Micro-electro-mechanical system heat sink, manufacturing method thereof and electronic device

Abstract

This application provides a microelectromechanical system (MEMS) heat sink, its manufacturing method, and an electronic device. The MEMS heat sink includes at least one airflow structure, each airflow structure comprising: a top cover, a bottom plate, a side wall, a cantilever beam, and a piezoelectric film. The top cover has an air inlet, and the bottom plate has an air outlet. The top cover and bottom plate are positioned opposite each other, with the side wall located between them, forming a cavity. The cantilever beam is located within the cavity and has a first end and a second end. The first end of the cantilever beam is connected to the side wall, and the second end is suspended. The air outlet is located within the projection area of ​​the cantilever beam along the thickness direction of the bottom plate. The piezoelectric film is located on the surface of the cantilever beam. The MEMS heat sink provided by this application can drive gas to form a unidirectional flow, removing heat through active cooling, resulting in high heat dissipation efficiency and meeting the high heat dissipation requirements of electronic devices.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a heat sink for a microelectromechanical system, its manufacturing method, and an electronic device thereof. Background Technology

[0002] With the continuous development of power electronics technology, electronic devices such as mobile phones and computers are gradually becoming smaller and thinner. The heat generated per unit volume in these devices is increasing, placing higher demands on heat dissipation components. Current technologies typically use thermal pads, thermal grease, and vapor chambers to extend heat dissipation, representing passive cooling. However, as the computing power of main chips in electronic devices continues to increase, the requirements for the heat dissipation capacity and size of heat dissipation components are becoming increasingly stringent. Passive cooling has reached its limit and can no longer meet the high heat dissipation demands of electronic devices. Summary of the Invention

[0003] This application provides a microelectromechanical system heat sink, its manufacturing method, and an electronic device for dissipating heat from heat-generating components in electronic devices, thereby meeting the high heat dissipation requirements of electronic devices.

[0004] In a first aspect, embodiments of this application provide a heat sink for a microelectromechanical system (MEMS). The heat sink provided in this application may include at least one airflow guiding structure, wherein each airflow guiding structure may include: a top cover, a bottom plate, a side wall, a cantilever beam, and a piezoelectric film. The top cover has an air inlet, and the bottom plate has an air outlet. The top cover and bottom plate are disposed opposite each other, and the side wall is located between the top cover and the bottom plate, forming a cavity. The cantilever beam is located within the cavity and has a first end and a second end opposite each other. The first end of the cantilever beam is connected to the side wall, and the second end of the cantilever beam is suspended; that is, the first end is the fixed end of the cantilever beam, and the second end is the movable end of the cantilever beam. In the thickness direction of the bottom plate, the air outlet is located within the projected coverage area of ​​the cantilever beam. The piezoelectric film is located on the surface of the cantilever beam. The piezoelectric film may be disposed on the side of the cantilever beam facing the top cover, or it may be disposed on the side of the cantilever beam facing the bottom plate.

[0005] In the microelectromechanical system (MEMS) heat sink provided in this embodiment, a cantilever beam and a piezoelectric film are provided in the flow-guiding structure. Under the control of a drive signal, the piezoelectric film can drive the cantilever beam to vibrate, causing a change in the pressure within the cavity and controlling the gas to flow unidirectionally within the cavity. When the second end of the cantilever beam moves towards the base plate, a negative pressure is formed in the space between the cantilever beam and the top cover, causing gas to be drawn in through the air inlet. When the second end of the cantilever beam moves towards the top cover, the gas, under the action of internal pressure, flows into the space between the cantilever beam and the base plate and is discharged through the air outlet. This cycle repeats, creating a unidirectional flow of gas in the flow-guiding structure. Therefore, the MEMS heat sink provided in this embodiment can drive the gas to form a unidirectional flow, removing heat through active cooling, resulting in high heat dissipation efficiency and meeting the high heat dissipation requirements of electronic devices. Furthermore, the MEMS heat sink does not require mechanical valves; it achieves fluid guidance and unidirectional flow without mechanical valves, resulting in high fluid efficiency. Furthermore, the microelectromechanical system heat sink provided in this application embodiment can be fabricated using microelectromechanical systems (MEMS) processing methods, resulting in a smaller-sized microelectromechanical system heat sink, which is beneficial for the miniaturization design of electronic devices.

[0006] In practical implementation, the driving signal applied to the piezoelectric film can be a high-frequency alternating current. Under the action of the inverse piezoelectric effect, the piezoelectric film can convert electrical energy into mechanical energy to drive the cantilever beam to vibrate. When the frequency of the alternating current, the vibration frequency of the cantilever beam, and the resonant frequency of the gas inside the cavity are matched, the gas inside the cavity can be made to couple and resonate to form a standing wave-like wave. This allows the gas to flow in a specific direction within the cavity, achieving gas drainage and improving the heat dissipation efficiency of the microelectromechanical system heat sink.

[0007] In this embodiment, the air inlet and outlet are located within the projection area of ​​the cantilever beam along the thickness direction of the base plate, with the air inlet located on the side of the outlet closer to the first end. When the microelectromechanical system (MEMS) radiator is operating, gas is drawn in through the air inlet, passes through the space between the cantilever beam and the top cover, the space near the second end of the cantilever beam, and the space between the cantilever beam and the base plate, before being discharged through the air outlet. This arrangement allows for a longer flow distance between the air inlet and outlet, fully utilizing the gas's inertia to form a unidirectional flow. In practical implementation, the horizontal distance between the air inlet and the first end of the cantilever beam can be reasonably set based on the air intake effect of the drainage structure, and the horizontal distance between the outlet and the first end of the cantilever beam can be reasonably set based on the air outlet effect of the drainage structure.

[0008] In one possible implementation, the cantilever beam has a groove on its surface facing the base plate, and the groove is located at the second end of the cantilever beam. In this embodiment, by providing a groove in the cantilever beam, the gas storage capacity of the drainage structure can be increased. During the vibration of the cantilever beam, the groove can promote the discharge of gas from the outlet. Furthermore, the size of the groove is related to the vibration frequency of the cantilever beam. The larger the width of the groove along the length of the cantilever beam, the lower the vibration frequency of the cantilever beam. Therefore, in specific implementations, the vibration frequency of the cantilever beam can be adjusted by reasonably setting the size of the groove.

[0009] Furthermore, in the thickness direction of the base plate, the vent can be located within the area covered by the projection of the groove, and the inlet can be located on the side of the groove near the first end of the cantilever beam. For example, the inlet can be positioned on the top cover corresponding to the first end. This arrangement further increases the flow distance between the inlet and outlet, facilitating resonance of the gas within the cavity. Moreover, positioning the vent on the base plate corresponding to the groove further promotes gas discharge.

[0010] In one possible implementation, the projection of the piezoelectric film and the projection of the groove do not overlap in the thickness direction of the base plate. That is, the piezoelectric film is positioned where the cantilever beam has a larger thickness, avoiding the location of the groove in the cantilever beam, thereby improving the structural stability of the cantilever beam. Of course, in some cases, the projection of the piezoelectric film and the projection of the groove can overlap in the thickness direction of the base plate, and can be reasonably set according to actual needs.

[0011] In this embodiment of the application, the drainage structure includes an upper cover and a bottom plate, that is, the drainage structure is a split structure. In this way, during the manufacturing process, the bottom plate, cantilever beam and upper cover can be manufactured separately using MEMS technology, making the drainage structure easy to manufacture and assemble.

[0012] In one possible implementation, the top cover may include a metallic or resin material, and the base plate may include single-crystal silicon (SCS) or a metallic material; for example, the base plate may include a metallic material with a high Young's modulus. The cantilever beam may include a single-crystal silicon or metallic material; for example, the cantilever beam may include a metallic material with a high Young's modulus. The piezoelectric thin film may include lead zirconate titanate (PZT) material. During the fabrication process, a sputtering process can be used to fabricate the piezoelectric thin film, resulting in an epitaxial single-crystal piezoelectric thin film with high crystal orientation uniformity and good piezoelectric properties.

