Integrated nanoprobe with cleaning and testing functions

Abstract

The invention relates to the technical field of semiconductor wafer testing, and particularly discloses an integrated nanoprobe with cleaning and testing functions, which comprises the following components: a fixed disc which is used for fixedly placing a semiconductor wafer; the test probe and the cleaning probe are respectively used for testing and cleaning a semiconductor wafer, the probe driving module is placed on the fixed disc, and the probe driving module is used for enabling the test probe and the cleaning probe to move in an X axis, a Y axis and a Z axis; the flat cable assembly is used for electrifying the probe driving module and acquiring an instruction; the scanning electron microscope is used for amplifying the semiconductor wafer and manually observing the relative positions of the test probe and the cleaning probe and the semiconductor wafer so as to adjust an input instruction of the probe driving module; and a micro-vibration cleaning assembly for improving the cleaning effect is arranged on the cleaning probe. The invention aims to solve the problem that an automatic solution for organically integrating pollution cleaning and probe testing is lacked in the prior art.

Description

Technical Field

[0001] This application relates to the field of semiconductor wafer testing technology, and specifically discloses an integrated nanoprobe with cleaning and testing functions. Background Technology

[0002] In precision technology fields such as nanomaterial characterization and semiconductor testing, nanoprobe testing technology has become one of the core means of material research and development and device quality control due to its high-resolution analysis capabilities of micro-area structure, mechanical properties and electrical characteristics. This technology obtains key performance parameters at the nanoscale through micro-area contact or near-field interaction between the probe and the sample surface, providing important data support for subsequent process optimization and performance improvement.

[0003] However, existing nanoprobe testing technologies face unavoidable contamination interference problems in practical applications, which severely restricts testing accuracy and result reliability. On the one hand, nanoprobe testing often needs to be carried out in a vacuum environment such as a scanning electron microscope (SEM). Impurities such as residual hydrocarbons inside the equipment are easily deposited on the sample surface under electron beam bombardment, forming a carbon contamination layer. On the other hand, during sample preparation, transfer, or storage, the sample surface may also adsorb contaminants such as dust and organic matter from the air. The scale of these contaminants is usually on the same order of magnitude as, or even smaller than, the micro-area of ​​the test target.

[0004] Please refer to the attached instruction manual. Figure 1 Under a scanning electron microscope (SEM), semiconductor wafers can be clearly seen to have impurities covering the test points, making it difficult for the test points to make contact with the nanoprobes used for testing.

[0005] Currently, there are significant limitations in methods for treating sample surface contamination: traditional overall cleaning methods, such as plasma cleaning or solvent cleaning, can remove large-scale surface contamination, but the procedures are complex and time-consuming, and may damage the microstructure or properties of the sample itself, making them particularly unsuitable for precise cleaning of localized micro-area contamination; while existing nanoprobe testing systems mostly use a single probe to complete the entire testing process. This probe is used to contact the sample for signal acquisition, but it cannot achieve targeted cleaning of contaminated areas, causing the contamination layer to directly affect the contact state between the probe and the sample surface, leading to problems such as test signal distortion and decreased positioning accuracy, and failing to meet the needs of high-precision micro-area testing.

[0006] Furthermore, existing technologies lack automated solutions that organically integrate contamination cleaning with probe testing. The cleaning steps and testing procedures are independent, increasing operational complexity, reducing testing efficiency, and potentially introducing new contamination or positioning errors due to human intervention. Therefore, achieving precise and non-destructive cleaning of micro-area contamination on sample surfaces at the nanoscale, and efficiently integrating the cleaning process with the probe testing procedure, has become a key technical challenge for improving the accuracy and automation level of nanoprobe testing. An innovative technical solution is urgently needed to address this issue. In view of this, the present invention provides an integrated nanoprobe with cleaning and testing functions to solve the aforementioned problems. Summary of the Invention

[0007] The purpose of this invention is to solve the problem of the lack of an automated solution in the prior art that organically integrates contamination cleaning and probe testing.

