Ultrasonic traveling wave piezoelectric micropump

Abstract

The invention relates to the technical field of piezoelectric micropumps, in particular to an ultrasonic traveling wave piezoelectric micropump which comprises a semiconductor substrate and further comprises a piezoelectric film arranged on the semiconductor substrate. The plurality of driving electrodes are arranged on the piezoelectric film; the micro-channel cavity is bonded with the piezoelectric film to form a sealed channel for liquid flowing, and the micro-channel cavity is provided with a liquid inlet / outlet; wherein the plurality of driving electrodes are configured to input alternating current electric signals with fixed phase difference, so as to excite ultrasonic traveling waves used for driving liquid in the sealed flow channel to directionally flow in the piezoelectric film. The invention aims to solve the technical problems that the piezoelectric micropump is low in directional driving efficiency and difficult to adapt to complex working conditions.

Description

Technical Field

[0001] This invention relates to the field of piezoelectric micropump technology, and more specifically to an ultrasonic traveling wave piezoelectric micropump. Background Technology

[0002] In the field of Microelectromechanical Systems (MEMS) technology, piezoelectric micropumps, as important miniature fluid actuation devices, have been widely used in applications such as semiconductor chip heat dissipation. In existing technologies, piezoelectric micropumps primarily use piezoelectric ceramic sheets or thin films as their core functional components. Their working principle is based on the inverse piezoelectric effect of piezoelectric materials. By applying an electric field externally to the piezoelectric component, the piezoelectric ceramic sheet or thin film is induced to reciprocate within a pre-designed cavity structure, causing the cavity volume to alternately increase or decrease in each vibration cycle. The fluid dynamics generated by this volume change drive the liquid within the cavity to flow. Simultaneously, through the design of the cavity's inlet and outlet structures, a difference in flow rate is created between the inlet and outlet during the alternating volume changes, ultimately resulting in a negative net flow rate at the inlet and a positive net flow rate at the outlet, thus achieving directional liquid actuation.

[0003] However, the fluid driving performance of existing piezoelectric micropumps is highly dependent on the design precision of the cavity structure. Due to the inherent characteristics of silicon-based fabrication processes, the cavity structure and its size fabricated on silicon substrates are difficult to fully meet the design goals, resulting in significant energy loss during liquid directional driving and making it difficult to achieve high-efficiency directional driving. At the same time, the steady-state operating frequency range and voltage adjustment range of this type of piezoelectric micropump based on the reciprocating vibration principle are relatively narrow, making it difficult to adapt to the liquid driving requirements of different scenarios through linear control of steady-state performance, thus limiting its practical application in complex working conditions. Summary of the Invention

[0004] To address the technical problems of low directional driving efficiency and difficulty in adapting to complex working conditions of piezoelectric micropumps, this invention provides an ultrasonic traveling wave piezoelectric micropump, the specific technical solution of which is as follows: The present invention provides an ultrasonic traveling wave piezoelectric micropump, comprising a semiconductor substrate and further comprising: a piezoelectric thin film disposed on the semiconductor substrate; Multiple driving electrodes are disposed on the piezoelectric film; And a microfluidic cavity, which is bonded to the piezoelectric film to form a sealed flow channel for liquid flow, wherein the microfluidic cavity is provided with a liquid inlet and outlet; The plurality of driving electrodes are configured to input an alternating current signal with a fixed phase difference to excite an ultrasonic traveling wave in the piezoelectric film for driving the directional flow of liquid within the sealed flow channel.

[0005] Traditional piezoelectric micropumps rely on reciprocating motion to create a difference in inflow and outflow flow rates, thereby driving the fluid. This method suffers from significant instability and limited performance adjustability, making it difficult to effectively adjust performance according to operating conditions. The ultrasonic traveling wave piezoelectric micropump proposed in this invention utilizes the principle of traveling wave-driven liquid flow, which offers higher stability. Furthermore, the traveling wave propels the liquid, resulting in a higher flow rate than traditional methods. By linearly adjusting the driving voltage, the amplitude of the traveling wave can be directly changed, thereby regulating the flow rate. Therefore, this invention allows for a wider range of performance adjustments, meeting more diverse operating requirements.

[0006] Furthermore, the driving electrode includes a first electrode and a second electrode, configured to receive a first AC signal and a second AC signal, respectively.

[0007] Furthermore, the phase difference between the first AC signal and the second AC signal is 90°.

