Preparation method of driving induction device based on piezoelectric film

Abstract

The invention discloses a preparation method of a driving induction device based on a piezoelectric film, and relates to the technical field of semiconductors. A first electrode layer, an induction / driving layer, a second electrode layer and a vibration function layer are etched at the same time; and an overlay error does not need to be considered in the whole etching process. Besides, the etching penetrates through the whole device layer at the same time, so that the etching selection ratio of different materials does not need to be considered, and the optimal etching perpendicularity can be obtained by selecting a physical bombardment mode such as IBE and the like. The performance of the driving induction device manufactured through the method is closer to the ideal design performance, and larger redundancy is reserved for process errors.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a method for fabricating a piezoelectric thin film-based driving sensing device. Background Technology

[0002] The structure of the driving sensing device is as follows Figure 1 As shown, the device layer, from bottom to top, includes a vibration functional layer 2, a second electrode layer 5, a sensing / driving layer 3, and a first electrode layer 4. The electrode layers are made of conductive materials, the sensing / driving layer is a piezoelectric thin film, and the vibration functional layer is made of single-crystal silicon. When etching the device layer, in addition to patterning each layer to achieve its function, a displacement / vibration structure 9 also needs to be formed. Traditional processes etch according to the different properties of each material layer, such as using ICP (Inductively Coupled Plasma) or RIE (Reactive Ion Etching). Since the displacement / vibration structure 9 penetrates the device layer, additional compensation is needed for its overlay accuracy and the perpendicularity of each layer during the process. Therefore, a larger minimum linewidth is required, resulting in poor resistance to processing errors and a low overall yield. Summary of the Invention

[0003] To overcome the shortcomings of the prior art, the present invention provides a method for fabricating a driving sensing device based on a piezoelectric thin film, which solves the problem that the prior art requires additional compensation for the overlay accuracy of the displacement / vibration structure and the perpendicularity of each layer, thus requiring a larger minimum linewidth, resulting in poor resistance to processing errors and low overall yield.

[0004] To achieve the above objectives, the present invention adopts the following technical solution, including: A method for fabricating a piezoelectric thin film-based driving sensing device includes the following steps: A vibration functional layer is prepared and bonded to a substrate layer; A second electrode layer, a sensing / driving layer, and a first electrode layer are sequentially formed on the vibration functional layer. The first electrode layer, the sensing / driving layer, and the second electrode layer are sequentially patterned. Simultaneous etching of the first electrode layer, the sensing / driving layer, the second electrode layer, and the vibration functional layer forms a displacement / vibration structure; A third wafer is bonded over the first electrode layer, and an external electrode is formed on the top of the third wafer.

[0005] Preferably, the preparation of the vibration functional layer includes the following steps: At least one surface of the first wafer is doped, and the doped area is annealed.

[0006] Preferably, if frequency trimming of the driving sensing device is required, the substrate layer is made of monocrystalline silicon material to allow laser transmission, and employs one or more of the following methods: Prior to bonding, a frequency trimming layer is deposited at the bottom of the vibration functional layer; or The frequency adjustment is achieved by using a laser to burn off the frequency trimming layer through the substrate layer, thereby adjusting the quality of the vibrating structure; or An additional laser blocking layer is deposited on one side of the substrate to control the laser trimming position.

[0007] Preferably, the step of sequentially forming a second electrode layer, a sensing / driving layer, and a first electrode layer on the vibration functional layer specifically includes the following steps: The top of the vibration functional layer is doped, and the doping concentration is controlled to form a second electrode layer with conductive function; or a metal material is deposited on the top of the vibration functional layer to form a second electrode layer. A piezoelectric material is deposited on the second electrode layer to form a sensing / driving layer; A metal material is deposited on the sensing / driving layer to form a first electrode layer.

[0008] Preferably, the step of sequentially patterning the first electrode layer, the sensing / driving layer, and the second electrode layer includes: The first electrode layer is patterned to form a conductive pattern; The sensing / driving layer is patterned to form piezoelectric material boundaries; The second electrode layer is patterned to form an electric field distribution that matches the first electrode layer.

