Micro-channel heat dissipation structure and heat dissipation method for high power density package

Abstract

The application provides a micro-channel heat dissipation structure and a heat dissipation method for high-power density packaging. The micro-channel heat dissipation structure comprises a carrier plate, a chip stack arranged on the carrier plate, a shell arranged on the carrier plate and accommodating the chip stack, a heat dissipation micro-channel formed by the shell and the carrier plate and surrounding the chip stack, an inlet and an outlet arranged on the shell for the cooling liquid to enter and exit the heat dissipation micro-channel, an external circulation pipeline connected to the heat dissipation micro-channel, a water press pump arranged in the external circulation pipeline close to the inlet, and a water suction pump arranged in the external circulation pipeline close to the outlet. The water press pump and the water suction pump are configured to work alternately to enable the cooling liquid to enter and exit the heat dissipation micro-channel, and the water suction pump works before the water press pump. The application can reduce the power of the pumped cooling liquid while ensuring the heat dissipation effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor, in particular to a micro-channel heat dissipation structure and heat dissipation method for high-power density packaging. BACKGROUND

[0002] At present, the laminated packaging technology is becoming mature, which can package more semiconductor chips in limited space. However, because multiple chips are laminated in limited space, the total heat generated by all elements is high, and the heat is difficult to be released smoothly from the limited space, which will affect the service life and running state of the elements. In the prior art, a fan is usually used to cool the semiconductor chips of the laminated packaging structure, but only the external cooling can be performed, which leads to poor cooling effect.

[0003] In order to meet the high-efficiency heat dissipation demand in high-power and high-density packaging, a micro-channel heat dissipation technology of liquid cooling can be used. The liquid heat conduction performance is 15-25 times that of air, so the liquid cooling is the key to the current high-power and high-density packaging (such as high-density integrated packaging of large computing power chips). However, the current liquid cooling micro-channel system still needs a great pumping power to pump the liquid. Although the heat dissipation is improved, the power consumption is very large, which will inevitably make the total system power consumption very large, leading to further increase of the power consumption of large computing power chips, especially when multiple large computing power chips are applied in the field of servers, the pumping power consumption is higher, and the large pumping power not only consumes energy, but also generates more heat. SUMMARY

[0004] The purpose of the present application is to provide a micro-channel heat dissipation structure and heat dissipation method for high-power density packaging, which can reduce the power of pumping cooling liquid while ensuring the heat dissipation effect.

[0005] To solve the above technical problems, the micro-channel heat dissipation structure for high-power density packaging provided by the present application comprises:

[0006] A carrier plate, which is provided with a chip stack;

[0007] A shell, which is provided on the carrier plate and accommodates the chip stack, and forms a heat dissipation micro-channel around the chip stack with the carrier plate, the heat dissipation micro-channel comprising an inlet and an outlet provided on the shell for the cooling liquid to enter and exit;

[0008] An external circulation pipeline, which is connected to the heat dissipation micro-channel;

[0009] A water press pump provided in the external circulation pipeline close to the inlet and a water suction pump provided in the external circulation pipeline close to the outlet, the water press pump and the water suction pump being configured to work alternately to make the cooling liquid enter and exit in the heat dissipation micro-channel, and the water suction pump works before the water press pump.

[0010] Optionally, the inlet and the outlet are arranged on a side of the shell away from the carrier plate.

[0011] Optionally, a channel layer is arranged on a top surface of the chip stack, the inlet and the outlet are arranged in the shell on the channel layer, and a groove is arranged in the channel layer and faces the inlet and the outlet.

[0012] Optionally, the shell comprises a bottom corner close to the carrier plate in a cavity accommodating the chip stack, and the bottom corner is in a slope shape.

[0013] Optionally, one inlet and one or more than one outlet are arranged on the shell.

[0014] Optionally, when the water press pump and the water suction pump work alternately, the power of the water suction pump is greater than or equal to the power of the water press pump.

[0015] Optionally, when the water press pump and the water suction pump work alternately, the working time of the water suction pump and the working power of the water suction pump are in an inverse relationship each time, and the working time of the water press pump and the working power of the water press pump are in an inverse relationship each time.

