A piezoelectric micro-pump heat dissipation chip, a preparation method and a piezoelectric heat dissipation device

Abstract

This invention relates to the field of semiconductor technology and discloses a piezoelectric micropump heat dissipation chip, its fabrication method, and a piezoelectric heat dissipation device. By setting a piezoelectric ceramic dual-boost structure on the second surface of a metal layer corresponding to a region of the air-cooled heat dissipation cavity structure on the first surface, the piezoelectric ceramic dual-boost structure drives the metal layer to generate a first boosting deformation and a second boosting deformation in the vertical direction. This, in turn, drives the cavity structure to perform synchronous volume adjustment actions in the discontinuous first and second regions of the metal layer, respectively. This improves the driving intensity and flow efficiency of the gas in the air-cooled heat dissipation cavity structure. By utilizing the discontinuous but synchronous first and second boosting deformations, while maintaining a high level of vibration amplitude and resonant frequency for the piezoelectric micropump heat dissipation chip, the vibration stress value of the piezoelectric ceramic structure and the probability of ceramic splitting due to vibration are reduced, significantly improving the durability of the piezoelectric micropump heat dissipation chip.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a piezoelectric micropump heat dissipation chip, its fabrication method, and a piezoelectric heat dissipation device. Background Technology

[0002] As global smart electronic devices continue to rapidly evolve towards miniaturization, high performance, high computing power, and high integration, cooling and heat dissipation have become a significant bottleneck restricting performance improvement and impacting reliability. Thermal management technologies are mainly divided into two categories: passive cooling and active cooling. While passive cooling solutions such as heat sinks and heat pipes have long held a dominant position, they often struggle to meet the demands of the continuously increasing heat flux density in next-generation electronic devices (such as smartphones and wearable devices). Traditional mechanical fan solutions, although relatively mature, are gradually revealing their limitations in space-constrained and power-sensitive applications. Therefore, there is an urgent need to develop miniaturized, low-power active cooling technologies and related solutions.

[0003] Micropump cooling chips are a novel heat dissipation technology developed based on the inverse piezoelectric effect of ceramics. Their working principle utilizes the inverse piezoelectric effect of piezoelectric materials. Under the influence of an electric field, the piezoelectric ceramic material undergoes tensile / compressive deformation, causing the metal sheet beneath the ceramic plate to bulge upwards or concave downwards. This alters the pump's cavity volume, generating suction or pressure on the gas, and, under the action of a one-way valve, creating unidirectional gas flow. Currently, due to process limitations, domestic smartphone manufacturers generate more heat in chips with the same performance, making heat dissipation a pressing need. Micropump air-cooling modules will be directly embedded in smartphones, becoming standard equipment, reducing power consumption by 90% compared to traditional air-cooling solutions. This integrated technology will not only significantly improve smartphone performance but also effectively solve heat dissipation problems during high-load operation, reducing frequency throttling and stuttering caused by overheating, thus enhancing the user experience. However, in practical applications, determining the performance of a piezoelectric micropump heat dissipation chip requires attention not only to its resonant frequency being high enough, but also to its oscillation amplitude being high enough (a high resonant frequency generates faster airflow, which helps with heat dissipation, and frequencies above 20kHz are ultrasonic, which helps with quiet operation; a high amplitude helps generate greater air pressure). However, improvements in these two aspects often lead to cracks or even damage to the bonded piezoelectric ceramic sheet due to long-term vibration.

[0004] Therefore, how to consider the stress on the piezoelectric ceramic part caused by vibration while taking into account the performance of the piezoelectric micropump heat dissipation chip, so as to reduce the probability of ceramic splitting due to vibration, is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides a piezoelectric micropump heat dissipation chip, a fabrication method, and a piezoelectric heat dissipation device, aiming to solve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides a piezoelectric micropump heat dissipation chip, comprising:

[0007] A metal layer, the metal layer being configured to have a first surface and a second surface disposed opposite to each other, the first surface forming a cavity structure for air cooling heat dissipation;

[0008] A piezoelectric ceramic layer is disposed on the second surface of the metal layer and has a piezoelectric ceramic dual-boost structure. The piezoelectric ceramic dual-boost structure is configured to generate a first boosting deformation and a second boosting deformation perpendicular to the metal layer when subjected to an electric field.

[0009] The first and second booster deformations drive the cavity structure to perform synchronized volume adjustment actions in the first and second regions of the metal layer, respectively.

[0010] Optionally, the piezoelectric ceramic dual-booster structure includes:

[0011] A first annular booster structure and a second annular booster structure are configured as a double booster region concentrically disposed on the second surface of the metal layer.

[0012] A booster synchronization structure is configured to connect a first ring booster structure and a second ring booster structure that are concentrically arranged.

[0013] Optionally, the vertical projection area of ​​the dual-boost region on the second surface of the metal layer onto the first surface of the metal layer is configured to be covered by the vertical projection area of ​​the cavity structure on the first surface of the metal layer, so that the first boost deformation generated by the first annular boost structure and the second boost deformation generated by the second annular boost structure act together on the cavity structure.

