JP2003017879A - Heat dissipation device - Google Patents

Abstract

(57) Abstract: When a printed circuit board on which a semiconductor device is mounted is housed in a shield case, heat generated from the mounted semiconductor device is trapped in the shield case, and the performance of a circuit element constituting a circuit module is reduced. Therefore, there is a need for a device that effectively dissipates heat. SOLUTION: A circuit pattern and a first ground pattern are formed on a first surface of a printed circuit board, and a second ground pattern is formed on a second surface. Connect with a through-hole conductor. Then, based on the connection of the terminals of the semiconductor device to the circuit pattern, the semiconductor device was mounted on the first surface of the printed circuit board so that the bottom portion of the semiconductor device was in contact with the first ground pattern, and these semiconductor devices were mounted. A heat radiator in which a printed board is covered with a shield case, a part of the shield case is cut and raised to form an elastic contact piece, and the contact piece is brought into contact with a second ground pattern.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation device that efficiently dissipates heat generated in a semiconductor device mounted on a printed board.

[0002]

2. Description of the Related Art In recent years, semiconductor devices integrated into various circuits have been widely used in electronic equipment as various signal processing circuits, and have been downsized and the degree of integration has been improved.
In addition, a high output element may be included in the integrated circuit elements forming the semiconductor device, and in recent years, many semiconductor devices with large power consumption have been seen.

Particularly, in a semiconductor device used for a circuit module covered with a shield case or a cover, it is necessary to efficiently dissipate heat generated by the semiconductor device as power consumption increases. If it is not performed sufficiently, the performance of the integrated circuit element incorporated therein will be deteriorated.

Therefore, a method of radiating heat from a printed circuit board on which such a semiconductor device with high power consumption is mounted is disclosed in, for example, Japanese Patent Laid-Open No. 5-160527. FIG. 5 shows a printed circuit board disclosed in JP-A-5-160527.

In FIG. 5, a printed board 51 has various circuit elements mounted on one surface of an insulating board 52a, and a copper foil pattern 52b is printed and wired to connect these circuit elements. In addition, on the surface on which the IC 53, which is a semiconductor device, is attached, the conduction portion 52 that conducts heat on the back surface of the IC package.
c is provided, and the IC 53 is an adhesive 56 with good thermal conductivity.
Is attached to the conductive portion 52c using. Also, I
C53 lead terminals 54a and 54b are copper foil patterns 52
On the other surface of the printed circuit board 51, which is connected to the solder b by solder 55 and faces the conductive portion 56, a heat radiation pattern 57 is formed.
Is provided, and the pattern 57 and the conductive portion 52c are electrically and thermally connected through a plurality of through holes 58.

In the printed circuit board having such a structure, the IC 53
Of the heat is conducted to the conduction portion 52c, the through hole 58, and the heat radiation pattern 57, and the heat radiation pattern 57.
I try to dissipate the heat from the outside.

However, when the IC 53 as described above is covered with a shield case or cover, the heat from the heat dissipation pattern 57 fills the case and cover and is not dissipated to the outside, so a higher heat dissipation effect is obtained. It wasn't enough to get.

For example, in a television receiver, a tuner circuit for receiving and selecting television broadcast waves and signal demodulation I
C is modularized and these modules are covered with a shield case to prevent harmonic components from leaking to other circuits.

On the other hand, the digital IC used as the demodulation IC is a surface mount type flat package IC.
Since it is used and its power consumption is large, when it is mounted on a printed circuit board together with other circuit elements and covered with a shield case, the heat radiated from the IC stays inside the shield case and sufficient heat is radiated. Can not.

Therefore, due to the heat generation of the IC itself,
There are problems that the performance of the circuit elements in the IC is deteriorated and the life is shortened.

Further, in order to radiate heat from the above-mentioned surface mount type flat package IC, the contact piece cut out from the shield case is brought into contact with the package of the IC with a strong elastic force, and the contact piece is heated to the outside. Although a method of diverging the IC may be considered, since the contact piece presses the package of the IC, mechanical stress is constantly applied to the IC,
There was a drawback that it became difficult to secure long-term reliability of.

There is also a method of contacting the IC package with a conductive adhesive without pressing the contact piece against the IC package. However, once the adhesive has been adhered, the adhesive must be removed when exchanging the IC. Therefore, there is an inconvenience in maintainability.

[0013]

As described above, when the conventional semiconductor device is covered with a shield case or the like, the heat radiated is contained in the shield case and cannot be sufficiently radiated. Further, in order to solve this problem, in the method of contacting the contact piece cut out from the shield case with the surface of the IC package by elastic force, mechanical stress is constantly applied to the IC, so that long-term reliability of the IC can be obtained. In addition, when the contact piece is adhered with an adhesive, there is a problem that maintainability deteriorates.