[0016] Based on another aspect of the present application, a micro-channel heat dissipation method for high-power density packaging is also provided, which applies the micro-channel heat dissipation structure for high-power density packaging as described above, and the heat dissipation method comprises:

[0017] Step S01: turn off the water press pump and turn on the water suction pump until the cooling liquid is pumped out of the outlet of the heat dissipation micro-channel and a negative pressure is formed in the heat dissipation micro-channel;

[0018] Step S02: turn off the water suction pump and turn on the water press pump until the cooling liquid is pumped into the inlet by the water press pump and the negative pressure in the heat dissipation micro-channel;

[0019] The step S01 and the step S02 are executed alternately to dissipate heat of the chip stack by the cooling liquid in the heat dissipation micro-channel.

[0020] Optionally, when the step S01 and the step S02 are executed alternately, the step S01 is switched immediately after the negative pressure in the step S02 disappears.

[0021] Optionally, when the step S01 and the step S02 are executed alternately, the step S01 is switched after a preset time after the negative pressure in the step S02 disappears.

[0022] In summary, in the present application, when the water pump is opened and the pressure pump is closed, because there is liquid seal at the inlet and outlet, and the water flow rate at the outlet is greater than the water flow rate at the inlet, a short-term negative pressure is formed in the micro flow channel. When the water pump is closed and the pressure pump is opened, the negative pressure acts on the inlet, so that the coolant enters the micro flow channel under a smaller pump pressure, and the negative pressure acts on the outlet, so that the coolant flows out of the outlet quickly. Therefore, in the above process, only one water pump works at the same time, and the power of the two water pumps is small, so that the total power of pumping coolant can be reduced under the premise of ensuring the heat dissipation effect. BRIEF DESCRIPTION OF DRAWINGS

[0023] Those skilled in the art will understand that the drawings provided are for a better understanding of the present application, and do not constitute any limitation on the scope of the present application.

[0024] Figure 1 is a structural schematic diagram of a micro flow channel heat dissipation structure provided by an embodiment of the present application;

[0025] Figure 1 b is a top view schematic diagram of a shell provided by an embodiment of the present application;

[0026] Figure 2a is a top view schematic diagram of another shell provided by an embodiment of the present application;

[0027] Figure 2b is a structural schematic diagram of another micro flow channel heat dissipation structure provided by an embodiment of the present application;

[0028] Figure 3 is a flow chart of a micro flow channel heat dissipation method for high-power density packaging provided by an embodiment of the present application.

[0029] In the drawings: 10 - carrier plate; 11 - packaging substrate; 12 - conductive via; 13 - metal solder ball; 20 - shell; 21 - side wall part; 22 - cover plate part; 23 - inlet; 24 - outlet; 25a - bottom corner; 25b - top corner; 30 - chip stack; 31 - chip; 32 - channel layer; 33 - groove; 40 - external circulation pipeline; 41 - pressure pump; 42 - water pump. DETAILED DESCRIPTION

[0030] In order to make the purpose, advantages and characteristics of the present application clearer, the present application will be further described in detail below in combination with the drawings and specific embodiments. It should be noted that the drawings are all very simplified and not drawn to scale, and are only used to facilitate and clearly assist the purpose of explaining the embodiments of the present application. In addition, the structures shown in the drawings are often part of the actual structure. In particular, the emphasis shown in each drawing is different, and sometimes different scales are used.

[0031] As used in the present application, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. The term "or" is generally employed in its sense including "and / or" unless the content clearly dictates otherwise. The term "at least two" is generally employed in its sense including "two or more" unless the content clearly dictates otherwise. The terms "first," "second," "third," etc. are used only to describe a particular aspect and do not imply relative importance or a limitation on the number of features that can be claimed. Thus, features limited by "first," "second," "third," etc. can explicitly or implicitly include one or at least two of such features unless the context clearly dictates otherwise.

[0032] The embodiment provides a micro-channel heat dissipation structure for high power density package.

[0033] Figure 1 is a structural schematic diagram of the micro-channel heat dissipation structure provided by an embodiment of the present application; Figure 1 b is a top view schematic diagram of the shell provided by an embodiment of the present application.