[0013] In one possible implementation, the sidewall may include a first elevation structure for connecting the cantilever beam and the base plate. The first elevation structure serves to connect the cantilever beam and the base plate, creating a gap between them. For example, the first elevation structure may be a bonding material such as gold (Au), allowing the cantilever beam and base plate to be connected by bonding; alternatively, the first elevation structure may be a high-strength adhesive material such as resin, allowing the cantilever beam and base plate to be connected by adhesive. Similarly, the sidewall may also include a second elevation structure for connecting the upper cover and the base plate. The second elevation structure serves to connect the upper cover and the base plate, creating a cavity between them. For example, the second elevation structure may be a bonding material such as gold (Au), allowing the upper cover and base plate to be connected by bonding; alternatively, the second elevation structure may be a high-strength adhesive material such as resin, allowing the upper cover and base plate to be connected by adhesive. In another possible implementation, the first and second elevation structures can be integrated with the base plate as a single unit. During manufacturing, the first and second elevation structures can be formed on the base plate using etching. Then, the cantilever beam is installed on the first elevation structure, and the top cover is installed on the second elevation structure. In another possible implementation, the sidewall may further include an extension, which can be located on the side of the first and second elevation structures facing away from the base plate, and can be integrated with the top cover. Of course, the sidewall of the drainage structure can have other implementations, which are not limited here.

[0014] In some cases, the lattice constant difference between the piezoelectric film and the cantilever beam is relatively large. If the piezoelectric film is formed directly on the surface of the cantilever beam, the adhesion between the piezoelectric film and the cantilever beam is poor. In some embodiments of this application, the current-draining structure may further include a transition layer located between the piezoelectric film and the cantilever beam. The transition layer may include strontium oxide (SrO), zirconium oxide (ZrO2), or platinum (Pt) materials, and the thickness of the transition layer can be on the nanometer scale. By setting the transition layer, the adhesion between the piezoelectric film and the cantilever beam can be increased, thereby improving the reliability of the current-draining structure.

[0015] In some embodiments of this application, MEMS fabrication can be used to manufacture the microelectromechanical system (MEMS) heat sinks in the embodiments of this application. MEMS fabrication has high precision and can fabricate microstructures with dimensions at the nanometer scale, thus enabling the fabrication of small-sized MEMS heat sinks. In one possible implementation, the thickness of the drainage structure can be in the range of 1mm to 2mm, the width of the drainage structure can be in the range of 1mm to 4mm, and the length of the drainage structure can be in the range of 5mm to 10mm. In specific settings, the shape of the drainage structure can also be cuboid, cube, cylinder, etc., and the shape and size of the drainage structure can be reasonably set according to actual needs, without limitation here.

[0016] In one possible implementation, the distance between the top cover and the base plate can be between 0.3 mm and 0.6 mm, and the distance between the cantilever beam and the base plate can be between 10 μm and 100 μm. For example, the distance between the cantilever beam and the base plate can be tens of micrometers. The distance between the second end of the cantilever beam and the sidewall of the drainage structure can be between tens of micrometers and hundreds of micrometers. The thickness of the cantilever beam is between tens of micrometers and hundreds of micrometers. For example, the thickness of the cantilever beam can be between 10 μm and 300 μm, and the length of the cantilever beam (i.e., the distance between the first and second ends of the cantilever beam) is between 1 mm and 3.5 mm. The thickness of the piezoelectric film can be less than 5 μm. For example, the thickness of the piezoelectric film can be between 2 μm and 5 μm. This configuration allows the end displacement of the cantilever beam to be greater than 40 μm, which is beneficial for forming a higher pressure chamber standing wave. In specific implementations, the size of the piezoelectric film and the distance between the piezoelectric film and the second end of the cantilever beam can be reasonably set according to the actual heat dissipation requirements. In this embodiment, the airflow of the drainage structure is related to factors such as the cavity length, the location of the air outlet, and the cavity thickness. A cavity length within the range of 4mm to 4.5mm, a distance between the air outlet and the sidewall of the drainage structure within the range of 0.9mm to 1.5mm, and a cavity thickness within the range of 0.4mm to 0.65mm all contribute to a higher airflow. Furthermore, the microelectromechanical system heat sink in this embodiment operates at an ultrasonic frequency (>20kHz), exceeding the vibration frequency perceptible to the human ear, thus achieving completely silent operation.

[0017] In some embodiments of this application, the microelectromechanical system (MEMS) heat sink may further include a heat-conducting plate. Exemplarily, the heat-conducting plate may include a metal material with high thermal conductivity, such as copper. The heat-conducting plate is located on the side of the flow-through structure with a base plate, and there is a gap between the heat-conducting plate and the base plate. During the manufacturing process, adhesive materials such as resin can be used to bond the flow-through structure to the heat-conducting plate. In practical applications, the heat-conducting plate may be located between the flow-through structure and the heat-generating device. During operation, the heat generated by the heat-generating device can be conducted to the heat-conducting plate. The flow-through structure draws gas in through the air inlet, pressurizes and accelerates the airflow within the cavity, and then blows it vertically to the heat-conducting plate through the air outlet, thereby dissipating the heat. The high-temperature airflow can dissipate from the upper surface and surrounding areas of the heat-conducting plate, which can improve the heat dissipation efficiency of the MEMS heat sink.

[0018] In one possible implementation, the microelectromechanical system (MEMS) heat sink may include multiple drainage structures, with the projections of each drainage structure within the thickness direction of the heat-conducting plate located within its projection range. In specific implementations, adjacent drainage structures may have a certain gap, or they may be arranged closely together, depending on actual needs. Of course, in some cases where the surface of the heat-generating device is relatively flat and the heat dissipation effect is good, a heat-conducting plate may not be required, and drainage structures may be directly placed on the surface of the heat-generating device, depending on the actual situation. In specific implementations, when the MEMS heat sink includes multiple drainage structures, the arrangement of each drainage structure can be reasonably set according to actual needs. For example, the drainage structures in the MEMS heat sink may be arranged sequentially along a first direction. Alternatively, the drainage structures in the MEMS heat sink may be distributed in an array along the first and second directions. Of course, the drainage structures in the MEMS heat sink may also be arranged in other ways, which will not be listed here.

[0019] Secondly, embodiments of this application also provide an electronic device, which may include: any of the microelectromechanical system (MEMS) heat sinks and heating devices mentioned in the first aspect above. The MEMS heat sink may include at least one drainage structure, in which the base plate is closer to the heating device than the top cover. The MEMS heat sink can be used to dissipate heat from the heating device. The MEMS heat sink can be placed near the heating device, and the MEMS heat sink can be in direct contact with the heating device. In specific implementations, the MEMS heat sink can be attached to the surface of the heating device; alternatively, the MEMS heat sink may not be in contact with the heating device. The MEMS heat sink can drive gas to form a unidirectional flow, removing heat through active heat dissipation, effectively dissipating heat from the heating device with high efficiency. The heating device can be any device in the electronic device that has heat dissipation requirements, such as a main chip, an image processing chip, etc.

[0020] In some embodiments, the microelectromechanical system (MEMS) heat sink may include at least one drainage structure, wherein the projection of each drainage structure in the MEMS heat sink may be located within the projection range of the heat-generating device in the thickness direction of the base plate, so that the heat of the heat-generating device can be dissipated through each drainage structure. In one possible implementation, a heat-conducting plate may also be provided between the heat-generating device and each drainage structure to further improve heat dissipation efficiency.

[0021] In other embodiments, the microelectromechanical system (MEMS) heat sink may include at least one heat-draining structure and a heat-conducting plate. The heat-conducting plate may be divided into a first region and a second region. In the thickness direction of the heat-conducting plate, the projections of each heat-draining structure in the MEMS heat sink may all be located in the first region of the heat-conducting plate, and the second region of the heat-conducting plate may be located within the projection range of the heat-generating device. During operation, the heat generated by the heat-generating device can be transferred to the second region of the heat-conducting plate, and then transferred to the first region via the heat-conducting plate. The heat is then dissipated by the heat-draining structures. High-temperature airflow can escape from the upper surface and surrounding areas of the first region of the heat-conducting plate, thereby achieving heat dissipation for the heat-generating device. This arrangement allows the heat generated by the heat-generating device to be conducted to the sides and dissipated through the heat-draining structures. The heat-draining structures do not occupy space in the thickness direction of the heat-generating device, which is beneficial for the miniaturization of electronic devices.

[0022] In some embodiments of this application, in order to drive the microelectromechanical system (MEMS) heat sink, the electronic device may further include a driving device. The MEMS heat sink may include at least one drainage structure. The driving device is electrically connected to the piezoelectric film in each drainage structure. The driving device is used to apply a driving signal to the piezoelectric film. The voltage range of the driving signal can be in the range of 1V to 15V, and the voltage frequency of the driving signal can be in the range of 20kHz to 50kHz.

