A production process of piezoelectric thin film capable of improving dielectric performance

Abstract

The application discloses a piezoelectric film production process capable of improving dielectric performance, and particularly relates to the field of functional material preparation technology. By analyzing the dielectric coefficient of the piezoelectric film and the influence of the process in the processing link on the dielectric coefficient of the piezoelectric film, it can be concluded that the crystalline phase intrinsic dielectric property of the piezoelectric film and the size effect of the piezoelectric film are the main change basis of the dielectric property. According to the analysis result, the initial film preparation, uniaxial stretching, high-voltage polarization, magnetron sputtering and other preparation processes are carried out. The parameters of each process step are explored, the PVDF sensitive material is packaged into a sensor, and the detection of the very important piezoelectric coefficient parameter of the sensor product is carried out. The static piezoelectric coefficient d 33 reaches 13.1 PC / N, which meets the use requirement, an engineering product capable of practical engineering matching is obtained, the automatic processing effect of the piezoelectric film is improved, and the dielectric property of the piezoelectric film is guaranteed while the processing efficiency is ensured.

Description

Technical Field

[0001] This invention relates to the field of functional material preparation technology, and more specifically, to a piezoelectric thin film production process that can improve dielectric properties. Background Technology

[0002] Polyvinylidene fluoride (PVDF) is a very commonly used piezoelectric material due to its excellent piezoelectric properties, including good flexibility, high mechanical strength, easy acoustic impedance matching, wide frequency response range, and resistance to chemical and oil corrosion. It is widely used in industrial applications such as laser power meters and reflection detectors, as well as in the medical field for heart rate detectors and sensors.

[0003] PVDF piezoelectric films are widely used in various industries, but domestic products have not yet been developed and are limited to the laboratory stage. A large number of imports are still needed. Therefore, actual production is often still at the small-scale research level, which makes it difficult to industrialize production when there is a large demand. As a result, the processing of PVDF piezoelectric films and the enhancement of their dielectric properties are difficult to meet the requirements, thus limiting the processing quality of PVDF piezoelectric films. Summary of the Invention

[0004] To overcome the aforementioned deficiencies of the prior art, the present invention provides a piezoelectric film production process that can improve dielectric properties. The technical problem to be solved by the present invention is that actual production is often still at the level of small-scale research, which makes it difficult to industrialize production when there is a large demand. This makes it difficult to meet the requirements for processing PVDF piezoelectric films and strengthening their dielectric properties, thus limiting the processing quality of PVDF piezoelectric films.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a piezoelectric thin film manufacturing process capable of improving dielectric properties, comprising the following preparation methods:

[0006] S1. Initial film preparation: First, PVDF raw material particles are ground into PVDF powder and then dissolved in dimethylformamide solution to prepare a PVDF solution with a volume concentration of 5%-15%. Then, after two process steps of stirring and filtration and vacuum degassing, the film is dried in a constant temperature oven to form a PVDF initial film of about 100μm.

[0007] S2. Uniaxial stretching: The prepared PVDF film is subjected to uniaxial stretching polarization. The initial PVDF film prepared by the casting method is cut into the required shape, marked, and the film is placed on the fixture and put into the stretching machine. The initial film is stretched at a uniform speed using a temperature controller. The stretching length is the ratio of the initial thickness to the required thickness. Under the tension, it is then fixed at a constant temperature to form the required PVDF film.

[0008] S3. High-voltage polarization: Uniaxial stretching greatly increases the proportion of β crystal content. Then, high-voltage polarization is used to orient the β crystal. A high-voltage power supply is used to apply electricity to the surface of the clamp holding the PVDF film through electrodes. A polarization field is formed on the surface of the PVDF film. The polarization temperature is controlled by a temperature control heating device to complete the polarization.

[0009] S4. Sputtering Electrode: Since the PVDF piezoelectric film is an insulator, a metal electrode needs to be deposited on the piezoelectric film as a conductive electrode, and the electrode is fabricated using a magnetron sputtering method.

