JP2804640B2 - Apparatus and method for cooling semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

(Table of Contents) ・ Industrial application fields ・ Prior art (FIG. 3) ・ Problems to be solved by the invention ・ Means for solving the problems ・ Function ・ Embodiments (1) First Embodiment ( (Fig. 1) (2) Second embodiment (Fig. 1) (3) Third embodiment (Fig. 2)-Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling device and a cooling method for a semiconductor device, and more particularly, to a cooling device and a cooling method for a semiconductor device which is mounted at a high density and generates a large amount of heat.

In recent years, as the density of semiconductor devices has increased, it has been necessary to suppress a rise in temperature due to heat generated during operation of the semiconductor device.
It is very important to improve the performance of a device using a semiconductor device.

[0004]

2. Description of the Related Art FIGS. 3A and 3B are configuration diagrams of a cooling device for explaining two different types of conventional cooling methods using a liquid as a refrigerant.

FIG. 3A shows a conduction water cooling device for cooling a semiconductor device with water through a heat conduction member. In the drawing, reference numeral 1 denotes a cooling pipe formed of a metal having a high thermal conductivity, in which cooling water flows. Flow through. Reference numerals 2a and 2b denote semiconductor chips, which are mounted on the circuit board 5 at high density and serve as objects to be cooled.
The heat conductive compound 3 is interposed so that the surfaces of the a and 2b and the surface of the cooling pipe 1 come into contact with each other with a small thermal resistance. Reference numeral 4 denotes an insulating film formed on the surface of the cooling pipe 1 so that the insulation between the semiconductor chips 2a and 2b and the cooling pipe 1 is maintained.

Although this conduction water cooling device has a considerably high cooling efficiency, if the unevenness of the surface of the object to be cooled becomes complicated, an air layer intervenes between the surfaces of the objects to be cooled 2a and 2b and the cooling pipe 1. Therefore, there is a problem that the contact thermal resistance increases. In order to solve this problem, the objects to be cooled 2a, 2b
May be immersed in a cooling liquid. In this case, it is necessary to use an insulating cooling liquid having low corrosivity and relatively high thermal conductivity instead of highly corrosive water.

FIG. 3B shows a boiling cooling device for directly immersing a semiconductor device in a fluorocarbon as such a cooling liquid 7 to cool the semiconductor device, and reference numeral 6 in the drawing denotes a container in which a cooling liquid 7 such as a fluorocarbon is put. The openings 8a and 8b are provided in the upper part of the container 6 so that the circuit boards 5a to 5d on which the semiconductor chips are mounted can be put in the container 6. 9a and 9b can be immersed in the cooling liquid 7 by suspending the circuit boards 5a to 5d, and close the openings 8a and 8b to
An external lead that is electrically connected to the circuit boards 5a to 5d is formed by a lid that seals the inside. Then, electric signals and the like can be sent to the semiconductor chips mounted on the circuit boards 5a to 5d via the external leads.

[0008] In such a cooling device, the cooling liquid 7 boils at a portion in contact with the semiconductor chip that is generating heat, thereby removing heat, thereby cooling the semiconductor chip.

[0009]

However, in the above-mentioned method using boiling cooling, water having a high thermal conductivity cannot be used as the cooling liquid 7, so that the cooling efficiency is not sufficient, and furthermore, the density of the semiconductor device is increased. There is a limit as the amount of heat generated increases.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a cooling device and a cooling method for a semiconductor device capable of greatly improving a cooling capacity. .

[0011]

The first object of the present invention is to provide a container for holding a cooling liquid, a semiconductor device as a member to be cooled, and internal and external pressure when immersed in the cooling liquid. A second aspect of the present invention is a solution to the semiconductor device cooling device, wherein the device has a flexible bag that contracts due to a difference and is in close contact with the semiconductor device. The first characterized in that
The first or second aspect of the present invention is a third aspect of the present invention, which has a means for reducing the pressure inside a container containing the cooling liquid, which is solved by the semiconductor device cooling device according to the invention.
According to a fourth aspect of the present invention, a semiconductor device as a cooled object is contracted by being immersed in a first cooling liquid and contracted by an internal and external pressure difference. The semiconductor device is stored in a flexible bag, and the semiconductor device is cooled by immersing the bag in the first cooling liquid stored in the container to cool the semiconductor device. According to a fifth aspect of the present invention, there is provided a method of cooling a semiconductor device according to a fourth aspect, wherein the semiconductor device is stored in the bag, and the inside of the bag is evacuated to cool the semiconductor device. ,
A sixth aspect of the present invention is the semiconductor device according to the fourth or fifth aspect, wherein the inside of the container is depressurized to lower the boiling point of the first cooling liquid to cool the semiconductor device. The periphery of the semiconductor device inside the bag, which is solved by the cooling device and is the seventh invention, is the first invention.
The semiconductor device is cooled by filling the semiconductor device with a second cooling liquid having a boiling point higher than that of the second cooling liquid and having an insulating property, and cooling the semiconductor device. An eighth aspect of the present invention is that the periphery of the semiconductor device inside the bag is filled with a second cooling liquid having an insulating property, and the inside of the container containing the first cooling liquid is depressurized, whereby The semiconductor device is cooled by setting the boiling point of the first cooling liquid lower than the boiling point of the second cooling liquid to cool the semiconductor device. The first cooling liquid is water, and the second cooling liquid is a fluorocarbon, and is solved by the semiconductor device cooling method according to any one of the fourth to seventh inventions. .

