Piezoelectric mems sensor and method of manufacturing the same, electronic device

Abstract

The application discloses a piezoelectric MEMS sensor and a preparation method thereof and electronic equipment. Before depositing a bottom electrode, an electrode with a preset thickness is formed on a substrate layer at a position of a preset bottom electrode Pad opening. Then, only one photoetching process is used to expose the bottom electrode Pad and form a film end part. The bottom electrode end part at the film end part position is aligned with other two film layer end parts. Because an electrode with a preset thickness is first deposited at the position of the preset bottom electrode Pad opening, the electrical connection at the bottom electrode Pad opening is not affected in the one photoetching process. The film end part position and the bottom electrode Pad opening both meet the requirements through one photoetching.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and more specifically, to a piezoelectric MEMS sensor and its fabrication method, as well as an electronic device. Background Technology

[0002] Existing piezoelectric MEMS sensors mostly consist of a structure with two layers of electrodes sandwiching a layer of piezoelectric material, forming a neat cantilever structure through a single etching process. For example, ... Figure 1 The image shown is a simplified cross-sectional view of a piezoelectric device. Typically, it is necessary to ensure... Figure 1 The three film layers at the end positions indicated in the text are aligned, and this alignment includes, but is not limited to, the alignment of the three film layers at the end positions of the film. Figure 1 The vertical alignment shown also includes slanted alignment at a certain angle.

[0003] But because Figure 1 A bottom electrode film layer needs to be retained under the bottom electrode pad to achieve electrical connection between the pad and the bottom electrode. If a single etching process is used, it is not possible to selectively etch only the bottom electrode at the end of the film while omitting the bottom electrode at the bottom electrode pad opening. Therefore, in the prior art, firstly, the bottom electrode layer is deposited separately; then, the bottom electrode layer is... Figure 1 The thin film end positions shown are patterned separately; finally, a piezoelectric layer and a top electrode are deposited, and then only the top electrode and the piezoelectric layer are etched.

[0004] However, because the bottom electrode and the other two layers are patterned separately, there is an unavoidable situation where alignment misalignment occurs during the two photolithography processes, and / or the linewidths of the two photolithography processes differ. This results in the bottom electrode end not aligning with the ends of the other two film layers at the film end position.

[0005] Therefore, it can be seen that the existing preparation method cannot guarantee that the openings at the ends of the thin film and the bottom electrode Pad meet the requirements. Summary of the Invention

[0006] In view of this, this application provides a piezoelectric MEMS sensor and its fabrication method and electronic device to solve the problem that existing fabrication methods cannot meet the requirements for both the thin film end portion and the opening of the bottom electrode Pad.

[0007] To address the above problems, embodiments of the present invention provide the following technical solutions:

[0008] The first aspect of this invention discloses a method for fabricating a piezoelectric MEMS sensor, the method comprising:

[0009] Provide a substrate layer;

[0010] An electrode of a predetermined thickness is formed at the location of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer;

[0011] A bottom electrode, a piezoelectric layer, and a top electrode are deposited on the upper surfaces of the electrode and the substrate layer;

[0012] A photolithography process is performed to form the bottom electrode pad opening and the thin film end.

[0013] Optionally, an electrode of a predetermined thickness is formed at the location of a predetermined bottom electrode Pad opening on the upper surface of the substrate, including:

[0014] One or more electrode films are deposited at the location of the bottom electrode Pad opening on the upper surface of the substrate layer, and the one or more electrode films are patterned to obtain an electrode with a predetermined thickness.

[0015] or,

[0016] At the location of the predetermined bottom electrode Pad opening on the upper surface of the substrate, a trench of predetermined depth is etched.

[0017] An electrode is deposited in the trench and CMP is performed so that the upper surface of the electrode is at the same level as the upper surface of the substrate.

[0018] Optionally, patterning the one or more electrode films includes:

[0019] The one or more electrode films are patterned according to single-step, polygonal, or right-angled trapezoidal shapes.