[0010] As a further aspect of the present invention: the stirring and mixing step in S1 is performed using a magnetic stirrer, the stirring time is 0.5 hours, and the stirring speed is 300 r / min.

[0011] As a further aspect of the present invention: the internal temperature of the temperature controller in S2 is maintained within the range of 60-40℃, and the initial PVDF film is stretched at a speed of 5mm / min.

[0012] As a further aspect of the present invention: the specific processing steps for high-voltage polarization in S3 include:

[0013] First, the equipment was drawn to 10. -2 Pa, turn on the heating device, and continue evacuating to 10. -4 Apply a polarizing electric field of 100-120V / m3 at Pa, and after polarizing for 30-60 minutes, turn off the heating and electric field.

[0014] As a further aspect of the present invention: the sputtering electrode processing step in S4 includes:

[0015] S401, Cleaning:

[0016] PVDF film cleaning:

[0017] Add tap water to the ultrasonic machine, place a beaker in the ultrasonic machine and pour in anhydrous ethanol, put the polarized PVDF film into the beaker, set the ultrasonic time, prepare two more beakers, pour in deionized water, place the PVDF film after ultrasonication with anhydrous ethanol in the first deionized beaker, ultrasonicate for the specified time, and then put it into the second deionized beaker for final ultrasonic treatment.

[0018] Mask cleaning: Put tap water into the ultrasonic machine, place the beaker in the ultrasonic machine and pour in acetone, put the mask into the beaker, set the ultrasonic time to 15 minutes, and repeat the PVDF film cleaning steps.

[0019] Substrate cleaning: First, clean with a mixture of sulfuric acid and hydrogen peroxide for 15 minutes, then rinse thoroughly with deionized water. Then clean with the mixture again for 15 minutes, and rinse thoroughly with deionized water.

[0020] S402, Fixed:

[0021] The cut area is prepared by using a mask. During magnetron sputtering, two masks are needed to place the PVDF film in the middle. The positioning pattern areas in the two masks are completely overlapped. The mask is then placed on the magnetron sputtering sample stage.

[0022] S403, sputtering growth:

[0023] Vacuum degree is 10 -3 -lO -5 The gas pressure is 1-5 Pa, the sputtering power is 50-120 W, the growth time is 1-3 min (Pt) and 5-10 min (Au), the enhancement adsorption layer is 300-500 angstroms, and the conductive gold layer is 1500-3000 angstroms. After sputtering, the film is taken out and the surface is observed to be flat. Then the sample is placed in the sample stage in reverse and mechanically cut along the ungrown metal area covered by the mask. The cutting is done by a dicing machine instead of manual cutting.

[0024] As a further aspect of the present invention: the first ultrasound time, the second ultrasound time, and the third ultrasound time in S401 are all set to 15 minutes.

[0025] As a further aspect of the present invention: the constant temperature chamber in S1 is placed for 1 hour, and the constant temperature inside the constant temperature chamber is 200-300℃.

[0026] As a further aspect of the present invention: the mixture in the S401 substrate cleaning process is prepared by mixing hydrochloric acid, hydrogen peroxide and deionized water.

[0027] As a further aspect of the present invention: the dielectric properties of the piezoelectric film mainly depend on two aspects: one is the intrinsic dielectric property of the crystalline phase of the piezoelectric film, and the other is the size effect of the PVDF piezoelectric film. The relationship between the dielectric effect and the applied force can be obtained through the following formula:

[0028]

[0029] In the formula, Q represents the charge generated by the PVDF piezoelectric film, and d 33 ε is the piezoelectric coefficient of the PVDF film, F is the force acting on the PVDF piezoelectric film, U is the voltage generated by the PVDF piezoelectric film, C is the capacitance of the PVDF piezoelectric film, ε is the effective area of ​​the PVDF piezoelectric film, S is the thickness of the piezoelectric film, and h is the dielectric constant of the PVDF piezoelectric film.