[0008] Furthermore, the method for exciting the ultrasonic traveling wave includes: inputting an alternating current signal with a fixed phase difference to a plurality of driving electrodes, exciting two standing waves with the same amplitude and frequency in the piezoelectric film, and the two standing waves superimposing in space to form an ultrasonic traveling wave that propagates directionally along the surface of the piezoelectric film.

[0009] Furthermore, the vibration direction of the two standing waves is perpendicular to the surface of the piezoelectric film, and the propagation direction of the ultrasonic traveling wave is parallel to the surface of the piezoelectric film and propagates along the sealed flow channel toward the liquid inlet and outlet.

[0010] Furthermore, the method for driving liquid in a sealed flow channel by an ultrasonic traveling wave includes: linearly adjusting the amplitude of the ultrasonic traveling wave by adjusting the voltage amplitude of an AC signal input to the driving electrode.

[0011] Furthermore, the method for preparing the piezoelectric thin film includes: depositing lead zirconate titanate or lithium niobate material onto the semiconductor substrate using microelectromechanical systems (MEMS) technology to form a thin film structure.

[0012] Furthermore, the method for configuring the driving electrodes includes: patterning multiple electrode regions on the surface of the piezoelectric film, and inputting AC signals to different electrode regions according to a preset phase relationship.

[0013] Furthermore, the semiconductor substrate also integrates a semiconductor power device located in the sealed flow channel projection area, and a cold end heat sink attached to the side of the semiconductor power device near the semiconductor substrate. The semiconductor power device, the cold end heat sink, the piezoelectric film, and the microchannel cavity form an integrated structure.

[0014] Furthermore, the microchannel cavity is bonded to the side of the semiconductor substrate away from the piezoelectric film, and the ultrasonic traveling wave excited by the piezoelectric film propagates along the extension direction of the sealed channel, driving the cooling liquid to flow through the heat source region of the semiconductor power device.

[0015] The present invention has the following beneficial effects: This invention provides an ultrasonic traveling wave piezoelectric micropump. By configuring multiple driving electrodes on a piezoelectric film and setting these electrodes to receive an AC signal with a fixed phase difference, an ultrasonic traveling wave is excited within the piezoelectric film to drive the directional flow of liquid. This wave then interacts with a sealed flow channel formed by bonding the piezoelectric film to the liquid. The ultrasonic traveling wave generates a continuous and directional driving force on the liquid within the sealed flow channel. Compared to traditional piezoelectric micropumps that rely on reciprocating motion to create a difference in inflow and outflow flow rates, this invention's traveling wave driving method eliminates the dependence on alternating changes in cavity volume, reduces energy loss during the driving process, and improves the efficiency of directional liquid driving. Furthermore, the amplitude of the ultrasonic traveling wave can be changed by adjusting the AC signal voltage input to the driving electrodes, thereby achieving flexible adjustment of the liquid flow rate. This allows the piezoelectric micropump to flexibly adapt to different workloads and heat dissipation requirements, overcoming the shortcomings of traditional reciprocating vibration piezoelectric micropumps in terms of control performance and adaptability to operating conditions. Attached Figure Description

[0016] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the ultrasonic traveling wave piezoelectric micropump provided in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the ultrasonic traveling wave piezoelectric micropump provided in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram illustrating the driving principle of an ultrasonic traveling wave according to an embodiment of the present invention; Icons: 1-Semiconductor substrate, 2-Piezoelectric thin film, 3-Microchannel cavity, 4-Semiconductor power device, 5-Cold end heat sink. Detailed Implementation

