JPH05326768A - Heat dissipating device - Google Patents

Abstract

PURPOSE:To reduce the thickness of a junction resin interposed between a semiconductor element and a heat radiator to an irreducible minimum so as to lessen the junction resistance in thermal conduction resistance and to mount the heat radiator on the semiconductor element without applying a mechanical external stress. CONSTITUTION:A semiconductor element 1, a junction resin 3, and a mounting board 4 are provided as usual. The upside of a heat radiator 22 is formed rugged to be high in heat dissipating properties, and a cavity 23 is provided inside the radiator 22. Three openings 24 are provided as uniformly dispersed to the center of the side face (a lower side in a figure) of the heat radiator 22 which bears against the semiconductor element 1 and where the cavity 23 is open. An exhaust vet 25 communicating with the above cavity 23 is provided to the other side face (a right side in a figure) of the heat radiator 22 in a sealable manner. That is, air inside the cavity 23 of the heat radiator is discharged out through the exhaust vent 25, whereby the cavity 23 is reduced in pressure to have a suction force act on four openings 24.

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 for dissipating heat generated during the operation of a semiconductor element used in various electronic equipment such as a computer into the air.

[0002]

2. Description of the Related Art Conventionally, semiconductor elements used in personal computer systems and the like generally generate a large amount of heat during operation, and it is a problem to keep the temperature of the semiconductor elements within the guaranteed operating temperature range. In order to dissipate the heat during operation into the air, various heat dissipating means are adopted.

FIG. 2 shows a conventional heat dissipation device for a semiconductor device, in which a semiconductor device 1 is mounted on a mounting substrate 4 made of a glass epoxy resin printed circuit board, a ceramic substrate or the like, and the heat dissipation device 2 is the semiconductor device. It is attached to the upper surface of 1 by a bonding resin 3.

In the heat dissipation device 2, generally, after the semiconductor element 1 is mounted on the mounting substrate 4, the heat dissipation device 2 having the end face of the semiconductor element 2 coated with the bonding resin 3 is placed, and the heat dissipation device 2 is mounted. The semiconductor device 1 is pressed and integrated by a method of pressing, or the heat dissipation device 2 and the semiconductor device 1 and the mounting substrate 4 are sandwiched in a state of being overlapped with each other, and both are attached by mechanical external stress to be integrated and pressure bonded. It was fixed by the method.

[0005]

However, according to the conventional method for mounting the heat dissipation device, a pressure load is applied to the semiconductor device 1 in order to fix the heat dissipation device 2 to the semiconductor device 1 by mechanical external stress. There is a problem that the semiconductor element 1 may be destroyed, or the inside of the semiconductor element 1 may be partially damaged, which may cause a decrease in reliability.

On the other hand, in order to prevent an unreasonable load from being applied to the semiconductor element 1, the amount of the bonding resin 3 is increased to increase the thickness of the resin layer so that the bonding resin 3 absorbs the load at the time of crimping. However, there is a drawback in that the thickness of the bonding resin 3 increases, so that the transferability of heat transferred from the semiconductor element 1 to the heat dissipation device 2 deteriorates, and a sufficient heat dissipation effect cannot be exhibited.

Further, in the case of repairing and replacing the semiconductor element 1, it is necessary to once remove the fixed heat dissipation device 2 from the semiconductor element 1 to repair or replace the semiconductor element 1.
There is also a problem that the semiconductor element 1 is damaged because mechanical stress must be applied to the semiconductor element 1 even when the heat dissipation device 2 is peeled off.

The present invention is to solve the above problems, and is a heat dissipation device for radiating heat generated in a semiconductor element, and a structure in which a semiconductor element and a heat dissipation device are brought into close contact with each other with a simple structure. It is possible to provide a heat dissipation device that can be attached without applying mechanical external stress while making the thickness of the joining resin interposed between the two to be the minimum necessary thickness to reduce the heat conduction resistance of the joining resin. It is intended.

[0009]

To achieve the above object, the invention provides a heat dissipation device mounted on a semiconductor element,
Inside the body of the heat dissipation device, there is provided a cavity part having one end face in contact with the semiconductor element formed in the opening part, and at the other end face is provided with a sealable exhaust port for reducing the air pressure in the cavity part. It is a heat dissipation device characterized in that it is configured so as to be in close contact with a semiconductor element by reducing the air pressure inside the section.

[0010]

Therefore, in the heat dissipation device of the present invention, when the semiconductor element and the heat dissipation device are closely contacted and integrated, the inside of the cavity part is decompressed from the exhaust port of the cavity part provided in the heat dissipation device so that the cavity part of the heat dissipation device is reduced. The semiconductor element is adsorbed by the opening communicating with and the thickness of the bonding resin for bonding between the semiconductor element and the heat dissipation device can be reduced to the minimum necessary thickness because the bonding is performed by the suction pressure. The heat resistance due to the bonding resin can be reduced to improve the heat dissipation effect.

Further, since the semiconductor element is brought into close contact with the semiconductor element by the suction force due to the decompression of the cavity, no external mechanical stress is applied to the semiconductor element, damage or destruction of the semiconductor element is prevented, and reliability is not impaired. It can be joined to.