[0012]

According to the semiconductor device cooling device of the present invention,
A container for containing a cooling liquid, and a flexible bag that accommodates the semiconductor device as the object to be cooled and contracts due to a pressure difference between the inside and the outside when immersed in the cooling liquid so as to be in close contact with the semiconductor device. ing. The semiconductor device does not directly contact the cooling liquid. Therefore, corrosion of the semiconductor device can be prevented. In addition, the semiconductor device has a flexible bag that shrinks due to a pressure difference between the inside and the outside when the semiconductor device is housed and immersed in a cooling liquid so as to be in close contact with the semiconductor device. For this reason, when the semiconductor device is stored in the bag for the test and immersed in the cooling liquid, the semiconductor device in the bag immediately comes into contact with the cooling liquid only via the bag wall,
In addition, no air having low thermal conductivity is interposed between the semiconductor device and the cooling liquid. Thus, heat can be efficiently radiated from the semiconductor device that has generated heat by the application of the power for the test.

Second, since the inside of the flexible bag is provided with a means for evacuating the inside of the flexible bag, the inside of the bag is decompressed. For this reason, the bag is shrunk by the external pressure and closely adheres to the housed semiconductor device, and the air having a small thermal conductivity interposed between the semiconductor device and the cooling liquid can be eliminated.

Third, since a means for reducing the pressure inside the container containing the cooling liquid is provided, the boiling point of the cooling liquid can be lowered. Therefore, when heat is generated by applying power to the semiconductor device, Since the boiling of the cooling liquid occurs at a lower temperature, the heat of vaporization can be efficiently removed from the semiconductor device.

According to the method of cooling a semiconductor device of the present invention, fourthly, the semiconductor device as the object to be cooled is stored in a flexible bag, and the bag is immersed in the first cooling liquid stored in the container. Therefore, the bag is brought into close contact with the semiconductor device due to the pressure of the liquid, and the air having a small thermal conductivity interposed between the cooling liquid and the semiconductor device can be removed.

Fifth, since the semiconductor device is housed in the bag and the inside of the bag is evacuated, the bag shrinks and has a low thermal conductivity interposed between the housed semiconductor device and the cooling liquid. The atmosphere can be excluded.

Sixth, since the boiling point of the first cooling liquid is lowered by depressurizing the inside of the container, the boiling of the cooling liquid due to the heat generated by the semiconductor device occurs at a lower temperature, so that the semiconductor device can be efficiently manufactured. From heat of vaporization.

Seventh, the periphery of the semiconductor device inside the bag is
Since the second cooling liquid having the insulating property is filled, it is possible to prevent the air from intervening between the semiconductor device and the cooling liquid while maintaining the insulating property. Further, since the first cooling liquid, for example, water outside the bag has a lower boiling point than the second cooling liquid, for example, fluorocarbon inside the bag, the semiconductor device can be more efficiently boiled by the first cooling liquid. From heat of vaporization. Further, since the evaporation mainly occurs outside the bag, the supply of the first cooling liquid can be easily performed.

Eighth, in some cases, the pressure around the first cooling liquid outside the bag is reduced to make the boiling point of the first cooling liquid lower than the boiling point of the second cooling liquid. As in the fourth case, the supply of the first cooling liquid is facilitated since the evaporation mainly takes place outside the bag.

[0020]

【Example】

(1) First Embodiment FIG. 1A is a configuration diagram illustrating a cooling device for a semiconductor device according to a first embodiment of the present invention.

