A MEMS piezoelectric device and its preparation method
By retaining the surface layer in the sensitive area of the piezoelectric layer of the MEMS piezoelectric device, the corrosion problem of alkaline solution cleaning on the sensitive area is solved, and the morphological integrity and performance of the device are improved.
Patent Information
- Application Number
- CN202411890405.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-04-08
AI Technical Summary
During the preparation of MEMS piezoelectric devices, when alkaline solutions are used for cleaning, it is easy to cause corrosion and damage to the sensitive areas of the piezoelectric material Al ScN or Al N, resulting in rough surface morphology, affecting the progress of subsequent processes.
By retaining the surface layer in the sensitive areas of the piezoelectric layer, corrosion of the sensitive areas by the alkaline solution is avoided. The specific method includes sequentially stacking the base layer, the piezoelectric layer and the surface layer on the substrate, etching the surface layer to expose the piezoelectric layer, and retaining the surface layer at least in the sensitive area to protect the sensitive area.
It effectively avoids corrosion and damage of the piezoelectric layer during cleaning, improves the morphological integrity of the device, and improves subsequent film deposition and device performance.
Smart Images
Figure CN119774542A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a MEMS piezoelectric device and a method for preparing the same. Background Art
[0002] As an advanced sensor technology, MEMS piezoelectric devices have many advantages such as low power consumption, fast response, and high reliability. MEMS piezoelectric devices are mainly composed of piezoelectric units and ASIC circuits; the piezoelectric film layer is the main core film layer of the piezoelectric device, which plays both a functional and structural role and is crucial.
[0003] In the actual MEMS device preparation process, generally, a cleaning operation is performed after the etching process. In this example, after the metal electrode layer on the piezoelectric material Al ScN or Al N is patterned, the mask on its surface and the polymer (i.e., Polymer) produced by the reaction need to be removed by a wet process using an alkaline solution before the subsequent process can be carried out. The alkaline solution commonly used in the industry has a certain corrosive effect on Al ScN or Al N, and will damage the sensitive areas on the Al ScN or Al N film layer that are not covered by the metal layer (sensitive areas refer to areas where some processes will still be carried out to prepare other structures in the future, such as Via areas, etc., and areas that are prone to bending, breaking, etc. although no other structural treatment will be carried out in the future, and also include some functional areas, areas where the surface damage will directly affect the device, such as the surface of cantilever beams, diaphragms, etc. The above and areas with similar conditions can be called sensitive areas.) The surface morphology becomes rough and uncontrollable, which has a great impact on the subsequent film deposition, exposure and subsequent etching processes. Summary of the invention
[0004] The purpose of the embodiments of the present application is to provide a MEMS piezoelectric device and a method for preparing the same, which can avoid damage to the sensitive area of the piezoelectric layer and improve the morphological integrity of the device.
[0005] In one aspect of an embodiment of the present application, a method for preparing a MEMS piezoelectric device is provided, comprising:
[0006] At least a base layer, a piezoelectric layer and a surface layer are sequentially stacked on a substrate;
[0007] The surface layer is etched to expose the piezoelectric layer, and the surface layer is retained at least in a sensitive region of the piezoelectric layer.
[0008] Optionally, etching the surface layer to expose the piezoelectric layer and retaining the surface layer at least in a sensitive region of the piezoelectric layer comprises:
[0009] preparing a first patterned mask on the surface layer;
[0010] Patterning the surface layer through the first patterned mask so that the surface layer at least covers the non-etched area of the sensitive area of the piezoelectric layer and exposes the etched area of the sensitive area of the piezoelectric layer;
[0011] The first patterned mask is removed.
[0012] Optionally, etching the surface layer to expose the piezoelectric layer and retaining the surface layer at least in a sensitive region of the piezoelectric layer comprises:
[0013] preparing a first patterned mask on the surface layer;
[0014] Patterning the surface layer through the first patterned mask so that the surface layer at least covers the non-etched area of the sensitive area of the piezoelectric layer and the etched area of the sensitive area of the piezoelectric layer;
[0015] The first patterned mask is removed.