[0014] Optionally, the inner diameter of the first annular booster structure is larger than the outer diameter of the second annular booster structure, and the booster synchronization structure is configured to connect the inner diameter of the first annular booster structure and the outer diameter of the second annular booster structure.

[0015] Optionally, the boost synchronization structure includes:

[0016] A plurality of booster synchronization blocks are configured in an equal-angled ring arrangement between the first ring booster structure and the second ring booster structure.

[0017] Wherein, each of the booster synchronization blocks is connected to the first position where the inner diameter of the first annular booster structure is close to the second annular booster structure and the second position where the outer diameter of the second annular booster structure is close to the first annular booster structure.

[0018] Optionally, the inner radius of the first annular booster structure ranges from 2.5mm to 3.5mm, and the outer radius ranges from 3.7mm to 4.5mm.

[0019] Optionally, the inner radius of the first annular booster structure is 25%-35% of the metal layer size, and the outer radius is 37%-45% of the metal layer size.

[0020] Optionally, the inner radius of the second annular booster structure ranges from 1.4mm to 1.6mm, and the outer radius ranges from 1.9mm to 2.1mm.

[0021] Optionally, the inner radius of the second annular booster structure is 14%-16% of the metal layer size, and the outer radius is 19%-21% of the metal layer size.

[0022] Optionally, the height range of the first annular booster structure and the second annular booster structure is 0.15mm-0.25mm.

[0023] Furthermore, to achieve the above objectives, the present invention also provides a method for fabricating a piezoelectric micropump heat dissipation chip as described in any one of the above claims, comprising the following steps:

[0024] S1: Prepare a piezoelectric ceramic sample to form the area to be etched on the piezoelectric ceramic sample;

[0025] S2: Perform the first etching action on the prepared piezoelectric ceramic sample; wherein, the first etching action is configured to etch for 160-200 seconds in a first etchant composed of 6% BHF: 4% HNO3: 90% deionized water to complete the initial etching.

[0026] S3: Perform a first cleaning action on the piezoelectric ceramic sample after the first etching action; wherein the first cleaning action is configured to rinse with deionized water to remove loose film and residual acid;

[0027] S4: Perform a second etching action on the piezoelectric ceramic sample after the first cleaning action; wherein, the second etching action is configured to etch for 20-40 seconds in a second etchant composed of 40% HCl: 60% deionized water, so as to form a piezoelectric ceramic double-boost structure after the area to be etched is etched.

[0028] S5: Perform a second cleaning operation on the piezoelectric ceramic dual-booster structure after the second etching operation; wherein, the second cleaning operation is configured to include deionized water rinsing, drying and photoresist removal;

[0029] S6: After the second cleaning action, silver electrodes are plated onto the piezoelectric ceramic double-booster structure, and the prepared piezoelectric ceramic double-booster structure with electrodes is then attached to the metal layer.

[0030] In addition, to achieve the above objectives, the present invention also provides a piezoelectric heat dissipation device, including a piezoelectric micropump heat dissipation chip as described in any one of the above claims or including a piezoelectric micropump heat dissipation chip prepared by the above piezoelectric micropump heat dissipation chip preparation method.

[0031] The beneficial effects of this invention are as follows: It proposes a piezoelectric micropump heat dissipation chip, a fabrication method, and a piezoelectric heat dissipation device. By setting a piezoelectric ceramic dual-boost structure on the second surface of the metal layer corresponding to the air-cooled heat dissipation cavity structure in the corresponding region of the first surface, the piezoelectric ceramic dual-boost structure drives the metal layer to generate a first booster deformation and a second booster deformation in the vertical direction. This drives the cavity structure to perform synchronous volume adjustment in the discontinuous first and second regions of the metal layer, thereby improving the driving intensity and flow efficiency of the gas in the air-cooled heat dissipation cavity structure. By utilizing the discontinuous but synchronous first and second booster deformations, while maintaining the piezoelectric micropump heat dissipation chip at a high level of vibration amplitude and resonant frequency, the vibration stress value of the piezoelectric ceramic structure and the probability of ceramic splitting due to vibration are reduced, significantly improving the durability of the piezoelectric micropump heat dissipation chip. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of the piezoelectric micropump heat dissipation chip according to an embodiment of the present invention;

[0033] Figure 2 The attached diagram in Comparative Example 1 shows a finite element analysis of a circular ceramic piezoelectric micropump chip.

[0034] Figure 3 The amplitude-frequency characteristic diagram of the circular ceramic piezoelectric micropump chip is attached to Comparative Example 1;

[0035] Figure 4 The first vibration mode diagram of the circular ceramic piezoelectric micropump chip in Comparative Example 1 is shown.

[0036] Figure 5 The second vibration mode diagram of the circular ceramic piezoelectric micropump chip attached to Comparative Example 1;

[0037] Figure 6 The amplitude distribution diagram of the circular ceramic piezoelectric micropump chip is attached to Comparative Example 1;

[0038] Figure 7 The equivalent stress distribution path diagram of the circular ceramic piezoelectric micropump chip attached to Comparative Example 1 is shown.