[0018] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an ultrasonic traveling wave piezoelectric micropump proposed according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] The specific solution of an ultrasonic traveling wave piezoelectric micropump provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0021] Please see Figure 1 and Figure 2 It shows a schematic diagram of the structure of an ultrasonic traveling wave piezoelectric micropump provided in two embodiments of the present invention. Figure 1 The arrows in the diagram indicate the direction of the ultrasonic traveling wave. Figure 2 The arrows in the diagram indicate liquid flow. This embodiment of the ultrasonic traveling wave piezoelectric micropump includes a semiconductor substrate 1, and further includes: a piezoelectric thin film 2 disposed on the semiconductor substrate 1; multiple driving electrodes disposed on the piezoelectric thin film 2; and a microchannel cavity 3 bonded to the piezoelectric thin film 2 to form a sealed flow channel for liquid flow. The microchannel cavity 3 has a liquid inlet and outlet. The multiple driving electrodes are configured to input an alternating current signal with a fixed phase difference to excite an ultrasonic traveling wave in the piezoelectric thin film 2 to drive the directional flow of liquid within the sealed flow channel. This embodiment of the ultrasonic traveling wave piezoelectric micropump is based on microelectromechanical systems (MEMS) technology and uses semiconductor manufacturing technology to fabricate a silicon-based chip actuator to drive liquid movement to meet the heat dissipation requirements of the semiconductor chip. Silicon or ceramic materials are preferred as the preparation material for the semiconductor substrate 1, which serves as the supporting foundation for the entire micropump. The piezoelectric thin film 2 is directly deposited on the surface of the semiconductor substrate 1 using microelectromechanical systems (MEMS) technology. The preferred materials are lead zirconate titanate or lithium niobate. The piezoelectric thin film 2 is fabricated into an ultrasonic traveling wave micro-actuator using MEMS fabrication technology. Multiple driving electrodes are prepared on the surface of the ultrasonic traveling wave micro-actuator through patterning. The inverse piezoelectric effect enables the conversion of electrical energy into mechanical energy, providing a power basis for liquid actuation. The driving electrodes are prepared on the surface of the piezoelectric thin film 2, and multiple independent electrode regions are formed through patterning. The driving electrodes are configured to accept AC signals with a fixed phase difference. Microchannel cavity 3 is fabricated using microelectromechanical systems (MEMS) fabrication technology. The fabrication material of microchannel cavity 3 is also selected as silicon or ceramic. After fabrication, liquid inlet and outlet are opened on microchannel cavity 3. Then, microchannel cavity 3 is fixedly connected to the side surface of piezoelectric film 2 away from semiconductor substrate 1 by bonding process, so that microchannel cavity 3 and piezoelectric film 2 are enclosed to form a sealed flow channel for liquid flow.

[0022] The working principle of this ultrasonic traveling wave piezoelectric micropump is based on the ultrasonic resonance principle. When an AC signal with a fixed phase difference is input to multiple driving electrodes, the inverse piezoelectric effect of the piezoelectric material excites two standing waves of the same frequency in the piezoelectric film 2. After the two standing waves are superimposed in space, they form an ultrasonic traveling wave that propagates directionally along the surface of the piezoelectric film 2. This ultrasonic traveling wave can generate a continuous directional driving force on the liquid in the sealed flow channel, thereby realizing the directional driving of the liquid. In this embodiment, through the above structure and excitation method, the directionally propagating ultrasonic traveling wave excited on the surface of the piezoelectric film 2 is used as a direct driving force to achieve efficient and stable delivery of liquid in the sealed flow channel. This driving method avoids the dependence of traditional reciprocating vibration pump chambers on complex flow channel structures and rectifier elements, reduces flow resistance loss, and thus improves the directional driving efficiency. Meanwhile, since the amplitude of the traveling wave is directly related to the voltage amplitude of the driving electrical signal, the liquid flow rate can be linearly and accurately controlled over a wide range by adjusting this electrical parameter. This allows the micropump to flexibly adapt to different heat dissipation or fluid control conditions, enhancing its performance regulation capability and adaptability in complex application environments.

[0023] In some embodiments, the driving electrode includes a first electrode and a second electrode, configured to receive a first AC signal and a second AC signal respectively, with a phase difference of 90° between the first AC signal and the second AC signal. The method for exciting the ultrasonic traveling wave includes: inputting AC signals with a fixed phase difference to a plurality of the driving electrodes to excite two standing waves with the same amplitude and frequency in the piezoelectric film 2; the two standing waves are spatially superimposed to form an ultrasonic traveling wave that propagates directionally along the surface of the piezoelectric film 2; and by inputting AC signals with a fixed phase difference of 90° into the driving electrode regions at different positions, two planar standing waves with a phase difference of 90° are excited and superimposed to form a planar traveling wave. The traveling wave drives the particles on the material surface to undergo elliptical motion, causing the material surface to produce wave-shaped deformation and continuous motion in a specified direction, thereby driving the liquid to move in a specified direction and realizing the function of a micro-pump.

