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

Abstract

The invention provides a micro-channel heat dissipation structure and heat dissipation method for high-power density packaging, and the structure comprises a carrier plate which is provided with a chip stacking body; the shell covers the carrier plate and accommodates the chip stacking body, a heat dissipation micro-channel surrounding the chip stacking body is formed by the shell and the carrier plate, and the heat dissipation micro-channel comprises an inlet and an outlet which are formed in the shell and used for allowing cooling liquid to flow in and out; the outer circulation pipeline is communicated with the heat dissipation micro-channel; the water pressing pump is arranged in the outer circulation pipeline and close to the inlet, the water suction pump is arranged in the outer circulation pipeline and close to the outlet, the water pressing pump and the water suction pump are configured to alternately work so that cooling liquid can enter and exit from the heat dissipation micro-channel, and the water suction pump works earlier than the water pressing pump. According to the invention, the cooling liquid pumping power can be reduced on the premise of ensuring the heat dissipation effect.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a microchannel heat dissipation structure and a heat dissipation method for high power density packaging. Background Art

[0002] At present, stacked packaging technology is becoming more and more mature, and it is possible to package more semiconductor chips in a limited space. However, because multiple chips are stacked in a limited space, the total heat generated by all components is high, and the heat is difficult to be released smoothly from the limited space, which will affect the service life and operation status of the components. In the prior art, fans are usually used to cool down semiconductor chips in a stacked packaging structure, but they can only cool down the outside, resulting in poor cooling effect.

[0003] In order to meet the demand for efficient heat dissipation in high-power, high-density packaging, liquid heat dissipation microfluidic cooling technology can be used. The thermal conductivity of liquid is 15-25 times that of air. Therefore, liquid heat dissipation is the key to current high-power, high-density packaging (such as high-density integrated packaging of high-computing power chips). However, the current liquid heat dissipation microfluidic system still requires a huge pumping power to pump the liquid. Although this means that the heat dissipation is improved, the power consumption is extremely large, which is bound to make the total system power consumption very large, leading to a further increase in the power consumption of high-computing power chips. In particular, when multiple high-computing power chips are used in servers and other fields, the pumping power consumed is higher. The larger pumping power not only consumes energy, but also generates more heat. Summary of the invention

[0004] The object of the present invention is to provide a microchannel heat dissipation structure and heat dissipation method for high power density packaging, which are used to reduce the power of pumping coolant while ensuring the heat dissipation effect.

[0005] In order to solve the above technical problems, the present invention provides a microchannel heat dissipation structure for high power density packaging, comprising:

[0006] A carrier board, on which a chip stack is arranged;

[0007] A shell, which is disposed on the carrier and accommodates the chip stack, and forms a heat dissipation microchannel surrounding the chip stack with the carrier, wherein the heat dissipation microchannel includes an inlet and an outlet disposed on the shell for the cooling liquid to enter and exit;

[0008] An external circulation pipeline connected to the heat dissipation microchannel;

[0009] A water pressure pump is arranged in the external circulation pipeline near the inlet and a water extraction pump is arranged 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.

[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 provided on the top surface of the chip stack, the inlet and the outlet are provided in a shell on the channel layer, and grooves facing the inlet and the outlet are provided in the channel layer.

[0012] Optionally, the cavity of the shell for accommodating the chip stack includes a bottom corner close to the carrier, and the bottom corner is sloped.

[0013] Optionally, the shell is provided with an inlet and one or more outlets.

[0014] Optionally, 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.

[0015] Optionally, 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.

[0016] Based on another aspect of the present invention, a microchannel heat dissipation method for high power density packaging is also provided, using the microchannel heat dissipation structure for high power density packaging as described above, the heat dissipation method comprises:

[0017] Step S01: turning off the water pressure pump and turning on the water 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;

[0018] Step S02: Turn off the water pump, turn on the water pressure pump, and pump the coolant into the cooling liquid from the inlet by the water pressure pump and the negative pressure in the heat dissipation microchannel;

[0019] The step S01 and the step S02 are performed alternately, and the cooling liquid in the heat dissipation microchannel is used to dissipate heat from the chip stack.