[0039] Figure 8 The equivalent stress distribution along the path of the circular ceramic piezoelectric micropump chip is attached to Comparative Example 1;

[0040] Figure 9The vibration stress distribution diagram of the circular ceramic piezoelectric micropump chip is attached to Comparative Example 1;

[0041] Figure 10 The accompanying diagram in Comparative Example 2 shows a finite element analysis of a ring-shaped ceramic piezoelectric micropump chip.

[0042] Figure 11 The amplitude-frequency characteristic diagram of the toroidal ceramic piezoelectric micropump chip is attached to Comparative Example 2;

[0043] Figure 12 The first vibration mode diagram of the toroidal ceramic piezoelectric micropump chip in Comparative Example 2 is shown.

[0044] Figure 13 The second vibration mode diagram of the toroidal ceramic piezoelectric micropump chip in Comparative Example 2 is shown.

[0045] Figure 14 The amplitude distribution diagram of the toroidal ceramic piezoelectric micropump chip is attached to Comparative Example 2;

[0046] Figure 15 The equivalent stress distribution path diagram of the annular ceramic piezoelectric micropump chip in Comparative Example 2 is shown.

[0047] Figure 16 The accompanying diagram shows the equivalent stress distribution along the path of the annular ceramic piezoelectric micropump chip in Comparative Example 2.

[0048] Figure 17 The accompanying diagram shows the vibration stress distribution of the annular ceramic piezoelectric micropump chip in Comparative Example 2.

[0049] Figure 18 This is a schematic diagram of the finite element analysis of the dual-ring ceramic piezoelectric micropump chip in Example 1;

[0050] Figure 19 The charge amplitude-frequency characteristic diagram of the dual-ring ceramic piezoelectric micropump chip in Example 1 is shown below.

[0051] Figure 20 This is the first vibration mode diagram of the dual-ring ceramic piezoelectric micropump chip in Example 1;

[0052] Figure 21 This is the second vibration mode diagram of the dual-ring ceramic piezoelectric micropump chip in Example 1;

[0053] Figure 22 The amplitude distribution diagram of the dual-ring ceramic piezoelectric micropump chip is shown in Example 1.

[0054] Figure 23 This is an equivalent stress distribution path diagram of the dual-ring ceramic piezoelectric micropump chip in Example 1;

[0055] Figure 24The equivalent stress distribution along the path of the dual-ring ceramic piezoelectric micropump chip in Example 1 is shown.

[0056] Figure 25 The vibration stress distribution diagram of the dual-ring ceramic piezoelectric micropump chip in Example 1 is shown.

[0057] Figure 26 The attached diagram in Comparative Example 3 shows a finite element analysis of a wide-ring ceramic piezoelectric micropump chip.

[0058] Figure 27 The charge amplitude-frequency characteristic diagram of the wide-ring ceramic piezoelectric micropump chip is attached to Comparative Example 3;

[0059] Figure 28 The first vibration mode diagram of the wide-ring ceramic piezoelectric micropump chip in Comparative Example 3 is shown.

[0060] Figure 29 The second vibration mode diagram of the wide-ring ceramic piezoelectric micropump chip in Comparative Example 3 is shown.

[0061] Figure 30 The amplitude distribution diagram of the wide-ring ceramic piezoelectric micropump chip is attached to Comparative Example 3;

[0062] Figure 31 The equivalent stress distribution path diagram of the wide-ring ceramic piezoelectric micropump chip in Comparative Example 3 is shown.

[0063] Figure 32 The equivalent stress distribution along the path of the wide-ring ceramic piezoelectric micropump chip is shown in Comparative Example 3.

[0064] Figure 33 The vibration stress distribution diagram of the wide-ring ceramic piezoelectric micropump chip is attached to Comparative Example 3;

[0065] Figure 34 This is a schematic flowchart of the piezoelectric micropump heat dissipation chip fabrication method according to an embodiment of the present invention.

[0066] Explanation of reference numerals in the attached figures:

[0067] 1-Metal layer; 2-Piezoelectric ceramic layer; 21-First annular booster structure; 22-Second annular booster structure; 23-Booster synchronization structure. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0069] like Figure 1 As shown, an embodiment of the present invention provides a piezoelectric micropump heat dissipation chip, comprising:

[0070] Metal layer 1, the metal layer 1 is configured to have a first surface and a second surface disposed opposite to each other, the first surface forming a cavity structure for air cooling heat dissipation;

[0071] The piezoelectric ceramic layer 2 is disposed on the second surface of the metal layer 1 and has a piezoelectric ceramic double-boost structure. The piezoelectric ceramic double-boost structure is configured to generate a first boost deformation and a second boost deformation perpendicular to the metal layer 1 when subjected to an electric field.

[0072] The first booster deformation and the second booster deformation respectively drive the cavity structure to perform synchronous volume adjustment actions in the first region and the second region of the metal layer 1.