[0016] Optionally, the etching of the surface layer exposes the piezoelectric layer, and the surface layer is retained at least in a sensitive region of the piezoelectric layer. Thereafter, the method further comprises:
[0017] Etching an etching area of a sensitive region of the piezoelectric layer;
[0018] A metal connection layer is formed on the surface layer, the piezoelectric layer and the etched area.
[0019] Optionally, the etching area for etching the sensitive area of the piezoelectric layer includes:
[0020] preparing a second patterned mask on the surface layer to expose an etched area of the piezoelectric layer;
[0021] Etching an etching area of the piezoelectric layer to form a preset structure;
[0022] The second patterned mask is removed.
[0023] Another aspect of an embodiment of the present application provides a MEMS piezoelectric device, which is prepared according to the above-mentioned method for preparing a MEMS piezoelectric device, and includes at least a substrate, a base layer, a piezoelectric layer and a surface layer stacked in sequence, and the surface layer at least covers the sensitive area of the piezoelectric layer.
[0024] Optionally, a groove is formed from the surface layer toward the base layer, the groove extends to the piezoelectric layer and exposes the base layer, and the groove is located in a sensitive area of the piezoelectric layer.
[0025] Optionally, a metal connection layer is formed along the surface layer, the piezoelectric layer, and the groove surface for electrical connection with an external device.
[0026] Optionally, the piezoelectric layer has multiple layers, the base layers are arranged correspondingly below the multiple piezoelectric layers, and an intermediate film layer is arranged between the lowest base layer and the substrate.
[0027] Optionally, the material of the base layer includes metal or non-metal.
[0028] The MEMS piezoelectric device and its preparation method provided in the embodiment of the present application can protect the top surface of the piezoelectric layer in the sensitive area by retaining the surface layer in the sensitive area on the surface of the piezoelectric layer, thereby preventing the piezoelectric layer from being corroded and damaged in the sensitive area by alkaline solution when cleaning the device in the wet cleaning step after the surface layer is patterned, thereby affecting the subsequent process. The provision of the surface layer greatly improves the roughness of the device's morphology, and can also simultaneously improve the deposition morphology of the subsequent film layer, thereby ensuring the integrity of the device's structural morphology and thereby improving the performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.
[0030] Figure 1a to Figure 1h It is a diagram of the preparation process of the existing device;
[0031] Figure 2 This is a morphology diagram showing the actual state of the existing device under an electron microscope;
[0032] Figure 3 to Figure 13 Schematic diagram of the preparation process of the first embodiment of the MEMS piezoelectric device provided in this embodiment;
[0033] Fig.14 is a SEM image of the VIA structure region of the surface layer protection of the MEMS piezoelectric device provided in this embodiment;
[0034] Figures 15 to 20 Schematic diagram of the preparation process of the second embodiment of the MEMS piezoelectric device provided in this embodiment;
[0035] Fig.21 It is a structural schematic diagram of a MEMS piezoelectric device in the prior art;
[0036] Fig. 22 It is a structural schematic diagram of the third embodiment of the MEMS piezoelectric device provided in this embodiment.
[0037] Icon: 10-base layer; 11-piezoelectric layer; 12-metal layer; 13-surface layer; 14-mask; 15-groove; 16-metal connection layer; 100-substrate; 101, 101a-base layer; 102, 102a-piezoelectric layer; 103-surface layer; 104-first patterned mask; 105-second patterned mask; 106-groove; 107-metal connection layer; 108-third patterned mask; 109-intermediate film layer; A-sensitive area; B-non-sensitive area; C-etching area. DETAILED DESCRIPTION
[0038] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.
[0039] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0040] It should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.
[0041] The overall process of the prior art is as follows Figure 1a to Figure 1h as well as Figure 2 As shown, Figure 1a to Figure 1h The process flow of devices with surfaces corroded by alkaline solutions is shown. Figure 2 The local SEM image of the device surface corroded by alkaline solution is shown. Figure 1c A schematic diagram of the morphology of the device after corrosion is shown.