[0008] To achieve the above objectives, the present invention provides the following basic solution: An integrated nanoprobe with cleaning and testing functions comprises the following components: Fixed disk: Used for fixing and placing semiconductor wafers; Test probes and cleaning probes: Test probes and cleaning probes are used for semiconductor wafer testing and cleaning, respectively, with cleaning probes used before test probes; A probe driving module is placed on a fixed disk, and the probe driving module is used to move the test probe and the cleaning probe along the X-axis, Y-axis and Z-axis. Ribbon cable assembly: used for powering on the probe driver module and acquiring commands; Scanning electron microscope: used to magnify semiconductor wafers and for human observation of the relative positions of test probes and cleaning probes with the semiconductor wafer, thereby adjusting the input commands of the probe drive module; The cleaning probe is equipped with a micro-vibration cleaning component to improve the cleaning effect.

[0009] Furthermore, the probe driving module adopts the miBot series from Imina Technologies. The probe driving module has built-in X-axis piezoelectric ceramic actuators, Y-axis piezoelectric ceramic actuators, and Z-axis piezoelectric ceramic actuators. When a specific voltage is applied to each piezoelectric ceramic actuator, the probe driving module will generate controllable micro-expansion and contraction deformation. This micro-expansion and contraction deformation serves as the power source for the movement of the test probe and the cleaning probe.

[0010] Furthermore, the micro-vibration cleaning assembly includes a cantilever beam and a piezoelectric vibrator mounted on the cantilever beam. The driving voltage of the piezoelectric vibrator is provided by a probe driving module, and the non-contact end of the cleaning probe is fixed to the cantilever beam.

[0011] Furthermore, the piezoelectric vibrator is a MEMS piezoelectric vibrator.

[0012] Furthermore, it also includes a system that adaptively adjusts the vibration frequency of the piezoelectric oscillator based on the obstruction formed by impurities and dust encountered by the cleaning probe; The system includes: Optical detector: used to detect the deflection of the cantilever beam; PID controller: used to regulate the drive voltage of the piezoelectric resonator; Adaptive algorithm: used to enable piezoelectric vibrators to adaptively adjust their vibration frequency.

[0013] An adaptive adjustment algorithm for the vibration frequency of a piezoelectric oscillator using an integrated nanoprobe with cleaning and testing functions is also disclosed. This algorithm, characterized by the following steps: Step S01: Set the piezoelectric oscillator driving frequency to its resonant frequency. The driving voltage is set to a small initial value V0; Step S02: Measure the deflection of the cantilever beam using an optical detector. The deflection of the cantilever beam was calculated using the cantilever beam deflection formula. , This refers to the detected dust-blocking force or impurity-blocking force. Step S03: Calculate the inertial force generated by the piezoelectric oscillator. ; Step S04: Adjust the drive voltage using a PID controller to control the inertial force. Greater than or equal to X X is taken as 1.3-1.5; Step S05: Calculate inertial force and X The PID controller adjusts the drive voltage and fine-tunes the drive frequency of the piezoelectric vibrator based on the absolute error value 'a'. ; Step S06: Until When the value is 0, vibration stops.

[0014] The principle and effect of this solution are as follows: 1. Compared with existing technologies, this invention uses an independent cleaning probe to perform customized nano-scraping, which can precisely target and remove micro-contamination on the surface of semiconductor samples. Compared with traditional overall cleaning methods, it avoids unnecessary intervention in non-contaminated areas of the sample, and the scrubbing force, range, and number of strokes can be customized and adjusted. It can thoroughly remove nanoscale contaminants without damaging the microstructure and properties of the sample itself, effectively solving the core pain point of existing technologies that cannot accurately clean micro-contamination.

[0015] 2. Compared with existing technologies, this invention employs a dual-probe separation design of "clean probe + brand-new test probe." The cleaning probe is only responsible for removing contaminants, while the test probe remains brand new. This avoids problems such as residual contamination and wear on the probe surface caused by a single probe that integrates cleaning and testing, thus eliminating the risk of cross-interference of test results by contaminants from the source. Simultaneously, the test probe performs puncture and micro-area motion tests on the cleaned area after scratching, ensuring that the object being tested is the actual surface of the sample. This significantly improves the accuracy and repeatability of material characterization and semiconductor detection data at the nanoscale.