[0034] As shown in Figure 1 and Figure 1 b The micro-channel heat dissipation structure for high power density package provided by the embodiment includes a carrier plate 10, a shell 20, an external circulation pipeline 40, a water press pump 41 and a water suction pump 42. The carrier plate 10 is provided with a chip stack 30. The shell 20 is arranged on the carrier plate 10 and accommodates the chip stack 30, and forms a heat dissipation micro-channel around the chip stack 30 with the carrier plate 10. The heat dissipation micro-channel includes an inlet 23 and an outlet 24 provided on the shell 20 for the cooling liquid to enter and exit. The external circulation pipeline 40 is connected to the heat dissipation micro-channel. The water press pump 41 is arranged in the external circulation pipeline 40 and close to the inlet 23, and the water suction pump 42 is arranged in the external circulation pipeline 40 and close to the outlet 24. The water press pump 41 and the water suction pump 42 are configured to work alternately to enable the cooling liquid to enter and exit the heat dissipation micro-channel, and the water suction pump 42 works before the water press pump 41.

[0035] In the embodiment, the carrier plate 10 can be an interposer, which has two opposite surfaces (i.e. a first surface and a second surface) and can be made of silicon or glass, etc. The interposer is provided with conductive through holes 12 (silicon through holes or glass through holes filled with metal materials such as copper), and the two sides of the conductive through holes 12 can be provided with metal solder balls 13 (such as tin solder balls). The chip stack 30 is bonded to the first surface of one side of the conductive through holes 12 (interposer) by the metal solder balls 13, and the second surface of the interposer is connected to other package substrates 11 (such as PCB printed boards). The chip stack 30 can include at least two chips 31 stacked in sequence, each chip 31 is provided with silicon through holes and pads, and the pads and the silicon through holes are provided with metal solder balls 13 for bonding the above-mentioned multiple chips 31.

[0036] Please continue to refer to the drawings as Figure 1 , the shell 20 can be a material that is easy to process and suitable for airtight connection (for example, bonding) with the surface of the carrier plate 10. In this embodiment, the material of the shell 20 can be silicon, that is, prepared by photolithography and etching from a silicon wafer. The shell 20 can be in the shape of a bowl, buckled (covered) on the carrier plate 10 and formed into a cavity accommodating the chip stack 30, which can include a sidewall part 21 perpendicular to the surface of the carrier plate 10 and a cover plate part 22 parallel to the surface of the carrier plate 10. The sidewall part 21 is connected to the surface of the carrier plate 10, and the cover plate part 22 is connected to the sidewall part 21 and away from the carrier plate 10. The cover plate part 22 can be provided with an inlet 23 and an outlet 24 for the cooling liquid to pass in and out. Thus, the above-mentioned cavity, inlet 23 and outlet 24 can constitute a heat dissipation micro-flow channel surrounding the chip stack 30, wherein the space between the sidewall part 21 of the shell 20 and the side of the chip stack 30 serves as a micro-flow branch of the heat dissipation micro-flow channel surrounding the chip stack 30. The top surface of the chip stack 30 is provided with a channel layer 32, and the surface of the channel layer 32 is provided with a plurality of grooves 33 as micro-flow branches of the heat dissipation micro-flow channel covering the surface of the chip stack 30.

[0037] In this embodiment, the channel layer 32 can also be used as a heat sink component to conduct heat from the chip stack 30. The top of the channel layer 32 is in contact with the cover plate part 22 of the shell 20, and the inlet 23 and the outlet 24 of the heat dissipation micro-flow channel are opened in the cover plate part 22 on the channel layer 32, so that the grooves 33 near the inlet 23 in the channel layer 32 serve as the distribution branch of the heat dissipation micro-flow channel, and the grooves 33 near the outlet 24 in the channel layer 32 serve as the collection branch of the heat dissipation micro-flow channel. Of course, in other examples of this embodiment, the cavity formed by the shell 20 and the carrier plate 10 can also be provided with at least two chip stacks 30 arranged at intervals, for simultaneously dissipating heat from multiple chip stacks 30.

