JPH06342862A - Liquid-cooled semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a liquid cooled semiconductor device equipped with a cooling device which improves a capacity of cooling each of semiconductor elements mounted in large numbers on a base, without being accompanied by an increase in the amount of circulation of a refrigerant, and also reduces a temperature distribution on an element surface. CONSTITUTION:A nozzle 3 which communicates with a refrigerant supply header 6 and wherein a restricting member 4 reducing the section of a flow passage in the nozzle sharply in the shape of steps is provided at the part of a refrigerant jetting port 10 positioned in the fore end of the nozzle is disposed for each of a number of semiconductor elements arranged on a base 1, so that it projects toward the semiconductor element 2, and a refrigerant return header 7 is provided between the refrigerant jetting port 10 and the refrigerant supply header 6 so that it traverses the nozzle 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device in which a semiconductor element or the like is immersed in a liquid and directly cooled, and more particularly to an ultra high speed computer having a high heat density element.

[0002]

2. Description of the Related Art With the progress of high integration technology of semiconductor devices and high-density mounting of devices on a substrate, liquid cooling in which a large amount of heat generated from the device is removed by directly immersing the device in a liquid Ultra-high speed computers have been proposed. For example, in Japanese Utility Model Publication No. 3-7960, a coolant is put in a compartment in which a substrate in which a plurality of elements are arranged is dipped and a pressure compartment in which a pressurized refrigerant is sprayed through nozzles provided facing each element. There has been proposed a liquid cooling device which constitutes a sealed container and cools an element by using jet boiling heat transfer of a refrigerant liquid.
In this device, since the collision jet and the boiling of the refrigerant liquid are used together, the cooling capacity thereof is remarkably increased as compared with the conventional device, but in order to further improve the cooling capacity, the refrigerant to each nozzle It is necessary to increase the supply amount and reduce the diameter of the nozzle to increase the jet velocity. However, in the present liquid cooling device, the refrigerant supply amount is increased, the load on the refrigerant circulation pump is increased due to the increase in the flow velocity, the device is enlarged, and the boiling is suppressed in the jet collision region caused by the increase in the flow velocity. No consideration is given to the delay of the computer operation caused by the nonuniform cooling on the element surface and the nonuniform element surface temperature distribution due to the action.

As a device for increasing the cooling capacity while suppressing the increase in the refrigerant circulation amount to a small extent, a device provided with a second nozzle having a narrowed cross-sectional shape around the first nozzle is disclosed in Japanese Patent Laid-Open No. 298054. Has been proposed to. With this device,
Due to a kind of jet pump effect, the refrigerant liquid filling the periphery of the element is made to flow again on the element surface, so that the refrigerant liquid can be effectively utilized and the refrigerant circulation amount can be reduced to some extent. However, driving the refrigerant liquid filling the periphery of the element reduces the jet speed of the refrigerant liquid ejected from the first nozzle, and increases the speed on the element surface and the cooling capacity by increasing the temperature boundary layer thickness. To bring about a decline,
The coolant liquid around the device warmed by the device is again guided to the surface of the device, and the cooling capacity is not lowered due to the rise of the coolant temperature.

[0004]

In the conventional liquid-cooled semiconductor device, in a substrate on which a large number of semiconductor elements that consume a large amount of power are mounted, the cooling capacity of each semiconductor element is limited and the cooling capacity is increased. In such a case, the amount of refrigerant circulation must be increased, which causes a problem that the cooling device becomes larger, the pump power increases, and the temperature distribution on the element surface increases.

An object of the present invention is to improve the cooling capacity of each semiconductor element mounted on a substrate without increasing the amount of refrigerant circulation, and to provide a liquid-cooled semiconductor equipped with a cooling device for reducing the temperature distribution on the element surface. To provide a device.

[0006]

In order to achieve the above object, a semiconductor cooling device of the present invention includes a refrigerant supply header for supplying a refrigerant to a plurality of semiconductor elements arranged on a substrate, and a refrigerant supply header. In a liquid-cooled semiconductor device including at least one jet nozzle that is provided to eject a refrigerant to each semiconductor element, and a refrigerant return header that is provided in communication with each jet nozzle and is provided adjacent to a refrigerant supply header, the jet flow Each jet nozzle is constituted by a nozzle provided with a member that rapidly reduces the nozzle cross section near the outlet.