[0016] 3. Compared with existing technologies, the scratching parameters of this invention can be flexibly adjusted by the user according to the sample type and degree of contamination, meeting the needs of high-precision micro-area cleaning and adapting to testing requirements in different scenarios. Its core design is not limited to specific types of nanoprobes or detection devices, and can be widely applied to various material characterization and semiconductor detection scenarios that rely on nanoprobes, possessing strong practicality and compatibility. 4. Compared with existing technologies, the dual-probe module design does not require significant modifications to existing nanoprobe testing equipment. Functional integration can be achieved simply by adding a cleaning probe and optimizing the control software. The mechanical structure and control logic are simple, and the R&D and industrialization costs are controllable. Furthermore, the cleaning probe is reusable, and the test probe can be replaced as needed, reducing equipment usage and maintenance costs while ensuring testing accuracy, thus demonstrating promising prospects for industrial application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This image shows an electron microscope image of the impurity coverage of an integrated nanoprobe with cleaning and testing functions according to an embodiment of this application. Figure 2 This illustration shows a schematic diagram of an integrated nanoprobe with cleaning and testing functions proposed in an embodiment of this application; Figure 3 A schematic diagram of the micro-vibration cleaning component in an integrated nanoprobe with cleaning and testing functions, as proposed in an embodiment of this application, is shown. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] The reference numerals in the accompanying drawings include: fixed disk 1, semiconductor wafer 2, fixed groove 3, first probe drive module 4, cleaning probe 5, cantilever beam 501, piezoelectric vibrator 502, second probe drive module 6, and test probe 7.

[0021] Implementation, for example Figure 1 , Figure 2 and Figure 3 As shown: An integrated nanoprobe with cleaning and testing functions comprises the following components: Fixed disk 1: used for fixing and placing semiconductor wafer 2; Test probe 7 and cleaning probe 5: test probe 7 and cleaning probe 5 are used for testing and cleaning semiconductor wafer 2 respectively, and cleaning probe 5 is used before test probe 7; A probe driving module placed on a fixed disk 1 is used to test probe 7 and cleaning probe 5 to move along the X, Y, and Z axes; a ribbon cable assembly is used to power on the probe driving module and acquire commands; a scanning electron microscope is used to magnify the semiconductor wafer 2 and to manually observe the relative positions of the test probe 7 and cleaning probe 5 with the semiconductor wafer 2, thereby adjusting the input commands of the probe driving module. The cleaning probe 5 is equipped with a micro-vibration cleaning component to improve the cleaning effect.

[0022] like Figure 1 As shown, the probe driving module consists of a first probe driving module 4 and a second probe driving module 6, which independently drive the cleaning probe 5 and the test probe 7, respectively.

[0023] The probe driving module adopts the miBot series of Imina Technologies. The probe driving module has built-in X-axis piezoelectric ceramic actuators, Y-axis piezoelectric ceramic actuators and Z-axis piezoelectric ceramic actuators. When a specific voltage is applied to each piezoelectric ceramic actuator, the probe driving module will produce controllable micro-expansion and contraction deformation. The micro-expansion and contraction deformation serves as the power source for the movement of the test probe 7 and the cleaning probe 5.

[0024] It also includes independent controllers, which control the X-axis piezoelectric ceramic actuator, the Y-axis piezoelectric ceramic actuator, and the Z-axis piezoelectric ceramic actuator respectively. For the X-axis direction: driven by the X-axis piezoelectric ceramic actuator, the probe drive module moves horizontally by extension and retraction. For the Y-axis direction: driven by the Y-axis piezoelectric ceramic actuator of the probe drive module, the probe drive module moves horizontally by extension and retraction. The probe drive module has built-in upper and lower telescopic parts, and the test probe 7 and the cleaning probe 5 are both mounted on the upper and lower telescopic parts. For the Z-axis direction: driven by the Z-axis piezoelectric ceramic actuator, the upper and lower telescopic parts move vertically by extension and retraction.