[0073] It should be noted that due to process limitations, domestic smartphone manufacturers currently generate more heat from chips with the same performance, making heat dissipation a pressing need. Micro-pump air cooling modules will be directly embedded in smartphones, becoming standard equipment, reducing power consumption by 90% compared to traditional air cooling solutions. The integration of piezoelectric micro-pump cooling technology will not only significantly improve smartphone performance but also effectively solve heat dissipation problems under high load, reducing frequency throttling and stuttering caused by overheating, thus enhancing the user experience.

[0074] However, in practical applications, determining the performance of a piezoelectric micropump heat dissipation chip requires attention not only to its resonant frequency but also to its oscillation amplitude. However, improvements in these two aspects often lead to cracking of the bonded piezoelectric ceramic sheet.

[0075] To address the aforementioned issues, this embodiment employs a piezoelectric ceramic dual-boost structure on the second surface of the metal layer 1, corresponding to the air-cooled heat dissipation cavity structure in the corresponding region of the first surface. Electrodes plated on the upper and lower surfaces of the piezoelectric ceramic drive the dual-boost structure to induce a first boosting deformation and a second boosting deformation in the metal layer 1 along the vertical direction. This, in turn, drives the cavity structure to perform synchronized volume adjustment in the discontinuous first and second regions of the metal layer 1, thereby enhancing the driving strength and flow efficiency of the gas in the air-cooled heat dissipation cavity structure. By utilizing the discontinuous yet synchronized first and second boosting deformations, while maintaining a high level of vibration amplitude and resonant frequency for the piezoelectric micropump heat dissipation chip, the vibration stress value of the piezoelectric ceramic structure and the probability of ceramic cracking due to vibration are reduced, significantly improving the durability of the piezoelectric micropump heat dissipation chip.

[0076] In a preferred embodiment, the piezoelectric ceramic dual-booster structure includes:

[0077] The first annular booster structure 21 and the second annular booster structure 22 are configured as a double booster region concentrically disposed on the second surface of the metal layer 1.

[0078] Specifically, the vertical projection area of ​​the dual booster region on the second surface of the metal layer 1 onto the first surface of the metal layer 1 is configured to be covered by the vertical projection area of ​​the cavity structure on the first surface of the metal layer 1, so that the first booster deformation generated by the first annular booster structure 21 and the second booster deformation generated by the second annular booster structure 22 act together on the cavity structure.

[0079] In this embodiment of the invention, the piezoelectric ceramic dual-boost structure includes a first annular booster structure 21 and a second annular booster structure 22. The first annular booster structure 21 and the second annular booster structure 22 are concentrically arranged on the second surface of the metal layer 1, and the vertical projection of the first annular booster structure 21 and the second annular booster structure 22 on the second surface of the metal layer 1 is covered by the vertical projection of the air-cooled heat dissipation cavity structure on the first surface of the metal layer 1.

[0080] Therefore, when the first annular booster structure 21 and the second annular booster structure 22 are subjected to an electric field, they undergo tensile / compressive deformation based on the inverse piezoelectric effect, which in turn causes the metal layer 1 to be concave upward or downward, thereby changing the volume of the air-cooled heat dissipation cavity, generating suction or pressure on the gas, and forming a unidirectional flow of gas under the action of the one-way valve, thereby improving the driving strength and flow efficiency of the gas in the air-cooled heat dissipation cavity structure.

[0081] It is easy to understand that the embodiments of the present invention adopt the method of the first annular booster structure 21 and the second annular booster structure 22 jointly generating a double booster region on the second surface of the metal layer 1. By utilizing the synchronous first booster deformation and the second booster deformation, a driving force is provided in the volume adjustment region corresponding to the air-cooled heat dissipation cavity structure on the metal layer 1, which acts together on the volume adjustment region.

[0082] It should be noted that this driving force is characterized by regional discontinuity and synchronous execution. Synchronous execution ensures that the piezoelectric ceramic layer 2 provides a sufficiently large amplitude through the superposition of two boosting actions, driving the piezoelectric ceramic chip to achieve the required driving strength and flow efficiency for the gas in the gas-cooled heat dissipation cavity structure. Regional discontinuity allows for the reservation of stress relief areas between the two boosting actions, reducing the superimposed stress on the piezoelectric ceramic layer 2 during the boosting action. Therefore, by utilizing the regionally discontinuous but synchronously executed first and second boosting deformations, while maintaining a high level of vibration amplitude and resonant frequency for the piezoelectric micropump heat dissipation chip, the vibration stress value of the piezoelectric ceramic structure and the probability of ceramic splitting due to vibration are reduced.

[0083] Furthermore, the inner diameter of the first annular booster structure 21 is larger than the outer diameter of the second annular booster structure 22, and the booster synchronization structure 23 is configured to connect the inner diameter of the first annular booster structure 21 and the outer diameter of the second annular booster structure 22.

[0084] Based on this, the piezoelectric ceramic dual-boost structure also includes a boosting synchronization structure 23, which is configured to connect the first annular boosting structure 21 and the second annular boosting structure 22 that are arranged concentrically.