In view of the above-mentioned problems, the present invention efficiently radiates heat generated from a semiconductor device housed in a shield case, does not give unnecessary stress to the semiconductor device, and performs repair work. An object is to provide a heat dissipation device that can improve efficiency.

[0015]

A heat dissipation device according to claim 1, wherein a circuit pattern and a first ground pattern are formed on a first surface, and the circuit pattern and the first ground pattern are opposed to the first surface on a second surface. A second ground pattern is formed at a position to be connected, and a printed board in which the first and second ground patterns are connected by a through-hole conductor and a plurality of terminals are connected to the circuit pattern. A semiconductor device mounted on the first surface of the printed board so that a bottom portion of the printed board is in contact with the first ground pattern; and the printed board having the semiconductor device mounted therein, and the printed board. A shield case in which an elastic contact piece is formed by cutting and raising a part of the portion facing the second surface, and the contact piece is brought into contact with the second ground pattern of the printed board. Is characterized by.

According to a second aspect of the present invention, there is provided a heat dissipation device having a semiconductor device having a plurality of terminals, a circuit pattern formed on a first surface, the semiconductor device mounted on the first surface, and the semiconductor device. And a printed circuit board on which a ground pattern is formed extending outward from the mounting portion and the mounting portion, and each terminal of the semiconductor device is connected to the circuit pattern,
The printed board on which the semiconductor device is mounted is housed inside, and a part of a portion of the printed board facing the first surface is cut and raised to form an elastic contact piece, and the contact piece is formed on the printed board. And a shield case adapted to be brought into contact with the extended portion of the ground pattern.

According to a fourth aspect of the present invention, there is provided a heat dissipation device in which a circuit board and a grounding pattern are formed on the first surface, and a terminal connecting hole is formed in the circuit pattern and the grounding pattern. A plurality of terminals including a grounding terminal, and the plurality of terminals are connected to the second board of the printed board.
A semiconductor device which is inserted into the hole for terminal connection from the surface side of the device and is connected to the circuit pattern and the ground pattern, and the printed board on which the semiconductor device is mounted is housed inside, and the printing is performed. A shield case is provided, in which a part of a portion of the substrate facing the first surface is cut and raised to form an elastic contact piece, and the contact piece is brought into contact with the ground pattern of the printed board. And

Further, the heat dissipation device according to claim 6 is a heat dissipation device for a high frequency module, wherein the high frequency signal processing circuit is formed on the first surface and the first contact pattern is formed, and the second surface is formed. A second ground pattern is formed at a position facing the first ground pattern, and a printed board in which the first and second ground patterns are connected by a through-hole conductor, and a plurality of terminals are provided. A demodulation IC mounted on the first surface of the printed board such that these terminals are connected to the output side of the high-frequency processing circuit formed on the first surface and the bottom surface portion is in contact with the first ground pattern; An elastic contact piece is formed by accommodating the printed circuit board inside and cutting and raising a part of a portion of the printed circuit board facing the second surface to form the elastic contact piece, and the contact piece is connected to the second ground of the printed circuit board. A seal designed to be in contact with the pattern Characterized by comprising a case.

In the heat dissipation device of the present invention, the heat generated from the semiconductor device is dissipated to the outside of the shield case through the ground pattern provided on the printed board and the contact piece formed on the shield case. In this case, heat can be efficiently dissipated even when the semiconductor device is covered with a case.

[0020]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing a heat dissipation device according to the present invention, and FIG. 2 is a sectional view.

FIG. 1 shows a high-frequency circuit module of, for example, a digital television receiver.
It has a rectangular printed board 11 and a shield case 21 that covers and shields the printed board 11. The shield case 21 is formed of a metal member and has a box shape.

A circuit pattern 14b is printed and wired on one surface 11a of the printed board 11, and various circuit elements (not shown) are connected to the circuit pattern 14b to form a high frequency signal processing circuit. Further, an integrated circuit 12 (hereinafter abbreviated as IC12) as a semiconductor device is mounted. FIG. 1 shows an example in which a flat package IC is used as the IC 12, and the terminal 13 of the IC 12 is shown.
a and 13b are connected to the circuit pattern 14b by solder 18. The IC 12 is, for example, a demodulation IC for demodulating an output signal from the high frequency signal processing circuit.

A ground pattern 14 is formed on a portion of the printed board 11 on which the IC 12 is mounted, and another surface 11 of the printed board 11 facing the ground pattern 14 is formed.
A grounding pattern 15 for heat dissipation is formed on b, and these grounding patterns 14 and 15 are provided in the plurality of through holes 1.
It is designed to be electrically and thermally connected via 6.

