Valveless inert gas one-way circulation device driven by dual / tetra piezoelectric vibrator

Abstract

The application discloses a valveless inert gas one-way circulation device driven by double / four piezoelectric vibrators, and belongs to the technical field of micro-fluid driving. The device comprises at least two piezoelectric vibrators symmetrically embedded in the side wall of a ring-shaped sealed gas cavity, and a driving control module for outputting 180-degree phase difference same-frequency driving signals to the symmetric vibrators. The two vibrators alternately vibrate to form a continuous one-way pressure gradient in the gas cavity, and push the inert gas to stably circulate. The application does not need a mechanical pump and a one-way valve, has small volume (micron level), low power consumption (<1mW), low noise and long service life, supports flexible configuration of 2 / 4 vibrators, and can be widely applied to the fields of three-dimensional stacked chip heat dissipation, micro-fluid chips, medical detection and the like.

Description

Technical Field

[0001] This invention belongs to the field of microfluidic drive and thermal management technology, specifically relating to a low-pressure, low-power, valveless inert gas unidirectional circulation drive device for micron-level closed channels, which can be widely used in semiconductor chip heat dissipation, microfluidic biochips, aerospace microdevices, medical testing equipment and other fields. Background Technology

[0002] With the rapid development of microelectronics and microelectromechanical systems (MEMS), the demand for gas circulation at the micrometer scale is becoming increasingly urgent. Especially in the field of heat dissipation for high-density three-dimensional stacked chips, traditional heat dissipation solutions can no longer meet the requirements, and gas circulation heat dissipation has become one of the most promising technical routes.

[0003] Existing micro gas circulation technologies are mainly divided into two categories: The first category is mechanical pump-driven solutions, such as miniature centrifugal pumps, peristaltic pumps, and diaphragm pumps. This type of solution has the following fatal flaws: Excessive size: The minimum size is usually in the millimeter range, which cannot be integrated into a three-dimensional stacked chip package with a thickness of only 0.3~0.8mm; Excessive power consumption: The operating power consumption is usually above 100mW, far exceeding the power consumption budget of less than 1mW that mobile terminal chips can withstand; Short lifespan: Due to mechanical friction and moving parts, the continuous working life is usually no more than 10,000 hours, which cannot meet the requirement of more than 10 years of service life for electronic equipment. High noise level: The noise generated during operation exceeds 30dB, which seriously affects the user experience of consumer electronics.

[0004] The second category is piezoelectric oscillator driving schemes, most of which currently disclosed technologies are single-oscillator structures. This type of scheme has the following drawbacks: Unable to form a stable unidirectional circulation: The single oscillator can only generate reciprocating vibration, and the gas flows back and forth in the channel, resulting in a very low net flow rate and an actual heat exchange efficiency of less than 30%. Severe eddy currents: The vibration of a single oscillator will generate a large number of eddy currents in the channel, resulting in an increase in energy loss of more than 40%; Vibration imbalance: Asymmetric vibration of a single oscillator can cause resonance, affecting the electrical performance and mechanical stability of the chip.

[0005] The few publicly disclosed dual piezoelectric oscillator solutions mostly employ in-phase or 90° phase difference driving, still exhibiting significant backflow and poor cycle stability. Furthermore, the oscillator size is too large to be embedded in micron-level air cavities, failing to meet the heat dissipation requirements of three-dimensional stacked chips. For example, Chinese patent CN115234678A discloses a dual piezoelectric pump using two in-phase driven piezoelectric oscillators, requiring a one-way valve to achieve unidirectional circulation. This results in a complex structure, and the one-way valve is prone to fatigue failure and has a short lifespan.

[0006] Therefore, there is an urgent need for a micron-scale drive device that is small in size, low in power consumption, noiseless, long in life, and can achieve stable unidirectional gas circulation without the need for a check valve. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned defects of the prior art and provide a valveless dual / quad piezoelectric vibrator driven inert gas unidirectional circulation device. Through symmetrically arranged piezoelectric vibrators and a 180° phase difference driving signal, a continuous unidirectional pressure gradient is formed in the annular sealed gas cavity, and stable unidirectional gas circulation can be achieved without any unidirectional valve.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A valveless piezoelectric vibrator-driven inert gas unidirectional circulation device, comprising at least two piezoelectric vibrators (2) and a drive control module. The piezoelectric vibrators are symmetrically embedded in the sidewall of an annular sealed gas cavity (1); the drive control module is electrically connected to all piezoelectric vibrators and is used to output AC drive signals with a phase difference of 180° to the symmetrically arranged piezoelectric vibrators at the same frequency.