[0038] It can be understood that the heat dissipation micro-flow channel shown in Figure 1 is only one example of this embodiment, and this embodiment does not limit the structure and form of the heat dissipation micro-flow channel constituted by the shell 20, the carrier plate 10 and the chip stack 30. For example, it does not limit the shape and number of the inlet 23 and the outlet 24, the arrangement form of the micro-flow branch on the surface, the sidewall or the inside of the chip stack 30, and the shape of the cavity formed by the shell 20 and the carrier plate 10. In another example of this embodiment, a plurality of micro-flow branches can also be provided in (inside) the chip stack 30 for the cooling liquid to flow through the chip stack 30 to conduct heat from the inside of the chip 31. In yet another example of this embodiment, as shown in the top view of Figure 2a , the cover plate part 22 of the shell 20 is provided with one inlet 23 and two outlets 24, and the two outlets 24 are arranged side by side and away from one end of the inlet 23, and maintain the same distance from the inlet 23. In other examples of this embodiment, as shown in the top view of Figure 2bAs shown in the sectional view, the bottom of the side wall 21 of the shell 20 and the bottom corner 25a of the carrier plate 10 can be inclined to have a flow guiding effect to reduce the resistance of the cooling liquid in the micro flow channel. Of course, the top of the side wall 21 of the shell 20 and the top corner 25b of the cover plate 22 can also be inclined, which is limited by the manufacturing process.

[0039] Please continue to refer to the drawings as Figure 1 The shell 20 is further provided with an external circulation pipeline 40, which is communicated with the micro flow channel through the inlet 23 and the outlet 24, so that the cooling liquid (cooling working medium) flows in both to form a complete circulation inside and outside the shell 20, that is, the cooling liquid is pumped into the shell 20 to absorb the heat of the chip stack 30, then the cooling liquid is pumped out of the shell 20 to dissipate heat, and then the heat dissipated cooling liquid is pumped into the micro flow channel of the shell 20. Compared with the related art which uses a water pressure pump 41 to continuously pump the cooling liquid at a high power, the embodiment sets a water pressure pump 41 (to press the cooling liquid into the micro flow channel) near the inlet 23 of the external circulation pipeline 40, and sets a water suction pump 42 (to suck the cooling liquid out of the micro flow channel) near the outlet 24 of the external circulation pipeline 40, and the water suction pump 42 and the water pressure pump 41 are alternately operated at a relatively small power to realize the switching of the cooling liquid in the micro flow channel. The water pressure pump 41 and the water suction pump 42 can be any suitable type of micro pump, for example, a piezoelectric micro pump. The external circulation pipeline 40 between the water pressure pump 41 and the water suction pump 42 can also be additionally provided with a heat dissipation structure.

[0040] In particular, the water pump 42 works before the water pump 41 to form a negative pressure in the micro channel, the negative pressure acts on the inlet 23 to make the coolant in the inlet 23 flow into the micro channel under a smaller pump pressure (even without pump pressure), and the negative pressure acts on the outlet 24 to make the coolant quickly flow out of the outlet 24, so that the total power of pumping the coolant can be greatly reduced under the condition that only one water pump works at the same time and the power of the two water pumps is small. The specific process of the above-mentioned alternating work can include: in the one-way circulation pipeline including the water pump 41 and the water pump 42 respectively arranged at the inlet 23 and the outlet 24, when the water pump 41 is closed and the water pump 42 is opened, the coolant flows out of the outlet 24 and forms a water seal at the outlet 24, the coolant flows into the inlet 23 and forms a water seal at the inlet 23, due to the pressure drop formed by the different distances from the water pump 42 in the micro channel and the resistance in the micro channel, the water outflow rate (water flow rate) of the outlet 24 is obviously greater than the water inflow rate of the inlet 23, at this time, a short negative pressure will be formed in the micro channel of the shell 20, so that the water pump 42 can be closed when the rates of the two are not equal (i.e. the negative pressure has not disappeared), the water pump 41 is opened and the power of the water pump 41 is operated at a low power, the above-mentioned negative pressure can make the coolant quickly flow into the micro channel of the shell 20 from the inlet 23 and flow out (spray) from the outlet 24, after the above-mentioned negative pressure gradually disappears due to the rapid flow of the coolant from the inlet 23 (for example, the inflow rate of the inlet is greater than the outflow rate of the outlet), the water pump 41 can be closed again and the water pump 42 can be opened to generate a negative pressure in the micro channel to continue the above-mentioned two modes of alternating work.