[0023] In some cases, when a microelectromechanical system (MEMS) heat sink includes multiple drainage structures, the superimposed vibrations of the cantilever beams in different drainage structures during the operation of the MEMS heat sink can cause the entire MEMS heat sink to vibrate, leading to vibration leakage. Therefore, to eliminate the overall vibration of the MEMS heat sink, this application embodiment improves the arrangement of the drainage structures and the driving signal of the piezoelectric film, which will be described in detail below.

[0024] In this embodiment of the application, the heat sink for a microelectromechanical system may include multiple drainage structures, which may be arranged in the following manner:

[0025] Arrangement Method 1:

[0026] In the heat sink of a microelectromechanical system, each flow-guiding structure can be arranged sequentially along a first direction, and the first end of the cantilever beam in each flow-guiding structure points in the same direction to the second end.

[0027] Arrangement Method Two:

[0028] In a microelectromechanical system (MEMS) heat sink, the various drainage structures can be arranged sequentially along a first direction, and the first end of the cantilever beam in two adjacent drainage structures points in opposite directions to the second end.

[0029] Arrangement method three:

[0030] A microelectromechanical system (MEMS) heat sink may include: a first group of cooling structures and a second group of cooling structures arranged along a first direction. The first group of cooling structures may include: a plurality of first cooling structures arranged sequentially along the first direction, wherein the first end of the cantilever beam in each first cooling structure points in the same direction to the second end. The second group of cooling structures may include: a plurality of second cooling structures arranged sequentially along the first direction, wherein the first end of the cantilever beam in each second cooling structure points in the same direction to the second end, while the first end of the cantilever beam in the first cooling structure and the second cooling structure points in opposite directions to the second end. In other words, the cooling structures in the MEMS heat sink are distributed in an axisymmetric manner.

[0031] In some embodiments of this application, for the above-described arrangement methods one to three, the overall vibration of the microelectromechanical system heat sink can be eliminated or reduced by applying an inverse driving signal to the piezoelectric films in two adjacent drainage structures.

[0032] In other embodiments of this application, for cases where the drainage structures in a microelectromechanical system (MEMS) heat sink are axially symmetrically distributed, such as the arrangements described in methods two and three above, other driving methods can be employed to eliminate or reduce the overall vibration of the MEMS heat sink. Arrangement method two can also be described as follows: the MEMS heat sink may include: a first drainage structure group and a second drainage structure group arranged along a first direction. The first drainage structure group may include: a plurality of first drainage structures arranged sequentially along the first direction. The second drainage structure group may include: a plurality of second drainage structures arranged sequentially along the first direction. In adjacent first drainage structures, the first end of the cantilever beam points in opposite directions to the second end; in adjacent second drainage structures, the first end of the cantilever beam points in opposite directions to the second end; and in adjacent first and second drainage structures, the first end of the cantilever beam points in opposite directions to the second end. The driving device can be specifically used to apply an opposite driving signal to the piezoelectric film in two adjacent first drainage structures, apply an opposite driving signal to the piezoelectric film in two adjacent second drainage structures, or apply the same driving signal to the piezoelectric film in adjacent first and second drainage structures, so that the vibration of the cantilever beam in the adjacent drainage structures can cancel each other out, effectively eliminating or reducing the overall vibration of the microelectromechanical system heat sink.

[0033] Thirdly, this application also provides a method for manufacturing a microelectromechanical system (MEMS) heat sink. The MEMS heat sink in this application may include at least one heat dissipation structure, wherein each heat dissipation structure may be manufactured using the following steps:

[0034] Step 1: Drill holes in the base plate to create vents. In some cases, when the microelectromechanical system heat sink has a heat-conducting plate, the base plate can be mounted or formed on the heat-conducting plate before step 1.

[0035] Step 2: Provide a cantilever beam with a piezoelectric film on its surface. Fix the first end of the cantilever beam to the edge of the base plate, leaving a gap between the cantilever beam and the base plate, with the second end of the cantilever beam suspended. In the thickness direction of the base plate, the vent holes are located within the area covered by the projection of the cantilever beam. In practice, bonding or adhesive methods can be used to fix the cantilever beam to the edge of the base plate.

[0036] Step 3: Install the top cover onto the cantilever beam to create a cavity between the top cover and the base plate, thus obtaining the drainage structure; the top cover is equipped with an air inlet.

[0037] In the method for fabricating a microelectromechanical system (MEMS) heat sink provided in this application embodiment, a cantilever beam with a piezoelectric thin film is installed in the flow-guiding structure. Under the control of a driving signal, the piezoelectric thin film drives the cantilever beam to vibrate, controlling the gas to form a unidirectional flow within the flow-guiding structure. This allows for active heat dissipation, resulting in high heat dissipation efficiency and meeting the high heat dissipation requirements of electronic devices. Furthermore, the fabrication method provided in this application embodiment can be implemented using MEMS processing, resulting in a smaller MEMS heat sink, which is beneficial for the miniaturization design of electronic devices.

[0038] In practice, to improve the efficiency of the manufacturing process, multiple heat dissipation structures can be made in the same process. After the structures are made, the microelectromechanical system heat sink is installed at the location of the heat-generating device that needs heat dissipation. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application;

[0040] Figure 2 This is a three-dimensional structural diagram of a heat sink for a microelectromechanical system provided in an embodiment of this application;

[0041] Figure 3a for Figure 2 A schematic diagram of the cross-section at the dashed line BB';

[0042] Figure 3b for Figure 2 A schematic diagram of another cross-section at the dashed line BB';

[0043] Figure 4 This is another three-dimensional structural schematic diagram of a heat sink for a microelectromechanical system provided in an embodiment of this application;

[0044] Figure 5 This is another three-dimensional structural schematic diagram of a heat sink for a microelectromechanical system provided in an embodiment of this application;

[0045] Figure 6 This is a schematic diagram of the planar structure of the electronic device provided in the embodiments of this application;

[0046] Figure 7 This is another three-dimensional structural schematic diagram of a heat sink for a microelectromechanical system provided in an embodiment of this application;

[0047] Figure 8 for Figure 7 A schematic diagram of the cross-section at the dashed line DD'.

[0048] Figure 9 for Figure 7 A schematic diagram of another cross-section at the dashed line DD';

[0049] Figure 10 for Figure 7 A schematic diagram of another cross-section at the dashed line DD';

[0050] Figure 11 This is a simulation diagram of Example 1 in this application;

[0051] Figure 12 This is a simulation diagram of Example 2 in this application;

[0052] Figure 13 This is a simulation diagram of Example 3 in this application;

[0053] Figure 14 A flowchart illustrating the manufacturing method of a microelectromechanical system heat sink provided in this application embodiment;

[0054] Figure 15 This is a schematic diagram of the structure of each step in the manufacturing method provided in the embodiments of this application.

[0055] Figure label:

[0056] 100 - Electronic device; 101 - Microelectromechanical system heat sink; 102 - Heating device; 200 - Drainage structure; 200a - First drainage structure; 200b - Second drainage structure; 201 - Top cover; 202 - Base plate; 203 - Cantilever beam; 204 - Piezoelectric film; 205 - First elevation structure; 206 - Second elevation structure; 207 - Extension; 300 - Heat-conducting plate; W1 - Air inlet; W2 - Air outlet; Q - Cavity; m - First end; n - Second end; K - Side wall; U - Groove; C1 - First region; C2 - Second region; P1 - First drainage structure group; P2 - Second drainage structure group. Detailed Implementation

[0057] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0058] It should be noted that the accompanying drawings in this application are for illustrative purposes only and do not represent actual scale. The same reference numerals in the accompanying drawings denote the same or similar structures, and therefore, repeated descriptions of them will be omitted.

[0059] The terms describing position and direction used in this application, such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," are merely illustrative examples based on the orientation or positional relationships shown in the accompanying drawings. They are intended solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Changes may be made as needed, and all such changes are included within the scope of protection of this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0060] To dissipate heat from heat-generating components in electronic devices and meet their high heat dissipation requirements, this application provides a microelectromechanical system (MEMS) heat sink, its manufacturing method, and an electronic device. The MEMS heat sink provided in this application can drive gas to form a unidirectional flow, actively dissipating heat and achieving high heat dissipation efficiency, thus meeting the high heat dissipation demands of electronic devices. Furthermore, the MEMS heat sink provided in this application can be fabricated using microelectromechanical systems (MEMS) processing methods, resulting in a smaller MEMS heat sink. Therefore, the MEMS heat sink provided in this application can be applied to small or micro electronic devices. For example, the MEMS heat sink provided in this application can be applied to terminal devices such as mobile phones, tablets, laptops, and smart wearable devices, or to other electronic devices such as smart TVs, smart door locks, and smart home appliances. Of course, in some cases, the MEMS heat sink provided in this application can also be applied to larger electronic devices; this is not a limitation.

