JPH10209358A - Radiation mechanism of semiconductor device mounted on printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain generation of a thermoelectromotive force and an electronic drift, and easily carry out inspection and check. SOLUTION: A water-cooling pipe 2 is arranged on one side of a cooling board 3 made of a metal. On the other side of the cooling board 3, a printed circuit board 7 is arranged, with a rubber-like plate 8 having good thermal conductivity provided between the boards. On the printed circuit board 7, an LSI 9 which is susceptible to heat or likely to generate heat is mounted. Over the printed circuit board 7, a metallic box 4 for closing the LSI 9 on the printed circuit board 7 is arranged. The box 4 and the printed circuit board 7 are compression-bonded and fixed to the cooling board 3 by a fixing member 12 such as a screw.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation mechanism for a semiconductor device mounted on a printed circuit board, and more particularly to a heat dissipation mechanism for a constant current power supply.

[0002]

2. Description of the Related Art Heat generated in a semiconductor device mounted on a printed circuit board is generated by a thermoelectromotive force (see-through) between dissimilar metals.
Beck effect), which causes noise in the signal, and also causes electron drift, resulting in signal disturbance (error).
Generate.

The thermoelectromotive force is generated in a portion where a temperature difference easily occurs between different kinds of metals such as a connection portion between an LSI lead and a wiring of a printed circuit board. Therefore, conventionally, the entire LSI lead on the printed circuit board and the entire wiring on the printed circuit board are covered with resin, and the temperature difference between the LSI lead and the wiring on the printed circuit board is reduced. Less
Noise generation is suppressed.

However, in this case, since the entire lead of the LSI and the entire wiring on the printed circuit board are covered with the resin, the LSI cannot be individually inspected and repaired. There is a disadvantage that it becomes difficult.

[0005] Signal disturbance due to electron drift can be avoided by disposing the printed circuit board in a thermostat and setting the temperature inside the thermostat higher than the temperature outside.

However, arranging all the printed circuit boards in a constant temperature bath has a disadvantage that the size of the constant temperature bath is increased and the cost is increased. In addition, the increase in the size of the thermostat causes unevenness in the temperature distribution inside the thermostat, and thus does not provide a sufficient measure against phenomena such as thermoelectromotive force and electron drift.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to efficiently release heat generated in a semiconductor device such as an LSI to the outside of the semiconductor device, and An object of the present invention is to provide a heat radiation mechanism that can prevent signal noise due to thermoelectromotive force and signal disturbance due to electron drift, and that can easily perform inspection and inspection.

[0008]

In order to achieve the above object, a heat radiating mechanism according to the present invention is provided with a cooling plate made of metal and a plate-shaped insulator interposed on one side of the cooling plate. And a plurality of semiconductor devices mounted on the printed circuit board.

The insulator is made of a rubber-like plate,
The printed circuit board is crimped and fixed to the cooling plate. The heat radiating mechanism of the present invention includes a cooling plate made of metal, a printed circuit board disposed on one surface side of the cooling plate with a plate-shaped insulator interposed therebetween, and a plurality of mounted on the printed circuit board. A semiconductor device; and a box that covers the printed circuit board and seals the plurality of semiconductor devices.

[0010] The insulator is formed of a rubber-like plate,
The box and the printed circuit board are pressed and fixed to the cooling plate by a fixing member. The box is made of metal.

The plurality of semiconductor devices have similar thermal properties to each other, for example, have a property that is susceptible to a change in the property due to a temperature change, or have a property that is easy to emit heat. .

The heat radiating mechanism of the present invention is further disposed on the other side of the cooling plate, and cooling means for cooling the cooling plate, for example, a water-cooled cooling pipe, a heat pipe, an electronic refrigeration element, and the like. Is provided.

[0013] An end of the cooling plate may be bent toward the other surface of the cooling plate, and a printed circuit board in contact with the end of the cooling plate may be provided on the other surface of the cooling plate. The heat dissipating mechanism of the present invention includes a unit case that covers elements such as the cooling plate, the insulator, the printed circuit board, the box, and the cooling means.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat radiating mechanism according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows the overall configuration of the heat dissipation mechanism of the present invention. Unit case 1
Is composed of an upper portion 1A and a lower portion 1B, and the upper portion 1A and the lower portion 1B can be freely combined and separated from each other. When the upper part 1A and the lower part 1B are joined, the unit case 1 becomes box-shaped, and the inside is closed. The unit case 1 is made of a metal such as aluminum or an aluminum alloy, and has a hole for the cooling pipe 2.