In FIG. 1A, reference numeral 10 denotes a sealed container for storing water 18 as a cooling liquid, and openings 17a and 17b for taking in and out the object to be cooled, and exhaust air for reducing the pressure inside the container 10. An exhaust port 16 connected to the apparatus and an inlet (not shown) for introducing a cooling liquid are provided. 11a and 11b are bags made of an imide resin film.
Semiconductor chips (cooling target) 1 mounted on the circuit boards 12a and 12b in the bags 11a and 11b are mounted inside the container 10 so that the openings of the openings 11a and 11b are common to the openings 17a and 17b.
3 are stored. Further, since the bags 11a and 11b are flexible and freely deformed, when the surroundings are filled with the cooling liquid or when the bags 11a and 11b are
When the pressure in the insides a and 11b is reduced, the bags 11a and 11b are contracted and deformed by the external pressure and come into close contact with the semiconductor chip 13. 14a and 14b suspend the circuit boards 12a and 12b and
a, 11b, which can be held inside, and which closes the openings 17a, 17b to seal the inside of the container 10 and the bags 11a, 11b.
It has exhaust ports 15a and 15b connected to an exhaust device for reducing the pressure inside the a and 11b. Also, lids 14a, 14b
Are formed with external leads (not shown) that are electrically connected to the circuit boards 12a to 12d.
An electric signal or the like can be sent to the semiconductor chip 13 mounted on 12a, 12b. The circuit boards 12a, 12b
The semiconductor chip 13 mounted on the device constitutes one semiconductor device.

As described above, according to the cooling device for a semiconductor device of the first embodiment of the present invention, the container 10 for storing water as the cooling liquid and the semiconductor chip 13 as the object to be cooled are stored. Since the semiconductor chip 13 has the flexible bags 11a and 11b immersed in water, the semiconductor chip 13 does not directly contact the water 18. Therefore, it is possible to prevent corrosion of the electrodes and the like on the semiconductor chip 13. Since the bags 11a and 11b are flexible, they deform according to the shape of the semiconductor chip 13 due to the pressure of water. For this reason, the adhesion to the semiconductor chip 13 is increased, and the air having a low thermal conductivity, which is interposed between the water and the semiconductor chip 13, can be eliminated.

Further, since an exhaust device for reducing the pressure inside the flexible bags 11a and 11b is connected through the exhaust port 16, the pressure inside the bags 11a and 11b is reduced. Because of this, the bag
11a and 11b are shrunk and deformed by external pressure and adhere to the housed semiconductor chip, so that air with low thermal conductivity, which is interposed between the semiconductor chip 13 and water, can be eliminated.

Further, since an exhaust device for reducing the pressure inside the container 10 containing water is connected through the exhaust port 16, the inside of the container 10 can be reduced in pressure to lower the boiling point of water. Therefore, when heat is generated by applying power to the semiconductor chip 13, the boiling of water occurs at a lower temperature.
Heat of vaporization can be efficiently removed from the semiconductor chip 13.

As described above, according to the semiconductor device cooling device of the first embodiment of the present invention, the cooling capacity can be greatly improved. In addition, removal by maintenance or the like is easier than that of directly immersing in a liquid.

In the first embodiment of the present invention, the bags 11a,
Although an imide resin film is used as the member of 11b,
Any material having high strength and thermal conductivity and being flexible may be used. (2) Second Embodiment Next, a method for cooling a semiconductor device according to a second embodiment of the present invention will be described with reference to FIGS. 1 (a) and 1 (b).

First, as shown in FIG. 1 (a), the bags 11a, 11a,
The semiconductor chip 13 mounted on the circuit boards 12a and 12b is housed inside the 11b.

Next, as shown in FIG. 1B, water 1 as a cooling liquid is introduced into the container 10 from a water inlet (not shown).
Insert 8. At this time, since the bags 11a and 11b are formed of a flexible imide resin film, the bags 11a and 11b contract and deform according to the shape of the semiconductor chip 13 by water pressure.
3 makes it more adherent. In order to further improve the adhesiveness, it is possible to positively reduce the pressure inside the bags 11a and 11b with an exhaust device. Thereby, the semiconductor chip 1
Atmosphere having a small thermal conductivity is excluded from between 3 and water 18, so that only bags 11a and 11b are interposed.

Next, power is applied to the semiconductor chip 13 from an external lead (not shown) to operate the semiconductor device. At this time, the semiconductor chip 13 generates heat, and when the ambient temperature reaches about 100 ° C. due to the heat, the water 18 boils and heat of vaporization is lost. Thereby, the temperature rise of the semiconductor chip 13 is suppressed.