[0061] Figure 1 This is a schematic diagram of the structure of the electronic device provided in the embodiments of this application. Figure 1 The left-hand side is a top view of the electronic device. Figure 1 The right side of the image shows a top view of the electronic device, with a cross-sectional view at the dashed line AA'. (See image below.) Figure 1 As shown, the electronic device 100 provided in this embodiment may include a microelectromechanical system (MEMS) heat sink 101 and a heat-generating device 102. The MEMS heat sink 101 is used to dissipate heat from the heat-generating device 102. The MEMS heat sink 101 can drive gas to form a unidirectional flow, removing heat through active cooling, thereby effectively dissipating heat from the heat-generating device 102 with high cooling efficiency. The heat-generating device 102 can be any device in the electronic device 100 that has heat dissipation requirements, such as a main chip, an image processing chip, etc. Figure 1The example shown is a mobile phone. When the electronic device 100 is another device, the position, shape, and size of the heat sink 101 and the heat-generating device 102 of the microelectromechanical system in the electronic device 100 can be reasonably set according to actual needs.

[0062] Figure 2 This is a three-dimensional structural diagram of a heat sink for a microelectromechanical system provided in an embodiment of this application. Figure 3a for Figure 2 A cross-sectional diagram at the dashed line BB', combined with... Figure 2 and Figure 3a The microelectromechanical system (MEMS) heat sink 101 provided in this application embodiment may include at least one air-guiding structure 200, wherein each air-guiding structure 200 may include: an upper cover 201, a bottom plate 202, a side wall K, a cantilever beam 203, and a piezoelectric film 204. The upper cover 201 has an air inlet W1, and the bottom plate 202 has an air outlet W2. The upper cover 201 and the bottom plate 202 are disposed opposite to each other, and the side wall K is located between the upper cover 201 and the bottom plate 202, forming a cavity Q. The cantilever beam 203 is located within the cavity Q, and the cantilever beam 203 has a first end m and a second end n. The first end m of the cantilever beam 203 is connected to the side wall K, and the second end n of the cantilever beam 203 is suspended, i.e., the first end m is the fixed end of the cantilever beam 203, and the second end n is the movable end of the cantilever beam 203. In the thickness direction of the base plate 202 (e.g., the direction indicated by arrow Z in the figure), the vent W2 is located within the projection coverage area of ​​the cantilever beam 203. The piezoelectric film 204 is located on the surface of the cantilever beam 203. The piezoelectric film 204 can be disposed on the side of the cantilever beam 203 facing the upper cover 201, or the piezoelectric film 204 can also be disposed on the side of the cantilever beam 203 facing the base plate 202.

[0063] In the microelectromechanical system (MEMS) heat sink 101 provided in this embodiment, a cantilever beam 203 and a piezoelectric film 204 are provided in the airflow structure 200. Under the control of a drive signal, the piezoelectric film 204 can drive the cantilever beam 203 to vibrate, causing a change in the pressure within the cavity Q and controlling the gas to flow unidirectionally within the cavity Q. When the second end n of the cantilever beam 203 moves towards the base plate 202, a negative pressure is formed in the space between the cantilever beam 203 and the upper cover 201, causing gas to be drawn in from the air inlet W1. When the second end n of the cantilever beam 203 moves towards the upper cover 201, the gas, under the action of internal pressure, flows into the space between the cantilever beam 203 and the base plate 202 and is discharged from the air outlet W2. This process repeats, causing the gas to flow unidirectionally in the airflow structure 200. Therefore, the MEMS heat sink 101 provided in this embodiment can drive the gas to form a unidirectional flow, removing heat through active cooling, resulting in high heat dissipation efficiency and meeting the high heat dissipation requirements of electronic devices. Furthermore, the microelectromechanical system (MEMS) heat sink 101 does not require mechanical valves, achieving fluid flow through a valveless method and forming unidirectional flow, which can result in higher fluid efficiency. In addition, the MEMS heat sink 101 provided in this embodiment can be fabricated using MEMS processing, resulting in a smaller MEMS heat sink 101, which is beneficial for the miniaturization design of electronic devices.

[0064] In this embodiment, the microelectromechanical system (MEMS) heat sink 101 can be used to dissipate heat from the heat-generating device 102. The MEMS heat sink 101 can be placed near the heat-generating device 102, either in direct contact or without direct contact. In each drainage structure 200, the base plate 202 is closer to the heat-generating device 102 than the top cover 201. This allows the cooler gas discharged from the vent W2 to carry away heat from the heat-generating device 102, thus dissipating heat.

[0065] In practical implementation, the driving signal applied to the piezoelectric film 204 can be a high-frequency alternating current. Under the action of the inverse piezoelectric effect, the piezoelectric film 204 can convert electrical energy into mechanical energy to drive the cantilever beam 203 to vibrate. When the frequency of the alternating current, the vibration frequency of the cantilever beam 203, and the resonant frequency of the gas in the cavity Q are matched, the gas in the cavity Q can be made to undergo coupled resonance to form a standing wave-like phenomenon. This allows the gas to flow in a specific direction within the cavity Q, thereby achieving gas diversion and improving the heat dissipation efficiency of the microelectromechanical system heat sink 101.

[0066] Continue to refer to Figure 2 and Figure 3aIn the thickness direction of the base plate 202 (e.g., the direction indicated by arrow Z in the figure), the air inlet W1 and the air outlet W2 are located within the area covered by the projection of the cantilever beam 203, with the air inlet W1 located on the side of the air outlet W2 closer to the first end m. When the microelectromechanical system heat sink 101 is working, gas is drawn in through the air inlet W1, passes through the space between the cantilever beam 203 and the top cover 201, the space near the second end n of the cantilever beam 203, and the space between the cantilever beam 203 and the base plate 202, and is then discharged through the air outlet W2. This arrangement allows for a longer flow distance between the air inlet W1 and the air outlet W2, fully utilizing the inertia of the gas to form a unidirectional flow. In practical implementation, the horizontal distance between the air inlet W1 and the first end m of the cantilever beam 203 (i.e., the distance in the direction of arrow X) can be reasonably set according to the air intake effect of the diversion structure 200. The horizontal distance between the air outlet W2 and the first end m of the cantilever beam 203 can be reasonably set according to the air outlet effect of the diversion structure 200.

[0067] In one possible implementation, the cantilever beam 203 has a groove U on its surface facing the base plate 202, and the groove U is located at the second end n of the cantilever beam 203. In this embodiment, by providing the groove U in the cantilever beam 203, the gas storage capacity of the drainage structure 200 can be increased. During the vibration of the cantilever beam 203, the groove U can promote the discharge of gas from the outlet W2. Furthermore, the size of the groove U is related to the vibration frequency of the cantilever beam 203. The larger the width of the groove U in the length direction of the cantilever beam 203, the lower the vibration frequency of the cantilever beam 203. Therefore, in specific implementations, the vibration frequency of the cantilever beam 203 can be adjusted by reasonably setting the size of the groove U.

[0068] Furthermore, in the thickness direction of the base plate 202, the vent W2 can be located within the area covered by the projection of the groove U, and the vent W1 is located on the side of the groove U closer to the first end m. For example, the vent W1 can be positioned on the upper cover 201 corresponding to the first end m. This arrangement further increases the flow distance between the vent W1 and the vent W2, facilitating resonance of the gas within the cavity Q. Moreover, positioning the vent W2 on the base plate 202 corresponding to the groove U further promotes gas discharge from the vent W2.

[0069] In one possible implementation, the projection of the piezoelectric film 204 and the projection of the groove U do not overlap in the thickness direction of the base plate 202. That is, the piezoelectric film 204 is positioned at a location with a larger thickness in the cantilever beam 203, avoiding the location of the groove U in the cantilever beam 203, thereby improving the structural stability of the cantilever beam 203. Of course, in some cases, the projection of the piezoelectric film 204 and the projection of the groove U can overlap in the thickness direction of the base plate 202, and can be reasonably set according to actual needs.