[0020] Optionally, when the step S01 and the step S02 are executed alternately, the process switches to the step S01 immediately when the negative pressure in the step S02 disappears.

[0021] Optionally, when the step S01 and the step S02 are executed alternately, the process switches to the step S01 after a preset time has passed since the negative pressure in the step S02 disappears.

[0022] To sum up, in the present invention, when the water pump is turned on and the water pressure pump is turned off, since there are liquid seals at both 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, a short negative pressure will be formed in the microchannel. When the water pump is turned off and the water pressure pump is turned on, the negative pressure is used to act on the inlet, so that the coolant at the inlet enters the microchannel under a smaller pumping pressure, and at the same time, the negative pressure is used to act 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 relatively small, so that the total power of pumping the coolant can be reduced while ensuring the heat dissipation effect. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0024] Figure 1 is a structural schematic diagram of a microchannel heat dissipation structure provided by an embodiment of the present invention;

[0025] Figure 1b is a schematic top view of a housing provided by an embodiment of the present invention;

[0026] Figure 2a is a schematic top view of another housing provided by an embodiment of the present invention;

[0027] Figure 2b is a structural schematic diagram of another microchannel heat dissipation structure provided by an embodiment of the present invention;

[0028] Figure 3 A flow chart of a microchannel heat dissipation method for high power density packaging provided by one embodiment of the present invention.

[0029] In the accompanying drawings: 10-carrier; 11-packaging substrate; 12-conductive through hole; 13-metal solder ball; 20-housing; 21-side wall; 22-cover plate; 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-water pressure pump; 42-water pump. DETAILED DESCRIPTION

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

[0031] As used in the present invention, the singular forms "one", "an", and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second", and "third" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features, unless the content clearly indicates otherwise.

[0032] This embodiment provides a microchannel heat dissipation structure for high power density packaging.

[0033] Figure 1 is a structural schematic diagram of a microchannel heat dissipation structure provided by an embodiment of the present invention; Figure 1b It is a schematic top view of a shell provided by an embodiment of the present invention.

[0034] like Figure 1 and Figure 1b As shown, the microfluidic heat dissipation structure for high power density packaging provided in this embodiment includes a carrier 10, a shell 20, an external circulation pipeline 40, a pressure pump 41 and a pump 42. A chip stack 30 is provided on the carrier 10. The shell 20 is covered on the carrier 10 and accommodates the chip stack 30, and forms a heat dissipation microfluidic channel surrounding the chip stack 30 with the carrier 10. The heat dissipation microfluidic channel includes an inlet 23 and an outlet 24 provided on the shell 20 for the coolant to enter and exit. The external circulation pipeline 40 is connected to the heat dissipation microfluidic channel. The pressure pump 41 is provided in the external circulation pipeline 40 and is close to the inlet 23, and the pump 42 is provided in the external circulation pipeline 40 and is close to the outlet 24. The pressure pump 41 and the pump 42 are configured to work alternately to allow the coolant to enter and exit the heat dissipation microfluidic channel, and the pump 42 works before the pressure pump 41.

[0035] In this embodiment, the carrier 10 may be an interposer having two opposite surfaces (i.e., a first surface and a second surface), and the material thereof may be, for example, silicon or glass. The interposer is provided with a conductive via 12 (a silicon through hole or a glass through hole, which is filled with a metal material, such as copper), and metal solder balls 13 (such as tin solder balls) may be provided on both sides of the conductive via 12. The chip stack 30 is bonded to the first surface of one side of the conductive via 12 (interposer) using the metal solder balls 13, and the second surface of the interposer is connected to other packaging substrates 11 (such as a PCB printed board). The chip stack 30 may include at least two sequentially stacked chips 31, each chip 31 is provided with a silicon through hole and a pad, and the pad and the silicon through hole are provided with metal solder balls 13 for bonding the above-mentioned multiple chips 31.