The inside of the container 10 can be evacuated by the exhaust device through the exhaust port 16 to reduce the pressure inside the container 10. As a result, since the boiling of water due to the heat generated by the semiconductor device occurs at a temperature lower than 100 ° C., the heat of vaporization can be more efficiently removed.

Further, by supplying fresh water as a cooling liquid from the outside without interruption and discharging heated water, the cooling effect can be further increased. As described above, according to the semiconductor device cooling method of the second embodiment of the present invention, the semiconductor chip 13 as the object to be cooled is placed in a bag.
Since the semiconductor chip 13 is immersed in the water 18 while being housed in the water 11a and 11b, the semiconductor chip 13 does not directly contact the water, so that the corrosion of the electrodes and the like on the semiconductor chip 13 can be prevented. Further, since the semiconductor chips 13 are housed in the flexible bags 11a and 11b, the bags 11a and 11b and the semiconductor chips 13 adhere to each other by the pressure of water, and the heat conductivity between the water and the semiconductor chips 13 is reduced. Intervention of small atmosphere can be reduced. Thereby, the cooling capacity can be significantly improved.

The semiconductor chips 13 are housed in the bags 11a and 11b, and the inside of the bags 11a and 11b is evacuated, thereby
The adhesion between the semiconductor chips 13 and 11a and 11b can be further increased. Thereby, the stored semiconductor chip 13
The air having a low thermal conductivity, which is interposed between the water and the water 18, can be further eliminated, and the cooling capacity can be further improved.

(3) Third Embodiment Next, a method for cooling a semiconductor device according to a third embodiment of the present invention will be described with reference to FIG.

The third embodiment differs from the second embodiment in that, as shown in FIG. 2, the peripheral portion of the semiconductor device inside the bags 11a and 11b is removed in order to exclude the atmosphere having low thermal conductivity. In addition, fluorocarbon (second cooling liquid) 19a, which has insulating properties and good thermal conductivity, is used as a cooling liquid.
19b. Since the fluorocarbons 19a and 19b have a boiling point (about 150 ° C.) higher than that of water, only the water (first cooling liquid) 20 that fills the outside of the bags 11a and 11b boils.

First, as shown in FIG. 2, a bag attached so that the openings 17a and 17b of the container 10 and the mouth are common.
After housing the semiconductor chip 13 mounted on the circuit boards 12a and 12b inside the 11a and 11b,
Fill the inside of the bags 11a and 11b with a and 19b.

Next, the container 10 is introduced through a water inlet (not shown).
Water 20 as a cooling liquid is put into the inside, and the outside of the bags 11a and 11b is filled. Next, power is applied to the semiconductor chip 13 from an external lead (not shown) to operate the semiconductor device. At this time, the semiconductor chip 13 generates heat due to power consumption, and the heat is transferred to the boundary with the water 20 partitioned by the bags 11a and 11b by the fluorocarbons 19a and 19b filled in the peripheral portion of the semiconductor chip 13. It is. This heat is removed as heat of vaporization by heating the water 20 and boiling the water 20. Thereby, the semiconductor chip 13
Temperature rise is suppressed.

The heat carried by the fluorocarbons 19a and 19b is removed by supplying the water 20 outside the bags 11a and 11b from the outside without interruption and discharging the warm water 20. . Thereby, the temperature rise of the semiconductor chip 13 is suppressed more efficiently.

As described above, according to the method for cooling a semiconductor device of the third embodiment of the present invention, the semiconductor device is
b, the periphery of the semiconductor device inside the bags 11a and 11b is filled with fluorocarbons 19a and 19b.
Therefore, since the semiconductor device does not come into direct contact with the water 20, corrosion of the semiconductor device can be prevented, and the presence of air between the semiconductor device and the water 20 is smaller than that in the second embodiment. Since the prevention can be further improved, the cooling effect can be further improved.

Further, since the fluorocarbons 19a and 19b inside the bags 11a and 11b have a higher boiling point than the water outside the bags 11a and 11b, the evaporation mainly occurs outside the bags 11a and 11b. Water can be easily supplied. Note that fluorocarbons 19a and 19b are used as the second cooling liquid.
In the case where another cooling liquid having a boiling point lower than or similar to the boiling point of water 20 is used instead of the bags 11a and 11b,
By reducing the pressure inside the container 10 containing the water 20 outside, the boiling point of the water 20 can be made lower than the boiling point of the second cooling liquid. Thereby, the same operation and effect as described above can be obtained.