A connector 17 is arranged on one side surface of the shield case 21, and the connector 17 is provided with a plurality of terminals 17b. Each circuit formed on the printed circuit board 11 through the terminals 17b. A signal is input, a power supply voltage or various control signals are supplied, or a signal is output.

On the other hand, the contact piece 22 faces the ground pattern 15 on the first surface 21a of the shield case 21.
Is provided. This contact piece 22 is a shield case 21.
3 pieces of rectangular cuts are provided on a part of the contact piece, and the other piece is cut and raised inward.
Are elastically contacted with the ground pattern 15 provided on the printed board 11.

FIG. 2 is a sectional view taken along the line X--X in FIG. 1, and particularly shows the relationship between the printed board 11 and the contact piece 22 of the shield case 21.

That is, the flat package IC 12
The heat generated at the ground pattern 1 of the printed board 11 is
4, the through hole 16, and the ground pattern 15, and the heat conducted to the ground pattern 15 is transferred to the contact piece 22 of the shield case 21 and is passed through the first surface 21a of the shield case 21. The heat is released into the outside air.

As a result, even when the printed circuit board 11 is housed in the shield case 21, the heat generated from the flat package IC 12 does not stay inside the shield case 21 and is efficiently dissipated to the outside air. can do.

Further, since the ground patterns 14 and 15 are located directly below the flat package IC 12, it is possible to prevent radiation of an interfering wave from the bottom surface of the flat package IC 12 and intrusion of external noise.

Next, a second embodiment of the heat dissipation device according to the present invention will be described with reference to FIG. The same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted.

A printed circuit board 11 'in FIG. 3 has a circuit pattern formed on only one surface of an insulating substrate. The flat package IC 12 is mounted on the surface of the printed circuit board 11' on which the circuit pattern is formed. The circuit pattern is electrically connected. Further, a grounding pattern 15 is provided on the printed board 11 ′ immediately below the flat package IC 12 to be mounted so that the bottom surface of the flat package IC 12 contacts. The ground pattern 15 is formed separately from the circuit pattern for connection with each circuit, and the ground pattern 15a located immediately below the flat package IC 12 and the ground pattern 1 are formed.
The ground pattern 15b extends from 5a in the outer peripheral direction of the flat package IC 12.

A contact piece 22 cut out from the shield case 21 comes into contact with the ground pattern 15b.

In such a structure, the heat generated in the flat package IC 12 is the ground pattern 1
5, the first surface 21a of the shield case 21 is transmitted via the contact piece 22 which is transmitted from the ground pattern 15a immediately below the flat package IC 12 to the ground pattern 15b and which is in contact with the ground pattern 15b.
Is transmitted to. As a result, the flat package I
The heat from C12 is radiated from the surface of the shield case 21 to the outside air.

That is, also in this embodiment, when the printed circuit board is housed in the shield case 21, the heat generated from the flat package IC 12 can be efficiently dissipated to the outside air.

Since the ground pattern 15a is provided directly below the flat package IC 12,
It is possible to prevent the emission of interfering waves from the bottom surface of the flat package IC 12 and the intrusion of external noise.

Next, a third embodiment of the heat dissipation device according to the present invention will be described with reference to FIG. The same parts as those in FIG. 2 are designated by the same reference numerals and detailed description thereof will be omitted.

The semiconductor device used in this third embodiment is an example using a dual in-line integrated circuit 12 '(hereinafter referred to as a dual in-line IC). The printed circuit board 11 "on which the dual in-line IC 12 'is mounted is a single-sided printed circuit board and has a plurality of holes 19 into which a plurality of terminal pins extending from both side surfaces of the dual in-line IC 12' are inserted. There is.

The dual in-line IC 12 '
Is a circuit pattern (not shown) formed on the other surface of the printed board 11 ″ by inserting the terminal pins into a plurality of holes 19 and projecting the tips from the other surface of the printed board 11 ″. It is connected to the solder 18 with. Also, among the terminal pins of the dual in-line IC 12 ', the grounding terminal pin 13
A'and 13b 'are connected to the ground pattern 15 formed on the other surface of the printed circuit board 11 "with solder 18.

The ground pattern 15 on the printed circuit board 11 "
The contact piece 22 cut and raised from the upper surface 21a of the shield case 21 is brought into contact with.

As a result, the dual in-line IC
The heat generated from 12 'is the dual in-line IC12
Via the grounding connection terminal pins 13a ', 13b' of the printed circuit board 11 ", and further from the contact piece 22 to the first surface 21a of the shield case 21. Heat is radiated from the surface of the case 21 to the outside air.