[0025] Regarding the principle of test probe 7 testing semiconductor wafer 2: It utilizes the interaction between the test probe 7 and the semiconductor sample at the micro-nano scale, combined with a high-precision probe driving module, to convert the microscopic interaction signal into morphological, electrical, and mechanical characteristic parameters of the semiconductor. A detailed description is provided below, broken down by dimension: Information such as the lattice arrangement and surface defects of the semiconductor crystal is mainly obtained through the mechanical interaction between the probe and the sample: Probe-sample contact: When the probe tip approaches the semiconductor crystal surface, the probe undergoes a slight deformation under the action of van der Waals forces; High-precision scanning: Driven by the X / Y axes of the probe driving module, the probe scans point by point along the semiconductor surface; Simultaneously, the Z-axis drive adjusts the probe height in real time to maintain constant probe deformation; Signal conversion to morphology: The adjustment displacement of the Z-axis directly corresponds to the height change of the semiconductor surface. Finally, the height data of the scanned points are stitched together to form a crystal surface morphology map with nanometer-level resolution, clearly showing the lattice atomic arrangement, surface steps, and other structures of the semiconductor.

[0026] Electrical parameters of semiconductors, such as carrier concentration, doping distribution, and interface barriers, depend on the electrical interaction between the probe and the sample: Carrier Concentration Distribution (SCM): The probe and semiconductor surface are typically covered with an oxide layer to form a MOS capacitor structure. When a bias voltage is applied to the probe, a depletion layer forms on the semiconductor surface. The width of the depletion layer is negatively correlated with the carrier concentration. During scanning, the capacitance change of the MOS capacitor is detected by a high-frequency signal. Combined with bias voltage adjustment, the capacitance signal is converted into the carrier concentration distribution inside the semiconductor, which can be used to analyze the doping uniformity of the semiconductor. Surface Potential and Contact Barrier (SKPM): The contact potential difference between the probe and the semiconductor surface is determined by the difference in their work functions. During scanning, the probe voltage is adjusted through a feedback circuit to keep the tunneling current caused by the contact potential difference between the probe and the sample constant. The adjusted probe voltage value directly corresponds to the potential distribution on the semiconductor surface, reflecting the differences in semiconductor doping type, interface barrier height, and surface charge distribution.

[0027] The remaining mechanical property tests and crystal surface defect tests will not be elaborated upon in this embodiment. It is important to clarify that all tests must ensure that the probes and semiconductor wafer 2 are physically aligned, as described in the background section and appendix of the specification. Figure 1 As mentioned above, existing nanoprobe testing technologies face unavoidable contamination interference problems in practical applications, which severely restricts testing accuracy and result reliability. On the one hand, nanoprobe testing often needs to be carried out in a vacuum environment such as a scanning electron microscope (SEM). Impurities such as residual hydrocarbons inside the equipment are easily deposited on the sample surface under electron beam bombardment, forming a carbon contamination layer. On the other hand, during sample preparation, transfer, or storage, the sample surface may also adsorb dust, organic matter, and other contaminants from the air. The scale of these contaminants is usually on the same order of magnitude as, or even smaller than, the micro-area of ​​the test target.

[0028] Therefore, the cleaning process before semiconductor testing is crucial. To this end, this embodiment proposes a dual-probe technology improvement, in which the cleaning probe 5 and the test probe 7 are independent. Both the cleaning probe 5 and the test probe 7 are integrated based on the probe driving module. The cleaning probe 5 is used before the test probe 7. In order to improve the cleaning effect of the cleaning probe 5, this embodiment sets a micro-vibration cleaning component on the cleaning probe 5. The micro-vibration cleaning component changes the position of the impurities, so that the test point is exposed at that position, which is beneficial to the testing work of the test probe 7.

[0029] Regarding the micro-vibration cleaning assembly: The micro-vibration cleaning assembly includes a cantilever beam 501 and a piezoelectric vibrator 502 mounted on the cantilever beam 501. The driving voltage of the piezoelectric vibrator 502 is provided by a probe driving module. The non-contact end of the cleaning probe 5 is fixed to the cantilever beam 501. The piezoelectric vibrator 502 is a MEMS piezoelectric vibrator 502.

[0030] Control section of the micro-vibration cleaning component: It also includes a system that adaptively adjusts the vibration frequency of the piezoelectric vibrator 502 based on the obstruction force formed by the impurities and dust encountered by the cleaning probe 5; the system includes: an optical detector for detecting the deflection of the cantilever beam 501; a PID controller for adjusting the driving voltage of the piezoelectric vibrator 502; and an adaptive algorithm for realizing the adaptive adjustment of the vibration frequency of the piezoelectric vibrator 502.

