pads of the LSI 14 and the pads of the multilayer wiring thin film 12 are connected by bonding wires 15. External connection pads 18 are formed on the outer peripheral surface of the ceramic substrate 10 . The LSI 14 and the multilayer wiring thin film 12 are collectively sealed with a cap 20, and the inside of the cap 20 is filled with nitrogen gas.

A heat dissipation block 22 is bonded to the back surface of the ceramic substrate 10 using an adhesive such as silver-epoxy. The reason why the multilayer wiring thin film 12 made of alternating layers of copper and polyimide is formed on the ceramic substrate 10 is because it is not possible to directly form a miniaturized pattern corresponding to the number of LSI pads on the ceramic substrate 10. Approximately 1 on 10
Although only a pattern of approximately 25 μm can be formed on the multilayer wiring thin film 12, a fine pattern of approximately 25 μm can be formed.

A connector block 24 with a built-in spring contact 26 is mounted on the printed wiring board 4, and the semiconductor module 6 is attached to the printed wiring board 4 by aligning the holding metal fittings 28 and 30 from above and below the printed wiring board 4. It will be installed. LS 114 and chip components 16 mounted on the conductor pattern of the printed wiring board 4 and the ceramic substrate 10
The electrical connection is achieved by the spring contact 26 coming into pressure contact with the external connection pad 18.

FIG. 7 schematically shows the adhesion state of the heat dissipation block 22 of the semiconductor module 6, and the heat dissipation block 22 is bonded to the ceramic substrate 1 by a thermally conductive silicone adhesive 21.
is glued to. Further, the LS 114 is bonded to the ceramic substrate 10 with a silver-epoxy adhesive 13, and the cap 20 is similarly bonded to the ceramic substrate 10 with a silver-epoxy adhesive 19.

Therefore, the heat generated from the LS 114 of the semiconductor module 6 is radiated by the heat radiation block 22 via the ceramic substrate 10.

Ode to be Solved by the Invention The above-described printed wiring board unit 2 has a structure in which the semiconductor module 6 is mounted with the component mounting side facing the printed wiring board 4. According to this structure, the semiconductor module 6 is printed Wiring board 41 = for electrical connection,
It is necessary to provide an input/output area such as a pad 18 outside the portion of the ceramic substrate 10 where the cap 20 is attached, which is an obstacle to miniaturization.
The dimension in the thickness direction of this printed wiring board unit 2 is the sum of the thickness of the semiconductor module 6 (including the heat radiation block 22) and the thickness of the printed wiring board.
There is a problem in that it is not possible to make the device thinner than this.

Furthermore, although the heat dissipation block 22 is bonded to the back surface of the ceramic substrate 10 using a silicone adhesive 21, the area of the base portion 22a of the heat dissipation block 22 is large, and air bubbles are generated from the adhesive 21 when the heat dissipation block 22 is bonded. The adhesive 21 cannot be removed, and as shown in FIG.
3 may be formed. When the bubbles 23 are formed in the adhesive 21 in this way, the heat resistance increases in the bubble portions, and there is also the problem that the heat radiation efficiency from the heat radiation block 22 deteriorates.

The present invention has been made in view of these points, and aims to overcome the drawbacks of the above-mentioned prior art and to reduce the size of a printed wiring board unit.

Means for Solving the Problems As a first structure for solving the above-mentioned problems, the following structure is provided. That is, a semiconductor component is mounted on one surface of an insulating substrate, a multilayer wiring thin film is formed, a cap is attached to collectively seal the semiconductor component and the multilayer wiring thin film, and a plurality of semiconductor components are mounted on one side of the base. A semiconductor module is mounted on a printed wiring board by bonding the base portion of a heat dissipation block formed with heat dissipation protrusions such as heat dissipation fins or pins to the other surface of the insulating substrate. In the printed wiring board unit, heat dissipation blocks bonded to the insulating substrate are provided only at positions corresponding to the semiconductor components.

Then, a plurality of I/O parts (bins or pads) of the sleeve that electrically connects the semiconductor module and the printed wiring board are connected to the other surface of the insulating substrate (the same surface as the surface to which the heat dissipation block is bonded). forming a punching part in the printed wiring board through which the heat radiation block of the insulating substrate can pass; and with the heat radiation block passing through the punching part, the semiconductor module is attached to the printed wiring board. Mount it to configure a printed wiring board unit.

Furthermore, the following configuration is provided as a second configuration.

That is, in addition to the first configuration described above, the heat dissipation block is configured by forming a plurality of heat absorption protrusions on the surface of the base portion opposite to the surface on which the heat dissipation protrusions are formed. A plurality of through parts into which the plurality of heat absorption protrusions of the heat dissipation block are inserted are formed at the positions where the semiconductor components of the heat dissipation block are mounted, and with the heat absorption protrusions inserted into the penetration parts, A heat dissipation block is bonded to the insulating substrate.