[0042] Specifically, Figure 1a The figure shows the morphology after the metal layer 12 is deposited on the surface of the substrate layer 10 and the piezoelectric layer 11. Figure 1a The metal layer 12 on the surface is patterned to form Figure 1b After etching the metal, an alkaline solution wet cleaning process is required. Figure 1cThe figure shows the morphology of the surface of the piezoelectric layer 11 after being corroded by an alkaline solution. Figure 1c The surface layer 13 is deposited on the piezoelectric layer 11 ( Figure 1d ), and then a patterned mask 14 is prepared on the surface ( Figure 1e ), etching to form a groove 15 ( Figure 1f ), after removing the patterned mask 14 ( Figure 1g ) and then prepare a patterned connection metal on the surface to form Figure 1h .
[0043] The groove 15 involved in electrical connection in the figure is generally named Via structure, because the metal deposited subsequently realizes electrical connection with the bottom metal electrode. The area related to Via groove 15 is not protected before cleaning, so its upper surface is extremely rough.
[0044] in, Figures 1b to 1c The etching and cleaning steps are inseparable. Because there is a mask 14 and other residual substances on the wafer surface during etching, especially the reaction products after metal etching need to be removed by alkaline cleaning. Therefore, it is unrealistic to protect the surface by depositing a new film layer after etching. The next deposition step can only be performed after cleaning, but the surface is already damaged after cleaning, so a new structure or process flow must be designed to avoid damage to the AlN surface.
[0045] Figure 1a to Figure 1h The area where the metal layer 12 is retained, the area damaged by wet cleaning, and the Vi a structure area in the process diagram do not represent the structural arrangement of the actual device, but are a way of expressing the characteristic morphology in the same figure.
[0046] The actual morphology SEM image is as follows Figure 2 As shown, Figure 2 The area shown in 1&2 is the area affected by wet cleaning on the top surface of the groove 15 structure. Due to the erosion of the alkaline solution, the top surface of AlN, which should be flat, becomes very rough. For example, in the VIA structure, metals such as Al or Au are subsequently deposited on the groove 15 and its top surface to form a metal connection layer 16, which serves as a wire to realize the electrical connection characteristics of the device. However, after the actual metal connection layer 16 is deposited, the surface is too uneven, so the metal connection layer 16 needs to be thicker to completely fill the rugged surface to realize the electrical connection of the device.
[0047] The rough surface prevents the deposition of a thinner metal connection layer 16 from achieving better electrical properties, and also makes the deposition of the metal connection layer 16 have the risk of fractures and gaps. This has a great impact on the deposition and adhesion of the metal connection layer 16, increases the disconnection of the metal wire, and thus reduces the reliability of the device, and increases the device instability, performance degradation, and scrapping caused by abnormal electrical connections during testing and use.
[0048] In view of this, in order to solve the above problems, an embodiment of the present application provides a method for preparing a MEMS piezoelectric device, which is used to protect the morphology structure of the piezoelectric layer 102 in the sensitive area A. The method includes:
[0049] Step 200: at least a base layer 101, a piezoelectric layer 102 and a surface layer 103 are stacked in sequence on a substrate 100.
[0050] A base layer 101, a piezoelectric layer 102 and a surface layer 103 are sequentially prepared on a substrate 100 to achieve the following Figure 3 The membrane structure shown.
[0051] Figure 3 The substrate 100 film layer is not shown schematically, and the substrate 100 film layer may include a base and other film layers, wherein the other film layers may be composite film layers.
[0052] The base layer 101 is only for illustration, because the Via structure is used as an example here, and a metal material must be selected as the base layer 101 to achieve electrical connection. If other structures do not need to achieve electrical connection, the base layer 101 can be a film layer of other materials, not necessarily a metal material.
[0053] The base layer 101 may be patterned after being deposited to achieve some electrical connection effects of the device, but its patterning does not conflict with the process of the present application.
[0054] The surface layer 103 may be a composite film layer, a single dielectric film layer or a metal film layer. When the surface layer 103 is a metal film layer, the selected metal material cannot react with the alkaline solution, for example, metal Al cannot be selected.
[0055] Step 201: Etching the surface layer 103 to expose the piezoelectric layer 102, and retaining the surface layer 103 at least in the sensitive area A of the piezoelectric layer 102.