[0020] A second aspect of this invention discloses a piezoelectric MEMS sensor, the piezoelectric MEMS sensor comprising:

[0021] Substrate layer;

[0022] An electrode of a predetermined thickness is disposed at the position of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer;

[0023] A bottom electrode, a piezoelectric layer, and a top electrode are deposited on the upper surfaces of the electrode and the substrate layer;

[0024] The bottom electrode Pad opening and the film end, wherein the bottom electrode end, the piezoelectric layer end and the top electrode end are aligned at the film end location.

[0025] Optionally, the substrate layer includes a semiconductor substrate layer.

[0026] Optionally, the width of the electrode with the preset thickness is greater than the width of the opening of the bottom electrode Pad.

[0027] Optionally, the thickness of the electrode with the preset thickness is greater than the thickness of the bottom electrode.

[0028] Optionally, the thickness of the electrode with the preset thickness is greater than 20% of the thickness of the bottom electrode.

[0029] Optionally, the electrode with the preset thickness is a patterned electrode composed of one or more electrode films;

[0030] The patterned electrode is positioned at the location of the pre-set bottom electrode Pad opening on the upper surface of the substrate.

[0031] Optionally, the width of the patterned electrode is greater than the width of the bottom electrode Pad opening.

[0032] Optionally, the patterned electrode is a single-stage stepped electrode, a polygonal electrode, or a right-angled trapezoidal electrode;

[0033] If it is a right-angled trapezoidal electrode, the inclined waist of the right-angled trapezoidal electrode faces the end of the thin film.

[0034] Optionally, a trench of a predetermined depth is formed at the position of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer;

[0035] An electrode is deposited in the trench, and the upper surface of the electrode is at the same level as the upper surface of the substrate.

[0036] Optionally, the groove opening width is greater than the width of the bottom electrode Pad opening.

[0037] A third aspect of the present invention discloses an electronic device, wherein the electronic device is provided with a piezoelectric MEMS sensor prepared using the piezoelectric MEMS sensor preparation method disclosed in the first aspect of the present invention; or, the electronic device is provided with a piezoelectric MEMS sensor disclosed in the second aspect of the present invention.

[0038] Based on the above embodiments of the present invention, a piezoelectric MEMS sensor and its fabrication method, and an electronic device, are provided by providing a substrate layer; forming an electrode of a predetermined thickness at a predetermined bottom electrode Pad opening position on the upper surface of the substrate layer; depositing a bottom electrode, a piezoelectric layer, and a top electrode on the electrode and the upper surface of the substrate layer; and forming the bottom electrode Pad opening and the thin film end in a single photolithography step. In this embodiment of the present invention, before depositing the bottom electrode, an electrode of a predetermined thickness is formed on the substrate layer at the predetermined bottom electrode Pad opening position. Then, the bottom electrode Pad opening and the thin film end are formed in a single photolithography step. This not only ensures that the bottom electrode end at the thin film end position is aligned with the ends of the other two film layers, but also ensures that the electrical connection at the bottom electrode Pad opening is not affected during the single photolithography step because an electrode of a predetermined thickness is deposited first at the predetermined bottom electrode Pad opening position. This achieves the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening in a single photolithography step. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the drawings used in the description of the embodiments or prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0040] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0041] Figure 1 This is a schematic cross-sectional view of a piezoelectric device in the prior art;

[0042] Figure 2 This is a schematic flowchart illustrating a method for fabricating a piezoelectric MEMS sensor according to an embodiment of the present invention.

[0043] Figures 3 to 8 A process flow diagram of a method for fabricating a piezoelectric MEMS sensor provided in an embodiment of the present invention;

[0044] Figures 9 to 15 A process flow diagram of another method for fabricating a piezoelectric MEMS sensor provided in an embodiment of the present invention.

[0045] Among them, substrate 1, upper surface 11 of substrate 1, lower surface 12 of substrate 1, electrode 2, bottom electrode 3, piezoelectric layer 4, top electrode 5, thin film end 6, bottom electrode Pad opening 7, and trench 8. Detailed Implementation

[0046] The embodiments of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0047] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] like Figure 2 The diagram shown is a flowchart illustrating a method for fabricating a piezoelectric MEMS sensor according to an embodiment of the present invention. The fabrication method includes:

[0049] S201: Provide a substrate layer.

