JPH037959Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling structure for a semiconductor device equipped with a refrigerant purification mechanism.

BACKGROUND ART In order to improve the processing power of computers, the unit elements of semiconductor devices such as LSIs are becoming smaller, and the number of elements is increasing.

That is, the electrode dimensions and conductor pattern widths that form unit elements have been extremely reduced, while the number of elements has increased to put VLSI into practical use.

In addition, the mounting method on wiring boards has been improved. Conventionally, each semiconductor chip was housed in a hermetic package and mounted on the wiring board, but in the future, multiple LSI chips will be mounted on ceramic chips. It has become common practice to create an LSI module by attaching it to a multilayer wiring board, such as a multilayer wiring board, and then attaching it to the wiring board as a replacement unit.

As unit elements become smaller and more dense, the amount of heat generated by semiconductor devices also increases.
Conventional air cooling methods make it impossible to maintain the temperature of the device within the maximum operating temperature range.

In other words, the maximum amount of heat generated by a unit chip was about 3 watts, but it is about to reach about 10 watts.

For these reasons, it is necessary to adopt a liquid cooling system in place of the conventional air cooling or forced air cooling system.

The present invention relates to a liquid cooling structure for semiconductor devices.

[Conventional technology]

Liquid cooling methods for electronic devices are well known for superconducting elements, etc., and use liquid nitrogen (N ₂ ),
Liquid Helicam (He) is used, and it is stored in a bottle-type container.

However, for air cooling semiconductor devices, there is no need to use such low temperatures, except for special applications such as gallium arsenide transistors that utilize high electron mobility. Any non-dissociable solution may be used, such as Freon (C ₂ Cl ₃ F ₃ , boiling point 49°C), various fluorocarbons such as C ₅ F ₁₂ (boiling point 30°C), C ₆ F ₁₄ (boiling point 56°C), etc. is used.

The boiling point of fluorocarbons can be adjusted by mixing fluorocarbons with various structural formulas.

FIG. 2 shows a conventional liquid cooling structure for semiconductor devices.

That is, a plurality of connectors 2 are installed on the bottom of a liquid cooling container 1 made of metal or plastic, and are configured to connect a wiring board 4 on which a semiconductor device 3 is mounted.

Further, a condenser 6 is placed above the liquid-cooled container 1 in which the refrigerant 5 is sealed, so that the container is cooled by water or the refrigerant.

In such a liquid cooling structure, when the semiconductor device 3 operates in a circuit and its temperature rises and exceeds the boiling point of the refrigerant 5, the refrigerant 5 in contact with the semiconductor device 3 boils, but at this time, the heat of vaporization is transferred from the semiconductor device 3. Temperature rise is suppressed to take away the heat.

Here, the vapor of the refrigerant vaporized by boiling is cooled in the condenser 6, liquefied, and dripped, and this cycle is repeated.

Although such liquid cooling devices are currently in use,
One of the drawbacks of this structure is the contamination of the refrigerant.

In other words, the semiconductor device 3 is attached to the wiring board 4 by a method such as soldering, but the flux used in this attachment process and the flux used when installing the connector to the liquid cooling container 1 are cleaned and cleaned. However, there is a problem in that when the circuit of the semiconductor device 3 is in operation, the refrigerant 5 dissolves due to convection inside the container at a high temperature, and the contaminated refrigerant 5 circulates inside the container. .

Although this is not a problem when the number of wiring boards mounted in the liquid cooling container 1 is small, as the number of wiring boards mounted increases, contamination of the refrigerant becomes a problem from the viewpoint of quality maintenance of the semiconductor device 3.

[Problem that the invention attempts to solve]

A problem when a semiconductor device is placed in a liquid-cooled container and cooled using a refrigerant is that the refrigerant becomes contaminated, and if this is significant, the impact on quality must be considered.

[Means for solving problems]

The above problem is that the liquid cooling device has an opening at the top.
Centered around the immersion chamber where semiconductor devices are installed,
In addition to having a preliminary chamber for storing refrigerant on the outer periphery,
It consists of a sealed container with a canopy above the preliminary chamber,
A cooling structure for semiconductor devices is adopted in which the refrigerant boils and overflows from the immersion chamber due to the temperature rise of the semiconductor device, vaporizes in the preliminary chamber, condenses in the canopy, and returns to the immersion chamber. This can be solved by

[Effect]

In this invention, the liquid cooling container has a double structure, and the contaminated refrigerant is stored in the preliminary chamber provided on the outer periphery, and the liquid refrigerant produced by condensing the vaporized refrigerant is stored in the central immersion chamber where the semiconductor device is installed. This prevents contamination of the refrigerant by adopting a device configuration that returns the refrigerant to

〔Example〕

FIG. 1A is a sectional view of a liquid cooling container according to the present invention, and FIG. 1B is a plan view illustrating the double structure of this container.