[0007]

According to the semiconductor cooling device of the present invention, since the nozzle cross section is sharply narrowed in the vicinity of the jet outlet of the jet nozzle, the refrigerant circulation amount and the pressure loss are not significantly increased. In addition, the jet speed of the refrigerant can be increased by the contraction effect in the throttle part, and the cavitation bubbles generated in the negative pressure region of the contraction part promote the generation of boiling bubbles in the jet collision region on the element surface. Therefore, boiling is performed on the element surface from the jet collision area to the wall jet area, the heat transfer form on the element surface is the same, and therefore the temperature distribution of the temperature distribution on the element surface is made uniform. .

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a liquid-cooled semiconductor module showing an embodiment of the present invention. Electrical connection member 5 on substrate 1
The nozzle 3 communicating with the coolant supply header 6 is provided in each of the plurality of semiconductor elements (elements) 2 arranged via the element 2.
The sleeve-shaped throttle member 4 that sharply reduces the cross-section of the flow path in the nozzle stepwise is provided at the portion of the refrigerant ejection port 10 located at the tip of the nozzle. A refrigerant return header 7 is provided across the nozzle 3 between the refrigerant ejection port 10 and the refrigerant supply header 6.

The operation of the present invention will be described with reference to FIG. The supercooled refrigerant, which has a boiling point lower than the element temperature represented by, for example, fluorocarbon, and is electrically insulated and guided to the nozzle 3 from the refrigerant supply header 6 is a throttle member provided at the refrigerant ejection port 10 portion. 4, the refrigerant is rapidly contracted and accelerated, and inside the throttle member 4, a part of the refrigerant flow is separated from the inner wall of the throttle member to form a contracted flow 11 which forms the refrigerant outlet 1
It is ejected from 0 toward the element 2. The jet flow colliding with each element 2 changes its flow direction by 90 degrees and flows radially on the element surface, but at this time, the sensible heat and latent heat absorb the heat from the element 2 to heat it and generate boiling bubbles. Flows to. Here, there are cases where only separation vortices are formed in the separation part and cases where cavitation bubbles are generated due to depressurization, depending on the degree of the strength of the refrigerant jet port 10 sudden reduction. A jet with a large turbulence component or a jet with a mixture of bubbles will be jetted to the element 2, promoting the generation of boiling bubbles on the element surface,
Boiling heat transfer rate increases. Further, the jet flow velocity is accelerated by the contraction flow or the inclusion of bubbles, and the convection heat transfer coefficient is increased.
The boiling and the increase in the convective heat transfer coefficient increase the amount of heat that can be removed from the device and enable higher integration of the device, which enables the high speed operation of the computer. Further, promotion of boiling bubble generation in the jet collision region can promote active boiling over the entire element surface, and can make the temperature distribution on the element surface uniform. As a result, the threshold of the element operation can be set within a narrow range, so that the operation speed of the computer can be further increased.

On the other hand, the refrigerant in the gas-liquid two-phase state containing the boiling bubbles reaching the end portion of the element 2 is collected in the refrigerant return header 7 and discharged from the element portion. Here, it is necessary to avoid that the refrigerant jet stream injected from the refrigerant jet port 10 is disturbed by the influence of the flow in the refrigerant return header 7 that flows substantially perpendicular to the jet stream, but for that purpose, It is necessary to make the refrigerant ejection port 10 as close as possible to the element surface, increase the flow passage cross-sectional area of the refrigerant return header 7 and reduce the flow velocity in the refrigerant return header, and to lengthen the nozzle 3. There must be. Here, the flow loss of the refrigerant in the nozzle increases in proportion to the length of the nozzle. However, by providing the throttle member 4 only at the refrigerant jet port 10 portion shown in this embodiment, the throttle flow is maintained while maintaining the required jet speed. In most of the nozzles other than the member 4, the nozzle diameter can be made large and the refrigerant flow velocity in the nozzle can be slowed down, so that the flow loss in the nozzle is small, and therefore the refrigerant circulation pump (not shown).
Can reduce the burden of. As a result, the volume of the cooling device can be reduced, so that the liquid cooling computer device can be downsized, and the transmission distance can be shortened to improve the operation speed. Further, the reduction of the burden of the refrigerant circulation pump serves to reduce the power consumption of the pump.

FIG. 3 is a sectional view showing another embodiment of the present invention. The throttle member 41 in the portion of the refrigerant ejection port 10 located at the tip of the nozzle 3 is constituted by an orifice ring, and the other configurations are the same as those of the embodiment shown in FIG.
In this embodiment, the formation of the separation vortex on the downstream side of the throttle member 41 becomes more remarkable than in the embodiment shown in FIG.