[0050] In this embodiment of the invention, the substrate layer may be a semiconductor layer. The substrate layer has an upper surface and a lower surface.

[0051] S202: An electrode of a predetermined thickness is formed at the position of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer.

[0052] In this embodiment of the invention, the position where the bottom electrode Pad opening will be made is predetermined on the upper surface of the substrate, and an electrode of a predetermined thickness is formed at the position of the bottom electrode Pad opening.

[0053] In one embodiment of the present invention, the width of the electrode with the preset thickness is greater than the width of the opening of the bottom electrode Pad, that is, the width of the electrode with the preset thickness is greater than the width of the opening of the preset bottom electrode Pad.

[0054] In one embodiment of the present invention, the thickness of the electrode with the preset thickness may be the same as or greater than the thickness of the bottom electrode.

[0055] In one embodiment of the present invention, the thickness of the electrode with the preset thickness is greater than 20% of the thickness of the bottom electrode.

[0056] S203: Deposit a bottom electrode, a piezoelectric layer, and a top electrode on the upper surface of the electrode and the substrate layer.

[0057] In this embodiment of the invention, the electrode is disposed on the substrate layer via S202, and a portion of the upper surface of the substrate layer overlaps with the electrode. On this basis, a bottom electrode, a piezoelectric layer and a top electrode are deposited.

[0058] It should be noted that the "on" in the substrate layer here does not simply indicate direction. It can indicate that the electrode is disposed on the substrate layer 1 in a protruding manner, or it can indicate that the electrode is disposed on the substrate layer in an embedded manner.

[0059] S204: Perform a photolithography step to form the bottom electrode Pad opening and the thin film end.

[0060] In this embodiment of the invention, the bottom electrode Pad opening and the thin film end are formed in a single photolithography step, ensuring that the end faces of the three film layers at the thin film end are aligned. That is, the end faces of the bottom electrode end, the piezoelectric layer end, and the top electrode end at the thin film end are aligned.

[0061] In this embodiment of the invention, the position of the preset bottom electrode Pad is different from the position of the pre-formed thin film end, with an electrode of a preset thickness added at the preset bottom electrode Pad position. During the execution of S204, the bottom electrode Pad opening and the thin film end are formed in one photolithography step. The end faces of the three film layers (bottom electrode, piezoelectric layer, and top electrode) at the formed thin film end position are aligned, while the preset bottom electrode Pad position has an electrode of a preset thickness added. After one photolithography step, the bottom electrode Pad position will retain all or part of the electrode, but it will not penetrate into the substrate layer, thus not affecting the electrical connection effect of the bottom electrode Pad.

[0062] In the fabrication method of the piezoelectric MEMS sensor disclosed in this embodiment of the invention, before depositing the bottom electrode, an electrode of a predetermined thickness is formed on the substrate layer at the position of the predetermined bottom electrode Pad opening. Then, the bottom electrode Pad is exposed and a thin film end is formed by a single photolithography process. This not only ensures that the bottom electrode end at the thin film end position is aligned with the ends of the other two film layers, but also ensures that the electrical connection at the bottom electrode Pad opening is not affected by the predetermined electrode layer at the position of the predetermined bottom electrode Pad opening, thus achieving the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening through a single photolithography process.

[0063] Based on the piezoelectric MEMS sensor fabrication method disclosed in the above embodiments of the present invention, such as Figures 3 to 6 The diagram shown is a process flow chart of a fabrication method for a piezoelectric MEMS sensor according to an embodiment of the present invention. The fabrication method includes:

[0064] S301: As Figure 3 As shown, a substrate layer 1 is provided.

[0065] S302: As Figure 4 As shown, one or more electrode films are deposited at the position of the preset bottom electrode Pad on the upper surface 11 of the substrate layer, and the one or more electrode films are patterned to obtain an electrode 2 with a preset thickness.