Furthermore, the following configuration is provided as a third configuration. That is, in addition to the second configuration, the heat dissipation block is formed from a conductive material, and the vicinity of the heat absorption protrusion of the heat dissipation block is adhered using a conductive adhesive to establish electrical conduction with the power supply terminal of the semiconductor component. A part of the heat dissipation block is connected to a power supply pattern of a printed wiring board.

Function According to the first configuration of the present invention, the I/O section for electrically connecting the semiconductor module and the printed wiring board is not limited to the outer peripheral portion of the insulating substrate, but is also located relatively inside the insulating substrate. Because it can be placed, there is no need to provide pads or the like for electrically connecting the semiconductor module and the printed wiring board outside the component mounting area of the semiconductor module, unlike in the past.
Its size can be reduced. The dimension in the thickness direction of the printed wiring board unit corresponds to the dimension in the thickness direction of the semiconductor module, and can be made thinner than the conventional one.

In addition, since the heat dissipation block is provided only on the part of the insulating substrate where the semiconductor components are provided, the area of the base part is small, and there is less generation of air bubbles in the adhesive when bonding the heat dissipation block to the insulating substrate. Decrease in heat radiation efficiency due to this can be reduced.

Furthermore, according to the second configuration of the present invention, the tip of the heat-absorbing protrusion of the heat dissipation protrusion is in contact with the semiconductor component or is located near the semiconductor component, so that the heat generated in the semiconductor component is transferred to the heat-absorbing protrusion. Heat is efficiently absorbed by the protrusion, and the heat dissipation efficiency can be increased.

Furthermore, according to the third configuration of the present invention, power is supplied to the semiconductor components provided on the insulating substrate through the heat dissipation block, and there is no need to separately provide an input/output section for the power supply. , its configuration can be simplified.

Embodiments Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings. I see you.

FIG. 1 is a sectional view showing the structure of an embodiment of the present invention. The ceramic substrate 32 has, as in the conventional example shown in FIG.
A multilayer wiring thin film 34 is formed by alternately laminating copper and polyimide, and an LSI 3
6 is directly bonded. Multilayer wiring thin film 3
A chip component 38 is mounted on the chip 4. Then, the multilayer wiring thin film 34 with the LSI 36 and the chip components 38 mounted on the ceramic substrate 32 is connected to the cap 4.
0, and nitrogen gas is filled in the cap 40. On the back surface of the ceramic substrate 32, an LSI 36 is installed at a position corresponding to each LSI 36.
A heat dissipation block 42 formed by arranging and forming a plurality of pins 42b on a base portion 42a having a size approximately equal to the adhesion area of is bonded with a thermally conductive silicone adhesive.

This heat radiation block 42 is made of aluminum, for example.

On the same back surface of the ceramic substrate 32, an I10 pin 46 for connection to a printed wiring board 44 is arranged in a portion other than the adhesive portion of the heat dissipation block 42, thereby forming a semiconductor module 48.

Printed wiring board 4 on which this semiconductor module 48 is mounted
4 is formed with a penetrating punched portion 44a having approximately the same size as the base portion 42a of the heat dissipation block 42, and a plurality of holes corresponding to the I10 pin 46 are formed therein.

Then, the side of the semiconductor module 48 where the heat dissipation block 42 and the work/○ pin 46 were provided faced the printed wiring board 44, and the heat dissipation block 42 was inserted into the punched hole 844a, and the ■/○ pin 46 was inserted into the hole. After that, the I10 pin 46 is soldered to the printed wiring board 44.

According to the configuration of this embodiment, since the I10 pin 46 for electrically connecting the semiconductor module 48 and the printed wiring board 44 is arranged in a relatively inner part of the ceramic substrate 32, the semiconductor module Compared to the conventional configuration in which pads, etc. for electrical connection between the semiconductor module and the printed wiring board are provided outside the component mounting area,
A small ceramic substrate can be used, and the mounting area occupied by the semiconductor module on the printed wiring board can be reduced.

And the dimensions of the printed wiring board unit in the thickness direction are:
It is the dimension in the thickness direction of the semiconductor module 48,
It is thinner than before by the thickness of the printed wiring board.

According to the embodiment described above, the heat dissipation block 42 is provided only on the back side of the ceramic substrate 32 where the LSI 36 is mounted, and the heat dissipation block is smaller compared to the conventional configuration. Although it is undeniable that the efficiency will decrease, if this makes it difficult to cool the semiconductor module below the predetermined operating temperature, it is possible to improve the heat dissipation efficiency by changing part of the configuration, as shown in Figure 2. It can be improved.

That is, instead of the heat dissipation block 42 in FIG.
As shown in Figures (A) and (B), heat dissipation fins 5
A heat dissipation block 50 is used in which a plurality of heat-absorbing protrusions 50c (which may be cylindrical, prismatic, or other shapes) are integrally formed on the opposite side of a base portion 50a in which a base portion 50a is integrally formed.

Then, a penetrating portion 32a that fits into the plurality of protrusions 50c is formed in a portion of the ceramic substrate 32 to which the LSI 36 is bonded, and a conductive silicone compound is applied to the protrusion B50c of the heat dissipation block 50. It is fitted into and adhered to the penetrating portion 32a of the ceramic substrate 32.