FIG. 4 is a sectional view showing a second embodiment of the present invention. The throttle member 42 at the portion of the refrigerant ejection port 10 located at the tip of the nozzle 3 is formed of a ring having a substantially arcuate cross section. In this embodiment, since the shape of the throttle portion is connected by a smooth curve, the effect is reduced in terms of formation of peeling, but since the throttle member 42 can be formed by drawing from the nozzle outer periphery, The nozzle can be easily manufactured.

FIG. 5 is a sectional view showing a third embodiment of the present invention. The thickness t of the nozzle wall at the portion of the refrigerant outlet 10 located at the tip of the nozzle 3 is formed thick so as to satisfy the relationship of t> D / 2 (D is the inner diameter of the nozzle), and the refrigerant outlet 10 and the element 2 are connected to each other. The distance H is set to be small so as to satisfy the relationship of H <D / 4. In the present embodiment, the flow of the refrigerant is accelerated by the narrow flow path formed by the refrigerant ejection port 10 and the element 2, so that the generation of cavitation bubbles due to the decrease in static pressure is promoted. Here, in the present embodiment, the case where the nozzle itself is configured by a thick pipe is shown,
Only the portion of the refrigerant ejection port 10 may be thickened.

FIG. 6 is a sectional view showing a fourth embodiment of the present invention. Four nozzles 3 are arranged for one element 2, and the structure of the refrigerant ejection port 10 is the same as that of the embodiment shown in FIG. In the present embodiment, the flow velocity distribution of the wall jet on the element surface can be made more uniform than in the case of one nozzle, so that the temperature distribution on the element surface can be made more uniform. Here, in the present embodiment, the case where the number of nozzles is four is illustrated, but the number of nozzles may be four or more or less depending on the size of the element 2.

FIG. 7 is a sectional view showing a fifth embodiment of the present invention. The nozzle is formed by a structure in which four refrigerant ejection ports 101 are provided on the end face plate of the nozzle 31 whose end face on the element 2 side is closed. This embodiment has the effects of the embodiments of the present invention shown in FIGS. 5 and 6 together. Here, in this embodiment, the case where the number of the refrigerant ejection ports 101 is four is illustrated, but
The number may be four or more or less depending on the size of the element 2.

FIG. 8 is a sectional view showing another embodiment of the present invention. A nozzle 3 communicating with the coolant supply header 6 is arranged so as to project in the direction of the element 2 on each of a large number of semiconductor elements (elements) 2 arranged on the substrate 1 via electrical connection members 5, and the nozzle tip is provided. A throttle member 4 that sharply reduces the cross section of the flow path in the nozzle in a stepwise manner is provided at the portion of the refrigerant ejection port 10 located at. Further, a partition member 12 having a predetermined height for partitioning each element is provided by forming an element cooling chamber 13 around each element 2, and the refrigerant ejection port 10 extends from the element 2 to a predetermined dimension and is included in the element cooling chamber 13. Has been done.
Further, the element cooling chamber 1 divided by the partition member 12
A coolant return header 7 is formed between the coolant supply header 3 and the coolant supply header 6, and each element cooling chamber 13 has a coolant discharge port 14 that opens to the coolant return header 7 on the opposite side of the element 2. In the present embodiment, it is possible to prevent the jet flow from the nozzle from being disturbed by the influence of the flow of the return refrigerant flowing through the inside of the refrigerant return header 7, so that stable element cooling can be performed.

[0018]

According to the present invention, since the nozzle cross section is sharply narrowed in the vicinity of the jet flow outlet of the jet nozzle, the throttle portion can be increased without increasing the refrigerant circulation amount and the pressure loss. The jet flow velocity of the refrigerant can be increased by the constriction effect in the jet, and the cavitation bubbles generated in the negative pressure region of the contraction part promote the generation of boiling bubbles in the jet collision region on the element surface, so that the jet collision Boiling is performed on the element surface from the region to the wall jet region, the heat transfer form on the element surface is the same, and therefore the temperature distribution on the element surface is uniform. As a result, it is possible to further increase the degree of integration of the element, reduce the temperature margin with respect to the threshold of the element, and speed up the computer logic operation. In addition, since the load of the refrigerant circulation pump can be reduced, the power consumption of the pump can be reduced and the cooling device can be reduced, and therefore the liquid cooling computer device can be reduced, and the transmission wiring length can be shortened to reduce the computer system. It is possible to speed up the operation.

[Brief description of drawings]

FIG. 1 is a perspective sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view for explaining the operation of the embodiment shown in FIG.

FIG. 3 is a sectional view of a nozzle portion showing an embodiment of the present invention.

FIG. 4 is a sectional view of a nozzle portion showing a second embodiment of the present invention.

FIG. 5 is a sectional view of a nozzle portion showing a third embodiment of the present invention.