[0041] In the above alternating operation of the water press pump 41 and the water suction pump 42, the working time and the working power of the water press pump 41 and the water suction pump 42 can be determined according to the type of the cooling liquid, the design of the micro flow channel and the rate (average flow rate) of the cooling liquid circulation, so that the working power of the water press pump 41 and the water suction pump 42 is reduced under the premise of ensuring the heat dissipation effect. In an example, the working power of the water suction pump 42 can be greater than the working power of the water press pump 41, so as to facilitate the generation of the negative pressure. In another example, in the alternating operation of the water press pump 41 and the water suction pump 42, the working time of the water suction pump 42 can be 2-20 seconds, the working time of the water press pump 41 can be 2-20 seconds, the time of the alternating operation of the water press pump 41 and the water suction pump 42 can be substantially the same, the time of the alternating operation of the water press pump 41 and the water suction pump 42 can be positively correlated with the volume of the micro flow channel (the maximum volume of the cooling liquid that can be accommodated in the shell), and the greater the volume of the micro flow channel, the longer the time of the alternating operation. In addition, the time of the alternating operation of the water press pump 41 and the water suction pump 42 is also related to the difference between the working power of the water suction pump 42 and the working power of the water press pump 41, and the smaller the working power of the water press pump 41, the longer the working time of the water press pump 41, and the smaller the working power of the water suction pump 42, the longer the working time of the water suction pump 42. In other words, in the alternating operation of the water press pump 41 and the water suction pump 42, the working time of the water suction pump 42 and the working power of the water suction pump 42 are inversely proportional to each other, and the working time of the water press pump 41 and the working power of the water press pump 41 are inversely proportional to each other.

[0042] The application further provides a micro flow channel heat dissipation method for high-power density packaging.

[0043] Figure 3 A flow chart of the micro flow channel heat dissipation method for high-power density packaging provided by the application.

[0044] As shown in Figure 3 The micro flow channel heat dissipation method for high-power density packaging provided by the application applies the micro flow channel heat dissipation structure for high-power density packaging as described above, and the method comprises the following steps:

[0045] Step S01: closing the water press pump and opening the water suction pump to pump out the cooling liquid from the outlet of the heat dissipation micro flow channel and form a negative pressure in the heat dissipation micro flow channel;

[0046] Step S02: closing the water suction pump and opening the water press pump to pump in the cooling liquid from the inlet by the water press pump and the negative pressure in the heat dissipation micro flow channel;

[0047] Step S03: alternately performing the step S01 and the step S02 to dissipate heat of the chip stack by the cooling liquid of the heat dissipation micro flow channel.

[0048] The heat dissipation method of the present embodiment can be performed by using the micro-channel heat dissipation structure as described above. In step S01, when the water pump is closed and the water pump is just started, the cooling liquid flows out of the outlet and forms a water seal at the outlet, and the cooling liquid flows into the inlet and forms a water seal at the inlet. Due to the pressure drop formed by the different distances from the water pump in the micro-channel and the resistance in the micro-channel, the water outflow rate (water flow rate) of the outlet is obviously greater than the water inflow rate of the inlet. At this time, a short-term negative pressure will be formed in the micro-channel of the shell. In step S02, the water pump can be closed when the rates of the two are not equal (i.e., the negative pressure has not disappeared), the water pump is started, and the power of the water pump is operated at a low power. The above-mentioned negative pressure can make the cooling liquid quickly flow into the micro-channel of the shell from the inlet and flow out (spray) from the outlet. In step S03, after the cooling liquid quickly flows into the inlet and the above-mentioned negative pressure gradually disappears, the water pump can be closed again and the water pump can be started to generate a negative pressure in the micro-channel to continue the above-mentioned two modes of alternating operation.

[0049] It can be understood that in other examples of the present embodiment, when steps S01 and S02 are alternately performed, in step S02, a period of time (preset time) can be continued after the negative pressure generated in step S01 disappears as the cooling liquid is pumped in, and then step S01 is performed, so as to further reduce the total power of pumping the cooling liquid in the case of low heat dissipation demand.