[0085] Specifically, the boosting synchronization structure 23 includes: a plurality of boosting synchronization blocks, which are configured in an equal-angle ring between the first annular boosting structure 21 and the second annular boosting structure 22; wherein each boosting synchronization block is connected to a first position where the inner diameter of the first annular boosting structure 21 is close to the second annular boosting structure 22 and a second position where the outer diameter of the second annular boosting structure 22 is close to the first annular boosting structure 21.

[0086] In this embodiment of the invention, by configuring the first annular booster structure 21 as a concentric annular structure with a larger radius and the second annular booster structure 22 as a concentric annular structure with a smaller radius, and by configuring the inner diameter of the first annular booster structure 21 as a concentric annular structure with a smaller radius, a stress relief area is reserved between the first annular booster structure 21 and the second annular booster structure 22. At the same time, in order to drive the first annular booster structure 21 and the second annular booster structure 22 to perform synchronous boosting operations, a plurality of annularly arranged boosting synchronization blocks are provided between the first annular booster structure 21 and the second annular booster structure 22. Each boosting synchronization block connects the first position where the inner diameter of the first annular booster structure 21 is close to the second annular booster structure 22 and the second position where the outer diameter of the second annular booster structure 22 is close to the first annular booster structure 21, so that the first annular booster structure 21 and the second annular booster structure 22 can achieve synchronous boosting operations when performing piezoelectric micropump heat dissipation.

[0087] In some embodiments, a plurality of booster synchronization blocks arranged in a ring between the first annular booster structure 21 and the second annular booster structure 22 are configured to be uniformly distributed in a ring at equal angles. In this embodiment of the invention, the angle between two adjacent booster synchronization blocks is set to 90°. It is readily understood that those skilled in the art can choose other angles to achieve a ring distribution of the plurality of booster synchronization blocks according to actual needs, so as to achieve synchronization of boosting action between the first annular booster structure 21 and the second annular booster structure 22. This application does not limit the specific arrangement of the booster synchronization blocks.

[0088] For example, in one embodiment, the inner radius of the first annular booster structure 21 is in the range of 2.5mm-3.5mm, preferably 3mm; and the outer radius is in the range of 3.7mm-4.5mm, preferably 4mm.

[0089] For example, in one embodiment, the inner radius of the first annular booster structure 21 is 25%-35% of the metal layer size, preferably 30%; the outer radius is 37%-45% of the metal layer size, preferably 40%.

[0090] For example, in one embodiment, the inner radius of the second annular booster structure 22 is in the range of 1.4mm-1.6mm, preferably 1.5mm; and the outer radius is in the range of 1.9mm-2.1mm, preferably 2mm.

[0091] For example, in one embodiment, the inner radius of the second annular booster structure 22 is 14%-16% of the metal layer size, preferably 15%; and the outer radius is 19%-21% of the metal layer size, preferably 20%.

[0092] For example, in one embodiment, the height range of the first annular booster structure 21 and the second annular booster structure 22 is 0.15mm-0.25mm, preferably 0.2mm.

[0093] The following section presents the optimized design and dimensional parameters of the piezoelectric ceramic dual-booster structure for the piezoelectric micropump heat dissipation chip, based on embodiments of the present invention. Combined with the original design of traditional piezoelectric micropump heat dissipation chips and similar designs, simulations and analyses of the piezoelectric micropump heat dissipation chip are performed, providing the following comparative examples and embodiments:

[0094] Comparative Example 1:

[0095] In traditional designs, the core of a conventional piezoelectric micropump heat dissipation chip is as follows: Figure 2 As shown, a layer of piezoelectric ceramic is laminated onto a thin stainless steel sheet. The dimensions of the stainless steel sheet are: L / W=10mm, T=0.5mm; the dimensions of the ceramic disc are: R=3mm, T=0.2mm.

[0096] Finite element resonant response analysis was performed on the above structure, and the charge amplitude-frequency characteristics were obtained by frequency sweeping, as follows: Figure 3 As shown in the figure, the resonant frequency of the micropump is clearly observed to be 41 kHz. This frequency meets the requirements for high harmonic response, and since the frequency response exceeds 20 kHz, it falls under the category of ultrasonic waves, achieving a silent vibration effect for the device. Its corresponding resonant modes are as follows: Figure 4 and Figure 5 As shown.

[0097] exist Figure 4and Figure 5 Based on this, the amplitude of each node was collected along the length of the square metal sheet, and its amplitude distribution is as follows: Figure 6 As shown, its maximum amplitude is 3.017e-7m. The corresponding equivalent stress distribution is as follows. Figures 7-9 As shown, within a diameter range of 6 mm, the maximum stress value on the piezoelectric ceramic is 1.346 MPa.