[0009] This invention allows for flexible configuration of the number of piezoelectric oscillators based on chip size and heat dissipation requirements: For small and medium-sized chips with a side length of ≤10mm, two piezoelectric oscillators symmetrically arranged on two opposite sidewalls at the bottom of the annular air cavity can meet the heat dissipation requirements. For large-size chips or high-power chips with a side length >10mm, four piezoelectric oscillators are arranged at the center of the four side walls of the annular gas cavity. The oscillators are driven by a 180° phase difference between each pair of opposite oscillators, which can provide a larger gas circulation flow rate and a stronger heat exchange capacity.

[0010] The core advantage of the 4-oscillator scheme is that the four oscillators work simultaneously, forming four continuous pressure gradient nodes in the annular air cavity. The gas circulation flow rate is increased by more than 80% compared with the 2-oscillator scheme, which can meet the full-load heat dissipation requirements of high-density three-dimensional stacked chips with more than 6 layers.

[0011] The core working principle of this invention is as follows: When two symmetrically arranged piezoelectric oscillators are driven by a 180° phase difference, when the first oscillator vibrates outward (expands), the second oscillator vibrates inward (contracts), creating a pressure difference between the two oscillators from the first oscillator to the second oscillator; when the first oscillator vibrates inward (contracts), the second oscillator vibrates outward (expands), reversing the direction of the pressure difference. Because the two oscillators are symmetrically arranged and the phase difference is precisely 180°, the pressure difference forms a continuous unidirectional gradient along the annular sealed gas cavity, thereby driving the gas to flow stably in a preset direction, completely eliminating backflow and eddy current phenomena. The driving principle of this invention is applicable to closed annular channels of any cross-sectional shape, with a rectangular cross-section being the preferred embodiment.

[0012] by Figure 1 The symmetrical dual-oscillator drive scheme shown is an example: When the left piezoelectric vibrator vibrates outward, the right piezoelectric vibrator vibrates inward, creating a pressure difference from left to right at the bottom of the annular gas cavity, which pushes the gas to flow to the right along the bottom channel; When the left piezoelectric vibrator vibrates inward, the right piezoelectric vibrator vibrates outward, creating a pressure difference from right to left at the top of the annular gas cavity, which pushes the gas to flow to the left along the top channel; This cycle repeats continuously, with the gas flowing in a stable unidirectional cycle from left to right, then from top to right, then from right to bottom, and finally from bottom to left. Figure 1 (As indicated by the middle arrow) During the flow process, some of the gas enters the vertical micro-hole heat conduction array (4) inside the chip, carrying out the heat generated by each layer of the chip, and finally flows into the main circulation loop, and is dissipated to the outside through the five-sided integrated heat dissipation layer (6).

[0013] The key innovations of this invention include: For the first time, a 180° phase difference symmetrical dual / quad oscillator drive scheme was proposed, realizing true valveless unidirectional gas circulation and completely solving the backflow and eddy current problems of the single oscillator scheme. Employing micron-level piezoelectric oscillators, it can be directly integrated into chip-level packaging, with a volume only 1 / 1000 that of traditional mechanical pumps; With an ultra-low power consumption design, the operating power consumption is less than 1mW, and it can be directly powered by the chip power supply without the need for an additional power module. With no mechanical friction or moving parts, its continuous working life exceeds 100,000 hours, which is more than 10 times that of traditional mechanical pumps; The preferred operating frequency is greater than 20kHz, and its operating noise is outside the range of human hearing. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the individual structure of the valveless dual / quad piezoelectric vibrator driven inert gas unidirectional circulation device of the present invention; Figure 2 This is a schematic diagram of the overall structure of the present invention applied to heat dissipation of three-dimensional stacked chips.