[0031] An adaptive adjustment algorithm for the vibration frequency of an integrated nanoprobe with cleaning and testing functions for a piezoelectric oscillator 502 includes the following steps: Step S01: Set the driving frequency of the piezoelectric oscillator 502 to its resonant frequency. The driving voltage is set to a small initial value V0; Step S02: Measure the deflection of the cantilever beam 501 using an optical detector. The deflection formula of cantilever beam 501 was used to calculate... , The detected dust or impurity blocking force; Step S03: Calculate the inertial force generated by the piezoelectric vibrator 502. ; Step S04: Adjust the drive voltage using a PID controller to control the inertial force. Greater than or equal to X X is taken as 1.3-1.5; Step S05: Calculate the inertial force. and X The PID controller adjusts the drive voltage and fine-tunes the drive frequency of the piezoelectric vibrator 502 based on the absolute error value 'a'. Step S06: Until When the value is 0, vibration stops.

[0032] Specifically: First: When the cleaning probe 5 comes into contact with dust, the cantilever beam 501 will deflect. The amount of deflection can be used to calculate the resistance force. Wherein: the deflection of cantilever beam 501 is , The spring constant of cantilever beam 501 depends on the material of cantilever beam 501. This refers to the detected dust-blocking force or impurity-blocking force. Then: The inertial force generated by the oscillator's vibration is the driving force for cleaning, and it must be greater than the dust-adhesive force. The inertial force is determined by both the oscillator's amplitude and frequency, firstly, by the following formula: ; in, The strain of the piezoelectric material is proportional to the electric field strength, which is determined by the driving voltage and the thickness of the piezoelectric layer, representing the oscillator amplitude. Transverse piezoelectric strain constant of MEMS piezoelectric oscillator 502; The length and piezoelectric layer thickness of the MEMS piezoelectric oscillator 502 : Drive voltage of piezoelectric vibrator 502.

[0033] Then, the inertial force generated by the piezoelectric oscillator 502 was calculated. The formula is as follows: ; in: For the mass of the dust particle, the inertial force is proportional to the vibration acceleration, and the acceleration is... ; Solving the two formulas together, we get: ; Next: The algorithm target was set, inertial force. Greater than or equal to X X is 1.3, that is Greater than or equal to 1.3 1.3 is the margin coefficient to ensure that the adsorption force is overcome, and then the absolute error value a is set: The PID controller controls the output voltage. , The proportional, integral, and derivative coefficients need to be calibrated experimentally, and then the drive frequency is adaptively locked. , For frequency adjustment step size, This is a sign function, and the frequency is finely adjusted according to the error direction.

[0034] The execution process is as follows: The driving frequency of the piezoelectric oscillator 502 is set to its resonant frequency. The driving voltage is set to a small initial value V0; The deflection of cantilever beam 501 is measured using an optical detector. ,pass Measure the detected dust-blocking force or impurity-blocking force; Setting inertial force Greater than or equal to 1.3 ;pass get This refers to the inertial force generated by the piezoelectric vibrator 502, which is the cleaning force. Calculate the error 'a' using the formula Update drive voltage Through formula Fine-tuning To keep the oscillator in a resonant state; Repeat steps 2-4 until... When the value is 0, vibration stops.

[0035] When using this invention: First step, such as Figure 2 As shown, the semiconductor wafer 2 is placed at the center of the fixed disk 1. The fixed disk 1 has a fixed groove 3 at its center, which is used to place the semiconductor wafer 2. The second step involves prioritizing the use of cleaning probe 5. The micro-vibration cleaning component of cleaning probe 5 removes impurities from the wafer through vibration. Impurities on the wafer, such as... Figure 1 As shown in the electron microscope, impurities can affect the contact between the test probe 7 and the wafer. The third step involves cleaning the wafer by vibrating the probe 5 to remove impurities, and then using the test probe 7 to test the wafer.