In the unit case 1, a cooling pipe 2, a cooling plate 3, boxes 4, 5 and a printed circuit board 6 are provided.
Are arranged respectively. The cooling pipe 2 is, for example, a water-cooled cooling pipe that circulates a liquid, and is made of a metal such as copper. The cooling plate 3 is made of aluminum, an aluminum alloy, or the like. Cooling pipe 2
Are arranged on one surface side of the cooling plate 3. Cooling pipe 2
Are meanderingly arranged on one side of the cooling plate 3 so as to cover all the one side of the cooling plate 3.

Two opposite ends of the cooling plate 3 are bent toward the cooling pipe 2. In this case, the cooling plate 3 is stabilized in the unit case 1 and the printed circuit board 6 can be mounted on one surface of the cooling plate 3.

When the printed circuit board 6 is mounted on one side of the cooling plate 3, the printed circuit board 6 has a digital circuit which is hardly affected by a temperature change and does not emit heat by itself. An LSI is mounted.

On the other side of the cooling plate 3, boxes 4 and 5 are arranged. The configuration on the other side of the cooling plate 3 is a main part of the present invention. That is, a plurality of boxes 4 and 5 are arranged on the other surface side of the cooling plate 3. Boxes 4 and 5 are made of metal such as iron, and LS
I (semiconductor device) is arranged. The boxes 4 and 5 are for reducing the influence of heat convection inside the boxes 4 and 5.

The number of boxes may be one, but in the case of a plurality of boxes, LSIs having thermal properties similar to each other are arranged in each box, so that the temperature in the boxes can be made uniform. Can contribute.

As shown in FIG. 2, in the boxes 4 and 5, an insulator (for example, a rubber plate) 8 having good thermal conductivity, a printed circuit board 7, and a plurality of LSIs 9 mounted thereon are provided.
Is arranged. In FIG. 2, reference numeral 10 denotes an external connection terminal mounted on the printed circuit board 7.

One surface of the insulator 8 having good thermal conductivity is in direct contact with the other surface of the cooling plate 3. The printed circuit board 7 is in direct contact with the other surface of the insulator 8 having good thermal conductivity.

Therefore, the heat generated from the LSI 9 is mainly led to the heat radiating plate 3 via the lead of the LSI 9 and the insulator 8 having good thermal conductivity. The printed circuit board 7 is also provided with a wiring 11.

When the insulator 8 having good thermal conductivity is formed of a rubber plate, the thickness of the rubber plate is most preferably about 3 mm in consideration of durability, insulation, heat dissipation and the like. It is effective.

The boxes 4 and 5 contain an LSI which is easily affected by a temperature change and a power which constitutes a power amplifier.
Like a transistor, a transistor with large power consumption that emits much heat by itself is mounted.

FIG. 3 is a sectional view of the heat radiation mechanism of FIG.
The section along the line is shown. An insulator 8 having good thermal conductivity is arranged between the printed circuit board 7 and the cooling plate (metal) 3. Fixing member (eg, screw) 12
Replaces the box 4, the printed circuit board 7 and the cooling plate 8 with
Each is provided for pressing and fixing to the cooling plate 3.
By using an elastic material such as a rubber plate for the insulator 8 having good thermal conductivity, the cooling plate 3 and the printed circuit board 7 are more closely adhered to each other with the insulator 8 interposed therebetween.
It becomes easy to guide the heat of I9 to the cooling plate 3.

The cooling plate 3 and the box 4 are provided inside the unit cases 1A and 1B.
A and 1B are arranged so as to float in the air so as not to make contact with them as much as possible. This is the cooling plate 3 and the box 4
However, this is because the influence of heat from the outside of the unit cases 1A and 1B is hard to float.

The cooling plate 3 is fixed to the lower case 1B of the unit case, for example, by a pin-shaped fixing member (such as a screw) 13.
It is fixed to. FIG. 4 shows the configuration of the cooling pipe. FIG. 5 is a sectional view taken along line VV of FIG.

The cooling pipe 2 is arranged in a meandering manner on one side of the cooling plate 3 so as to cover the entire one side of the cooling plate 3. The cooling pipe 2 is arranged, for example, in contact with one surface of the cooling plate 3 so that the LSI 9 can be arranged on the cooling pipe 2 when the printed circuit board 6 is mounted on one surface of the cooling plate 3. It is. Further, in this embodiment, a water-cooling cooling pipe is used for the cooling unit, but a heat pipe or an electronic refrigeration element may be used instead.

The first feature of the heat radiating mechanism is that the printed circuit board 7 is formed by interposing an insulator (for example, a rubber-like plate (rubber plate)) 8 having good thermal conductivity on the cooling plate 3. It is directly mounted on the top.