[0024] In some embodiments, see Figure 3 As shown, when a first AC signal is input to the first electrode and a second AC signal is input to the second electrode, the phase difference between the first and second AC signals is set to 90 degrees. Based on the inverse piezoelectric effect of the piezoelectric material, standing waves A and B are excited at different positions of the piezoelectric film 2. The two standing waves have the same frequency and amplitude, and both vibrate up and down at their initial positions. According to the spatial distribution relationship of the two standing waves, their superposition will form a series of ultrasonic traveling waves propagating in a specified direction on the surface of the piezoelectric film 2. The mode of this traveling wave is determined by the physical structure and material of the ultrasonic traveling wave micro-actuator, and is related to the inherent resonant frequency of the ultrasonic traveling wave micro-actuator itself. During the propagation of the ultrasonic traveling wave, it will drive the particles on the surface of the piezoelectric film 2 to perform elliptical motion, causing the surface of the piezoelectric film 2 to produce a continuous forward wave-shaped deformation. When the surface of the piezoelectric film 2 that generates the traveling wave vibration is sealed and bonded to the microfluidic cavity 3 through a bonding process, the wave-shaped deformation of its surface will directly act on the liquid in contact with it in the flow channel. The forward-propagating surface waves exert continuous tangential and normal forces on the liquid, thereby propelling the liquid to flow in a directional and continuous manner following the direction of the wave motion, realizing the pumping function of converting electrical energy into liquid kinetic energy through mechanical traveling waves.

[0025] In this embodiment, two AC signals with a 90-degree phase difference drive a specially arranged electrode to reliably and efficiently generate a stable ultrasonic traveling wave in the piezoelectric thin film 2. The generated traveling wave has the characteristics of clear propagation direction and consistent waveform, providing a continuous and uniform directional driving force for the liquid, thereby significantly improving the driving efficiency and output flow stability of the micropump.

[0026] In some embodiments, the vibration directions of the two standing waves are perpendicular to the surface of the piezoelectric film 2, and the propagation direction of the ultrasonic traveling wave is parallel to the surface of the piezoelectric film 2 and propagates along the sealed flow channel toward the liquid inlet / outlet. Specifically, the vibration directions of the two standing waves are both perpendicular to the surface of the piezoelectric film 2, that is, they reciprocate up and down in a direction perpendicular to the semiconductor substrate 1; according to the spatial distribution and phase relationship of the two standing waves, they are superimposed to form an ultrasonic traveling wave, the propagation direction of which is parallel to the surface of the piezoelectric film 2 and propagates directionally along the extension direction of the sealed flow channel, ensuring a directional driving force for the liquid in the sealed flow channel.

[0027] In some embodiments, the method of driving liquid within a sealed flow channel using an ultrasonic traveling wave includes: linearly adjusting the amplitude of the ultrasonic traveling wave by adjusting the voltage amplitude of an AC signal input to the driving electrode. This embodiment, based on the aforementioned basic structure and standing wave excitation mechanism, achieves flexible control of the ultrasonic traveling wave amplitude. The configuration of the driving electrode and the input method of the AC signal remain unchanged; that is, an AC signal with a fixed phase difference is input through multiple patterned electrode regions to excite the ultrasonic traveling wave. The control process involves changing the voltage amplitude of the AC signal input to the driving electrode. Since the amplitude of the ultrasonic traveling wave is linearly correlated with the voltage amplitude of the input AC signal, an increase or decrease in the voltage amplitude directly leads to a synchronous linear increase or decrease in the ultrasonic traveling wave amplitude, thereby achieving linear control of the liquid flow rate within the sealed flow channel to adapt to flow requirements under different operating conditions.

[0028] In some embodiments, the method for configuring the driving electrodes includes: patterning multiple electrode regions on the surface of the piezoelectric thin film 2, and inputting AC signals to different electrode regions according to a preset phase relationship. After the piezoelectric thin film 2 is prepared and pretreated, an electrode pattern is formed on the surface of the piezoelectric thin film 2 using a photolithography process. According to the ultrasonic traveling wave excitation requirements, multiple independent electrode regions are patterned, and the position, shape, and size of each electrode region must be adapted to the excitation position requirements of two standing waves. After the electrode pattern is formed, conductive material is deposited on the patterned regions using a coating process to form multiple driving electrodes. Finally, the driving electrodes are connected by leads to ensure that each driving electrode can independently receive external AC signals and input AC signals to different electrode regions according to a preset phase relationship to excite specific standing waves and synthesize the expected ultrasonic traveling waves.