[0036] Please continue to refer to Figure 1 The shell 20 can be made of a material that is easy to process and suitable for being tightly connected (e.g., bonded) to the surface of the carrier 10. In this embodiment, the shell 20 can be made of silicon, that is, prepared from a silicon wafer by photolithography and etching. The shell 20 can be bowl-shaped, buckled (covered) on the carrier 10 and forming a cavity for accommodating the chip stack 30. It can include a side wall portion 21 perpendicular to the surface of the carrier 10 and a cover portion 22 parallel to the surface of the carrier 10. The side wall portion 21 is connected to the surface of the carrier 10, and the cover portion 22 is connected to the side wall portion 21 and is away from the carrier 10. The cover portion 22 can be provided with an inlet 23 and an outlet 24 for the coolant to enter and exit. Thus, the above-mentioned cavity, inlet 23 and outlet 24 can form a heat dissipation microfluidic channel surrounding the chip stack 30, wherein the space between the side wall portion 21 of the shell 20 and the side of the chip stack 30 serves as a microfluidic branch of the heat dissipation microfluidic channel surrounding the chip stack 30, and a channel layer 32 is provided on the top surface of the chip stack 30, and a plurality of grooves 33 are provided on the surface of the channel layer 32 as microfluidic branches covering the surface of the chip stack 30 of the heat dissipation microfluidic channel.

[0037] In this embodiment, the channel layer 32 can also be used as a heat sink component to extract the heat of the chip stack 30. The top of the channel layer 32 is in contact with the cover portion 22 of the housing 20. The inlet 23 and the outlet 24 of the heat dissipation microchannel are opened in the cover portion 22 on the channel layer 32, so that the groove 33 near the inlet 23 in the channel layer 32 serves as a liquid distribution branch of the heat dissipation microchannel, and the groove 33 near the outlet 24 in the channel layer 32 serves as a liquid collection branch of the heat dissipation microchannel. Of course, in other examples of this embodiment, the cavity formed by the housing 20 and the carrier 10 can also be provided with at least two spaced chip stacks 30 for dissipating heat from multiple chip stacks 30 at the same time.

[0038] It is understandable that if Figure 1 The heat dissipation microchannel shown is only an example of this embodiment. This embodiment does not limit the structure and form of the heat dissipation microchannel formed by the housing 20, the carrier 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 of the microchannel on the surface, side wall or inside of the chip stack 30, or the shape of the cavity formed by the housing 20 and the carrier 10. In another example of this embodiment, a plurality of microchannels may be provided in (inside) the chip stack 30 for cooling liquid to flow through the chip stack 30 to remove the heat inside the chip 31. In another example of this embodiment, as Figure 2a In the top view shown in FIG. 1 , an inlet 23 and two outlets 24 are provided on the cover portion 22 of the housing 20. The two outlets 24 are arranged side by side at one end away from the inlet 23 and maintain the same distance from the inlet 23. In other examples of this embodiment, such as Figure 2bAs shown in the cross-sectional view, the bottom of the side wall portion 21 of the shell 20 and the carrier 10 (bottom corner 25a) can be sloped to provide a guiding effect to reduce the resistance of the coolant in the microchannel. Of course, limited by the manufacturing process, it is also feasible that the top of the side wall portion 21 of the shell 20 and the cover portion 22 (top corner 25b) are sloped.