As a result, the tip of the protrusion 50c of the heat dissipation block 50 is
Since it is located in contact with or near the lower surface of the SI 36, the heat generated by the LSI 36 is efficiently conducted, and the heat is efficiently radiated through the fins 50b of the heat radiation block 50. By employing such a structure, heat dissipation efficiency can be increased, and the semiconductor module can be cooled to a predetermined operating temperature or lower. As shown in FIG. 4, the structure of the heat dissipation block is such that a plurality of heat dissipation pins 52b are integrally formed on the - side of the base member 52a, and a plurality of heat absorption protrusions (cylindrical) are formed on the other surface. , prismatic, or other shapes are also acceptable)
52c may be integrally formed.

Further, in FIG. 2, a stepped portion 50d is formed at the end of the base portion 50a of the heat dissipation block 5°, and the printed wiring board 44 is sandwiched between the stepped portion 5 (ld) and the ceramic substrate 32. A power supply pattern is formed near the portion of the printed wiring board 44 that is screwed, and this pattern and the heat dissipation block 50 are electrically connected by the screws. , this pattern and the power supply terminal of the LSI 36 are connected via the heat radiation block 50 (if the power supply terminal of the LSI'36 and the heat radiation block 50 are not in contact with each other, also through a conductive silicone compound), They are electrically connected and power is supplied to the LSI 36.

By adopting this configuration, there is no need to separately provide a connection pin for supplying power to the LSI 36, which contributes to miniaturization of the printed wiring board unit.

Effects of the Invention Since the present invention is constructed as described in detail above, it has the effect that the printed wiring board unit can be downsized without reducing the heat dissipation efficiency of the semiconductor modular on which heat generating components are mounted.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of one embodiment of the present invention, FIG. 2 is a cross-sectional view of another embodiment of the present invention, and FIG. 3 is a diagram showing an example of a heat dissipation block in another embodiment. A front view, and (B) a bottom view. FIG. 4 is a diagram showing another example of a heat dissipation block in another embodiment, in which (A) is a front view and (B) is a bottom view. 5th Il! 1 is a perspective view of a conventional example in which a semiconductor module is mounted on a printed wiring board; FIG. 6 is an exploded sectional view of the semiconductor module shown in FIG. 5; FIG. is a diagram for explaining one of the problems of the conventional example. 2... Ceramic substrate 2a... Penetration part, 4... Multilayer wiring thin film, 6... LSI, 2.50.52... Heat dissipation plotter, 4... Printed wiring board, 4a...・Punching part, 6...I10 pin, Oa, 52a...Base part, Oc, 52c...Protruding part for heat absorption.

Claims (3)

[Claims] 1. Semiconductor components (36) are placed on one side of the insulating substrate (32).
) and form a multilayer wiring thin film (34),
A cap (40) is attached to collectively seal the semiconductor component (36) and the multilayer wiring thin film (34), and the base portion (4
The base portion (42a) of the heat radiation block (42) has a plurality of heat radiation protrusions (42b) formed on one surface of the base portion (42a) of the heat radiation block (42).
) is attached to the other surface of the insulating substrate (32).
) In the printed wiring board unit mounted on
a heat dissipation block (42) adhered to the insulating substrate (32);
) are provided only at positions corresponding to the semiconductor component (36), and the semiconductor module (48) and the printed wiring board (44) are provided only at positions corresponding to the semiconductor component (36).
) multiple I/O units (46) for electrically connecting
is provided on the other surface of the insulating substrate (32), and the printed wiring board (44) has a punched portion (44) through which a heat dissipation block (42) bonded to the insulating substrate (32) can penetrate.
a), and the semiconductor module (48) is mounted on a printed wiring board (44) with the heat dissipation block (42) penetrating the punched portion (44a). Wiring board unit. 2. A plurality of heat absorption protrusions (50c) are formed on a surface of the base portion (50a) of the heat dissipation block (50) opposite to the surface on which the heat dissipation protrusions (50b) are formed; A plurality of penetration portions (into which the plurality of heat absorption protrusions (50c) of the heat dissipation block (50) can be inserted, respectively) are provided at positions where the semiconductor components (36) are mounted.
32a), and the heat dissipation block (50) is inserted into the insulating substrate (32a) with the heat absorption protrusion (50c) inserted into the penetration part (32a).
2) The printed wiring board unit according to claim 1, wherein the printed wiring board unit is formed by adhering to the printed wiring board unit 2). 3. The heat dissipation block (50) is formed from a conductive material, and the heat dissipation block (50) is bonded to the insulating substrate (32) using a conductive adhesive. The tip of the heat absorption protrusion (50c) is electrically connected to the power supply terminal of the semiconductor component (36), and a part of the base portion (50a) of the heat dissipation block (50) is connected to the power supply terminal of the printed wiring board (44). 3. The printed wiring board unit according to claim 2, wherein the printed wiring board unit is connected to a pattern.