[0070] Continue to refer to Figure 3a In this embodiment of the application, the drainage structure 200 includes an upper cover 201 and a bottom plate 202, that is, the drainage structure 200 is a split structure. In this way, during the manufacturing process, the bottom plate 202, the cantilever beam 203 and the upper cover 201 can be manufactured separately using MEMS technology, making the drainage structure 200 easy to manufacture and assemble.

[0071] In one possible implementation, the upper cover 201 may include a metallic or resin material, and the base plate 202 may include single-crystal silicon (SCS) or a metallic material. For example, the base plate 202 may include a metallic material with a high Young's modulus. The cantilever beam 203 may include a single-crystal silicon or metallic material. For example, the cantilever beam 203 may include a metallic material with a high Young's modulus. The piezoelectric thin film 204 may include lead zirconate titanate (PZT) material. During the fabrication process, the piezoelectric thin film 204 can be fabricated using a sputtering process to obtain an epitaxial single-crystal piezoelectric thin film 204 with high crystal orientation uniformity and good piezoelectric properties.

[0072] In one possible implementation, Figure 3b for Figure 2 Another cross-sectional diagram at the dashed line BB' is shown below. Figure 3bAs shown, the sidewall K may include a first elevation structure 205 for connecting the cantilever beam 203 and the base plate 202. The first elevation structure 205 serves to connect the cantilever beam 203 and the base plate 202, and creates a certain gap between them. For example, the first elevation structure 205 may be a bonding material such as gold (Au), allowing the cantilever beam 203 and the base plate 202 to be connected by bonding; alternatively, the first elevation structure 205 may also be a high-strength adhesive material such as resin, allowing the cantilever beam 203 and the base plate 202 to be connected by adhesive. Similarly, the sidewall K may also include a second elevation structure 206 for connecting the upper cover 201 and the base plate 202. The second elevation structure 206 serves to connect the upper cover 201 and the base plate 202, and creates a cavity Q between them. For example, the second elevation structure 206 can be a bonding material such as gold (Au), and the upper cover 201 and the base plate 202 can be connected by bonding; alternatively, the second elevation structure 206 can also be a high-strength adhesive material such as resin, and the upper cover 201 and the base plate 202 can be connected by adhesive. In another possible implementation, the first elevation structure 205 and the second elevation structure 206 can be connected to the base plate 202 as a whole. During the manufacturing process, the first elevation structure 205 and the second elevation structure 206 can be formed on the base plate 202 by etching. Then, the cantilever beam 203 is installed on the first elevation structure 205, and the upper cover 201 is installed on the second elevation structure 206.

[0073] Continue to refer to Figure 3b In one possible implementation, the sidewall K may further include an extension 207, which may be located on the side of the first raised structure 205 and the second raised structure 206 away from the base plate 202, and the extension 207 may be connected to the top cover 201 as a whole. Of course, the sidewall K of the drainage structure 200 may also have other implementations, which are not limited here.

[0074] In some cases, the lattice constant difference between the piezoelectric film 204 and the cantilever beam 203 is relatively large. If the piezoelectric film 204 is directly formed on the surface of the cantilever beam 203, the adhesion between the piezoelectric film 204 and the cantilever beam 203 is poor. In some embodiments of this application, the drainage structure 200 may further include a transition layer located between the piezoelectric film 204 and the cantilever beam 203. Figure 3b (Not shown in the image), the transition layer may include strontium oxide (SrO), zirconium oxide (ZrO2), or platinum (Pt) materials, and the thickness of the transition layer can be in the nanometer range. By setting the transition layer, the adhesion between the piezoelectric film 204 and the cantilever beam 203 can be increased, thereby improving the reliability of the drainage structure 200.

[0075] In some embodiments of this application, combined with Figure 2 and Figure 3b The microelectromechanical system heat sink 101 in this embodiment can be fabricated using MEMS processing. MEMS processing offers high precision and can fabricate microstructures with dimensions at the nanometer scale, thus enabling the fabrication of a relatively small microelectromechanical system heat sink 101. In one possible implementation, the thickness h1 of the drainage structure 200 can be in the range of 1 mm to 2 mm, the width L1 of the drainage structure 200 can be in the range of 1 mm to 4 mm, and the length L2 of the drainage structure 200 can be in the range of 5 mm to 10 mm. Figure 2 and Figure 3b The diagram uses a cuboid shape for the drainage structure 200 as an example. In actual settings, the shape of the drainage structure 200 can also be a cube, cylinder, or other shapes. The shape and size of the drainage structure 200 can be reasonably set according to actual needs, and there are no restrictions here.

[0076] In one possible implementation, such as Figure 3b As shown, the distance h2 between the upper cover 201 and the base plate 202 can be in the range of 0.3 mm to 0.6 mm, and the distance h3 between the cantilever beam 203 and the base plate 202 can be in the range of 10 μm to 100 μm. For example, the distance h3 between the cantilever beam 203 and the base plate 202 can be tens of micrometers. The distance h4 between the second end n of the cantilever beam 203 and the sidewall of the drainage structure 200 can be tens of micrometers to hundreds of micrometers. The thickness of the cantilever beam 203 is in the range of tens of micrometers to hundreds of micrometers. For example, the thickness of the cantilever beam 203 can be in the range of 10 μm to 300 μm, and the length of the cantilever beam 203 (i.e., the distance between the first end m and the second end n of the cantilever beam 203) is in the range of 1 mm to 3.5 mm. The thickness of the piezoelectric film 204 can be less than 5 μm. For example, the thickness of the piezoelectric film 204 can be in the range of 2 μm to 5 μm. This setting allows the end displacement of the cantilever beam 203 to be greater than 40 μm, which is beneficial for forming a higher pressure chamber standing wave. In specific implementations, the size of the piezoelectric film 204 and the distance between the piezoelectric film 204 and the second end n of the cantilever beam 203 can be reasonably set according to the actual heat dissipation requirements.

[0077] In some embodiments of this application, combined with Figure 2 and Figure 3bThe microelectromechanical system heat sink 101 in this embodiment may further include a heat-conducting plate 300. Exemplarily, the heat-conducting plate 300 may include a metal material with high thermal conductivity, such as copper. The heat-conducting plate 300 is located on the side of the flow-guiding structure 200 with the base plate 202, and there is a gap between the heat-conducting plate 300 and the base plate 202. During the manufacturing process, an adhesive material such as resin can be used to bond the flow-guiding structure 200 and the heat-conducting plate 300. In practical applications, the heat-conducting plate 300 may be disposed between the flow-guiding structure 200 and the heating device 102. The heat-conducting plate 300 may be in direct contact with the heating device 102, or it may be attached to the surface of the heating device 102; alternatively, the heat-conducting plate 300 may not be in contact with the heating device 102. During operation, the heat generated by the heating element 102 can be conducted to the heat-conducting plate 300. The airflow structure 200 draws in gas through the air inlet W1, pressurizes and accelerates the airflow within the cavity Q, and then blows it vertically through the air outlet W2 to the heat-conducting plate 300, thereby dissipating the heat. The high-temperature airflow can dissipate from the upper surface and surrounding areas of the heat-conducting plate 300, which can improve the heat dissipation efficiency of the microelectromechanical system heat sink 101.

[0078] In one possible implementation, the microelectromechanical system (MEMS) heat sink 101 may include multiple drainage structures 200. Along the thickness direction of the heat-conducting plate 300 (e.g., the direction indicated by arrow Z in the figure), the projection of each drainage structure 200 in the MEMS heat sink 101 lies within the projection range of the heat-conducting plate 300. In specific implementations, adjacent drainage structures 200 may have a certain gap, or they may be arranged closely together, depending on actual needs. Of course, in some cases, where the surface of the heat-generating device 102 is relatively flat and the heat dissipation effect is good, the heat-conducting plate 300 may not be provided, and the drainage structures 200 may be directly provided on the surface of the heat-generating device 102, depending on the actual situation.

[0079] In some embodiments, the microelectromechanical system (MEMS) heat sink 101 may include at least one drainage structure 200. In the thickness direction of the base plate, the projection of each drainage structure 200 in the MEMS heat sink 101 may be located within the projection range of the heat-generating device 102, so that the heat from the heat-generating device 102 can be dissipated through each drainage structure 200. In one possible implementation, a heat-conducting plate 300 may also be provided between the heat-generating device 102 and each drainage structure 200 to further improve heat dissipation efficiency. When the MEMS heat sink 101 includes multiple drainage structures 200, the arrangement of each drainage structure 200 can be reasonably set according to actual needs. For example, as... Figure 2 As shown, the various flow-guiding structures 200 in the microelectromechanical system heat sink 101 can be arranged sequentially along the first direction X. Alternatively, as... Figure 4 As shown, Figure 4This is another three-dimensional structural diagram of the microelectromechanical system heat sink provided in the embodiments of this application. The various flow-guiding structures 200 in the microelectromechanical system heat sink 101 can be arranged in an array along the first direction X and the second direction Y, for example... Figure 4 The various drainage structures 200 in the heat sink 101 are arranged in a two-row, six-column configuration. Of course, the various drainage structures 200 in the heat sink 101 of the microelectromechanical system can also be arranged in other ways, which will not be listed here.