[0039] Please continue to refer to Figure 1 , an external circulation pipeline 40 is also provided outside the shell 20, which is connected to the microchannel through the inlet 23 and the outlet 24, so that the coolant (cooling medium) flows in both to form a complete cycle through the inside and outside of the shell 20, that is, the coolant is pumped into the shell 20 to absorb the heat of the chip stack 30, and then the coolant is pumped out to the outside of the shell 20 to dissipate heat, and then the coolant after heat dissipation is pumped into the microchannel of the shell 20. Compared with the related art that uses a pressure pump 41 to pump the coolant continuously at a high power, this embodiment sets a pressure pump 41 near the inlet 23 of the external circulation pipeline 40 (to pump the coolant into the microchannel), and sets a pumping pump 42 near the outlet 24 of the external circulation pipeline 40 (to pump the coolant out of the microchannel), and the switching of the coolant in the microchannel is realized by the pumping pump 42 and the pressure pump 41 working alternately at a relatively small power. The water pressure pump 41 and the water suction pump 42 can be any suitable type of micro pumps, such as a piezoelectric micro pump, and a heat dissipation structure can be additionally provided in the external circulation pipeline 40 between the water pressure pump 41 and the water suction pump 42 .

[0040] In particular, the water pump 42 works before the water pump 41 to form a negative pressure in the microchannel, and uses the negative pressure to act on the inlet 23, so that the coolant at the inlet 23 enters the microchannel under a relatively small pumping pressure (or even without a pumping pressure), and at the same time uses the negative pressure to act on the outlet 24, so that the coolant flows out of the outlet 24 quickly. Therefore, when only one water pump works at the same time and the power of the two water pumps is relatively small, the total power of pumping the coolant can be greatly reduced. The specific process of the above-mentioned alternating operation may include: in a one-way circulation pipeline including a water pressure pump 41 and a water pump 42 respectively arranged at the inlet 23 and the outlet 24, when the water pressure pump 41 is turned off and the water pump 42 is turned on, the coolant flows out from the outlet 24 and forms a water seal at the outlet 24, and the coolant flows in from 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 microchannel and the resistance in the microchannel, 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 water seal will be formed in the microchannel of the shell 20. A short-term negative pressure can be generated, so that when the rates of the two are not equal (that is, the negative pressure has not disappeared), the water pump 42 can be turned off, and the water pressure pump 41 can be turned on and the water pressure pump 41 can be operated at a lower power. The above negative pressure can make the coolant flow quickly from the inlet 23 into the microchannel of the shell 20 and flow out (spray) from the outlet 24. After the above negative pressure gradually disappears due to the rapid inflow of coolant from the inlet 23 (for example, the inflow rate of the inlet is greater than the outflow rate of the outlet), the water pressure pump 41 can be turned off again and the water pump 42 can be turned on to generate negative pressure in the microchannel to continue the above two modes of alternating operation.

[0041] When the pressure pump 41 and the pump 42 work alternately, the working time and working power of the pressure pump 41 and the pump 42 can be determined according to the type of coolant, the design of the microchannel and the rate (average flow rate) of the coolant circulation, so as to reduce the power of pumping the coolant while ensuring the heat dissipation effect by utilizing the negative pressure generated by the different working of the two and the pump 42 working first. In one example, the power of the pump 42 when working can be greater than the power of the pressure pump 41 when working, so as to facilitate the generation of the above-mentioned negative pressure. In another example, when the pressure pump 41 and the pump 42 work alternately, the working time of each pump 42 can be, for example, 2 to 20 seconds, and the working time of each pressure pump 41 can be, for example, 2 to 20 seconds. The time for the pressure pump 41 and the pump 42 to work alternately can be roughly the same, and the time for the two to work alternately can be positively correlated with the volume of the microchannel (the maximum volume of the coolant that can be accommodated in the shell). The larger the volume of the microchannel, the longer the time for the above-mentioned alternating work. In addition, the time for the water pressure pump 41 and the water pump 42 to work alternately is also related to the difference between the power of the water pump 42 when working and the power of the water pressure pump 41 when working. When the working power and working time of the water pump 42 are determined, the smaller the working power of the water pressure pump 41, the longer the working power of the water pressure pump 41 is. When the working power and working time of the water pressure pump 41 are determined, the smaller the working power of the water pump 42, the longer the working power of the water pump 42 is. In other words, when the water pressure pump 41 and the water pump 42 work alternately, the working time of each water pump 42 is inversely proportional to the working power of the water pump 42, and the working time of each water pressure pump 41 is inversely proportional to the working power of the water pump 42.