As a result, heat generated in the LSI 9 is mainly released to the cooling plate 3 via the lead of the LSI 9 and the insulator 8 having good thermal conductivity.
In addition, the temperature of the printed circuit board 7 can be made equal to the temperature of the cooling plate 3 and the temperature of the printed circuit board 7 can be made uniform.

Further, since the printed circuit board 7 is pressed and fixed to the cooling plate 3 with a rubber-like plate having good thermal conductivity and elasticity interposed therebetween, the heat of the LSI 9 is further released to the cooling plate 3. Easier to do.

The second feature of the heat radiation mechanism is that one side of the printed circuit board 7 on which the LSI is mounted is covered with metal (for example, iron) boxes 4 and 5, and the boxes 4 and 5 are heated. It is mounted on the cooling plate 3 with an insulator 8 having good conductivity.

Thus, the heat in the space inside the boxes 4 and 5 is released to the cooling plate 3 via the boxes 4 and 5 and the insulator 8 having good thermal conductivity. Further, since the temperature inside the boxes 4 and 5 does not fluctuate due to the temperature outside the boxes 4 and 5 and further outside the unit case 1, the temperature inside the boxes 4 and 5 is made uniform. At the same time, the effects of thermal convection can be eliminated.

Since the boxes 4 and 5 are attached to the cooling plate 3 by fixing members 12 such as screws, the inspection and inspection of the LSI 9 on the printed circuit board 7 can be easily performed by removing the fixing members. Can be performed.

A third feature of the heat dissipation mechanism is that a block is formed for each LSI whose thermal properties are similar, for example, a block made of an LSI which is easily affected by heat is arranged in the box 4, The point is that a block composed of an LSI which easily emits a large amount of heat is arranged in the box 5 and blocks composed of other LSIs are arranged on the printed circuit board 6.

As a result, the heat convection inside the boxes 4 and 5 can be reduced, and the signal noise due to the thermoelectromotive force and the signal disturbance due to the electron drift can be prevented in the LSI which is easily affected by heat. .

As described above, according to the heat dissipation mechanism of the present invention, heat generated in a semiconductor device such as an LSI can be efficiently released to the outside of the semiconductor device, and signal noise due to thermoelectromotive force and signal noise due to electron drift. Can be prevented, and inspection and inspection can be easily performed.

[0038]

Embodiments of the present invention will be described below. FIG. 6 shows a circuit configuration of a constant current power supply device.
The constant current power supply circuit 20 is formed on a printed circuit board, and the printed circuit board is disposed in a power supply device to which the heat dissipation mechanism of the present invention is applied. That is, the elements constituting the constant current power supply circuit 20 are divided into a plurality of blocks each composed of elements having similar thermal properties, and each block is a printed circuit board inside the box or a printed circuit board outside the box. Mounted on

The power supply 21 is provided outside the power supply unit (outside the unit case) to which the heat radiation mechanism of the present invention is applied, and supplies power to the constant current power supply circuit 20 inside the power supply unit (inside the unit case). It is provided through terminals P and P '.

The load 22 is provided outside the power supply device (outside the unit case) to which the heat radiation mechanism of the present invention is applied. The load 22 receives a constant current generated by the constant current power supply circuit 20 at an output terminal. It is supplied via O, O '.

The digital / analog converter 23 receives digital signals S and S ′ for determining the value of the output current via input terminals C and C ′. The reference voltage of the reference voltage generator 27 is input to the digital / analog converter 23.

The digital / analog converter 23 converts the reference voltage into analog signals corresponding to digital signals (digital numerical values) S and S ′, and supplies the analog signals to the error amplifier 24.

The voltage between the current detection resistors 25 is input to a current detection buffer amplifier 28. The error amplifier 24 compares the output signal of the digital / analog converter 23 with the output signal of the current detection buffer amplifier 28, and outputs the output signal of the current detection buffer amplifier 28 (the voltage between the current detection resistors 25).
Control the current power amplifier 26 so that the output signal of the digital / analog converter 23 matches the output signal of the digital / analog converter 23.

In the constant current power supply circuit 20, the load 2
The accuracy of the current supplied to 2 depends on signal noise and electron drift due to thermoelectromotive force in the digital / analog converter 23, the error amplifier 24, the current detection resistor 25, and the reference voltage generation circuit 27, together with the resolution and gain of the circuit element. It is also affected by signal disturbances.

That is, in order to improve the accuracy of the output current in the constant current power supply device, the signal noise due to the thermo-electromotive force in the digital / analog converter 23, the error amplifier 24, the current detection resistor 25, and the reference voltage generation circuit 27 is reduced. It is important to prevent signal disturbance due to electron drift.