[0080] In other embodiments, such as Figure 5 As shown, Figure 5 This is another three-dimensional structural diagram of the microelectromechanical system (MEMS) heat sink provided in this application embodiment. The MEMS heat sink 101 may include at least one flow-guiding structure 200 and a heat-conducting plate 300. The heat-conducting plate 300 can be divided into a first region C1 and a second region C2. In the thickness direction of the heat-conducting plate 300, the projections of each flow-guiding structure 200 in the MEMS heat sink 101 can all be located in the first region C1 of the heat-conducting plate 300, and the second region C2 of the heat-conducting plate 300 is located within the projection range of the heat-generating device 102. During operation, the heat generated by the heat-generating device 102 can be transferred to the second region C2 of the heat-conducting plate 300, and the heat is transferred to the first region C1 via the heat-conducting plate 300. The flow-guiding structures 200 dissipate heat from the heat-conducting plate 300, and the high-temperature airflow can dissipate from the upper surface and surrounding area of ​​the first region C1 of the heat-conducting plate 300, thereby achieving heat dissipation for the heat-generating device 102. With this arrangement, the heat generated by the heating device 102 can be conducted to the side and dissipated through the drainage structure 200. The drainage structure 200 does not occupy the space in the thickness direction of the heating device 102, which is conducive to the miniaturization of electronic devices.

[0081] Figure 6 This is a schematic diagram of the planar structure of the electronic device provided in the embodiments of this application, such as... Figure 6 As shown, when the electronic device 100 includes multiple heat-generating devices 102, the number, size, and location of the microelectromechanical system heat sink 101 can be set according to actual needs to achieve multi-point distributed heat dissipation and quickly dissipate the heat generated by each heat-generating device 102. For example, in Figure 6 In the middle, the two columns of heating devices 102 on the left are thinner, with enough space to set up the microelectromechanical system heat sink 101, which can be set up directly at the position of the heating device 102; while the heating device 102 on the right is thicker, so a heat dissipation structure 200 can be set up near the heating device 102, and the heat is transferred to the heat dissipation structure 200 through the heat conduction plate 300.

[0082] In some embodiments of this application, in order to drive the microelectromechanical system (MEMS) heat sink, the electronic device may further include a driving device. The MEMS heat sink may include at least one drainage structure. The driving device is electrically connected to the piezoelectric film in each drainage structure. The driving device is used to apply a driving signal to the piezoelectric film. The voltage range of the driving signal can be in the range of 1V to 15V, and the voltage frequency of the driving signal can be in the range of 20kHz to 50kHz.

[0083] In some cases, when a microelectromechanical system (MEMS) heat sink includes multiple drainage structures, the superimposed vibrations of the cantilever beams in different drainage structures during the operation of the MEMS heat sink can cause the entire MEMS heat sink to vibrate, leading to vibration leakage. Therefore, to eliminate the overall vibration of the MEMS heat sink, this application embodiment improves the arrangement of the drainage structures and the driving signal of the piezoelectric film, which will be described in detail below with reference to the accompanying drawings.

[0084] Figure 7 This is another three-dimensional structural diagram of the heat sink for a microelectromechanical system provided in an embodiment of this application. Figure 8 for Figure 7 A schematic diagram of the cross-section at the dashed line DD', combined with... Figure 7 and Figure 8 The microelectromechanical system (MEMS) heat sink 101 may include a plurality of drainage structures 200 arranged sequentially along a first direction X, wherein the first end m of the cantilever beam 203 in each drainage structure 200 points in the same direction to the second end n. During operation of the MEMS heat sink 101, the driving device may be specifically used to apply an opposite driving signal to the piezoelectric film 204 in two adjacent drainage structures 200. Figure 8 Taking the four drainage structures 200 shown as an example, the driving device can apply in-phase driving signals to the piezoelectric films 204 in the first and third drainage structures 200, apply in-phase driving signals to the piezoelectric films 204 in the second and fourth drainage structures 200, and apply out-of-phase driving signals to the piezoelectric films 204 in the first and second drainage structures 200. With this configuration, the vibrations of the cantilever beams 203 in adjacent drainage structures 200 can cancel each other out, thereby eliminating or reducing the overall vibration of the microelectromechanical system heat sink 101.

[0085] In the embodiments of this application, the driving signal can be an alternating current signal. Two driving signals in phase can be understood as the two driving signals being 0° out of phase, and two driving signals out of phase can be understood as the two driving signals being 180° out of phase.

[0086] Figure 9 for Figure 7 Another cross-sectional diagram at the dashed line DD', combined with... Figure 7 and Figure 9The microelectromechanical system (MEMS) heat sink 101 may include a plurality of drainage structures 200 arranged sequentially along a first direction X, wherein the first end m of the cantilever beam 203 in two adjacent drainage structures 200 points in opposite directions to the second end n. During operation of the MEMS heat sink 101, the driving device may be specifically used to apply an inverse driving signal to the piezoelectric film 204 in two adjacent drainage structures 200. Figure 9 Taking the four drainage structures 200 shown as an example, the driving device can apply in-phase driving signals to the piezoelectric films 204 in the first and third drainage structures 200, apply in-phase driving signals to the piezoelectric films 204 in the second and fourth drainage structures 200, and apply out-of-phase driving signals to the piezoelectric films 204 in the first and second drainage structures 200. With this configuration, the vibrations of the cantilever beams 203 in adjacent drainage structures 200 can cancel each other out, thereby eliminating or reducing the overall vibration of the microelectromechanical system heat sink 101.

[0087] Figure 10 for Figure 7 Another cross-sectional diagram at the dashed line DD', combined with... Figure 7 and Figure 10 The microelectromechanical system (MEMS) heat sink 101 may include: a first drainage structure group P1 and a second drainage structure group P2 arranged along a first direction X. The first drainage structure group P1 may include: a plurality of first drainage structures 200a arranged sequentially along the first direction X, wherein the first end m of the cantilever beam 203 in each first drainage structure 200a points in the same direction to the second end n. The second drainage structure group P2 may include: a plurality of second drainage structures 200b arranged sequentially along the first direction X, wherein the first end m of the cantilever beam 203 in each second drainage structure 200b points in the same direction to the second end n, while the first end m of the cantilever beam in the first drainage structure 200a and the second drainage structure 200b points in opposite directions to the second end n. That is, the drainage structures 200 in the MEMS heat sink 101 are axially symmetrically distributed. The driving device may specifically be used to apply an opposite driving signal to the piezoelectric film 204 in two adjacent drainage structures 200. Figure 10 Taking the four drainage structures 200 shown as an example, the driving device can apply in-phase driving signals to the piezoelectric films 204 in the first and third drainage structures 200, apply in-phase driving signals to the piezoelectric films 204 in the second and fourth drainage structures 200, and apply out-of-phase driving signals to the piezoelectric films 204 in the first and second drainage structures 200. With this configuration, the vibrations of the cantilever beams 203 in adjacent drainage structures 200 can cancel each other out, thereby eliminating or reducing the overall vibration of the microelectromechanical system heat sink 101.

[0088] In other words, in some embodiments of this application, for Figures 8 to 10The arrangement of the drainage structures 200 shown can eliminate or reduce the overall vibration of the microelectromechanical system heat sink 101 by applying an opposite driving signal to the piezoelectric films 204 in two adjacent drainage structures 200.