[0042] The invention also provides a microchannel heat dissipation method for high power density packaging.

[0043] Figure 3 The present invention provides a flow chart of a microchannel heat dissipation method for high power density packaging.

[0044] like Figure 3 As shown, the microchannel heat dissipation method for high power density packaging provided in this embodiment uses the microchannel heat dissipation structure for high power density packaging as described above, and the method includes:

[0045] Step S01: turning off the water pressure pump and turning on the water 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;

[0046] Step S02: Turn off the water pump, turn on the water pressure pump, and pump the coolant into the cooling liquid from the inlet by the water pressure pump and the negative pressure in the heat dissipation microchannel;

[0047] Step S03: alternately executing the step S01 and the step S02, and utilizing the cooling liquid in the heat dissipation microchannel to dissipate heat from the chip stack.

[0048] The heat dissipation method of the present embodiment can be performed by using the microchannel heat dissipation structure as described above. In step S01, when the pressure pump is turned off and the pump is just turned on, the coolant flows out from the outlet and forms a water seal at the outlet, and the coolant flows in from the inlet and forms a water seal at the inlet. Due to the pressure drop formed by the different distances from the pump in the microchannel and the resistance in the microchannel, 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 negative pressure will be formed in the microchannel of the shell. In step S02, the pump can be turned off when the rates of the two are not equal (i.e., the negative pressure has not disappeared), and the pressure pump can be turned on and the power of the pressure pump is operated at a lower power. The above negative pressure can make the coolant flow quickly from the inlet into the microchannel of the shell and flow out (spray) from the outlet. In step S03, as the coolant flows quickly from the inlet and the above negative pressure gradually disappears, the pressure pump can be turned off again and the pump can be turned on to generate negative pressure in the microchannel to continue the above two modes to work alternately.

[0049] It can be understood that in other examples of this embodiment, when step S01 and step S02 are executed alternately, in step S02, the negative pressure generated in step S01 can be continued for a period of time (preset time) after it disappears as the coolant is pumped in, and then step S01 is executed, thereby further reducing the total power of pumping coolant when the heat dissipation demand is not high.

[0050] To sum up, in the present invention, when the water pump is turned on and the water pressure pump is turned off, since there are liquid seals at both 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, a short negative pressure will be formed in the microchannel. When the water pump is turned off and the water pressure pump is turned on, the negative pressure is used to act on the inlet, so that the coolant at the inlet enters the microchannel under a smaller pumping pressure, and at the same time, the negative pressure is used to act 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 relatively small, so that the total power of pumping the coolant can be reduced while ensuring the heat dissipation effect.

[0051] The above description is only a description of the preferred embodiments of the present invention, and is not intended to limit the scope of the present invention. Any changes or modifications made by a person skilled in the art in the field of the present invention based on the above disclosure shall fall 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 arranged; A shell, which is disposed on the carrier and accommodates the chip stack, and forms a heat dissipation microchannel surrounding the chip stack with the carrier, wherein the heat dissipation microchannel includes an inlet and an outlet disposed on the shell for the cooling liquid to enter and exit; An external circulation pipeline connected to the heat dissipation microchannel; A water pressure pump is arranged in the external circulation pipeline near the inlet and a water extraction pump is arranged 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 housing 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 disposed on the top surface of the chip stack, the inlet and the outlet are disposed in a housing on the channel layer, and grooves facing the inlet and the outlet are disposed 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 shell 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, and the heat dissipation method comprises: Step S01: turning off the water pressure pump and turning on the water 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: Turn off the water pump, turn on the water pressure pump, and pump the coolant into the cooling liquid from the inlet by the water pressure pump and the negative pressure in the heat dissipation microchannel; The step S01 and the step S02 are performed alternately, and the cooling liquid in the heat dissipation microchannel is used to dissipate heat from the chip stack.

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

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

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