[0030] As a further aspect of the present invention: the size effect of the piezoelectric film specifically includes: the thickness change of the PVDF piezoelectric film will generate dielectric properties, and the premise for the generation of such piezoelectric properties is that the dipole is rigid. When the thickness of the film increases, the induced charge on the film surface will decrease, and conversely, the induced charge will increase. These two aspects directly affect the dielectric constant of the film.

[0031] Furthermore, a crucial parameter for piezoelectric materials is the dielectric constant, which reflects the energy conversion efficiency of the piezoelectric material. The higher the dielectric constant, the higher the energy conversion efficiency.

[0032] The trimmed PVDF sensitive element is passed through a quasi-static d... 33 The tester measures the dielectric constant of the sensing element. Using tweezers, the sensing element is placed at the upper and lower electrodes of the testing equipment. The pressure knob is slowly tightened until the sensing element is clamped. The test value is recorded as d after it stabilizes. 33 value.

[0033] The beneficial effects of this invention are as follows: By analyzing the dielectric constant of piezoelectric thin films and the influence of the processing steps on the dielectric constant of piezoelectric thin films, this invention can conclude that the intrinsic dielectric properties of the crystalline phase and the size effect of the piezoelectric thin film are the main factors affecting the dielectric properties. Furthermore, by using quasi-static d-type processing on the cut PVDF sensitive units... 33 The tester measures the dielectric constant of the sensing element. Using tweezers, the sensing element is placed at the upper and lower electrodes of the testing equipment. The pressure knob is slowly tightened until the sensing element is clamped. The test value is recorded as d after it stabilizes. 33 Based on the analysis results, the following fabrication processes were carried out: initial thin film preparation, uniaxial stretching, high-pressure polarization, and magnetron sputtering. The parameters for each process step were explored, and the PVDF sensitive material was encapsulated into a sensor. The piezoelectric coefficient, a crucial parameter for the sensor product, was measured, and its static piezoelectric coefficient d... 33 Reaching 13.1 PC / N meets the usage requirements, resulting in an engineered product that can be used in actual engineering projects. This improves the automated processing effect of piezoelectric films and ensures the dielectric properties of the piezoelectric films while maintaining processing efficiency. Attached Figure Description

[0034] Figure 1 This is a process flow diagram of the present invention;

[0035] Figure 2 This is a diagram illustrating the manufacturing process of the thin film of the present invention;

[0036] Figure 3 This is a process flow diagram of the internal polarization of the present invention;

[0037] Figure 4This is a diagram illustrating the process steps for internal polarization in this invention.

[0038] Figure 5 This is a process flow diagram of the cleaning steps of the present invention. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] like Figure 1-5 As shown, the present invention provides a piezoelectric thin film manufacturing process that can improve dielectric properties, including the following preparation method:

[0042] S1. Initial film preparation: First, PVDF raw material particles are ground into PVDF powder and then dissolved in dimethylformamide solution to prepare a PVDF solution with a volume concentration of 5%-15%. Then, after two process steps of stirring and filtration and vacuum degassing, the film is dried in a constant temperature oven to form a PVDF initial film of about 100μm.

[0043] S2. Uniaxial stretching: The prepared PVDF film is subjected to uniaxial stretching polarization. The initial PVDF film prepared by the casting method is cut into the required shape, marked, and the film is placed on the fixture and put into the stretching machine. The initial film is stretched at a uniform speed using a temperature controller. The stretching length is the ratio of the initial thickness to the required thickness. Under the tension, it is then fixed at a constant temperature to form the required PVDF film.

[0044] S3. High-voltage polarization: Uniaxial stretching greatly increases the proportion of β crystal content. Then, high-voltage polarization is used to orient the β crystal. A high-voltage power supply is used to apply electricity to the surface of the clamp holding the PVDF film through electrodes. A polarization field is formed on the surface of the PVDF film. The polarization temperature is controlled by a temperature control heating device to complete the polarization.

[0045] S4. Sputtering Electrode: Since the PVDF piezoelectric film is an insulator, a metal electrode needs to be deposited on the piezoelectric film as a conductive electrode, and the electrode is fabricated using a magnetron sputtering method.