[0029] In some embodiments, the semiconductor substrate 1 is further integrated with a semiconductor power device 4 located in the sealed flow channel projection area and a cold end heat sink 5 attached to the side of the semiconductor power device 4 near the semiconductor substrate 1. The semiconductor power device 4, the cold end heat sink 5, the piezoelectric film 2 and the microflow channel cavity 3 form an integrated structure. Based on the fabrication of the basic structure, the ultrasonic traveling wave piezoelectric micropump in this embodiment further achieves integrated integration with the semiconductor power device 4 and the cold-end heat sink 5. The specific steps are as follows: First, a semiconductor substrate 1 is prepared according to a preset process, using silicon or ceramic as the substrate material to ensure structural stability and process compatibility. A semiconductor power device 4 is integrated into a preset area on one side of the semiconductor substrate 1. This preset area must correspond to the projection range of the subsequent sealed flow channel to ensure that the cooling liquid within the sealed flow channel can effectively cover the heat-generating area of ​​the semiconductor power device 4. Then, a cold-end heat sink 5 is attached to the side of the semiconductor power device 4 closest to the semiconductor substrate 1. On the same side of the semiconductor substrate 1, lead zirconate titanate or lithium niobate material is deposited using microelectromechanical systems (MEMS) technology to form a piezoelectric thin film 2. Multiple driving electrodes are patterned on the surface of the piezoelectric thin film 2, divided into different regions and receiving AC signals according to a preset phase relationship. A microchannel cavity 3 is prepared using MEMS technology, with liquid inlets and outlets. It is then bonded to the side of the piezoelectric thin film 2 away from the semiconductor substrate 1, forming a sealed flow channel. At this point, the semiconductor power device 4, the cold-end heat sink 5, the piezoelectric thin film 2, the microchannel cavity 3, and the semiconductor substrate 1 together constitute a complete integrated structure. During operation, an alternating current signal with a fixed phase difference is input to the driving electrode, which excites a directionally propagating ultrasonic traveling wave in the piezoelectric film 2. The ultrasonic traveling wave drives the cooling liquid in the sealed flow channel to circulate. When the cooling liquid flows through the heat source area of ​​the semiconductor power device 4, it absorbs the heat generated therein and then carries the heat to the area corresponding to the cold end heat sink 5. The heat is transferred to the cold end heat sink 5 through thermal conduction and dissipated, thereby cooling the semiconductor power device 4. At the same time, by adjusting the voltage amplitude of the alternating current signal input to the driving electrode, the amplitude of the ultrasonic traveling wave can be linearly changed, thereby controlling the flow rate of the cooling liquid and achieving flexible adjustment of the cooling performance.

[0030] In some embodiments, the microchannel cavity 3 is bonded to the side of the semiconductor substrate 1 away from the piezoelectric film 2, and the ultrasonic traveling wave excited by the piezoelectric film 2 propagates along the extension direction of the sealed flow channel, driving the cooling liquid to flow through the heat source region of the semiconductor power device 4. For the above integrated structure, the microchannel cavity 3 is explicitly bonded to the side of the semiconductor substrate 1 away from the piezoelectric film 2 it supports. In this arrangement, the ultrasonic traveling wave excited in the piezoelectric film 2 is designed to propagate parallel to the surface of the semiconductor substrate 1 and along the geometric extension path of the sealed flow channel inside the microchannel cavity 3. When the cooling liquid is poured into the sealed flow channel, the directionally propagating traveling wave effectively drives the liquid to continuously flow through the heat source region generated by the semiconductor power device 4 located above the sealed flow channel, thereby achieving active heat dissipation for the power device.

[0031] The above embodiment achieves a compact and fully functional on-chip active cooling system by monolithically integrating an ultrasonic traveling wave piezoelectric micropump with the semiconductor power device 4 and the cold-end heat sink 5. This structure utilizes the directional traveling wave generated by the micropump to directly drive the coolant through the heat source, achieving efficient and low-thermal-resistance heat extraction and transport. Simultaneously, based on the direct correlation between the traveling wave amplitude and the driving voltage, the system's heat dissipation capacity can be linearly controlled over a wide range with sensitive response by adjusting the electrical signal. This allows it to actively adapt to the dynamically changing heat dissipation and power consumption of the semiconductor power device 4, achieving a match between heat dissipation performance and thermal load, and improving the reliability and application adaptability of thermal management under complex operating conditions.