[0066] In one embodiment of the present invention, the patterning includes: patterning the one or more electrode films according to a single-level step, a polygon, or a right-angled trapezoid.

[0067] If patterned as a right trapezoid, the sloping waist of the right trapezoidal electrode faces the end of the pre-formed thin film.

[0068] In one embodiment of the present invention, the width of the electrode 2 with a preset thickness, obtained through patterning, is greater than the width of the bottom electrode Pad opening 7. That is, the width of the electrode 2 with the preset thickness is greater than the width of the bottom electrode Pad opening 7 formed by pre-etching.

[0069] Figure 5 This is another perspective view of the graphical representation of a right-angled trapezoid.

[0070] S303: As Figure 6 As shown, a bottom electrode 3, a piezoelectric layer 4, and a top electrode 5 are deposited on the upper surface 11 of the electrode 2 and the substrate layer.

[0071] In one embodiment of the present invention, the thickness of electrode 2 is greater than the thickness of bottom electrode 3.

[0072] In one embodiment of the present invention, the thickness of electrode 2 is greater than 20% of the thickness of bottom electrode 3.

[0073] S304: As Figure 7 As shown, a photolithography process is performed to form the bottom electrode Pad opening 7 and the thin film end 6.

[0074] In this embodiment of the invention, when the materials of electrode 2 and bottom electrode 3 are different, and the materials of electrode 2 and bottom electrode 3 have a high etching selectivity, then a single photolithography step will form a structure as shown below. Figure 7 The structure shown.

[0075] In this embodiment of the invention, when electrode 2 and bottom electrode 3 are made of the same material, or when the etching selectivity of the materials of electrode 2 and bottom electrode 3 is relatively low, a single photolithography step is performed to form a shape as shown in the image. Figure 8 The structure shown.

[0076] Compared to Figure 7 , Figure 8The electrode 2 in the structure shown will also be partially etched away at the opening 7 of the bottom electrode Pad. However, due to the presence of the electrode 2, even if part of it is etched away, it will not penetrate to the substrate layer 1, and therefore will not affect the electrical connection effect of the bottom electrode Pad.

[0077] In the fabrication method of the piezoelectric MEMS sensor disclosed in this embodiment of the invention, before depositing the bottom electrode, an electrode of a preset thickness is formed on the substrate layer at the position of the preset bottom electrode Pad opening. Then, the bottom electrode Pad is exposed and a thin film end is formed by a single photolithography process. This not only ensures that the bottom electrode end at the thin film end position is aligned with the ends of the other two film layers, but also ensures that the electrical connection at the bottom electrode Pad opening is not affected by the added electrode of the preset bottom electrode Pad opening position during a single photolithography process. This achieves the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening through a single photolithography process.

[0078] Based on the piezoelectric MEMS sensor fabrication method disclosed in the above embodiments of the present invention, such as Figures 9 to 14 The diagram shown is a process flow chart of a fabrication method for a piezoelectric MEMS sensor according to an embodiment of the present invention. The fabrication method includes:

[0079] S801: As Figure 9 As shown, a substrate layer 1 is provided.

[0080] S802: As Figure 10 As shown, a trench 8 of a predetermined depth is etched at the position of the predetermined bottom electrode Pad opening on the upper surface 11 of the substrate layer.

[0081] In one embodiment of the present invention, the width of the groove 8 is greater than the width of the bottom electrode Pad opening. That is, the width of the groove 8 is greater than the width of the bottom electrode Pad opening 7 formed by pre-etching.

[0082] In one embodiment of the present invention, the preset depth is less than the thickness of the substrate layer 1 and greater than the thickness of the bottom electrode.

[0083] S803: such as Figure 11 As shown, an electrode 2 is deposited in the trench 8 and CMP (planarization) is performed so that the upper surface of the electrode 2 is at the same level as the upper surface of the substrate layer 1.