[0009] Preferably, bonding the third wafer over the first electrode layer includes the following steps: An isolation layer is formed on the first electrode layer, and a first bonding / conductive layer is formed on the isolation layer, wherein the first bonding / conductive layer is made of a first eutectic material; A TSV structure is formed on the third wafer; The bottom of the third wafer is oxidized to form a first oxide layer, and a second bonding / conductive layer is formed on the first oxide layer. The second bonding / conductive layer is made of a second eutectic material. The first bonding / conductive layer is bonded to the second bonding / conductive layer.

[0010] Preferably, the formation of an isolation layer on the first electrode layer and the formation of a first bonding / conductive layer on the isolation layer are performed before the formation of the displacement / vibration structure, and include the following steps: Silicon oxide is deposited on the surface of the first electrode layer and then patterned. The first eutectic material is deposited on the surface of the isolation layer and then patterned.

[0011] Preferably, forming the TSV structure on the third wafer includes the following steps: Deep reactive ion etching is performed on one side surface of the third wafer to form a shallow cavity and a deep trench; Silicon oxide and polysilicon are deposited on the same side surface of the third wafer, so that the silicon oxide and polysilicon fill the deep trench; The same side surface of the third wafer is etched back and CMP planarized.

[0012] Preferably, an air-absorbing layer is formed in the shallow cavity.

[0013] Preferably, forming an external electrode on the top of the third wafer includes the following steps: The top of the third wafer is thinned, a second oxide layer is deposited, and the second oxide layer is patterned. Deposit conductive metal, pattern the conductive metal, and form an external electrode; A protective layer is formed by depositing silicon oxide, and the protective layer is patterned to expose the external electrode.

[0014] The present invention also provides a driving sensing device based on a piezoelectric thin film, which is prepared by the aforementioned method.

[0015] The advantages of this invention are: (1) This invention simultaneously etches the first electrode layer, the sensing / driving layer, the second electrode layer, and the vibration functional layer, unlike the prior art which etches multiple thin films separately. Therefore, overlay errors do not need to be considered during the entire etching process. Furthermore, since the simultaneous etching extends through the entire device layer, the selection ratio of different materials for etching is not required, and physical bombardment methods such as IBE can be used to obtain the optimal etching perpendicularity. The driving sensing device fabricated using this method has performance closer to the ideal design performance and provides greater redundancy for process errors.

[0016] (2) The present invention performs patterning processing on the first electrode layer, the sensing / driving layer and the second electrode layer respectively, without involving the displacement / vibration structure of the driving sensing device, and will not affect the displacement / vibration structure of the overall device.

[0017] (3) The present invention uses doping annealing to prepare the vibration functional layer, which modifies the surface of the first wafer and thereby adjusts the rigidity and temperature drift properties of the first wafer. Compared with the prior art, the technical solution adopted in the present invention will not bring additional stress to the entire driving sensing device. At the same time, the thickness of the adjustment layer formed by doping is much smaller than that of the silicon oxide adjustment layer used in the prior art, reducing its impact on the overall performance of the driving sensing device.

[0018] (4) The substrate layer is made of single crystal silicon material, and a frequency trimming layer is set at the bottom of the vibration function layer. The frequency can be trimmed after the drive sensing device has been processed, without affecting its performance.

[0019] (5) The present invention achieves the packaging of the driving sensing device through eutectic bonding and TSV process, so that in the entire process, except for the high temperature environment used in the initial bonding of the first and second wafers, no subsequent processing steps require the use of a high temperature environment, which will not affect the performance of the driving sensing device. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the driving sensing device in this invention.

[0021] Figure 2 This is a schematic diagram of the structure of the first wafer used to prepare the vibration functional layer.

[0022] Figure 3 This is a schematic diagram of the structure in which an adjustment layer is formed on the surface of the first wafer after doping treatment.

[0023] Figure 4 This is a schematic diagram of the structure after the first and second wafers are bonded together.

[0024] Figure 5 This is a schematic diagram of the structure after thinning the other side surface of the first wafer after bonding.

[0025] Figure 6 This is a schematic diagram of the structure of the second electrode layer, the sensing / driving layer, and the first electrode layer in the driving sensing device.