[0046] In step S1, a magnetic stirrer is used for mixing. The mixing time is 0.5 hours and the stirring speed is 300 r / min.

[0047] The internal temperature of the temperature controller in S2 is maintained within the range of 40-60℃, and the initial PVDF film is stretched at a speed of 5mm / min.

[0048] The specific processing steps for high-voltage polarization in S3 include:

[0049] First, the equipment was drawn to 10. -2 Pa, turn on the heating device, and continue evacuating to 10. -4 Apply a polarizing electric field of 100-120V / m3 at Pa, and after polarizing for 30-60 minutes, turn off the heating and electric field.

[0050] The sputtering electrode fabrication steps in S4 include:

[0051] S401, Cleaning:

[0052] PVDF film cleaning:

[0053] Add tap water to the ultrasonic machine, place a beaker in the ultrasonic machine and pour in anhydrous ethanol, put the polarized PVDF film into the beaker, set the ultrasonic time, prepare two more beakers, pour in deionized water, place the PVDF film after ultrasonication with anhydrous ethanol in the first deionized beaker, ultrasonicate for the specified time, and then put it into the second deionized beaker for final ultrasonic treatment.

[0054] Mask cleaning: Put tap water into the ultrasonic machine, place the beaker in the ultrasonic machine and pour in acetone, put the mask into the beaker, set the ultrasonic time to 15 minutes, and repeat the PVDF film cleaning steps.

[0055] Substrate cleaning: First, clean with a mixture of sulfuric acid and hydrogen peroxide for 15 minutes, then rinse thoroughly with deionized water. Then clean with the mixture again for 15 minutes, and rinse thoroughly with deionized water.

[0056] S402, Fixed:

[0057] The cut area is prepared by using a mask. During magnetron sputtering, two masks are needed to place the PVDF film in the middle. The positioning pattern areas in the two masks are completely overlapped. The mask is then placed on the magnetron sputtering sample stage.

[0058] S403, sputtering growth:

[0059] Vacuum degree is 10 -3 -lO -5The gas pressure is 1-5 Pa, the sputtering power is 50-120 W, the growth time is 1-3 min (Pt) and 5-10 min (Au), the enhancement adsorption layer is 300-500 angstroms, and the conductive gold layer is 1500-3000 angstroms. After sputtering, the film is taken out and the surface is observed to be flat. Then the sample is placed in the sample stage in reverse and mechanically cut along the ungrown metal area covered by the mask. The cutting is done by a dicing machine instead of manual cutting.

[0060] In S401, the time for the first, second, and third ultrasounds is set to 15 minutes.

[0061] The constant temperature chamber in S1 is placed for 1 hour, and the internal temperature of the constant temperature chamber is 200-300℃.

[0062] The cleaning solution for S401 substrate is made by mixing hydrochloric acid, hydrogen peroxide, and deionized water.

[0063] The dielectric properties of piezoelectric thin films mainly depend on two aspects: the intrinsic dielectric properties of the crystalline phase of the piezoelectric thin film and the size effect of the PVDF piezoelectric thin film. The relationship between the dielectric effect and the applied force can be obtained through the following formula:

[0064]

[0065] In the formula, Q represents the charge generated by the PVDF piezoelectric film, and d 33 ε is the piezoelectric coefficient of the PVDF film, F is the force acting on the PVDF piezoelectric film, U is the voltage generated by the PVDF piezoelectric film, C is the capacitance of the PVDF piezoelectric film, S is the effective area of ​​the PVDF piezoelectric film, h is the thickness of the piezoelectric film, and ε is the dielectric constant of the PVDF piezoelectric film.

[0066] The size effect of piezoelectric films specifically includes: the thickness variation of PVDF piezoelectric films generates dielectric properties, and the premise for this piezoelectricity is that the dipole is rigid. When the thickness of the film increases, the induced charge on the film surface decreases, and vice versa. These two aspects directly affect the dielectric constant of the film.

[0067] A crucial parameter for piezoelectric materials is the dielectric constant, which reflects the energy conversion efficiency of the material. The higher the dielectric constant, the higher the energy conversion efficiency.