[0036] This device addresses the lack of an automated solution in existing technologies that organically integrates contamination cleaning with probe testing.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. An integrated nanoprobe with cleaning and testing functions, characterized in that, It includes the following components: Fixed disk: Used for fixing and placing semiconductor wafers; Test probes and cleaning probes: Test probes and cleaning probes are used for semiconductor wafer testing and cleaning, respectively, with cleaning probes used before test probes; A probe driving module is placed on a fixed disk, and the probe driving module is used to move the test probe and the cleaning probe along the X-axis, Y-axis and Z-axis. Ribbon cable assembly: used for powering on the probe driver module and acquiring commands; Scanning electron microscope: used to magnify semiconductor wafers and for human observation of the relative positions of test probes and cleaning probes with the semiconductor wafer, thereby adjusting the input commands of the probe drive module; The cleaning probe is equipped with a micro-vibration cleaning component to improve the cleaning effect.

2. The integrated nanoprobe with cleaning and testing functions according to claim 1, characterized in that, The probe driving module adopts the miBot series of Imina Technologies. The probe driving module has built-in X-axis piezoelectric ceramic actuators, Y-axis piezoelectric ceramic actuators and Z-axis piezoelectric ceramic actuators. When a specific voltage is applied to each piezoelectric ceramic actuator, the probe driving module will produce controllable micro-expansion and contraction deformation. The micro-expansion and contraction deformation serves as the power source for the movement of the test probe and the cleaning probe.

3. The integrated nanoprobe with cleaning and testing functions according to claim 2, characterized in that, It also includes independent controllers, which control the X-axis piezoelectric ceramic actuator, the Y-axis piezoelectric ceramic actuator, and the Z-axis piezoelectric ceramic actuator respectively. For the X-axis direction: driven by the X-axis piezoelectric ceramic actuator, the probe drive module moves horizontally by extension and retraction. For the Y-axis direction: driven by the Y-axis piezoelectric ceramic actuator of the probe drive module, the probe drive module moves horizontally by extension and retraction. The probe drive module has built-in upper and lower telescopic parts, and the test probe and the cleaning probe are both mounted on the upper and lower telescopic parts. For the Z-axis direction: driven by the Z-axis piezoelectric ceramic actuator, the upper and lower telescopic parts move vertically by extension and retraction.

4. An integrated nanoprobe with cleaning and testing functions according to claim 3, characterized in that, The micro-vibration cleaning assembly includes a cantilever beam and a piezoelectric vibrator mounted on the cantilever beam. The driving voltage of the piezoelectric vibrator is provided by a probe driving module, and the non-contact end of the cleaning probe is fixed to the cantilever beam.

5. An integrated nanoprobe with cleaning and testing functions according to claim 4, characterized in that, The piezoelectric vibrator is a MEMS piezoelectric vibrator.

6. An integrated nanoprobe with cleaning and testing functions according to claim 4, characterized in that, It also includes a system that adaptively adjusts the vibration frequency of the piezoelectric vibrator based on the obstruction force formed by impurities and dust encountered by the cleaning probe; The system includes: Optical detector: used to detect the deflection of the cantilever beam; PID controller: used to regulate the drive voltage of the piezoelectric resonator; Adaptive algorithm: used to enable piezoelectric vibrators to adaptively adjust their vibration frequency.

7. An adaptive adjustment algorithm for the vibration frequency of a piezoelectric oscillator based on an integrated nanoprobe with cleaning and testing functions according to claim 6, characterized in that, Includes the following steps: Step S01: Set the piezoelectric oscillator driving frequency to its resonant frequency. The driving voltage is set to a small initial value V0; Step S02: Measure the deflection of the cantilever beam using an optical detector. The deflection of the cantilever beam was calculated using the cantilever beam deflection formula. , The detected dust-blocking force or impurity-blocking force; Step S03: Calculate the inertial force generated by the piezoelectric oscillator. ; Step S04: Adjust the drive voltage using a PID controller to control the inertial force. Greater than or equal to X X is taken as 1.3-1.5; Step S05: Calculate inertial force and X The PID controller adjusts the drive voltage and fine-tunes the drive frequency of the piezoelectric vibrator based on the absolute error value 'a'. ; Step S06: Until When the value is 0, vibration stops.

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