[0056] Process: Figure 3 A first patterned mask 104 ( Figure 4), the surface layer 103 is patterned through the first patterned mask 104, and the surface layer 103 is etched to expose at least the etching area C of the sensitive area A of the piezoelectric layer 102 thereunder, and the non-etching area C of the sensitive area A of the piezoelectric layer 102 is covered by the surface layer 103 ( Figure 5 ), cleaning the device surface to remove the etching byproducts and the first patterned mask 104 ( Figure 6 ).
[0057] In the prior art, after etching the surface layer 103 and cleaning it, the top surface morphology of the piezoelectric layer 102 in the exposed sensitive area A becomes rough, which may lead to subsequent failure problems.
[0058] And as Figure 6 As shown, in the sensitive area A, except for the area to be subsequently etched which is damaged, the rest of the area is protected by the surface layer 103 and has a smooth and intact morphology.
[0059] The non-sensitive area B is not protected because damage to its surface has no effect on the device. The reasons are as follows: If the non-sensitive area B is fully covered, the pressure during etching will be greater. From a process perspective, the more material is etched, the shorter the stable operating time of the machine, which is not friendly to production efficiency. Secondly, if the non-sensitive area B is completely covered, some electrical connections will be short-circuited or some functional structural areas will be covered. Therefore, there is no need to protect the non-sensitive area B.
[0060] exist Figures 5 and 6 In the cleaning process, it is impossible to add a deposition step to protect the top surface of the piezoelectric layer 102, because after the etching process, the first patterned mask 104 and other residual substances remain on the device surface. At this time, direct deposition will cause subsequent film layers to be deposited on the first patterned mask 104 and other residual substances, which is not feasible. Therefore, only by adopting the method of this application: by directly processing the surface layer 103, so that the surface layer 103 directly covers the top surface of the piezoelectric layer 102, can the sensitive area A be protected.
[0061] The surface layer 103 is retained in the sensitive area A on the surface of the piezoelectric layer 102 to protect the top surface of the piezoelectric layer 102 in the sensitive area A. The purpose is to avoid corrosion damage to the sensitive area A caused by the alkaline solution when cleaning the device during the wet cleaning step after the surface layer 103 is patterned, thereby affecting the subsequent process.
[0062] Step 202: Etching the etching area C of the sensitive area A of the piezoelectric layer 102.
[0063] exist Figure 6 On the basis of the above, a second patterned mask 105 is prepared on the surface layer 103 to expose the etching area C ( Figure 7), etching the etching area C of the piezoelectric layer 102, and forming a related preset structure, for example, Figure 8 As shown, in this example, the relevant structure is an inverted trapezoidal groove 106, and the second patterned mask 105 ( Fig. 9 ).
[0064] Step 203: Form a metal connection layer 107 on the surface layer 103.
[0065] exist Fig. 9 The metal connection layer 107 is deposited on the surface of Fig.10 The metal connection layer 107 covers the exposed piezoelectric layer 102 and the preset structure; then a third patterned mask 108 ( Fig.11 ), the metal connection layer 107 is etched through the third patterned mask 108, so that the metal connection layer 107 is patterned ( Fig.12 ), and then remove the third patterned mask 108 by cleaning to obtain Fig.13 The morphology and structure shown.
[0066] Without adding a new film layer, the present application utilizes the original film layer to protect the sensitive area A on the top surface of the piezoelectric layer 102; without increasing or reducing the process steps, the corrosion effect of the original film layer post-etching cleaning step on the sensitive area A on the top surface of the piezoelectric layer 102 is eliminated.
[0067] Through the above arrangement, the damage to the sensitive area A on the top surface of the piezoelectric layer 102 caused by the alkaline solution wet cleaning process is successfully eliminated, ensuring the flatness of the topographic surface. Fig.14 shown.
[0068] In some other embodiments, step 201: etching the surface layer 103 to expose the piezoelectric layer 102, retaining the surface layer 103 at least in the sensitive area A of the piezoelectric layer 102, and can also be prepared in other ways.
[0069] Specifically, in Figure 3 A first patterned mask 104 ( Fig.16 ), patterning the surface layer 103 through the first patterned mask 104, etching the surface layer 103, so that the surface layer 103 at least covers the non-etched area C of the sensitive area A of the piezoelectric layer 102 and the etched area C of the sensitive area A of the piezoelectric layer 102, that is, the surface layer 103 covers the entire sensitive area A of the piezoelectric layer 102, and cleaning the device to remove the etching byproducts and the mask together ( Fig.17 ).