[0026] Figure 7 This is a graphical schematic diagram of the first electrode layer.

[0027] Figure 8 This is a graphical schematic diagram of the sensing / driving layer.

[0028] Figure 9 This is a graphical schematic diagram of the second electrode layer.

[0029] Figure 10 This is a schematic diagram of the displacement / vibration structure in the drive sensing device.

[0030] Figure 11 This is a schematic diagram of a structure in which silicon oxide is deposited on the surface of the first electrode layer to form an isolation layer.

[0031] Figure 12 This is a graphical representation of the isolation layer.

[0032] Figure 13 This is a schematic diagram of the structure of the first bonding / conductive layer.

[0033] Figure 14 This is a schematic diagram of the structure after deep reactive ion etching on one side of the third wafer.

[0034] Figure 15 This is a schematic diagram of the structure after silicon oxide and polysilicon are deposited on the same side surface of the third wafer.

[0035] Figure 16 This is a schematic diagram of the structure after the same side surface of the third wafer has been etched back and CMP planarized.

[0036] Figure 17 This is a schematic diagram of the structure of the second bonding / conductive layer.

[0037] Figure 18 This is a schematic diagram of the air intake layer structure.

[0038] Figure 19 This is a schematic diagram of the external electrodes of the driving sensing device.

[0039] Explanation of reference numerals in the attached figures: Substrate layer 1, vibration function layer 2, sensing / driving layer 3, first electrode layer 4, second electrode layer 5, third wafer 6, isolation layer 7, first bonding / conductive layer 8, displacement / vibration structure 9, gas-absorbing layer 10, second bonding / conductive layer 11, first wafer 21, adjustment layer 22, shallow cavity 61, deep trench 62, first oxide layer 64, second oxide layer 65, external electrode 66, protective layer 67. Detailed Implementation

[0040] 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.

[0041] This invention discloses a method for fabricating a piezoelectric thin film-based driving sensing device, the structure of which is as follows: Figure 1 As shown, the specific steps include: S1: Figure 2The disclosed structure is a first wafer 21 used to fabricate the vibration functional layer 2. At least one surface of the first wafer 21 is doped using either full-area doping or localized doping, and the doped area is annealed. After doping, an adjustment layer 22 is formed on the surface of the first wafer 21, with the structure as shown below. Figure 3 As shown. Specific doping methods can include PSG spin coating; for localized doping, hard mask stripping or hard mask ion implantation can be used.

[0042] In the above steps, the vibration functional layer is prepared by doping and annealing, which modifies the surface of the first wafer 21 and thereby adjusts its rigidity and temperature drift properties. Existing technology involves adding a layer of silicon oxide beneath the vibration functional layer, combining them into a composite material through stacking to adjust the temperature drift coefficient. However, this approach introduces additional stress to the entire drive sensing device. Furthermore, if the silicon oxide layer constitutes a large proportion of the overall vibration structure layer, the different crystal orientations of single-crystal silicon and silicon oxide lead to additional energy transfer losses, causing a significant deviation between the actual performance of the drive sensing device and its intended design performance. Compared to existing technologies, the solution adopted in this invention does not introduce additional stress to the entire drive sensing device. Simultaneously, the thickness of the doped adjustment layer 22 is much smaller than that of the silicon oxide adjustment layer used in existing technologies, reducing its impact on the overall performance of the drive sensing device.

[0043] Furthermore, the surface of the first wafer 21 is subjected to multiple doping and annealing processes. The number of doping and annealing processes can be selected according to the stiffness requirements and temperature drift requirements of the vibration functional layer that need to be changed.

[0044] Furthermore, the first wafer 21 can be an SOI wafer, and the top silicon layer of the first wafer 21 is subjected to double-sided polishing. The thickness of the first wafer 21 can be selected according to the performance design of the device and actual needs. Simultaneously, the doping concentration can be selected according to the performance design of the device and actual needs. These selections do not limit the present invention.

