JPH06276741A - Heat sink for semiconductor element - Google Patents

Abstract

PURPOSE:To reduce temperature difference at the time of the operation of elements on the upstream side and downstream side of cooling air mounted on a block-shaped heat receiving section. CONSTITUTION:A heat sink is composed of heat pipes 3A, 3B, 3C, 3D, 3E, 3F inserted and fixed into holes, which are arrayed on a heat receiving block 2 in a row and cross sections of which are formed in a circular shape, radiation fins 4, 4 inserted and fastened into the heat pipes 3A, 3B, 3C, 3D, 3E, 3F and arranged on both end sides, a plurality of radiation fins 11A inserted and fixed into the heat pipes 3A, 3B, 3C and a plurality of radiation fins 11B put into and fastened into the heat pipes 3D, 3E, 3F.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat sink for cooling a semiconductor device, and more particularly to improvement of a radiation fin having a small thermal resistance.

[0002]

2. Description of the Related Art In a semiconductor device, a high frequency PWM control system using a high speed switching element has been increasingly adopted in order to improve the performance of a power converter. In these devices, large-capacity elements are used in parallel because of the large current and high frequency.

Further, in the high frequency PWM control system,
Since it is necessary to reduce the reactance between the high speed switching elements and suppress the surge voltage generated by switching, the high speed switching elements are mounted close to each other.

Therefore, since the heat generated in the high speed switching element is locally concentrated, an air-cooled heat sink using a heat pipe is conventionally used to radiate the locally concentrated heat.

FIG. 4 shows an example of a conventional heat sink for cooling semiconductor elements (hereinafter referred to as heat sink).
(A) is a front view, (b) is a EE arrow line view. 1A and 1B, a heat sink 1 includes a heat receiving block 2 formed of a metal thick plate having good heat conductivity in a substantially square shape, and a right side of the heat receiving block 2 in FIG. A heat pipe 3 which has been processed from the above, is airtightly inserted and fixed in a hole having a circular cross section, and pure water as a refrigerant is injected into the hole.
A, 3B, 3C, 3D, 3E, 3F and a plurality of radiating fins 4 of a plurality of plates inserted into and fixed to these heat pipes 3A, 3B, 3C, 3D, 3E, 3F, and on both side surfaces of the heat receiving block Is a high-speed switching element of the same rating (hereinafter referred to as element) 5A, 5B, 5C, 5D to be cooled.
Are attached via bolts (not shown).

FIG. 5 shows an example in which a semiconductor stack 6 formed by attaching the respective elements 5A, 5B, 5C and 5D to the heat sink 1 described above is housed in a box body 7 to form a power conversion device. A side view and (b) are front views. In FIGS. 1A and 1B, a door 8 is openably and closably attached to the front surface of the box body 7, and an intake port 8a to which a filter (not shown) is detachably attached is attached to a lower portion of the door 8. A ventilation fan 9 is attached to the inside of the box body 7 at the bottom of the ceiling surface. The semiconductor stack 6 is provided below the ventilation fan 9.
The three heat receiving blocks 2 are housed in a state in which the heat receiving blocks 2 are brought close to the door 8 and slightly inclined.

In the semiconductor stack 6 housed in the box body 7 as described above, when the power converter is operating, the cooling air flows into the box body 7 from the intake port 8a as shown by the arrow F, and the cooling fins 4 are discharged. Heat is dissipated due to contact. The cooling air whose temperature has risen due to this heat radiation is discharged above the box body 7 through the ventilation fan 9 as indicated by an arrow G.

Regarding the relationship between the cooling surfaces of the elements 5A, 5B, 5C and 5D and the mounting density of the box body 7, four elements 5A, 5B, 5C and 5 are provided on both sides of the heat receiving block 2, respectively.
By mounting D, the element mounting portion and the heat receiving portion can be downsized, and the heat receiving block 2 can be vertically arranged inside the box body 7 to make the cooling conditions uniform by the cooling air flowing on both sides of the heat receiving block 2. Has been planned. In the above example, the number of elements is eight and the number of heat pipes is six in order to make the description easy to understand, but it goes without saying that other elements are the same.

[0009]

However, in the heat sink 1 configured as described above and cooled inside the box body 7, the heat pipe 3F located at the lower end in FIG. Although well cooled, the upper heat pipe is cooled through the lower heat pipe and the cooling air whose temperature is raised by the radiation fins, so that the cooling temperature is gradually increased and the uppermost heat pipe 3A is cooled. The temperature is highest.