That is, the liquid cooling container 7 according to the present invention is an immersion chamber 8 in which a wiring board 4 with a semiconductor device 3 mounted thereon is installed.
It has a double structure with a preliminary chamber 9 surrounding it, and a partition wall 10 separating these two chambers is made of a pleated metal plate with good heat conduction, and an opening 11 is provided in the center of the upper part. There is.

Next, there is a canopy part 12 above the opening 11,
The vaporized refrigerant condenses in the canopy section 12, descends along this, accumulates in the gutter section 13, and returns to the immersion chamber 8 through the vertical gutter 14.

Further, cooling water is allowed to flow between the canopy part 12 and the liquid-cooled container 7 to improve condensation efficiency in the canopy part 12.

The mechanism of the cooling structure according to the present invention will be explained as follows.

The immersion chamber 8 is filled with a refrigerant 5, and when the semiconductor device 3 connected to the circuit through the connector 2 generates heat and its temperature rises to exceed the boiling point of the refrigerant 5, the refrigerant 5 in contact with it begins to boil. At this time, temperature rise is suppressed because the heat of vaporization is taken away from the semiconductor device.

Here, since the amount of heat generated per chip of the semiconductor device is huge, several watts, boiling generally occurs violently and bubbles are ejected from the opening 11, but at this time, a considerable amount of the refrigerant 5 is also pumped out into the preliminary chamber 9. flows.

Here, a partition wall 1 separating the immersion chamber 8 and the preliminary chamber 9
Since the refrigerant 5 has good heat conductivity and is formed in a pleated shape with a large contact area, the temperature of the refrigerant 5 flowing into the preliminary chamber 9 is not much different from the temperature of the immersion chamber 8.

Here, the canopy part 12 of the cold container and the immersion chamber 8 are in contact only through the opening part 11, whereas the refrigerant 5 that has flowed into the preliminary chamber 9 has a large amount of evaporation due to the contact over a wide area, and the vaporized gas is transferred to the canopy part 12. It is cooled, condensed and liquefied, and returned to the soaking chamber 8 through the downspout 14.

As described above, by repeatedly ejecting from the opening 11 and evaporating from the preliminary chamber 9, the contaminants in the preliminary chamber 9 gradually become concentrated, while the contaminant content in the immersion chamber 8 gradually decreases. go.

As described above, by using the apparatus according to the present invention, it is possible to eliminate the problem of refrigerant containing impurities circulating within the apparatus.

If the degree of contamination of the refrigerant 5 in the preliminary chamber 9 becomes severe, the tank 15 may be opened to drain the refrigerant, and an equal amount of new refrigerant may be injected to replace the refrigerant.

[Effect of idea]

As described above, by implementing the present invention, the problem of refrigerant contamination is eliminated, and the semiconductor device can be maintained in a clean environment.

Although the present invention has been described with reference to the case where a semiconductor device is cooled, the present invention can be implemented in the same manner even when other evaporated substances are liquid-cooled.

[Brief explanation of drawings]

FIG. 1A is a side sectional view of a liquid cooling container according to the present invention;
Figure B is a plan view illustrating the double structure. FIG. 2 is a side sectional view of a conventional liquid cooling container. It is. In the figure, 1 and 7 are liquid cooling containers, 2 is a connector,
3 is a semiconductor device, 4 is a wiring board, 5 is a refrigerant, 8 is an immersion chamber, 9 is a preliminary chamber, 10 is a partition, 11 is an opening, 12 is a canopy, 13 is a gutter, and 14 is a downspout. .

Claims (1)

[Scope of utility model registration request] The liquid cooling device has an opening at the top, is centered around an immersion chamber in which a semiconductor device is installed, and is equipped with an auxiliary chamber around the outer periphery of the immersion chamber for storing a refrigerant, and is composed of a sealed container having a canopy above the auxiliary chamber, A cooling structure for a semiconductor device, characterized in that a refrigerant that boils and overflows from an immersion chamber due to an increase in temperature of the semiconductor device vaporizes in a preliminary chamber, condenses in a canopy, and returns to the immersion chamber.