Therefore, it is very significant to apply the heat dissipation mechanism of the present invention to a circuit element constituting a constant current power supply. The present invention can be applied not only to the constant current power supply described in the above embodiment but also to a constant voltage power supply, a measuring instrument having a circuit for amplifying a small signal, a control device requiring high precision, and the like. it can.

Further, if the present invention is applied to, for example, a circuit for amplifying a signal of a thermocouple, it is possible to detect a signal of a level which was conventionally buried in noise and could not be detected. Become.

[0048]

As described above, according to the heat dissipation mechanism of the semiconductor device mounted on the printed circuit board of the present invention, the following effects are obtained. First, since the printed circuit board is directly mounted on the cooling plate with an insulator having good thermal conductivity interposed, the heat of the LSI can be efficiently released. Further, one surface side of the printed circuit board on which the LSI is mounted is covered with a metal box.
As a result, the temperature of the printed circuit board in the box becomes
Because of the uniformity, for example, the temperature difference between the wiring on the printed circuit board and the lead of the LSI is eliminated, and the signal noise due to the thermoelectromotive force is also reduced. The temperature inside the box is
Since it is not affected by the temperature outside the box, LSI
, And drift of the signal is also eliminated.

That is, if the circuit in the box is used, a minute current can be detected. For example, the control of the load of the constant current power supply device can cope with a minute change in the load amount.

Further, if the box is attached to the cooling plate with a fixing member such as a screw, the inspection and inspection of the LSI on the printed circuit board can be easily performed by removing the fixing member.

Also, since LSIs having similar thermal properties are classified and each LSI is arranged in a different box, the heat convection inside each box can be reduced, and the inside of the box can be reduced. In this LSI, signal noise due to thermal electromotive force and signal disturbance due to electron drift can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration of a heat radiation mechanism according to an embodiment of the present invention.

FIG. 2 is a diagram showing a main part of a heat radiation mechanism according to the embodiment of the present invention.

FIG. 3 is a sectional view taken along the line III-III in FIG. 1;

FIG. 4 is a diagram showing the arrangement of cooling pipes in detail.

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

FIG. 6 is a diagram showing a circuit configuration of a constant current power supply device to which the present invention is applied.

[Explanation of symbols]

 1: unit case, 2: cooling pipe, 3: cooling plate, 4,5: box, 6,7: printed circuit board, 8: insulator with good thermal conductivity, 9: LSI, 10: external connection Terminal: 11: wiring, 12, 13: fixing member, 20: constant current power supply circuit, 21: power supply, 22: load, 23: digital / analog converter, 24: error amplifier, 25: current detection resistor, 26: Current power amplifier, 27: reference voltage generation circuit, 28: current detection buffer amplifier.

Claims (10)

[Claims] 1. A cooling plate made of metal, a printed circuit board arranged on one side of the cooling plate with a plate-shaped insulator interposed therebetween, and a plurality of semiconductor devices mounted on the printed circuit board A heat radiation mechanism comprising: 2. The heat radiating mechanism according to claim 1, wherein the insulator is formed of a rubber-like plate, and the printed circuit board is pressed and fixed to the cooling plate. 3. A cooling plate made of metal, a printed circuit board arranged on one side of the cooling plate with a plate-shaped insulator interposed therebetween, and a plurality of semiconductor devices mounted on the printed circuit board And a box that covers the printed circuit board and hermetically seals the plurality of semiconductor devices. 4. The box according to claim 3, wherein the insulator is formed of a rubber-like plate, and the box and the printed circuit board are pressed and fixed to the cooling plate by a fixing member. Heat dissipation mechanism. 5. The heat radiating mechanism according to claim 3, wherein said box is made of metal. 6. The heat radiating mechanism according to claim 3, wherein said plurality of semiconductor devices have similar thermal properties to each other. 7. The heat radiating mechanism according to claim 3, wherein the plurality of semiconductor devices have a property of being easily affected by a change in characteristics due to a temperature change or a property of easily emitting heat. 8. The heat radiating mechanism according to claim 1, further comprising a cooling unit disposed on the other surface side of said cooling plate for cooling said cooling plate. 9. The heat dissipation mechanism according to claim 8, wherein an end of the cooling plate is bent toward the other surface of the cooling plate,
A heat dissipating mechanism, comprising: a printed circuit board in contact with an end of the cooling plate on another side of the cooling plate. 10. A heat radiation mechanism according to claim 1, further comprising a unit case for sealing the heat radiation mechanism according to claim 1.