[0032] In summary, the ultrasonic traveling wave piezoelectric micropump provided by this invention, by configuring multiple driving electrodes on a piezoelectric film 2 and setting these electrodes to receive an AC signal with a fixed phase difference, can excite an ultrasonic traveling wave in the piezoelectric film 2 to drive the directional flow of liquid. This wave then cooperates with a sealed flow channel formed by bonding the piezoelectric film 2 for liquid flow. The ultrasonic traveling wave can generate a continuous and directional driving force on the liquid within the sealed flow channel. Compared to traditional piezoelectric micropumps that rely on reciprocating motion to create the inflow-outflow flow difference, the traveling wave driving method of this invention eliminates the dependence on alternating changes in cavity volume, reduces energy loss during the driving process, and improves the efficiency of directional liquid driving. Furthermore, by adjusting the AC signal voltage input to the driving electrodes, the amplitude of the ultrasonic traveling wave can be changed, thereby achieving flexible adjustment of the liquid flow rate. This allows the piezoelectric micropump to flexibly adapt to different workloads and heat dissipation requirements, overcoming the shortcomings of traditional reciprocating vibration piezoelectric micropumps in terms of control performance and adaptability to operating conditions.

[0033] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0034] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. An ultrasonic traveling wave piezoelectric micropump, comprising a semiconductor substrate, characterized in that, Also includes: A piezoelectric thin film is disposed on the semiconductor substrate; Multiple driving electrodes are disposed on the piezoelectric film; And a microfluidic cavity, which is bonded to the piezoelectric film to form a sealed flow channel for liquid flow, wherein the microfluidic cavity is provided with a liquid inlet and outlet; The plurality of driving electrodes are configured to input an alternating current signal with a fixed phase difference to excite an ultrasonic traveling wave in the piezoelectric film for driving the directional flow of liquid within the sealed flow channel.

2. The ultrasonic traveling wave piezoelectric micropump as described in claim 1, characterized in that, The driving electrode includes a first electrode and a second electrode, configured to receive a first AC signal and a second AC signal, respectively.

3. The ultrasonic traveling wave piezoelectric micropump as described in claim 2, characterized in that, The phase difference between the first AC signal and the second AC signal is 90°.

4. The ultrasonic traveling wave piezoelectric micropump as described in claim 1, characterized in that, The method for exciting the ultrasonic traveling wave includes: inputting an alternating current signal with a fixed phase difference to a plurality of driving electrodes, exciting two standing waves with the same amplitude and frequency in the piezoelectric film, and the two standing waves superimposing in space to form an ultrasonic traveling wave that propagates directionally along the surface of the piezoelectric film.

5. The ultrasonic traveling wave piezoelectric micropump as described in claim 4, characterized in that, The vibration direction of the two standing waves is perpendicular to the surface of the piezoelectric film, and the propagation direction of the ultrasonic traveling wave is parallel to the surface of the piezoelectric film and propagates along the sealed flow channel toward the liquid inlet and outlet.

6. The ultrasonic traveling wave piezoelectric micropump as described in claim 1, characterized in that, The method for driving liquid in a sealed flow channel by an ultrasonic traveling wave includes: linearly adjusting the amplitude of the ultrasonic traveling wave by adjusting the voltage amplitude of the AC signal input to the driving electrode.

7. The ultrasonic traveling wave piezoelectric micropump as described in claim 1, characterized in that, The method for preparing the piezoelectric thin film includes: depositing lead zirconate titanate or lithium niobate material onto the semiconductor substrate using microelectromechanical systems (MEMS) technology to form a thin film structure.

8. The ultrasonic traveling wave piezoelectric micropump as described in claim 1, characterized in that, The method for configuring the driving electrodes includes: patterning multiple electrode regions on the surface of the piezoelectric film, and inputting AC signals to different electrode regions according to a preset phase relationship.

9. The ultrasonic traveling wave piezoelectric micropump according to any one of claims 1 to 8, characterized in that, The semiconductor substrate also integrates a semiconductor power device located in the sealed flow channel projection area, and a cold end heat sink attached to the side of the semiconductor power device near the semiconductor substrate. The semiconductor power device, the cold end heat sink, the piezoelectric film, and the microchannel cavity form an integrated structure.

10. The ultrasonic traveling wave piezoelectric micropump as described in claim 9, characterized in that, The microchannel cavity is bonded to the side of the semiconductor substrate away from the piezoelectric film, and the ultrasonic traveling wave excited by the piezoelectric film propagates along the extension direction of the sealed channel, driving the cooling liquid to flow through the heat source region of the semiconductor power device.

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