[0045] S2: Using the second wafer as substrate layer 1, the second wafer is bonded to one doped side of the first wafer 21, as shown in the structure. Figure 4 As shown; the other surface of the first wafer 21 is thinned, and the thinned structure is as follows. Figure 5 As shown. The thinning method includes physical thinning followed by CMP thinning. After thinning, doping can be performed, with the doping steps the same as in S1, to further adjust the rigidity and temperature drift properties of the vibrational functional layer. In addition, the bonding method in this step can be one of Si-SiO2 bonding, SiO2-SiO2 bonding, or Si-Si bonding.

[0046] In the above steps, the second wafer can be pre-formed using DRIE (Deep Reactive Ion Etching) to create a cavity, and then subjected to double-sided passivation (silicon oxide) protection. Furthermore, if subsequent processes require frequency trimming of the driving sensing device, the second wafer can be selected as a single-crystal silicon material to transmit laser light of a specific wavelength, and one or more of the following methods can be used: Prior to bonding, a frequency trimming layer is deposited at the bottom of the vibrational functional layer 2; or The frequency adjustment is achieved by using a laser to burn the frequency trimming layer through substrate layer 1, thereby adjusting the mass of the vibrating structure; or A laser blocking layer can also be additionally deposited on one side surface of substrate layer 1 (second wafer) to precisely control the laser trimming position.

[0047] S3: The second electrode layer 5, the sensing / driving layer 3, and the first electrode layer 4 are formed sequentially, as shown in the structure. Figure 6 As shown, the specific steps include: S31: Perform doping treatment on the top of the vibration functional layer 2, the doping steps are the same as in S1, and control the doping concentration to form a second electrode layer 5 with conductive function; or deposit a metal material on the top of the vibration functional layer 2 to form a second electrode layer 5, the metal material is preferably molybdenum (Mo) or platinum (Pt).

[0048] S32: Deposit piezoelectric material on the second electrode layer 5 to form the sensing / driving layer 3. The piezoelectric material is preferably aluminum nitride (AlN) or lead zirconate titanate ceramic (PZT).

[0049] S33: Deposit a metal material on the sensing / driving layer 3 to form the first electrode layer 4. The metal material is preferably molybdenum (Mo) or platinum (Pt).

[0050] Specifically, if the metal material used in the electrode layer is Mo, then the piezoelectric material is AlN, forming a Mo / AlN / Mo three-layer structure to form a transmitting or receiving device such as a piezoelectric micromechanical ultrasonic transducer; if the metal material used in the electrode layer is Pt, then the piezoelectric material is PZT, forming a Pt / PZT / Pt three-layer structure, which is suitable for high-sensitivity sensors or high-power actuators.

[0051] S4: The first electrode layer 4, the sensing / driving layer 3, and the second electrode layer 5 are sequentially patterned, specifically including the following steps: S41: As Figure 7As shown, the first electrode layer 4 is patterned to form a conductive pattern, which can be achieved using methods such as photolithography or dry etching. In this step, the patterned portion serves only as an electrical signal transmission channel and therefore will not affect the overall device's displacement / vibration structure.

[0052] S42: As Figure 8 As shown, the sensing / driving layer 3 is patterned to form the piezoelectric material boundary, which can be achieved using photolithography or dry etching. The goal of the patterning design in this step is to define the isolation region of the device, without involving the displacement / vibration structure of the driving sensing device, and will not affect the displacement / vibration structure of the overall device.

[0053] S43: As Figure 9 As shown, the second electrode layer 5 is patterned to form an electric field distribution that matches the first electrode layer 4. This can be achieved using methods such as photolithography or dry etching. The patterning design in this step does not involve the displacement / vibration structure of the driving sensing device and will not affect the overall displacement / vibration structure of the device.

[0054] S5: Simultaneously etch the first electrode layer 4, the sensing / driving layer 3, the second electrode layer 5, and the vibration functional layer 2 to form the displacement / vibration structure 9, specifically as follows: Figure 10 The simultaneous etching step described here refers to etching the first electrode layer 4, the sensing / driving layer 3, the second electrode layer 5, and the vibration functional layer 2 in a single process using a single photomask. This differs from existing technologies that etch multiple thin films separately, eliminating the need to consider overlay errors during the entire etching process. Furthermore, since simultaneous etching extends throughout the entire device layer, there is no need to consider the selection ratio of different materials; physical bombardment methods such as IBE can be used to obtain optimal etching perpendicularity. The driving sensing device fabricated using this method has performance closer to the ideal design performance and allows for greater redundancy in terms of process errors.