FIG. 6 is a sectional view of a nozzle portion showing a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a nozzle portion showing a fifth embodiment of the present invention.

FIG. 8 is a perspective sectional view showing another embodiment of the present invention.

[Explanation of symbols]

1 ... Substrate, 2 ... Semiconductor element, 3, 31 ... Nozzle, 4, 4
1, 42 ... Throttling member, 5 ... Electrical connection member, 6 ... Refrigerant supply header, 7 ... Refrigerant return header, 8 ... Refrigerant supply pipe, 9 ... Refrigerant discharge pipe, 10 ... Refrigerant ejection port.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideyuki Kimura 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Prefecture Hiritsu Manufacturing Co., Ltd.Mechanical Research Laboratory (72) Kenji Takahashi 502 Jinre-cho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Co., Ltd. Inside the Mechanical Research Institute (72) Inventor Atsushi Nishihara 502 Jinritsu-cho, Tsuchiura-shi, Ibaraki Hiritsu Manufacturing Co., Ltd. Inside the Mechanical Research Laboratory (72) Noriyuki Ashibu No. 502 Jinmachi-cho, Tsuchiura-shi, Ibaraki Inside the Hiritsu Manufacturing Mechanical Research Co., Ltd. (72) Inventor Keizo Kawamura 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture

Claims (12)

[Claims] 1. A plurality of semiconductor elements arranged on a substrate,
A coolant supply header for supplying a coolant to the semiconductor element, and at least one nozzle projecting from the coolant supply header and ejecting the coolant on the upper surface of each semiconductor element,
In a liquid-cooled semiconductor device that is in communication with each nozzle and is provided with a refrigerant return header provided adjacent to the refrigerant supply header, a tip end portion of the nozzle is provided with a throttle member that sharply reduces the cross section of the flow path in the nozzle. A liquid-cooled semiconductor device, characterized in that it is provided with a refrigerant outlet having a sharp reduction flow path. 2. The liquid-cooled semiconductor device according to claim 1, wherein the throttle member is a sleeve-shaped member that reduces the flow path in the nozzle in a stepwise manner. 3. The liquid-cooled semiconductor device according to claim 1, wherein the throttle member is an orifice ring member. 4. The liquid-cooled semiconductor device according to claim 1, wherein the throttle member is a ring-shaped member having a substantially arcuate cross-sectional shape. 5. A liquid cooling system according to claim 1, wherein a partition member is provided around said semiconductor element to partition adjacent semiconductor elements, and said coolant outlet is provided inside said partition member on the semiconductor element side. Semiconductor device. 6. The liquid-cooled semiconductor device according to claim 1, wherein the refrigerant is a supercooled liquid having a boiling point lower than the temperature of the semiconductor element. 7. The liquid-cooled semiconductor device according to claim 1, wherein the refrigerant is a perfluorocarbon-based refrigerant. 8. A plurality of semiconductor elements arranged on a substrate,
A coolant supply header for supplying a coolant to the semiconductor element, at least one nozzle projecting from the coolant supply header and ejecting the coolant on the upper surface of each semiconductor element, and the coolant supply header communicating with each nozzle In a liquid-cooled semiconductor device including a refrigerant return header provided adjacent to, a wall thickness t of a refrigerant jet port located at the tip of the nozzle, and a distance between the refrigerant jet port and the semiconductor element surface. The liquid cooling semiconductor device is characterized in that H has a relationship with the refrigerant outlet diameter D of t> D / 2, H <D / 4 (Equation 1). 9. The liquid-cooled semiconductor device according to claim 8, wherein a throttle member that sharply reduces the refrigerant flow path is provided at the refrigerant outlet portion. 10. The liquid-cooled semiconductor device according to claim 8, wherein the wall thickness of the refrigerant ejection port is substantially the same throughout the entire nozzle. 11. The liquid-cooled semiconductor device according to claim 8, wherein a wall thickness of the refrigerant ejection port has a predetermined thickness only in a refrigerant ejection port portion. 12. A plurality of semiconductor elements arranged on a substrate, a refrigerant supply header for supplying a refrigerant to the semiconductor element, and a refrigerant projected on the refrigerant supply header and ejecting the refrigerant on an upper surface of each semiconductor element. In a liquid-cooled semiconductor device comprising at least one nozzle and a refrigerant return header which communicates with each nozzle and is provided adjacent to the refrigerant supply header, at least one or more nozzles are provided on an end face of the nozzle on the semiconductor element side. A liquid-cooled semiconductor device, wherein a perforated plate having a refrigerant outlet is provided in close contact therewith.