[0070] Step 202 : etching the etched area C of the sensitive area A of the piezoelectric layer 102 .
[0071] exist Fig.17 A second patterned mask 105 is prepared on the surface to expose the etching area C ( Fig.18 ), and the above embodiment Figure 6 The difference is that Fig.18 The etched area C of the middle piezoelectric layer 102 is also covered with a surface layer 103. The surface layer 103 is etched once in the etched area C to form a corresponding preset structure ( Fig.19 ), and then a cleaning process is performed to obtain Fig. 20 The morphology shown is equivalent to Fig. 9 , and the subsequent process is consistent with the main process and will not be repeated.
[0072] One etching process refers to preparing a graphic mask and performing an etching process only once, wherein one etching process may have multiple etching steps.
[0073] The process of this embodiment differs from that of the above embodiment in the difference in the processing order of the sensitive area A, that is, the etching area C of the sensitive area A can also be etched in one step to achieve the corresponding preset structure. The specific process flow is determined according to the actual device and process requirements.
[0074] In addition, the present application can also protect non-structural sensitive areas A, and such non-structural sensitive areas A do not need to be etched in the area. Figure 16 to Figure 17 As shown in the steps, no need Fig.18 The following steps describe etching in the protected area.
[0075] like Fig.21 The figure shows a schematic diagram of a diaphragm without the protection of the surface layer 13. The portion of the surface layer 13 at the edge is a chain of connection areas around the diaphragm. The area in the center showing the piezoelectric layer 11 and the base layer 10 (electrode) is the core functional area of the diaphragm. The lateral base layer 10 is connected to the metal connection layer 16 (electrode) to communicate with the outside world to achieve electrical connection. Its main defect is that the surface of the piezoelectric layer 102 between the electrode and the peripheral area will be corroded.
[0076] Use Fig. 22 The protection scheme shown in the figure has been realized in the process of Fig.16 , Fig.17 This solution protects a large area of the piezoelectric layer 102, enhancing the protection and reliability of the diaphragm functional area. At the same time, it avoids unnecessary electrical interconnection and ensures the normal function of the diaphragm.
[0077] Therefore, the preparation method of the MEMS piezoelectric device provided in the embodiment of the present application can protect the top surface of the piezoelectric layer 102 in the sensitive area A by retaining the surface layer 103 in the sensitive area A on the surface of the piezoelectric layer 102, thereby preventing the piezoelectric layer 102 from being corroded and damaged in the sensitive area A by the alkaline solution when cleaning the device in the wet cleaning step after the surface layer 103 is patterned, thereby affecting the subsequent process. The provision of the surface layer 103 greatly improves the roughness of the device morphology, and can also improve the deposition morphology of the subsequent film layer, thereby ensuring the integrity of the device structure morphology and thus improving the performance of the device.
[0078] In particular, in all the preparation processes of the present application, the piezoelectric layer 102 may be more than one layer, and other film layers may be added between each piezoelectric layer 102 and the base layer 101, which is specifically configured according to actual needs.
[0079] On the other hand, an embodiment of the present application provides a MEMS piezoelectric device, comprising at least a substrate 100, a base layer 101, a piezoelectric layer 102 and a surface layer 103 stacked in sequence, wherein the surface layer 103 at least covers a sensitive area A of the piezoelectric layer 102. The material of the base layer 101 includes metal or non-metal.
[0080] In some embodiments, a groove 106 is formed from the surface layer 103 toward the base layer 101 , the groove 106 extends to the piezoelectric layer 102 and exposes the base layer 101 , and the groove 106 is located in a sensitive region A of the piezoelectric layer 102 .
[0081] In some embodiments, a metal connection layer 107 is formed along the surface layer 103 and the surface of the groove 106 for electrical connection with an external device.
[0082] In some embodiments, the piezoelectric layer 102 may have multiple layers, and the base layer 101 is disposed correspondingly below the multiple piezoelectric layers 102 , and an intermediate film layer 109 is disposed between the bottom base layer 101 and the substrate 100 .