[0055] S6: A third wafer 6 is bonded on top of the first electrode layer 4 to realize the packaging of the driving sensing device.

[0056] In existing technologies, to ensure sufficient space for vibration displacement in the device layer of a driving sensing device, the bottom substrate wafer is typically drilled through. However, for driving sensing devices requiring a vacuum operating environment, a support wafer (common materials such as glass and silicon) needs to be bonded to the bottom after processing for sealing. This method, however, requires high-temperature / pressure bonding again after processing, which is unsuitable for low-melting-point materials used in previous processes or can generate additional stress, thus affecting the performance of the driving sensing device. To address this problem, the present invention employs the following steps: S61: An isolation layer 7 is formed on the first electrode layer 4. The isolation layer 7 is made of silicon oxide. The specific steps are as follows: silicon oxide is deposited on the surface of the first electrode layer 4 (see...). Figure 11 ), and use etching and other methods for graphic processing (see Figure 12 It should be noted that, in order to avoid the isolation layer 7 affecting the displacement / vibration structure 9, this step needs to be performed before the displacement / vibration structure 9 is formed.

[0057] S62: A first bonding / conductive layer 8 is formed on the isolation layer 7. The first bonding / conductive layer 8 uses a first eutectic material, including aluminum (Al) or gold (Au). Specifically, the first eutectic material is deposited on the surface of the isolation layer 7 and patterned, as shown in the following structure. Figure 13 As shown. It should be noted that, in order to avoid the first bonding / conductive layer 8 affecting the displacement / vibration structure 9, this step needs to be performed before the displacement / vibration structure 9 is formed.

[0058] S63: Forming a TSV (Through-Silicon Via) structure on the third wafer 6, specifically including the following steps: Deep reactive ion etching is performed on one side surface of the third wafer 6 to form a shallow cavity 61 and a deep trench 62, as shown in the figure. Figure 14 As shown; Silicon oxide and polysilicon are deposited on the same side surface of the third wafer 6, filling the deep trench 62 to form an isolated via for conducting electrical signals. Figure 15 As shown; The same side surface of the third wafer 6 was etched back and planarized using CMP (chemical mechanical polishing), such as... Figure 16 As shown.

[0059] S64: An oxide layer 64 is formed on the same side surface of the third wafer 6. A second bonding / conductive layer 11 is then formed on the first oxide layer 64. The second bonding / conductive layer 11 uses a second eutectic material, including germanium (Ge), gold (Au), or silicon (Si). Specifically, the second eutectic material is deposited on the oxide layer and patterned. The specific structure is as follows: Figure 17 As shown

[0060] In the above steps, the first eutectic material and the second eutectic material correspond to each other: if the first eutectic material is Al, then the second eutectic material is Ge, forming an Al-Ge bond; if the second eutectic material is Au, then the second eutectic material can be Au or Si, forming an Au-Au bond or an Au-Si bond.

[0061] S65: A getter layer 10 is formed in the shallow cavity 61. The specific steps are to deposit a getter in the shallow cavity 61 and then etch it, as shown in the figure. Figure 18 As shown. If the driving sensing device requires a high level of airtightness, this can be achieved through the air intake layer 10.

[0062] S66: Bond the first bonding / conductive layer 8 to the second bonding / conductive layer 11 to realize the encapsulation of the driving sensing device.

[0063] Regarding the above technical solution, the present invention achieves the packaging of the driving sensing device through eutectic bonding and TSV process, so that except for the high temperature environment used in the initial bonding of the first and second wafers, no subsequent processing steps require the use of a high temperature environment, and will not affect the performance of the driving sensing device.

[0064] S7: An external electrode is formed on the top of the third wafer 6, with the structure as follows. Figure 19 As shown, the specific steps include: The top of the third wafer 6 is thinned, a second oxide layer 65 is deposited, and the second oxide layer 65 is patterned. A conductive metal is deposited and patterned to form an external electrode 66. The conductive metal includes aluminum (Al). Silicon oxide is deposited to form a protective layer 67, and the protective layer 67 is patterned to expose the external electrode 66.