[0084] In this embodiment of the invention, one or more electrode films are deposited in the trench 8 to form an electrode 2. Then, the electrode 2 is subjected to CMP treatment to remove the electrode material outside the trench 8 and make its surface smooth, so that the upper surface of the electrode 2 is at the same level as the upper surface of the substrate layer 1.

[0085] Figure 12 Another perspective view after CMP is performed on the electrode 2 deposited in the trench 8.

[0086] S804: As Figure 13 As shown, a bottom electrode 3, a piezoelectric layer 4, and a top electrode 5 are deposited on the upper surface 11 of the electrode 2 and the substrate layer.

[0087] S805: As Figure 14 As shown, a photolithography process is performed to form the bottom electrode Pad opening 7 and the thin film end 6.

[0088] In this embodiment of the invention, when the materials of electrode 2 and bottom electrode 3 are different, and the materials of electrode 2 and bottom electrode 3 with a preset thickness have a high etching selectivity, then a single photolithography step will form a structure as shown in the image. Figure 14 The structure shown.

[0089] In this embodiment of the invention, when electrode 2 and bottom electrode 3 are made of the same material, or when the etching selectivity of the materials of electrode 2 and bottom electrode 3 is relatively low, a single photolithography step is performed to form a shape as shown in the image. Figure 15 The structure shown.

[0090] Compared to Figure 14 , Figure 15 The electrode 2 in the structure shown will also be partially etched at the bottom electrode Pad opening 7, but it will not penetrate to the substrate layer 1, so it will not affect the electrical connection effect of the bottom electrode Pad.

[0091] In the fabrication method of the piezoelectric MEMS sensor disclosed in this invention embodiment, before depositing the bottom electrode, a trench is made on the substrate layer at the location of the preset bottom electrode Pad opening, and an electrode is filled or deposited in the trench. Then, the bottom electrode Pad is exposed and a thin film end is formed by a single photolithography process. This not only ensures that the bottom electrode end at the thin film end position is aligned with the ends of the other two film layers, but also ensures that the electrical connection at the bottom electrode Pad opening is not affected by the additional electrode deposited at the location of the preset bottom electrode Pad opening during a single photolithography process. This achieves the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening through a single photolithography process.

[0092] This invention discloses a piezoelectric MEMS sensor, which includes:

[0093] Substrate layer 1. In one embodiment of the present invention, the substrate layer 1 may be a semiconductor substrate layer or other conductive layer.

[0094] An electrode 2 of a predetermined thickness is disposed at the position of the predetermined bottom electrode Pad opening 7 on the upper surface 11 of the substrate.

[0095] The bottom electrode 3, the piezoelectric layer 4, and the top electrode 5 are deposited on the upper surface 11 of the electrode 2 and the substrate layer.

[0096] The bottom electrode Pad opening 7 and the thin film end 6 are provided, wherein the bottom electrode end, the piezoelectric layer end and the top electrode end are aligned at the thin film end position.

[0097] In one embodiment of the present invention, the thickness of the electrode 2 with a preset thickness can be the same as or greater than the thickness of the bottom electrode.

[0098] In one embodiment of the present invention, the thickness of the electrode 2 with the preset thickness is greater than 20% of the thickness of the bottom electrode.

[0099] In one embodiment of the present invention, the width of the electrode 2 with the preset thickness is greater than the width of the bottom electrode Pad opening 7.

[0100] In one embodiment of the present invention, the electrode 2 of a predetermined thickness can be a patterned electrode 2 composed of one or more electrode films. The patterned electrode 2 is disposed at a predetermined bottom electrode Pad position on the upper surface 11 of the substrate layer.

[0101] In one embodiment of the present invention, the width of the patterned electrode 2 is greater than the opening width of the bottom electrode Pad.

[0102] In one embodiment of the present invention, the thickness of the patterned electrode 2 is greater than the thickness of the bottom electrode 3.

[0103] In one embodiment of the present invention, the thickness of electrode 2 is greater than 20% of the thickness of bottom electrode 3. In one embodiment of the present invention, the patterned electrode 2 is a single-stage stepped electrode, a polygonal electrode, or a right-angled trapezoidal electrode.