[0083] For example Fig.15 The piezoelectric layer may have two layers, namely, the piezoelectric layer 102 and the piezoelectric layer 102a. Correspondingly, the base layer also has two layers, namely, the base layer 101 and the base layer 101a. An intermediate film layer 109 may be provided between the substrate 100 and the base layer 101a. The intermediate film layer 109 may be a composite film layer. Fig.15 Three or more piezoelectric layers 102 may also be provided.
[0084] In addition, it should be noted that Fig.15What is to be protected should be a part of the entire device structure; it may be directly stacked from the substrate 100 , or it may not be stacked from the substrate 100 .
[0085] It can be seen that what is shown in the present application is only a part of the entire MEMS piezoelectric device structure, and each membrane layer may be formed by directly stacking on the substrate or may not be formed by stacking on the substrate.
[0086] The MEMS piezoelectric device has the same structure and beneficial effects as the MEMS piezoelectric device in the aforementioned embodiment. The structure and beneficial effects of the MEMS piezoelectric device have been described in detail in the aforementioned embodiment, and will not be repeated here.
[0087] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.
Claims
1. A method for preparing a MEMS piezoelectric device, characterized in that: include: At least a base layer, a piezoelectric layer and a surface layer are sequentially stacked on a substrate; The surface layer is etched to expose the piezoelectric layer, and the surface layer is retained at least in a sensitive region of the piezoelectric layer.
2. The method for preparing a MEMS piezoelectric device according to claim 1, characterized in that: The etching of the surface layer to expose the piezoelectric layer and retaining the surface layer at least in a sensitive region of the piezoelectric layer comprises: preparing a first patterned mask on the surface layer; Patterning the surface layer through the first patterned mask so that the surface layer at least covers the non-etched area of the sensitive area of the piezoelectric layer and exposes the etched area of the sensitive area of the piezoelectric layer; The first patterned mask is removed.
3. The method for preparing a MEMS piezoelectric device according to claim 1, characterized in that: The etching of the surface layer to expose the piezoelectric layer and retaining the surface layer at least in a sensitive region of the piezoelectric layer comprises: preparing a first patterned mask on the surface layer; Patterning the surface layer through the first patterned mask so that the surface layer at least covers the non-etched area of the sensitive area of the piezoelectric layer and the etched area of the sensitive area of the piezoelectric layer; The first patterned mask is removed.
4. The method for preparing a MEMS piezoelectric device according to any one of claims 1 to 3, characterized in that: The etching of the surface layer exposes the piezoelectric layer, and the surface layer is retained at least in the sensitive region of the piezoelectric layer. After that, the method further comprises: Etching an etching area of a sensitive region of the piezoelectric layer; A metal connection layer is formed on the surface layer, the piezoelectric layer and the etched area.
5. The method for preparing a MEMS piezoelectric device according to claim 4, characterized in that: The etching area for etching the sensitive area of the piezoelectric layer includes: preparing a second patterned mask on the surface layer to expose an etched area of the piezoelectric layer; Etching an etching area of the piezoelectric layer to form a preset structure; The second patterned mask is removed.
6. A MEMS piezoelectric device, prepared according to the method for preparing a MEMS piezoelectric device according to any one of claims 1 to 5, characterized in that: The invention comprises at least a substrate, a base layer, a piezoelectric layer and a surface layer which are stacked in sequence, wherein the surface layer at least covers a sensitive area of the piezoelectric layer.
7. The MEMS piezoelectric device according to claim 6, characterized in that: A groove is formed from the surface layer toward the base layer, the groove extends to the piezoelectric layer and exposes the base layer, and the groove is located in a sensitive area of the piezoelectric layer.
8. The MEMS piezoelectric device according to claim 7, characterized in that: A metal connection layer is formed along the surface layer, the piezoelectric layer and the groove surface for electrical connection with an external device.
9. The MEMS piezoelectric device according to any one of claims 6 to 8, characterized in that: The piezoelectric layer has multiple layers, the base layers are arranged correspondingly below the multiple piezoelectric layers, and an intermediate film layer is arranged between the lowest base layer and the substrate.
10. The MEMS piezoelectric device according to claim 9, characterized in that: The material of the base layer includes metal or non-metal.