As a result, the lower side of the heat receiving block 2 is also cooled well, but the cooling is not performed as well as it goes to the upper side, so that there is a difference in output characteristics due to the difference in temperature rise between the elements 5A and 5C and the elements 5B and 5D. However, the characteristics of the power conversion device may deteriorate.

Therefore, an object of the present invention is to reduce the temperature difference between the upstream side element and the downstream side element of the cooling air attached to the block-shaped heat receiving part during operation, and to reduce the characteristics of the power converter. An object of the present invention is to provide a heat sink for cooling a semiconductor device without a problem.

[0012]

In order to achieve the above-mentioned object, the present invention provides a plurality of heat pipes which are partially embedded in a heat receiving portion to which a plurality of semiconductor elements are attached and which are arranged in a row and project. In a heat sink for a semiconductor device formed by inserting and fixing a plurality of heat radiation fins, the heat radiation fins are divided in the vicinity of an intermediate portion on the upstream side and the downstream side in the flow direction of the cooling air, and the divided heat radiation fins are individually heated. It is characterized in that a boundary layer is formed.

[0013]

[Function] Since the thermal boundary layers are formed individually on the upstream side radiating fins and the downstream side radiating fins, the heat radiating effect of the downstream side radiating fins is increased, the thermal resistance is improved as a whole, and the heat receiving It is possible to reduce the temperature difference during the operation of the elements attached to the section.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B show an embodiment of the present invention, in which FIG. 1A is a front view, FIG. 1B is an AA arrow view, and FIG. 1C is a BB sectional view. The same parts as those of the above-described conventional device are designated by the same reference numerals,
A duplicate description will be omitted.

In the figures (a), (b) and (c), 10
Is a heat sink, and this heat sink 10 is a heat receiving block 2 and a heat pipe 3 fixed to the heat receiving block 2 by inserting the heat receiving block 2 into a hole having a circular cross section.
A, 3B, 3C, 3D, 3E, 3F, radiation fins 4, 4 inserted and fixed to the heat pipes 3A, 3B, 3C, 3D, 3E, 3F and arranged at both ends, and the radiation fins 4, 4 Heat pipes 3A, 3B, 3C arranged between
A plurality of heat radiation fins 11A inserted into and fixed to the heat radiation fins and heat pipes 3D, 3E, 3F having the same shape as the heat radiation fins 11A.
It is composed of a plurality of heat radiation fins 11B which are inserted and fixed to. Further, the radiation fins 11A and 11B are made of the same material as the radiation fin 4, and are arranged so as to be at the same position in the vertical direction. Here, the heat dissipating fins 4, 4 are arranged on both end sides in order to dispose the heat pipes 3A, 3B, 3C,
This is to reinforce the mechanical strength of 3D, 3E, and 3F.
When the heat sink 10 is incorporated in a semiconductor stack and used, the heat pipe 3F side is located upstream of the heat pipe 3A side in the cooling air flow direction.

Next, the operation of the embodiment configured as described above will be described. In the heat sink 10 of this embodiment, the element 5A,
When the semiconductor stack configured by mounting 5B, 5C, and 5D is housed under the ventilation fan below the ceiling surface of the box in the same manner as in the conventional case described above, the cooling air has the same path when the power converter is operating. However, since the heat dissipation fins 11A and 11B except the heat dissipation fins 4 and 4 at both ends are separate bodies, a heat boundary layer is formed in each of them as compared with the integrated heat dissipation fin 4.

Therefore, the cooling effect is improved and the thermal resistance as a whole is significantly improved as compared with the case where the radiation fins are integrated. In particular, it has been confirmed that the effect is great when the flow velocity of the cooling air is low. Therefore, the radiation fin
Heat pipes 3A, 3B, 3 cooled by 11A, 11B
C, 3D, 3E, 3F and the heat receiving block 2 are cooled substantially evenly in the upper half and the lower half, and the upper and lower elements 5A,
The temperature difference during operation of 5C and the elements 5B and 5E is reduced, and the characteristics of the power conversion device are not degraded.

The present invention is based on the above-described embodiment (hereinafter,
The present invention is not limited to the first embodiment), and various modifications can be implemented. FIG. 2 shows another embodiment of the present invention (hereinafter referred to as the second embodiment), and (a) is a front view, b) is C
-C sectional drawing and (c) are the elements on larger scale of the radiation fin part of (a).