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Any modifications, equivalent substitutions, and improvements 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 method for fabricating a piezoelectric thin film-based driving sensing device, characterized in that, Includes the following steps: A vibration functional layer is prepared and bonded to a substrate layer. A second electrode layer, a sensing / driving layer, and a first electrode layer are sequentially formed on the vibration functional layer. The first electrode layer, the sensing / driving layer, and the second electrode layer are sequentially patterned. Simultaneous etching of the first electrode layer, the sensing / driving layer, the second electrode layer, and the vibration functional layer forms a displacement / vibration structure; A third wafer is bonded over the first electrode layer, and an external electrode is formed on the top of the third wafer.

2. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, The preparation of the vibration functional layer includes the following steps: At least one surface of the first wafer is doped, and the doped area is annealed.

3. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, If frequency trimming of the drive sensing device is required, the substrate layer is made of monocrystalline silicon to allow laser transmission, and employs one or more of the following methods: Prior to bonding, a frequency trimming layer is deposited at the bottom of the vibration functional layer; or The frequency adjustment is achieved by using a laser to burn off the frequency trimming layer through the substrate layer, thereby adjusting the quality of the vibrating structure; or An additional laser blocking layer is deposited on one side of the substrate to control the laser trimming position.

4. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, The process of sequentially forming a second electrode layer, a sensing / driving layer, and a first electrode layer on the vibration functional layer specifically includes the following steps: The top of the vibration functional layer is doped, and the doping concentration is controlled to form a second electrode layer with conductive function; or a metal material is deposited on the top of the vibration functional layer to form a second electrode layer. A piezoelectric material is deposited on the second electrode layer to form a sensing / driving layer; A metal material is deposited on the sensing / driving layer to form a first electrode layer.

5. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, The sequential patterning of the first electrode layer, the sensing / driving layer, and the second electrode layer includes: The first electrode layer is patterned to form a conductive pattern; The sensing / driving layer is patterned to form piezoelectric material boundaries; The second electrode layer is patterned to form an electric field distribution that matches the first electrode layer.

6. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, The bonding of the third wafer over the first electrode layer includes the following steps: An isolation layer is formed on the first electrode layer, and a first bonding / conductive layer is formed on the isolation layer, wherein the first bonding / conductive layer is made of a first eutectic material; A TSV structure is formed on the third wafer; The bottom of the third wafer is oxidized to form a first oxide layer, and a second bonding / conductive layer is formed on the first oxide layer. The second bonding / conductive layer is made of a second eutectic material. The first bonding / conductive layer is bonded to the second bonding / conductive layer.

7. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 6, characterized in that, The formation of an isolation layer on the first electrode layer, and the formation of a first bonding / conductive layer on the isolation layer, is performed before the formation of the displacement / vibration structure, and includes the following steps: Silicon oxide is deposited on the surface of the first electrode layer and then patterned. The first eutectic material is deposited on the surface of the isolation layer and then patterned.

8. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 6, characterized in that, The formation of the TSV structure on the third wafer includes the following steps: Deep reactive ion etching is performed on one side surface of the third wafer to form a shallow cavity and a deep trench; Silicon oxide and polysilicon are deposited on the same side surface of the third wafer, so that the silicon oxide and polysilicon fill the deep trench; The same side surface of the third wafer is etched back and CMP planarized. An air-absorbing layer is formed in the shallow cavity.

9. The method for fabricating a piezoelectric thin film-based driving sensing device according to claim 1, characterized in that, The process of forming an external electrode on the top of the third wafer includes the following steps: The top of the third wafer is thinned, a second oxide layer is deposited, and the second oxide layer is patterned. Deposit conductive metal, pattern the conductive metal, and form an external electrode; A protective layer is formed by depositing silicon oxide, and the protective layer is patterned to expose the external electrode.

10. A driving sensing device based on a piezoelectric thin film, characterized in that, It is prepared by any one of the preparation methods described in claims 1-9.

Images