[0015] Explanation of reference numerals in the attached figures: 1-Annular sealed gas cavity; 2-Gas circulation drive component (piezoelectric vibrator); 3-Miniature insulating support column; 4-Vertical microporous thermal conductive array; 5-Three-dimensional stacked chip body; 6-Five-sided integrated heat dissipation layer; 7-Chip interlayer interface; The arrow direction indicates the direction of high-pressure inert gas circulation flow. Detailed Implementation

[0016] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. Example 1

[0017] This embodiment is a two-oscillator driving device for mobile terminal chips.

[0018] The annular sealed gas cavity (1) has a width of 80 μm and a height of 0.5 mm. Miniature insulating support columns (3) with a diameter of 15 μm and a spacing of 300 μm are uniformly arranged inside. Two piezoelectric oscillators are symmetrically embedded on two opposite sidewalls at the bottom of the annular gas cavity. The oscillators have dimensions of 50 × 50 × 10 μm and are made of PZT-5H piezoelectric ceramic. The diameter of the miniature insulating support columns (3) is preferably 10~20 μm, and the spacing is 200~500 μm.

[0019] The drive control module outputs a 2V drive signal voltage at a frequency of 50kHz, with a precise phase difference of 180°. The oscillator's vibration amplitude is 2μm, and the overall power consumption of the device is 0.5mW.

[0020] Based on fluid dynamics simulation and experimental testing, the gas circulation flow rate of this embodiment is 10 mL / min, the heat exchange efficiency is 85%, and there is no backflow or eddy current phenomenon. It can meet the heat dissipation requirements of a 4-layer 7nm process 3D stacked chip, and the chip operating temperature can be reduced by 15~20℃. Example 2

[0021] This embodiment is a two-oscillator drive device for microfluidic biochips.

[0022] The annular sealed gas chamber (1) has a width of 50 μm and a height of 20 μm, which is suitable for low-flow, high-precision gas sample delivery scenarios. Two piezoelectric oscillators are symmetrically arranged on the upper and lower side walls of the gas chamber. The oscillators are circular with a diameter of 30 μm and a thickness of 5 μm, and are made of aluminum nitride (AlN).

[0023] The drive control module outputs a drive signal voltage of 1.5V, a frequency of 120kHz, and a phase difference of 180°. The oscillator's vibration amplitude is 1μm, and the overall power consumption of the device is 0.2mW.

[0024] This embodiment can be used for gas sample delivery in microfluidic biochips, with a flow rate accuracy of ±0.1 μL / min, meeting the requirements of high-precision biological detection. Example 3

[0025] This embodiment is a two-oscillator drive device for aerospace micro sensors.

[0026] The annular sealed gas cavity (1) has a width of 20μm and a height of 30μm. Two piezoelectric oscillators are symmetrically embedded on the two opposite sidewalls of the annular gas cavity. The oscillators are 30×30×5μm in size and made of polyvinylidene fluoride (PVDF).

[0027] The drive control module outputs a drive signal voltage of 1V, a frequency of 200kHz, and a phase difference of 180°. The oscillator vibration amplitude is 0.5μm, and the overall power consumption of the device is 0.1mW.

[0028] This embodiment can operate stably in extreme temperature environments ranging from -55℃ to 125℃, meeting the stringent environmental requirements of aerospace equipment. Example 4

[0029] This embodiment is a 4-oscillator drive device for high-power server chips.

[0030] The annular sealed air cavity (1) has a width of 100μm and a height of 0.8mm. Miniature insulating support columns (3) with a diameter of 20μm and a spacing of 400μm are uniformly arranged inside. Four piezoelectric oscillators are embedded in the center of the four side walls of the annular air cavity. The oscillators have a size of 80×80×15μm and are made of PZT-5H material.

[0031] The drive control module outputs drive signals with a 180° phase difference to the two opposing upper and lower oscillators, and another set of drive signals with a 180° phase difference to the two opposing left and right oscillators. The drive voltage is 3V and the frequency is 80kHz. The power consumption of a single oscillator is 0.4mW, and the overall power consumption of the device is 1.6mW.