[0089] In other embodiments of this application, for Figure 9 and Figure 10 The arrangement of the drainage structure 200 shown can also employ other driving methods to eliminate or reduce the overall vibration of the microelectromechanical system heat sink 101. For example... Figure 9 and Figure 10 As shown, the heat dissipation structures 200 in the microelectromechanical system (MEMS) heat sink 101 are distributed in an axisymmetric manner. Specifically, the MEMS heat sink 101 may include: a first heat dissipation structure group P1 and a second heat dissipation structure group P2 arranged along a first direction X. The first heat dissipation structure group P1 may include: a plurality of first heat dissipation structures 200a arranged sequentially along the first direction X. The second heat dissipation structure group P2 may include: a plurality of second heat dissipation structures 200b arranged sequentially along the first direction X. Figure 9 As shown, in two adjacent first drainage structures 200a, the first end m of the cantilever beam 203 points in opposite directions to the second end n; in two adjacent second drainage structures 200b, the first end m of the cantilever beam 203 points in opposite directions to the second end n; and in adjacent first drainage structures 200a and second drainage structures 20b, the first end m of the cantilever beam 203 points in opposite directions to the second end n. Figure 10 As shown, in each of the first drainage structures 200a, the direction from the first end m of the cantilever beam 203 to the second end n is consistent; in each of the second drainage structures 200b, the direction from the first end m of the cantilever beam 203 to the second end n is consistent; however, the directions from the first end m of the cantilever beam 203 to the second end n are opposite in the first drainage structure 200a and the second drainage structure 200b. In practical applications, when the drainage structures 200 in the microelectromechanical system heat sink 101 are axially symmetrically distributed, the driving device can specifically be used to apply opposite driving signals to the piezoelectric films 204 in two adjacent first drainage structures 200a, apply opposite driving signals to the piezoelectric films 204 in two adjacent second drainage structures 200b, and apply the same driving signal to the piezoelectric films in adjacent first drainage structures 200a and second drainage structures 200b. This allows the vibrations of the cantilever beams 203 in adjacent drainage structures 200 to cancel each other out, effectively eliminating or reducing the overall vibration of the microelectromechanical system heat sink 101. Figure 9 and Figure 10Taking the four drainage structures 200 shown as an example, the driving device can apply in-phase driving signals to the piezoelectric films 204 in the first and fourth drainage structures 200, apply in-phase driving signals to the piezoelectric films 204 in the second and third drainage structures 200, and apply out-of-phase driving signals to the piezoelectric films 204 in the first and second drainage structures 200.

[0090] The foregoing has provided a detailed description of the specific implementation of the microelectromechanical system (MEMS) heat sink provided in the embodiments of this application. In actual implementation, the MEMS heat sink can be reasonably arranged on or around the surface of the heat-generating device according to actual needs. In addition, to verify the heat dissipation effect of the MEMS heat sink provided in the embodiments of this application, a simulation was performed on the MEMS heat sink provided in the embodiments of this application.

[0091] Figure 11 This is a simulation diagram of Example 1 in this application. Figure 11 (1) in the figure is the curve showing the relationship between the air volume and the length of the chamber. Figure 11 (2) is the simulation diagram of Example 1, such as Figure 11 As shown, in Example 1, the drainage structure 200 draws gas in through the air inlet W1, pressurizes and accelerates the airflow within the cavity Q, and then discharges it through the air outlet W2, as shown. Figure 11 As shown in the diagram, red indicates a higher airflow velocity, and blue indicates a lower airflow velocity. The simulation clearly shows that the airflow discharged from the outlet W2 of the air intake structure 200 can carry away heat, achieving a good heat dissipation effect. Furthermore, in Example 1, the relationship between the airflow volume of the air intake structure 200 and the chamber length L3 of the cavity Q was analyzed. The curve showing the relationship between airflow volume and chamber length indicates that when the chamber length L3 of the cavity Q is within the range of 4mm to 4.5mm, the airflow volume of the air intake structure 200 is greater than 0.11cfm, meaning that the airflow volume of the air intake structure 200 is relatively high.

[0092] Figure 12 This is a simulation diagram of Example 2 in this application. Figure 12 (1) is the curve showing the relationship between air volume and the position of the air outlet. Figure 12 (2) is the simulation diagram of Example 2, such as Figure 12As shown in the simulation diagram, similar to Example 1 above, it is clear from the simulation diagram that the airflow discharged from the air outlet W2 by the air diversion structure 200 in Example 2 can carry away heat, achieving a good heat dissipation effect. Unlike Example 1, Example 2 also analyzes the relationship between the airflow volume of the air diversion structure 200 and the position of the air outlet W2. The curve showing the relationship between airflow volume and air outlet position indicates that when the distance h5 between the air outlet W2 and the sidewall of the air diversion structure 200 is within the range of 0.9mm to 1.5mm, the airflow volume of the air diversion structure 200 is greater than or equal to 0.1cfm, meaning that the airflow volume of the air diversion structure 200 is relatively high.

[0093] Figure 13 This is a simulation diagram of Example 3 in this application. Figure 13 (1) is the curve showing the relationship between air volume and chamber thickness. Figure 13 (2) is the simulation diagram of Example 3, such as Figure 13 As shown in the simulation diagram, similar to Example 1 above, it is clear from the simulation diagram that the airflow discharged from the air outlet W2 by the air diversion structure 200 in Example 3 can carry away heat, achieving a good heat dissipation effect. Unlike Example 1, Example 3 also analyzes the relationship between the airflow volume of the air diversion structure 200 and the cavity thickness of the cavity Q (i.e., the distance h2 between the top cover and the bottom plate). The curve showing the relationship between airflow volume and cavity thickness indicates that when the cavity thickness is within the range of 0.4mm to 0.65mm, the airflow volume of the air diversion structure 200 is greater than or equal to 0.1cfm, meaning that the airflow volume of the air diversion structure 200 is relatively high.

[0094] Furthermore, verification shows that when the size of the airflow structure 200 in this embodiment is approximately 18mm*18mm, the airflow volume of the airflow structure 200 can reach approximately 0.2 cfm. Moreover, the airflow velocity of the airflow structure 200 in this embodiment is relatively high, reaching over 80m / s. The operating frequency of the microelectromechanical system heat sink 101 in this embodiment can be in the ultrasonic range (>20kHz), exceeding the vibration frequency perceptible to the human ear, achieving completely silent operation.

[0095] Based on the same technical concept, this application also provides a method for manufacturing a heat sink for a microelectromechanical system. Figure 14 This is a flowchart illustrating the manufacturing method of a microelectromechanical system heat sink provided in an embodiment of this application. Figure 15 This is a schematic diagram illustrating the structure of each step in the manufacturing method provided in the embodiments of this application. (In conjunction with...) Figure 14 and Figure 15 The microelectromechanical system heat sink in this embodiment may include at least one cooling structure, wherein each cooling structure may be fabricated using the following steps:

[0096] S401, reference Figure 15In step (1), holes are drilled in the base plate 202 to form vent holes W2 in the base plate 202; in some cases, when the microelectromechanical system heat sink 101 is provided with a heat-conducting plate, the base plate 202 can be mounted or formed on the heat-conducting plate before step S401.

[0097] S402, reference Figure 15 In (2), a cantilever beam 203 with a piezoelectric film 204 on its surface is provided. The first end m of the cantilever beam 203 is fixed to the edge position above the base plate 202, and a gap is formed between the cantilever beam 203 and the base plate 202. The second end n of the cantilever beam 203 is suspended. In the thickness direction of the base plate 202, the vent W2 is located within the area covered by the projection of the cantilever beam 203. In specific implementation, the cantilever beam 203 can be fixed to the edge above the base plate 202 by bonding or adhesive.

[0098] S403, reference Figure 15 In (3), the upper cover 201 is installed on the cantilever beam 203, so that a cavity Q is formed between the upper cover 201 and the bottom plate 202, thereby obtaining the drainage structure 200; the upper cover 201 is provided with an air inlet W1.

[0099] In the method for fabricating a microelectromechanical system (MEMS) heat sink provided in this application embodiment, a cantilever beam 203 with a piezoelectric thin film 204 is installed in the flow-guiding structure 200. Under the control of a driving signal, the piezoelectric thin film 204 can drive the cantilever beam 203 to vibrate, controlling the gas to form a unidirectional flow within the flow-guiding structure 200. In this way, heat can be removed through active heat dissipation, resulting in high heat dissipation efficiency and meeting the high heat dissipation requirements of electronic devices. Furthermore, the fabrication method provided in this application embodiment can be implemented using MEMS processing, resulting in a smaller MEMS heat sink 101, which is beneficial for the miniaturization design of electronic devices.

[0100] In practical implementation, to improve the efficiency of the manufacturing process, multiple drainage structures 200 can be manufactured in the same process flow, for example... Figure 15 The following example illustrates the fabrication of four heat-draining structures 200 using the same process. After fabrication, the fabricated microelectromechanical system heat sink 101 is installed at the location of the heat-generating device requiring heat dissipation.