[0068] The trimmed PVDF sensitive element is passed through a quasi-static d... 33 The tester measures the dielectric constant of the sensing element. Using tweezers, the sensing element is placed at the upper and lower electrodes of the testing equipment. The pressure knob is slowly tightened until the sensing element is clamped. The test value is recorded as d after it stabilizes. 33 value.

[0069] Example 2

[0070] A piezoelectric thin film manufacturing process that can improve dielectric properties includes the following preparation method:

[0071] S1. Initial film preparation: First, PVDF raw material particles are ground into PVDF powder and then dissolved in dimethylformamide solution to prepare a PVDF solution with a volume concentration of 5%-15%. Then, after two process steps of stirring and filtration and vacuum degassing, the film is dried in a constant temperature oven to form a PVDF initial film of about 100μm.

[0072] S2. Uniaxial stretching: The prepared PVDF film is subjected to uniaxial stretching polarization. The initial PVDF film prepared by the casting method is cut into the required shape, marked, and the film is placed on the fixture and put into the stretching machine. The initial film is stretched at a uniform speed using a temperature controller. The stretching length is the ratio of the initial thickness to the required thickness. Under the tension, it is then fixed at a constant temperature to form the required PVDF film.

[0073] S3. High-voltage polarization: Uniaxial stretching greatly increases the proportion of β crystal content. Then, high-voltage polarization is used to orient the β crystal. A high-voltage power supply is used to apply electricity to the surface of the clamp holding the PVDF film through electrodes. A polarization field is formed on the surface of the PVDF film. The polarization temperature is controlled by a temperature control heating device to complete the polarization.

[0074] S4. Sputtering Electrode: Since the PVDF piezoelectric film is an insulator, a metal electrode needs to be deposited on the piezoelectric film as a conductive electrode, and the electrode is fabricated using a magnetron sputtering method.

[0075] In step S1, a magnetic stirrer is used for mixing. The mixing time is 0.5 hours and the stirring speed is 300 r / min.

[0076] The internal temperature of the temperature controller in S2 is maintained within the range of 40-60℃, and the initial PVDF film is stretched at a speed of 5mm / min.

[0077] The specific processing steps for high-voltage polarization in S3 include:

[0078] First, the equipment was drawn to 10. -2 Pa, turn on the heating device, and continue evacuating to 10. -4 Apply a polarizing electric field of 100-120V / m3 at Pa, and after polarizing for 30-60 minutes, turn off the heating and electric field.

[0079] The sputtering electrode fabrication steps in S4 include:

[0080] S401, Cleaning:

[0081] PVDF film cleaning:

[0082] Add tap water to the ultrasonic machine, place a beaker in the ultrasonic machine and pour in anhydrous ethanol, put the polarized PVDF film into the beaker, set the ultrasonic time, prepare two more beakers, pour in deionized water, place the PVDF film after ultrasonication with anhydrous ethanol in the first deionized beaker, ultrasonicate for the specified time, and then put it into the second deionized beaker for final ultrasonic treatment.

[0083] Mask cleaning: Put tap water into the ultrasonic machine, place the beaker in the ultrasonic machine and pour in acetone, put the mask into the beaker, set the ultrasonic time to 15 minutes, and repeat the PVDF film cleaning steps.

[0084] Substrate cleaning: First, clean with a mixture of sulfuric acid and hydrogen peroxide for 15 minutes, then rinse thoroughly with deionized water. Then clean with the mixture again for 15 minutes, and rinse thoroughly with deionized water.

[0085] S402, Fixed:

[0086] The cut area is prepared by using a mask. During magnetron sputtering, two masks are needed to place the PVDF film in the middle. The positioning pattern areas in the two masks are completely overlapped. The mask is then placed on the magnetron sputtering sample stage.