[0050] In summary, in the present application, when the water pump is started and the water pump is closed, because there is a liquid seal at the inlet and the outlet, and the water outflow rate (water flow rate) of the outlet is greater than the water inflow rate of the inlet, at this time a short-term negative pressure will be formed in the micro-channel. When the water pump is closed and the water pump is started, the negative pressure acts on the inlet to make the cooling liquid of the inlet enter the micro-channel under a smaller pumping pressure, and at the same time the negative pressure acts on the outlet to make the cooling liquid quickly flow out of the outlet. Therefore, in the above process, only one water pump works at the same time and the power of the two water pumps is small, so as to reduce the total power of pumping the cooling liquid under the premise of ensuring the heat dissipation effect.

[0051] The above description is only a description of the preferred embodiments of the present application, and is not any limitation on the scope of the present application. Any changes and modifications made by those skilled in the art based on the above disclosure are within the scope of protection of the claims.

Claims

1. A microchannel heat dissipation structure for high power density packaging, characterized in that: include: a carrier board on which a chip stack is provided; a housing, which is disposed on the carrier and accommodates the chip stack, and forms a heat dissipation microchannel surrounding the chip stack with the carrier, the heat dissipation microchannel including an inlet and an outlet provided on the housing for the inlet and outlet of a cooling liquid; An external circulation pipeline connected to the heat dissipation microchannel; A water pressure pump is provided in the external circulation pipeline near the inlet, and a water extraction pump is provided in the external circulation pipeline near the outlet. The water pressure pump and the water extraction pump are configured to work alternately to allow coolant to flow in and out of the heat dissipation microchannel, and the water extraction pump works before the water pressure pump.

2. The microchannel heat dissipation structure for high power density packaging according to claim 1, characterized in that: The inlet and the outlet are arranged on a side of the shell away from the carrier plate.

3. The microchannel heat dissipation structure for high power density packaging according to claim 2, characterized in that: A channel layer is provided on the top surface of the chip stack, the inlet and the outlet are provided in a housing on the channel layer, and grooves facing the inlet and the outlet are provided in the channel layer.

4. The microchannel heat dissipation structure for high power density packaging according to claim 1, characterized in that: The cavity of the housing for accommodating the chip stack includes a bottom corner close to the carrier, and the bottom corner is sloped.

5. The microchannel heat dissipation structure for high power density packaging according to claim 1, characterized in that: The shell is provided with an inlet and one or more outlets.

6. The microchannel heat dissipation structure for high power density packaging according to claim 1, characterized in that: When the water pressure pump and the water suction pump work alternately, the power of the water suction pump is greater than or equal to the power of the water pressure pump.

7. The microchannel heat dissipation structure for high power density packaging according to claim 1, characterized in that: When the water pressure pump and the water suction pump work alternately, the working time of the water suction pump each time is inversely proportional to the working power of the water suction pump, and the working time of the water pressure pump each time is inversely proportional to the working power of the water pressure pump.

8. A microchannel heat dissipation method for high power density packaging, characterized in that: The microchannel heat dissipation structure for high power density packaging according to any one of claims 1 to 7 is applied, wherein the heat dissipation method comprises: Step S01: turning off the water pressure pump and turning on the water extraction pump until the coolant is pumped out from the outlet of the heat dissipation microchannel and a negative pressure is formed in the heat dissipation microchannel; Step S02: turning off the water pump and turning on the pressure pump, so that the cooling liquid is pumped into the cooling channel from the inlet by the pressure pump and the negative pressure in the cooling microchannel; Step S01 and step S02 are performed alternately to dissipate heat from the chip stack using the cooling liquid in the heat dissipation microchannel.

9. The microchannel heat dissipation method for high power density packaging according to claim 8, characterized in that: When step S01 and step S02 are alternately executed, the process switches to step S01 immediately when the negative pressure in step S02 disappears.

10. The microchannel heat dissipation method for high power density packaging according to claim 8, characterized in that: When step S01 and step S02 are alternately executed, the process switches to step S01 after a preset time period has passed since the negative pressure in step S02 disappears.

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