[0032] Tests showed that the gas circulation flow rate of this embodiment is 18 mL / min, and the heat exchange efficiency is 92%, which can meet the heat dissipation requirements of a 6-layer 7nm process high-power server chip, and the chip's full-load operating temperature can be controlled below 85℃. Beneficial effects

[0033] Compared with the prior art, the present invention has the following significant advantages: Significantly improved circulation efficiency: Compared with the single-oscillator drive scheme, the gas circulation flow rate is increased by more than 60%, the heat exchange efficiency is increased by more than 45%, and the backflow and eddy current phenomena are completely eliminated. Miniaturization: The oscillator is micron-sized and can be directly integrated into a chip-level package, with a volume only 1 / 1000 that of a traditional mechanical pump; Ultra-low power consumption: Operating power consumption is less than 1mW, standby power consumption is less than 1μW, and it can be directly powered by the chip power supply; Ultra-long lifespan: With no mechanical friction or moving parts, its continuous working life exceeds 100,000 hours, which is more than 10 times that of traditional mechanical pumps; Low noise: The preferred operating frequency is greater than 20kHz, and its operating noise sound pressure level is less than 20dB (A), which is below the threshold of human hearing and cannot be perceived by the human ear; Wide range of applications: It can be widely used in many fields such as heat dissipation of three-dimensional stacked chips, microfluidic biochips, aerospace micro-devices, and medical testing equipment.

[0034] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A valveless piezoelectric oscillator-driven inert gas unidirectional circulation device, characterized in that, include: At least two piezoelectric vibrators (2) are symmetrically embedded in the sidewall of the annular sealed gas cavity (1); The drive control module is electrically connected to all piezoelectric vibrators (2) and is used to output AC drive signals with a phase difference of 180° to the symmetrically arranged piezoelectric vibrators (2). The piezoelectric vibrator (2) generates high-frequency micro-amplitude vibration under the action of the driving signal, forming a continuous unidirectional pressure gradient in the annular sealed gas cavity (1), which drives the high-pressure inert gas in the cavity to form a stable unidirectional circulating flow in a preset direction.

2. The apparatus according to claim 1, characterized in that, The number of piezoelectric vibrators (2) is two, symmetrically embedded on two opposite sidewalls at the bottom of the annular sealed air cavity (1); or the number is four, respectively embedded at the center of the four sidewalls of the annular sealed air cavity (1).

3. The apparatus according to claim 1, characterized in that, The piezoelectric vibrator is a micron-sized vibrator, which can be square, circular, or ring-shaped. The square vibrator has a size of 30~100μm×30~100μm×5~20μm, and the circular vibrator has a diameter of 30~100μm, a thickness of 5~20μm, and a vibration amplitude of 0.5~10μm.

4. The apparatus according to claim 1, characterized in that, The material of the piezoelectric vibrator is selected from any one of lead zirconate titanate (PZT), zinc oxide (ZnO), aluminum nitride (AlN), or polyvinylidene fluoride (PVDF).

5. The apparatus according to claim 1, characterized in that, The drive control module outputs a drive signal voltage of 1~3V and a frequency of 10~200kHz. The power consumption of a single piezoelectric vibrator is less than 0.5mW; the overall power consumption of the 2-vibrator scheme is less than 1mW, and the overall power consumption of the 4-vibrator scheme is less than 2mW.

6. The apparatus according to claim 1, characterized in that, The piezoelectric vibrator is fixed to the inner wall of the annular sealed gas cavity (1) by a low-temperature bonding process. The bonding material is any one of epoxy resin, polyimide or gold-gold alloy, and the sealing leakage rate at the bonding point is ≤10⁻¹¹mbar・L / s.

7. The apparatus according to claim 1, characterized in that, The annular sealed air cavity (1) has a rectangular cross-section with a width of 50~100μm and a height of 0.3~0.8mm, and is uniformly provided with several micro-insulating support columns (3).

8. The apparatus according to claim 1, characterized in that, The annular sealed air cavity (1) is arranged around the periphery of the cuboid three-dimensional stacked chip body (5) and is connected to the vertical micro-hole heat conduction array (4) inside the chip body, together forming a connected fluid circuit.

9. A driving method for the device as described in any one of claims 1 to 8, characterized in that, Includes the following steps: (1) The drive control module outputs the first AC drive signal to the first group of piezoelectric vibrators; (2) The drive control module outputs a second AC drive signal to the second group of piezoelectric vibrators arranged symmetrically with the first group. The second AC drive signal has the same frequency as the first AC drive signal but a phase difference of 180°. (3) The two sets of oscillators vibrate alternately, forming a continuous unidirectional pressure gradient in the annular sealed gas cavity (1), which drives the high-pressure inert gas to circulate stably in the preset direction.

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