[0087] S403, sputtering growth:

[0088] Vacuum degree is 10 -3 -lO -5 The gas pressure is 1-5 Pa, the sputtering power is 50-120 W, the growth time is 1-3 min (Pt) and 5-10 min (Au), the enhancement adsorption layer is 300-500 angstroms, and the conductive gold layer is 1500-3000 angstroms. After sputtering, the film is taken out and the surface is observed to be flat. Then the sample is placed in the sample stage in reverse and mechanically cut along the ungrown metal area covered by the mask. The cutting is done by a dicing machine instead of manual cutting.

[0089] In S401, the time for the first, second, and third ultrasounds is set to 15 minutes.

[0090] The constant temperature chamber in S1 is placed for 1 hour, and the internal temperature of the constant temperature chamber is 200-300℃.

[0091] The cleaning solution for S401 substrate is made by mixing hydrochloric acid, hydrogen peroxide, and deionized water.

[0092] The dielectric properties of piezoelectric thin films mainly depend on two aspects: the intrinsic dielectric properties of the crystalline phase of the piezoelectric thin film and the size effect of the PVDF piezoelectric thin film. The relationship between the dielectric effect and the applied force can be obtained through the following formula:

[0093]

[0094] In the formula, Q represents the charge generated by the PVDF piezoelectric film, and d 33 ε is the piezoelectric coefficient of the PVDF film, F is the force acting on the PVDF piezoelectric film, U is the voltage generated by the PVDF piezoelectric film, C is the capacitance of the PVDF piezoelectric film, S is the effective area of ​​the PVDF piezoelectric film, h is the thickness of the piezoelectric film, and ε is the dielectric constant of the PVDF piezoelectric film.

[0095] The size effect of piezoelectric films specifically includes: the thickness variation of PVDF piezoelectric films generates dielectric properties, and the premise for this piezoelectricity is that the dipole is rigid. When the thickness of the film increases, the induced charge on the film surface decreases, and vice versa. These two aspects directly affect the dielectric constant of the film.

[0096] Conclusions: By analyzing the dielectric constant of piezoelectric thin films and the influence of processing steps on the dielectric constant, it can be concluded that the intrinsic dielectric properties of the crystalline phase and the size effect of the piezoelectric thin film are the main factors influencing its dielectric characteristics. Based on the analysis results, preparation processes including initial film preparation, uniaxial stretching, high-voltage polarization, and magnetron sputtering were carried out. The parameters of each process step were explored, and PVDF sensitive material was used for sensor encapsulation. The piezoelectric coefficient, a crucial parameter for sensor products, was measured, and its static piezoelectric coefficient d was determined. 33 Reaching 13.1 PC / N meets the usage requirements, resulting in an engineered product that can be used in actual engineering projects. This improves the automated processing effect of piezoelectric films and ensures the dielectric properties of the piezoelectric films while maintaining processing efficiency.

[0097] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0098] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A piezoelectric thin film manufacturing process capable of improving dielectric properties, characterized in that, The preparation methods include the following: S1. Initial film preparation: First, PVDF raw material particles are ground into PVDF powder and then dissolved in dimethylformamide solution to prepare a PVDF solution with a volume concentration of 5%-15%. Then, the solution is stirred with a magnetic stirrer, filtered, and vacuum degassing process. The stirring time is 0.5h and the stirring speed is 300r / min. Finally, the solution is dried in a constant temperature oven to form a PVDF initial film of about 100μm. S2. Uniaxial stretching: The prepared PVDF film is subjected to uniaxial stretching polarization. The initial PVDF film prepared by casting is cut into the required shape, marked, and then placed on a fixture and put into a stretching machine. The temperature is maintained within the range of 40-60℃ using a temperature controller. The initial film is stretched at a uniform speed of 5mm / min. The stretching length is the ratio of the initial thickness to the required thickness. Under the tension, the film is then fixed at a constant temperature to form the required PVDF film. S3, High-voltage polarization: Uniaxial stretching significantly increases the proportion of β-crystal content, followed by high-voltage polarization to orient the β-crystals. First, the equipment is drawn to 10... -2 Pa, turn on the heating device, and continue evacuating to 10. -4 Apply a polarization electric field of 100-120V / m³ to the PVDF film, polarize for 30-60 minutes, then turn off the heating and electric field. Use a high-voltage power supply to apply electricity to the surface of the clamp holding the PVDF film through the electrodes. A polarization field is formed on the surface of the PVDF film. The polarization temperature is controlled by a temperature-controlled heating device to complete the polarization. S4. Sputtering Electrode: Since the PVDF piezoelectric film is an insulator, a metal electrode needs to be deposited on the piezoelectric film as a conductive electrode, and the electrode is fabricated using a magnetron sputtering method.