[0098] Comparative Example 2:

[0099] In some similar designs, in order to balance the resonant frequency and amplitude of the piezoelectric micropump chip while improving the stress value generated by the vibration of the piezoelectric ceramic sheet to prevent cracking due to excessive stress, it is necessary to consider both the amplitude to ensure the heat dissipation performance of the piezoelectric micropump chip and the stress reduction to prevent the ceramic from cracking due to long-term vibration. Therefore, the excitation piezoelectric ceramic is changed to a ring shape according to the distribution of the resonant modes.

[0100] The corresponding finite element model is as follows Figure 10 As shown, the dimensions of the stainless steel plate are: L / W = 10 mm, T = 0.5 mm; the dimensions of the circular ceramic ring are: R = 3 mm, r = 2 mm, T = 0.2 mm. Finite element harmonic response analysis was performed on the above structure, and the charge amplitude-frequency characteristics were obtained by frequency sweeping as follows: Figure 11 As shown. Its micropump structure has a resonant frequency of 41kHz, achieving the same effect as the traditional design. Its resonant mode is as follows. Figure 12 and Figure 13 The design shown is basically the same as the traditional one. The corresponding resonant amplitude is 2.228e-7m, which is reduced by 0.8um. Figure 14 .

[0101] But from Figures 15-17 The stress distribution shows that the maximum stress on the piezoelectric ceramic in the 2-3 mm and 7-8 mm ranges is 0.6365 MPa. Compared with the traditional design, the stress value of the piezoelectric ceramic in this structure is reduced by half, which can improve the safety of the piezoelectric ceramic. However, considering the reduction in vibration amplitude, it is still difficult to meet the performance requirements.

[0102] Example 1:

[0103] In this embodiment of the invention, a double-ring structure is considered. The amplitude is increased by two boosts, one from the inner ring and one from the outer ring. The inner and outer radii of the inner ring are 2.0 mm and 1.5 mm, respectively, while the inner and outer radii of the outer ring become 4 mm and 3 mm, respectively. Its finite element harmonic response analysis is as follows: Figure 18 As shown, its resonant frequency can still satisfy the main oscillation frequency of 41kHz, as... Figure 19 As shown. The corresponding vibration modes are as follows. Figures 20-21 As shown.

[0104] The vibration amplitude along the length of the corresponding bottom stainless steel is as follows: Figure 22As shown, the vibration amplitude is 3.107e-7m, which is 28.3% higher than that of the single-ring structure, and basically the same as that of the disk.

[0105] like Figure 23-25 As shown, the equivalent stress on the surface piezoelectric ceramic ring was collected, and its maximum stress was 0.7791 MPa. This means that the stress value generated by the vibration of this structure is 31.3% lower than that of the disk type and only 18% higher than that of the single ring, which can simultaneously measure the vibration amplitude and surface stress value.

[0106] Comparative Example 3:

[0107] In some similar designs, to contrast with the aforementioned double-ring structure, a wide single-ring structure is considered. This wide single-ring design increases the amplitude; the inner and outer radii of the inner ring are 4.0 mm and 1.5 mm, respectively. Its model is as follows: Figure 26 As shown.

[0108] Its resonant frequency, calculated by frequency sweep, is 42.5 kHz. This resonant frequency meets the requirements for high-frequency vibration. Figure 27 As shown. The corresponding vibration modes are as follows. Figures 28-29 As shown. The corresponding amplitude distribution on the stainless steel surface is as follows. Figure 30 As shown, the equivalent stress on the surface piezoelectric ceramic ring is collected, such as... Figures 31-33 As shown, its vibration amplitude is 2.262e-6m, which is 7 times higher than the vibration amplitude of the model in the embodiment of the present invention. However, the stress on the ceramic surface is 11 times higher than the stress in the embodiment of the present invention, which increases the risk of ceramic cracking and is not suitable for actual production and application.

[0109] Through simulation and analysis of the above embodiments and comparative examples, the piezoelectric ceramic dual-booster structure provided by the embodiments of the present invention achieves a significant optimization effect compared with single-ring structures and wide single-ring structures, balancing stress reduction and vibration amplitude improvement. Compared with disk structures, it shows a significant decrease in stress value while maintaining vibration amplitude. Therefore, compared with the original design of traditional piezoelectric micropump heat dissipation chips and similar designs, the embodiments of the present invention, by utilizing discontinuous but synchronous first and second booster deformations, reduce the vibration stress value of the piezoelectric ceramic structure and the probability of ceramic splitting due to vibration while maintaining a high level of vibration amplitude and resonant frequency for the piezoelectric micropump heat dissipation chip, significantly improving the durability of the piezoelectric micropump heat dissipation chip and possessing significant technical advantages.

[0110] like Figure 34 As shown in the embodiment of the present invention, a method for fabricating a piezoelectric micropump heat dissipation chip is provided for fabricating the piezoelectric micropump heat dissipation chip as described above, comprising the following steps:

[0111] S1: Prepare a piezoelectric ceramic sample to form the area to be etched on the piezoelectric ceramic sample;

[0112] S2: Perform the first etching action on the prepared piezoelectric ceramic sample; wherein, the first etching action is configured to etch for 160-200 seconds in a first etchant composed of 6% BHF: 4% HNO3: 90% deionized water to complete the initial etching.