[0101] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0102] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A heat sink for a microelectromechanical system, characterized in that, include: At least one drainage structure; wherein each of the drainage structures comprises: The top cover has an air inlet. The base plate has air vents in it; The sidewall is located between the upper cover and the bottom plate, with the upper cover and the bottom plate facing each other; the upper cover, the bottom plate and the sidewall form a cavity; A cantilever beam is located within the cavity. The cantilever beam has a first end and a second end opposite to each other. The first end is connected to the side wall, and the second end is suspended. In the thickness direction of the base plate, the air vent is located within the area covered by the projection of the cantilever beam. A piezoelectric film is located on the surface of the cantilever beam.

2. The microelectromechanical system heat sink as described in claim 1, characterized in that, In the thickness direction of the base plate, the air inlet is located within the area covered by the projection of the cantilever beam, and the air inlet is located on the side of the air outlet closer to the first end.

3. The microelectromechanical system heat sink as described in claim 1 or 2, characterized in that, The cantilever beam has a groove on the surface facing the base plate, and the groove is located at the second end of the cantilever beam.

4. The microelectromechanical system heat sink as described in claim 3, characterized in that, In the thickness direction of the base plate, the air outlet is located within the area covered by the projection of the groove, and the air inlet is located on the side of the groove closer to the first end.

5. The microelectromechanical system heat sink as described in claim 3 or 4, characterized in that, In the thickness direction of the base plate, the projection of the piezoelectric film and the projection of the groove do not overlap.

6. The microelectromechanical system heat sink according to any one of claims 1 to 5, characterized in that, The top cover is made of metal or resin material, the bottom plate is made of monocrystalline silicon or metal material, the cantilever beam is made of monocrystalline silicon or metal material, and the piezoelectric film is made of lead zirconate titanate material.

7. The microelectromechanical system heat sink as described in claim 6, characterized in that, The drainage structure further includes a transition layer located between the piezoelectric film and the cantilever beam, the transition layer comprising strontium oxide, zirconium oxide, or platinum.

8. The microelectromechanical system heat sink according to any one of claims 1 to 7, characterized in that, The thickness of the drainage structure is in the range of 1mm to 2mm, the width of the drainage structure is in the range of 1mm to 4mm, and the length of the drainage structure is in the range of 5mm to 10mm.

9. The microelectromechanical system heat sink as described in claim 8, characterized in that, The distance between the top cover and the bottom plate is in the range of 0.3mm to 0.6mm, the distance between the cantilever beam and the bottom plate is in the range of 10μm to 100μm, the thickness of the cantilever beam is in the range of 10μm to 300μm, and the thickness of the piezoelectric film is in the range of 2μm to 5μm.

10. The microelectromechanical system heat sink according to any one of claims 1 to 9, characterized in that, The microelectromechanical system heat sink further includes a heat-conducting plate, which is located on the side of the drainage structure having the base plate, and there is a gap between the heat-conducting plate and the base plate.

11. The microelectromechanical system heat sink as described in claim 10, characterized in that, The microelectromechanical system heat sink includes multiple flow-guiding structures, and in the thickness direction of the heat-conducting plate, the projection of each flow-guiding structure in the microelectromechanical system heat sink is located within the projection range of the heat-conducting plate.

12. The microelectromechanical system heat sink according to any one of claims 1 to 11, characterized in that, The microelectromechanical system heat sink includes: a plurality of the aforementioned air-draining structures arranged sequentially along a first direction, wherein the first end of the cantilever beam in each of the aforementioned air-draining structures points in the same direction to the second end; Alternatively, the microelectromechanical system heat sink includes: a plurality of the aforementioned drainage structures arranged sequentially along a first direction, wherein the first end of the cantilever beam in two adjacent drainage structures points in opposite directions to the second end; Alternatively, the microelectromechanical system heat sink includes: a first drainage structure group and a second drainage structure group arranged along a first direction. The first drainage structure group includes: a plurality of first drainage structures arranged sequentially along the first direction, wherein the first end of the cantilever beam in each first drainage structure points to the second end in the same direction. The second drainage structure group includes: a plurality of second drainage structures arranged sequentially along the first direction, wherein the first end of the cantilever beam in each second drainage structure points to the second end in the same direction, and the first end of the cantilever beam in the first drainage structure and the second drainage structure points to the second end in opposite directions.

13. An electronic device, characterized in that, include: The microelectromechanical system heat sink and heating device as described in any one of claims 1 to 12; The microelectromechanical system heat sink includes at least one heat dissipation structure, in which the base plate is closer to the heat-generating device than the top cover; the microelectromechanical system heat sink is used to dissipate heat from the heat-generating device.

14. The electronic device as claimed in claim 13, characterized in that, In the thickness direction of the base plate, the projections of each of the current-draining structures in the microelectromechanical system heat sink are located within the projection range of the heat-generating device; Alternatively, the gas drainage structure may further include a heat-conducting plate, which is divided into a first region and a second region; in the thickness direction of the heat-conducting plate, the projections of each drainage structure in the microelectromechanical system heat sink are located in the first region of the heat-conducting plate, and the second region of the heat-conducting plate is located within the projection range of the heat-generating device.

15. The electronic device as claimed in claim 13 or 14, characterized in that, The microelectromechanical system heat sink includes at least one drainage structure, and the electronic device further includes a driving device electrically connected to the piezoelectric film in each of the drainage structures, the driving device being used to apply a driving signal to the piezoelectric film.

16. The electronic device as claimed in claim 15, characterized in that, The microelectromechanical system heat sink includes: a plurality of the aforementioned air-draining structures arranged sequentially along a first direction, wherein the first end of the cantilever beam in each of the aforementioned air-draining structures points in the same direction to the second end; Alternatively, the microelectromechanical system heat sink includes: a plurality of the aforementioned drainage structures arranged sequentially along a first direction, wherein the first end of the cantilever beam in two adjacent drainage structures points in opposite directions to the second end; Alternatively, the microelectromechanical system heat sink includes: a first drainage structure group and a second drainage structure group arranged along a first direction. The first drainage structure group includes: a plurality of first drainage structures arranged sequentially along the first direction. In each of the first drainage structures, the first end of the cantilever beam points to the second end in the same direction. The second drainage structure group includes: a plurality of second drainage structures arranged sequentially along the first direction. In each of the second drainage structures, the first end of the cantilever beam points to the second end in the same direction. The first end of the cantilever beam in the first drainage structure and the second drainage structure points to the second end in opposite directions. The driving device is specifically used to apply an opposite driving signal to the piezoelectric films in two adjacent drainage structures.

17. The electronic device as claimed in claim 15, characterized in that, The microelectromechanical system heat sink includes: a first drainage structure group and a second drainage structure group arranged along a first direction, wherein the first drainage structure group includes: a plurality of first drainage structures arranged sequentially along the first direction, and the second drainage structure group includes: a plurality of second drainage structures arranged sequentially along the first direction. In each of the first drainage structures, the first end of the cantilever beam points in the same direction to the second end; in each of the second drainage structures, the first end of the cantilever beam points in the same direction to the second end; however, in the first and second drainage structures, the first end of the cantilever beam points in opposite directions to the second end. Alternatively, in two adjacent first drainage structures, the first end of the cantilever beam points in opposite directions to the second end; in two adjacent second drainage structures, the first end of the cantilever beam points in opposite directions to the second end; and in adjacent first and second drainage structures, the first end of the cantilever beam points in opposite directions to the second end. The driving device is specifically used to apply an inverse driving signal to the piezoelectric films in two adjacent first drainage structures, to the piezoelectric films in two adjacent second drainage structures, and to apply the same driving signal to the piezoelectric films in adjacent first and second drainage structures.

18. A method for manufacturing a heat sink for a microelectromechanical system, characterized in that, The microelectromechanical system heat sink includes at least one heat dissipation structure; Each of the aforementioned drainage structures is fabricated using the following steps: Drill holes in the base plate to create vents. A cantilever beam with a piezoelectric film on its surface is provided. The first end of the cantilever beam is fixed to the edge position above the base plate, and there is a gap between the cantilever beam and the base plate. The second end of the cantilever beam is suspended. In the thickness direction of the base plate, the air vent is located within the area covered by the projection of the cantilever beam. The top cover is installed on the cantilever beam, so that a cavity is formed between the top cover and the bottom plate; the top cover is provided with an air inlet.

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