Therefore, the dual in-line IC1
Even when the printed circuit board formed by mounting 2 ′ is housed in the shield case 21, the heat generated from the dual in-line IC 12 ′ does not stay in the shield case 21 and the outside air is efficiently discharged. Can dissipate heat inside.

In the above embodiments, an example in which an integrated circuit is used as the semiconductor device has been described, but the heat dissipation device of the present invention can be applied to semiconductor devices other than the integrated circuit.

[0043]

As described above, in the heat dissipation device of the present invention, even when the printed circuit board on which the semiconductor device is mounted is covered with a case such as a shield case, the heat generated from the semiconductor device can be applied to the ground pattern and the shield case. It is possible to radiate heat to the outside air through the contact piece, and to improve heat radiation efficiency. In addition, when the semiconductor device is repaired, the shield case can be easily removed, which has the effect of simplifying the repair work.

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a heat dissipation device according to the present invention.

FIG. 2 is a sectional view showing a first embodiment of a heat dissipation device according to the present invention.

FIG. 3 is a sectional view showing a second embodiment of a heat dissipation device according to the present invention.

FIG. 4 is a sectional view showing a third embodiment of a heat dissipation device according to the present invention.

FIG. 5 is a sectional view illustrating a conventional heat dissipation device for a semiconductor element.

[Explanation of symbols]

11 ... Printed circuit board 12 ... Semiconductor device 13 ... Input / output terminal 14 ... Ground pattern 15 ... Ground pattern (heat radiation ground pattern) 16 ... Through hole 17 ... Connector 18 ... Solder 21 ... Shield case 22 ... Contact piece

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Claims (6)

[Claims] 1. A circuit pattern and a first ground pattern are formed on a first surface, and a second ground pattern is formed on a second surface at a position facing the first ground pattern. A printed board having a through-hole conductor connecting between the first and second ground patterns, and a plurality of terminals connected to the circuit pattern so that the bottom surface portion contacts the first ground pattern. A semiconductor device mounted on the first surface of the printed circuit board, the printed circuit board on which the semiconductor device is mounted is housed inside, and a part of a portion facing the second surface of the printed circuit board is cut off. A heat dissipation device comprising: a shield case that is raised to form an elastic contact piece, and the contact piece is brought into contact with the second ground pattern of the printed board. 2. A semiconductor device having a plurality of terminals, a circuit pattern is formed on a first surface, the semiconductor device is mounted on the first surface, and the semiconductor device is mounted on the semiconductor device. A printed circuit board extending from the portion to the outside to form a ground pattern, each terminal of the semiconductor device being connected to the circuit pattern, and the printed circuit board on which the semiconductor device is mounted are housed inside and printed. A shield case, in which a part of a portion of the substrate facing the first surface is cut and raised to form an elastic contact piece, and the contact piece is brought into contact with the extended portion of the ground pattern of the printed board. A heat dissipation device comprising: 3. The heat dissipation device according to claim 1, wherein the semiconductor device is a surface mount type flat package IC in which a plurality of terminals are extended from a side surface of the package. 4. A printed board on which a circuit pattern and a ground pattern are formed on the first surface, and holes for connecting terminals are formed in the circuit pattern and the ground pattern, and a plurality of terminals including a ground terminal. And a semiconductor device in which these terminals are inserted into the hole for terminal connection from the second surface side of the printed board and connected to the circuit pattern and the ground pattern, The mounted printed circuit board is housed inside, and a part of the portion facing the first surface of the printed circuit board is cut and raised to form an elastic contact piece, and this contact piece is used as a ground pattern for the printed circuit board. A heat dissipation device comprising: a shield case adapted to be in contact with the heat dissipation device. 5. The heat dissipation device according to claim 4, wherein the semiconductor device is a dual in-line type IC in which a plurality of terminals are extended from both side surfaces of the package. 6. A high frequency signal processing circuit is formed on a first surface, a first contact pattern is formed, and a second ground pattern is formed on a second surface at a position facing the first ground pattern. A printed circuit board in which the first and second ground patterns are connected by a through-hole conductor, and a plurality of terminals are connected to the output side of the high frequency processing circuit formed on the first surface. A demodulation IC mounted on the first surface of the printed circuit board so that the bottom surface portion contacts the first ground pattern; and the second printed circuit board containing the demodulated IC therein.
A shield case in which an elastic contact piece is formed by cutting and raising a part of a portion facing the surface of the printed circuit board, and the contact piece is brought into contact with the second ground pattern of the printed board. Radiator for high frequency module.