In the third embodiment of the present invention, the water 20 is used as the first cooling liquid, but another cooling liquid may be used. In addition, fluorocarbon is used as the second cooling liquid.
Although 19a and 19b are used, other cooling liquids having insulating properties and high thermal conductivity may be used. Further, the boiling point of the second cooling liquid may be higher or lower than that of the first cooling liquid.

[0041]

As described above, according to the apparatus and method for cooling a semiconductor device of the present invention, the object to be cooled is stored in the bag and immersed in the cooling liquid. In this case, corrosion of the semiconductor device can be prevented.

Further, since the bag is flexible, the bag contracts and deforms in accordance with the shape of the object to be cooled in the bag by the pressure outside the bag or when the inside of the bag is decompressed, and the semiconductor device and the cooling liquid are separated. It is possible to reduce the atmosphere having a small thermal conductivity interposed therebetween. Thereby, the cooling capacity can be improved.

Further, by reducing the pressure inside the container containing the cooling liquid, the boiling point of the cooling liquid can be lowered. Therefore, when heat is generated by applying electric power to the semiconductor device, the boiling of the cooling liquid becomes lower. Therefore, the heat of vaporization can be efficiently removed from the semiconductor device.

Further, by filling the periphery of the semiconductor device inside the bag with the second cooling liquid having an insulating property, the atmosphere is interposed between the semiconductor device and the cooling liquid while maintaining the insulating property. Can be better prevented. Thereby, the cooling capacity can be further improved.

Further, since the first cooling liquid outside the bag has a lower boiling point than the second cooling liquid inside the bag,
The vaporization heat can be efficiently removed from the semiconductor device by the boiling of the first cooling liquid. In addition, since the evaporation mainly occurs outside the bag, the supply of the first cooling liquid can be easily performed. Further, the same operation and effect can be obtained by reducing the pressure around the first cooling liquid outside the bag so that the boiling point of the first cooling liquid is lower than the boiling point of the second cooling liquid.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a cooling device and a cooling method of a semiconductor device according to first and second embodiments of the present invention.

FIG. 2 is a configuration diagram illustrating a method for cooling a semiconductor device according to a third embodiment of the present invention.

FIG. 3 is a configuration diagram illustrating a conventional cooling device for a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cooling pipe, 2a, 2b, 13 Semiconductor chip (cooled body), 3 Heat conductive compound, 4 Insulating film, 5, 5a-5d, 12a, 12b Circuit board, 6,10 Container, 7 Cooling liquid, 8a , 8b, 17a, 17b opening, 9a, 9b, 14a, 14b lid, 11a, 11b bag, 15a, 15b, 16 exhaust port, 18 water (cooling liquid), 19a, 19b fluorocarbon (second cooling liquid), 20 water (first cooling liquid).

Claims (9)

(57) [Claims] A container for containing a cooling liquid, a semiconductor device as a member to be cooled, and a flexible material which is immersed in the cooling liquid and contracts due to a pressure difference between the inside and the outside to adhere to the semiconductor device. A cooling device for a semiconductor device, comprising: a bag; 2. The cooling device for a semiconductor device according to claim 1, further comprising means for exhausting the inside of the bag. 3. The apparatus according to claim 1, further comprising means for reducing the pressure inside the container containing the cooling liquid.
4. The cooling device for a semiconductor device according to claim 1. 4. The semiconductor device is housed in a flexible bag that contracts due to a pressure difference between inside and outside when immersed in the first cooling liquid and is in close contact with the semiconductor device as a cooled object, and is housed in a container. Cooling the semiconductor device by immersing the bag in the first cooling liquid. 5. The method for cooling a semiconductor device according to claim 4, wherein the semiconductor device is stored in the bag, and the inside of the bag is evacuated to cool the semiconductor device. 6. The method for cooling a semiconductor device according to claim 4, wherein the semiconductor device is cooled by reducing the boiling point of the first cooling liquid by reducing the pressure inside the container. . 7. The semiconductor device is cooled by filling a periphery of the semiconductor device inside the bag with a second cooling liquid having a higher boiling point than the first cooling liquid and having an insulating property. The method for cooling a semiconductor device according to claim 4, wherein: 8. The semiconductor device according to claim 1, wherein the periphery of said semiconductor device inside said bag is filled with a second cooling liquid having an insulating property.
5. The semiconductor device according to claim 4, wherein the semiconductor device is cooled by depressurizing the inside of the container containing the cooling liquid so that the boiling point of the first cooling liquid is lower than the boiling point of the second cooling liquid. Semiconductor device cooling method. 9. The method according to claim 4, wherein said first cooling liquid is water, and said second cooling liquid is fluorocarbon.