[0113] S3: Perform a first cleaning action on the piezoelectric ceramic sample after the first etching action; wherein the first cleaning action is configured to rinse with deionized water to remove loose film and residual acid;

[0114] S4: Perform a second etching action on the piezoelectric ceramic sample after the first cleaning action; wherein, the second etching action is configured to etch for 20-40 seconds in a second etchant composed of 40% HCl: 60% deionized water, so as to form a piezoelectric ceramic double-boost structure after the area to be etched is etched.

[0115] S5: Perform a second cleaning operation on the piezoelectric ceramic dual-booster structure after the second etching operation; wherein, the second cleaning operation is configured to include deionized water rinsing, drying and photoresist removal;

[0116] S6: After the second cleaning action, silver electrodes are plated onto the piezoelectric ceramic double-booster structure, and the prepared piezoelectric ceramic double-booster structure with electrodes is then attached to the metal layer.

[0117] In this embodiment of the invention, the piezoelectric ceramic layer with a double-ring structure is first wire-cut into a circular wafer by sintering a circular ceramic tube, then ground and polished to form a circular wafer, and finally etched using MEMS technology. The process steps are as follows:

[0118] PZT (lead zirconate titanate) piezoelectric ceramic wafers were spin-coated using 3μm photoresist, followed by soft baking at 110°C for 90 seconds. After exposure and development, the substrate was hard-baked at 120°C for 25 minutes. Following photolithography, the bottom of the photoresist needed to be treated to ensure all areas to be etched were fully exposed. After these preparations, the samples were etched using different formulations.

[0119] The experimental design of the two-step etching process is as follows: The first step is preparatory etching and cleaning, the main task of which is to remove the dielectric oxide layer (such as SiO2) and activate the piezoelectric ceramic surface to ensure that subsequent etching can proceed uniformly and smoothly. The second step is the main etching step, which uses the strong solubility of concentrated hydrochloric acid to quickly and deeply etch the piezoelectric ceramic body to form the desired three-dimensional structure or release the suspended structure.

[0120] It should be noted that this invention, through a clever, step-by-step process design, combines two mature etchants with different functional focuses, thereby systematically solving the multiple challenges faced by a single etchant in the micromachining of piezoelectric ceramics (such as PZT). Specifically:

[0121] Step 1 (BHF / HNO3): Focus on "interface preparation" and "controlled startup". The goal is to gently remove the oxide dielectric layer, clean and activate the PZT surface, and potentially form slight sidewall passivation, creating an ideal starting surface and geometric profile for the next step of high-speed, uniform bulk etching.

[0122] Step 2 (HCl): Focusing on "high-efficiency bulk etching" and "morphology control". On the optimized interface, the high etching rate of HCl on PZT is used to quickly remove the host material, forming the final structure, and the underlying layer is protected by its good material selectivity.

[0123] Therefore, by adopting this approach, through a separate design of "interface treatment first, followed by body etching", the problem of the etchant needing to simultaneously meet multiple conflicting requirements (such as high speed and high selectivity, depth and sidewall protection) in a single step is solved.

[0124] Compared with traditional single-acid etching (such as HF, HCl, HNO3 or their mixtures), this method achieves significant optimization in the following aspects: (1) Improved sidewall morphology and roughness. The two-step method can reduce the "pits" or "erosion" of the sidewalls and obtain more vertical and uniform sidewalls. (2) Enhanced process controllability and repeatability: The etching rate of PZT is extremely sensitive to material composition, crystallization state and surface conditions. The first step of "preparatory etching" plays a role in standardizing the surface state, reducing batch-to-batch differences, and making the etching rate of the second step more stable and predictable.

[0125] In this embodiment of the invention, by combining pre-etching with BHF / HNO3 mixture and main etching with HCl, the traditional wet etching process is transformed from a relatively rough and difficult-to-control bulk material removal process into a more controllable, more uniform, more selective, and better sidewall morphology quasi-fine micromachining technology.

[0126] To obtain the minimum undercut under experimental conditions and to study the influence of different components on the etching results, embodiments of the present invention adjusted different components close to the baseline formulation. The baseline etchant for the two-step wet etching was a first etchant of 6% BHF: 4% HNO3: 90% deionized water and a second etchant of 40% HCl: 60% deionized water aqueous solution.

[0127] The etching process includes the following steps: First, the prepared sample is etched in the first etchant for approximately 180 seconds. Second, it is rinsed with deionized water (DI water) to remove loose film and residual acid. Third, the sample is etched again in the second etchant for approximately 30 seconds to fully expose the bottom electrode. After these steps are completed, the sample is rinsed with deionized water and dried, and then the photoresist is removed with acetone.

[0128] Silver electrodes are deposited on the etched double-ring structure surface using an evaporation coating method. During the evaporation process, a mask (metal mask) is used to expose the areas to be coated, while the empty areas are protected by a mask to ensure that the electrodes on the upper and lower surfaces are short-circuited.