In FIGS. 3A, 3B and 3C, 12
Indicates a heat sink, and this heat sink 12 has the same configuration as that of the above-described first embodiment except that the arrangement of the radiation fins 11A and 11B is different. That is, the heat pipe 3
The radiating fins 11B inserted and fixed in the D, 3E, and 3F are one position above and below the radiating fins 11A inserted and fixed in the heat pipes 3A, 3B, and 3C, that is, the pitch is doubled. It was done. Therefore, the number of the radiation fins 11B is almost half that of the radiation fins 11A. With this configuration, the cooling air easily flows to the downstream side in the radiation fin portion, and the radiation fin 11A
Since the cooling performance on the side is improved, the elements 5A and 5C and the element 5 are
The temperature difference during B and 5D operation can be reduced.

FIG. 3 shows still another embodiment of the present invention (hereinafter referred to as a third embodiment), (a) is a front view,
(B) is DD sectional drawing, (C) is the elements on larger scale of the radiation fin part of (a).

13 (a), (b) and (c) in FIG.
Indicates a heat sink, and this heat sink 13 has the same configuration as that of the second embodiment described above except that the arrangement of the radiation fins 11A and 11B is different. That is, the heat pipe 3
A heat radiation fin 11A which is inserted and fixed to A, 3B and 3C and a heat radiation fin 11B which is inserted and fixed to the heat pipes 3D, 3E and 3F.
Are staggered vertically, that is, they are arranged alternately. Therefore, the radiation fin 11A and the radiation fin 11
The numbers of B are almost the same. With this configuration, as in the second embodiment described above, the cooling air easily flows to the downstream side in the radiation fin portion, and the radiation fin 11
Since the cooling performance on the A side is improved, the temperature difference between the elements 5A, 5C and the elements 5B, 5D during operation can be reduced.

[0022]

As described above, according to the present invention, a plurality of heat radiating fins are provided in a plurality of heat pipes which are partially embedded in a heat receiving portion to which a plurality of semiconductor elements are attached and which are arranged in a row and project. In a heat sink for a semiconductor device formed by inserting and fixing, a radiation fin is divided in the vicinity of an intermediate portion on the upstream side and the downstream side in the flow direction of cooling air, and a thermal boundary layer is formed on each of the divided radiation fins. Therefore, it is possible to provide a heat sink for a semiconductor element that reduces the temperature difference during operation of the element attached to the heat receiving section and does not deteriorate the characteristics of the power conversion device.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, (a) is a front view,
(B) is an AA arrow line view, (c) is a BB sectional view.

FIG. 2 shows another embodiment (second embodiment) of the present invention,
(A) is a front view, (b) is CC sectional drawing, (c) is the elements on larger scale of a radiation fin part.

FIG. 3 shows still another embodiment (third embodiment) of the present invention, in which (a) is a front view and (b) is a D-D sectional view.
FIG. 7C is a partially enlarged view of the radiation fin portion.

FIG. 4 shows a conventional heat sink for a semiconductor device,
(A) is a front view, (b) is a EE arrow line view.

5A and 5B show a power conversion device in which a conventional heat sink for a semiconductor element is incorporated in a semiconductor stack and housed in a box, wherein FIG. 5A is a side view and FIG. 5B is a front view.

[Explanation of symbols]

2 ... Heat receiving block, 3A-3F ... Heat pipe, 4, 11
A, 11B ... Radiating fins, 5A-5D ... Semiconductor element, 6 ...
Semiconductor stack, 7 ... Box, 9 ... Ventilation fan.

Claims (3)

[Claims] 1. A heat sink for a semiconductor device, wherein a plurality of heat-dissipating fins are inserted into and fixed to a plurality of heat pipes which are partially embedded in a heat receiving portion to which a plurality of semiconductor devices are attached and which are arranged in a row and project. A heat sink for a semiconductor device, characterized in that the radiating fins are divided in the vicinity of an intermediate portion on the upstream side and the downstream side in the flow direction of cooling air, and a thermal boundary layer is individually formed on each of the divided radiating fins. . 2. The heat sink for a semiconductor element according to claim 1, wherein the heat radiation fins on the upstream side in the flow direction of the cooling air are arranged at a pitch almost twice that of the heat radiation fins on the downstream side. Heat sink for element. 3. The heat sink for a semiconductor element according to claim 1, wherein the heat radiating fins on the upstream side and the heat radiating fins on the downstream side in the flow direction of the cooling air are alternately arranged.