Further, by using a non-curing type resin as the bonding resin for the semiconductor element, when the semiconductor element is repaired or replaced, the suction force of the cavity is removed by unsealing the exhaust port of the cavity. Since it can be released, the heat dissipation device can be detached and repaired and replaced without applying external stress to the semiconductor element during repair and replacement.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat dissipation device according to an embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a semiconductor element, 3
Is a bonding resin, and 4 is a mounting substrate, which is the same as a conventional one. Reference numeral 22 denotes a heat dissipation device of the present invention, which is formed of a metal material having a high thermal conductivity, has an upper surface formed in an uneven shape having a high heat dissipation property, and has a cavity portion 23 provided therein. In addition, openings 24, 24, and 24 in which the cavity 23 is opened are formed uniformly in the center of the end surface (lower surface side in the drawing) where the heat dissipation device 22 contacts the semiconductor element. Further, an exhaust port 25 communicating with the hollow portion 23 is formed on the other end surface (right side surface in the figure) so as to be sealed.

That is, the air in the cavity portion 23 of the heat dissipation device 22 is discharged from the exhaust port 25 to reduce the pressure inside the cavity portion 23 and the openings 24, 24, 24 of the cavity portion 23.
It is configured to exert a suction force on.

The exhaust port 25 of the heat radiating device 22 is formed so that it can be sealed from the outside by a seal member 26 as appropriate, and is configured to maintain the depressurized state of the cavity 23.

In the following, the heat dissipation device 22 is attached to the semiconductor element 1
The procedure for attaching to is explained. First, the semiconductor element 1 is mounted on the mounting board 4. Next, the heat dissipation device 22
After the bonding resin 3 is applied to the end faces of the openings 24, 24, 24 side, the end faces of the openings 24, 24, 24 are placed in contact with the upper surface of the semiconductor element 1. After that, a decompression device such as a vacuum pump is connected to the exhaust port 25 of the heat dissipation device 22 to exhaust the air inside the cavity 23 of the heat dissipation device 22 to apply suction force to the opening 24 communicated with the cavity 23. Then, the semiconductor element 1 is attracted and the heat dissipation device 22 is pressure-bonded with the bonding resin 3.

Then, when the air pressure inside the cavity 23 of the heat dissipation device 22 reaches a predetermined pressure reduction level, the exhaust port 25 is sealed to maintain the pressure reduction level inside the cavity 23.

Therefore, the semiconductor element 1 and the heat dissipation device 22
From the openings 24, 24, 24 to the heat dissipation device 22
The suction force toward the inside of the cavity 23 always acts to adsorb the semiconductor element 1 and seal the contact portion with the bonding resin 3 to integrally bond the two.

At this time, if the bonding resin 3 is a non-hardening type resin, the sealing of the exhaust port 25 is released and the cavity 2 is removed.
When the reduced pressure of 3 is released, the action of the suction force is eliminated and the heat dissipation device 22 can be removed from the semiconductor element 1.

As described above, according to the above-described embodiment, when the semiconductor element 1 and the heat dissipation device 22 are brought into close contact with each other, the inside of the cavity 23 provided in the heat dissipation device 22 is depressurized, so that the end face of the semiconductor element 1 in contact with the semiconductor device 1 is reduced. Since the openings 24, 24, 24 attract the semiconductor element 1 and bring them into close contact with each other, the thickness of the bonding resin 3 can be reduced and good bonding can be performed. Less decrease,
The heat dissipation device 22 can quickly conduct and absorb the temperature of the semiconductor element 1 and dissipate the heat in the air.

Further, since the suction force inside the cavity portion 23 of the heat dissipation device is used, no external mechanical force is applied from the outside, and the semiconductor element 1 may be damaged or destroyed by the external force. Therefore, the heat dissipation device 22 can be attached without anxiety.

[0023]

As described above, according to the present invention, there is provided a heat dissipation device mounted on a semiconductor element, wherein a heat dissipation device main body is provided with a cavity portion having an opening at one end face which contacts the semiconductor element. In addition, the other end surface is provided with a sealable exhaust port for reducing the air pressure in the cavity, and by reducing the air pressure in the cavity, the heat radiation is characterized by being configured so as to be in close contact with the semiconductor element. Since the device is a device, when the semiconductor element and the heat dissipation device are brought into close contact with each other, the air in the cavity is exhausted from the exhaust port of the heat dissipation device to reduce the pressure inside the cavity to a predetermined level, so that the opening of the heat dissipation device removes the semiconductor element. By adsorbing, the bonding resin can be made as thin as necessary to reduce the thermal resistance due to the bonding resin and achieve the mounting state of the heat dissipation device with high heat dissipation effect.

Further, since the distance between the two can be made narrow without applying a mechanical external force, the semiconductor element can be prevented from being damaged or destroyed, and the highly reliable connection of the heat dissipation device can be secured.

Further, if the bonding resin between the heat dissipating device and the semiconductor element is bonded using a non-curing type resin such as an adhesive resin, the exhaust port of the heat dissipating device can be connected even after the heat dissipating device is bonded. The semiconductor device can be easily removed by simply removing the seal, and the heat dissipation device can be removed easily. This has the effect of preventing damage to the semiconductor element due to repair and replacement of the element.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a heat dissipation device of the present invention and a mounting state thereof,

FIG. 2 is a cross-sectional view illustrating a conventional heat dissipation device and a mounting state thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Semiconductor element 3 Bonding resin 4 Mounting board 22 Radiator 23 Cavity 24 Opening 25 Exhaust port 26 Sealing member

Claims (1)

[Claims] 1. A heat dissipation device to be mounted on a semiconductor element, wherein a heat dissipation device main body is provided with a cavity portion having an opening at one end surface in contact with the semiconductor element,
A heat dissipation device, characterized in that a sealable exhaust port for reducing the air pressure in the cavity is provided on the other end surface, and is configured to be in close contact with a semiconductor element by reducing the air pressure in the cavity.