[0129] Once a double-ring piezoelectric ceramic sheet with electrodes is prepared, it can be bonded to a metal sheet using adhesive bonding or welding.

[0130] In another embodiment, the present invention also provides a piezoelectric heat dissipation device, comprising a piezoelectric micropump heat dissipation chip as described in any one of the preceding claims, or a piezoelectric micropump heat dissipation chip prepared by a piezoelectric micropump heat dissipation chip preparation method as described in any one of the preceding claims.

[0131] Other embodiments or specific implementations of the quartz resonator of the present invention can be referred to the above-described method embodiments, and will not be repeated here.

[0132] It is understood that in the description of this specification, references to terms such as "one embodiment," "another embodiment," "other embodiments," or "first embodiment to Nth embodiment," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0133] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0134] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A piezoelectric micropump heat dissipation chip, characterized in that, include: A metal layer, the metal layer being configured to have a first surface and a second surface disposed opposite to each other, the first surface forming a cavity structure for air cooling heat dissipation; A piezoelectric ceramic layer is disposed on the second surface of the metal layer and has a piezoelectric ceramic dual-boost structure. The piezoelectric ceramic dual-boost structure is configured to generate a first boosting deformation and a second boosting deformation perpendicular to the metal layer when subjected to an electric field. The piezoelectric ceramic dual-booster structure includes: A first annular booster structure and a second annular booster structure are configured as a double booster region concentrically disposed on the second surface of the metal layer. A booster synchronization structure, wherein the booster synchronization structure is configured to connect a first ring booster structure and a second ring booster structure that are concentrically arranged; The first and second booster deformations drive the cavity structure to perform synchronized volume adjustment actions in the first and second regions of the metal layer, respectively.

2. The piezoelectric micropump heat dissipation chip as described in claim 1, characterized in that, The vertical projection area of ​​the dual-boost region on the second surface of the metal layer onto the first surface of the metal layer is configured to be covered by the vertical projection area of ​​the cavity structure on the first surface of the metal layer, so that the first boosting deformation generated by the first annular boosting structure and the second boosting deformation generated by the second annular boosting structure act together on the cavity structure.

3. The piezoelectric micropump heat dissipation chip as described in claim 1, characterized in that, The inner diameter of the first annular booster structure is larger than the outer diameter of the second annular booster structure, and the booster synchronization structure is configured to connect the inner diameter of the first annular booster structure and the outer diameter of the second annular booster structure.

4. The piezoelectric micropump heat dissipation chip as described in claim 3, characterized in that, The boost synchronization structure includes: A plurality of booster synchronization blocks are configured in an equal-angled ring arrangement between the first ring booster structure and the second ring booster structure. Wherein, each of the booster synchronization blocks is connected to the first position where the inner diameter of the first annular booster structure is close to the second annular booster structure and the second position where the outer diameter of the second annular booster structure is close to the first annular booster structure.

5. The piezoelectric micropump heat dissipation chip as described in claim 3, characterized in that, The inner radius of the first annular booster structure ranges from 2.5mm to 3.5mm, and the outer radius ranges from 3.7mm to 4.5mm.

6. The piezoelectric micropump heat dissipation chip as described in claim 3, characterized in that, The inner radius of the second annular booster structure ranges from 1.4mm to 1.6mm, and the outer radius ranges from 1.9mm to 2.1mm.

7. The piezoelectric micropump heat dissipation chip as described in claim 3, characterized in that, The height range of the first annular booster structure and the second annular booster structure is 0.15mm-0.25mm.

8. A method for fabricating a piezoelectric micropump heat dissipation chip, characterized in that, The process for fabricating the piezoelectric micropump heat dissipation chip as described in any one of claims 1-7 includes the following steps: S1: Prepare a piezoelectric ceramic sample to form the area to be etched on the piezoelectric ceramic sample; S2: Perform the first etching action on the prepared piezoelectric ceramic sample; wherein, the first etching action is configured to etch for 160-200 seconds in a first etchant composed of 6% BHF: 4% HNO3: 90% deionized water to complete the initial etching. S3: Perform a first cleaning action on the piezoelectric ceramic sample after the first etching action; wherein the first cleaning action is configured to rinse with deionized water to remove loose film and residual acid; S4: Perform a second etching action on the piezoelectric ceramic sample after the first cleaning action; wherein, the second etching action is configured to etch for 20-40 seconds in a second etchant composed of 40% HCl: 60% deionized water, so as to form a piezoelectric ceramic double-boost structure after the area to be etched is etched. S5: Perform a second cleaning operation on the piezoelectric ceramic dual-booster structure after the second etching operation; wherein, the second cleaning operation is configured to include deionized water rinsing, drying and photoresist removal; S6: After the second cleaning action, silver electrodes are plated onto the piezoelectric ceramic double-booster structure, and the prepared piezoelectric ceramic double-booster structure with electrodes is then attached to the metal layer.

9. A piezoelectric heat dissipation device, characterized in that, Including the piezoelectric micropump heat dissipation chip as described in any one of claims 1-7 above.

Images