2. The piezoelectric thin film manufacturing process according to claim 1, characterized in that: The sputtering electrode processing step in S4 includes: S401, Cleaning: PVDF film cleaning: Add tap water to the ultrasonic machine, place a beaker in the ultrasonic machine and pour in anhydrous ethanol, put the polarized PVDF film into the beaker, set the ultrasonic time, prepare two more beakers, pour in deionized water, put the PVDF film after ultrasonication with anhydrous ethanol into the first deionized beaker, ultrasonicate for the specified time, and then put it into the second deionized beaker for final ultrasonic treatment. Mask cleaning: Put tap water into the ultrasonic machine, place the beaker in the ultrasonic machine and pour in acetone, put the mask into the beaker, set the ultrasonic time to 15 minutes, and repeat the PVDF film cleaning steps. Substrate cleaning: First, clean with a mixture of sulfuric acid and hydrogen peroxide for 15 minutes, then rinse thoroughly with deionized water. Then clean with the mixture for 15 minutes, and rinse thoroughly with deionized water. S402, Fixed: The cut area is prepared by using a mask. During magnetron sputtering, two masks are needed to place the PVDF film in the middle. The positioning pattern areas in the two masks are completely overlapped. The mask is then placed on the magnetron sputtering sample stage. S403, sputtering growth: Vacuum degree is 10 -3 -lO -5 The gas pressure is 1-5 Pa, the sputtering power is 50-120 W, the growth time is 1-3 min (Pt) and 5-10 min (Au), the enhancement adsorption layer is 300-500 angstroms of titanium, and the conductive gold layer is 1500-3000 angstroms of gold. After sputtering, the film is taken out and the surface is observed to be flat. Then the sample is placed in the sample stage in reverse and mechanically cut along the ungrown metal area covered by the mask. The cutting is done by a dicing machine instead of manual cutting.

3. The piezoelectric thin film production process according to claim 2, characterized in that: In S401, the time for the first, second, and third ultrasounds is set to 15 minutes.

4. The piezoelectric thin film production process capable of improving dielectric properties according to claim 2, characterized in that: The constant temperature chamber in S1 is placed for 1 hour, and the internal temperature of the constant temperature chamber is 200-300℃.

5. The piezoelectric thin film manufacturing process according to claim 2, characterized in that: The cleaning solution for the S401 substrate is made by mixing hydrochloric acid, hydrogen peroxide, and deionized water.

6. The piezoelectric thin film manufacturing process according to claim 1, characterized in that: The dielectric properties of the piezoelectric film mainly depend on two aspects: first, the intrinsic dielectric property of the crystalline phase of the piezoelectric film; and second, the size effect of the PVDF piezoelectric film. The relationship between the dielectric effect and the applied force can be obtained through the following formula: In the formula The charge generated by the PVDF piezoelectric thin film, The piezoelectric coefficient of the thin film. The force acting on the PVDF piezoelectric film, The voltage generated by the PVDF piezoelectric film. Let S be the capacitance of the PVDF piezoelectric film, S be the effective area of ​​the PVDF piezoelectric film, h be the thickness of the piezoelectric film, and ε be the dielectric constant of the PVDF piezoelectric film.

7. The piezoelectric thin film manufacturing process according to claim 6, characterized in that: The size effect of the piezoelectric film specifically includes: the thickness change of the PVDF piezoelectric film will generate dielectric properties, and the premise for the generation of this piezoelectricity is that the dipole is rigid. When the thickness of the film increases, the induced charge on the film surface will decrease, and vice versa.

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