[0104] If it is a right-angled trapezoidal electrode, the inclined waist of the right-angled trapezoidal electrode faces the end of the thin film, as detailed in [reference needed]. Figure 7 .

[0105] In one embodiment of the present invention, when the materials of electrode 2 and bottom electrode 3 are different, and the materials of electrode 2 and bottom electrode 3 have a high etching selectivity, then a single photolithography step will form a structure as shown in the image. Figure 7 The structure shown.

[0106] In one embodiment of the present invention, when electrode 2 and bottom electrode 3 are made of the same material, or when the etching selectivity ratio of the materials of electrode 2 and bottom electrode 3 is relatively low, a single photolithography step is performed to form a shape as shown in the image. Figure 8 The structure shown.

[0107] Compared to Figure 7 , Figure 8The electrode 2 in the structure shown will also be partially etched at the bottom electrode Pad opening 7, but it will not penetrate to the substrate layer 1, so it will not affect the electrical connection effect of the bottom electrode Pad.

[0108] In the piezoelectric MEMS sensor disclosed in this embodiment of the invention, an electrode of a preset thickness is added at the position of the preset bottom electrode Pad opening. During a single photolithography process, it can be ensured that the electrical connection at the bottom electrode Pad opening is not affected, thus achieving the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening through a single photolithography process.

[0109] Another piezoelectric MEMS sensor disclosed in this embodiment of the invention includes:

[0110] Substrate 1.

[0111] An electrode 2 of a predetermined thickness is disposed at the position of the predetermined bottom electrode Pad opening on the upper surface 11 of the substrate.

[0112] A trench 8 of a predetermined depth is formed at the location of the predetermined bottom electrode Pad opening on the upper surface 11 of the substrate layer. This predetermined depth is less than the depth of the substrate layer 1.

[0113] An electrode 2 is deposited in the trench 8, and the upper surface of the electrode 2 is at the same level as the upper surface 11 of the substrate. The width of the trench 8 opening is greater than the opening width of the bottom electrode Pad.

[0114] The bottom electrode 3, the piezoelectric layer 4, and the top electrode 5 are deposited on the upper surface 11 of the electrode 2 and the substrate layer.

[0115] The bottom electrode Pad opening 7 and the thin film end 6 are provided, wherein the bottom electrode end, the piezoelectric layer end and the top electrode end are aligned at the thin film end position.

[0116] In this embodiment of the invention, when the materials of electrode 2 and bottom electrode 3 are different, and the materials of electrode 2 and bottom electrode 3 have a high etching selectivity, then a single photolithography step will form a structure as shown below. Figure 14 The structure shown.

[0117] In this embodiment of the invention, when electrode 2 and bottom electrode 3 are made of the same material, or when the etching selectivity of the materials of electrode 2 and bottom electrode 3 is relatively low, a single photolithography step is performed to form a shape as shown in the image. Figure 15 The structure shown.

[0118] Compared to Figure 14 , Figure 15 The electrode 2 in the structure shown will also be partially etched at the bottom electrode Pad opening 7, but it will not penetrate to the substrate layer 1, so it will not affect the electrical connection effect of the bottom electrode Pad.

[0119] In the piezoelectric MEMS sensor disclosed in this embodiment of the invention, a groove is made on the substrate layer at the position of the preset bottom electrode Pad opening, and an electrode is filled or deposited in the groove. Then, the bottom electrode Pad is exposed and a thin film end is formed by a single photolithography process. This not only ensures that the bottom electrode end at the thin film end position is aligned with the ends of the other two film layers, but also ensures that the electrical connection at the bottom electrode Pad opening is not affected during a single photolithography process because an extra electrode layer is deposited at the position of the preset bottom electrode Pad opening. This achieves the goal of meeting the requirements of both the thin film end and the bottom electrode Pad opening through a single photolithography process.

[0120] This invention also discloses an electronic device, which is equipped with the above-described... Figure 2 , Figures 3 to 8 ,or Figures 9 to 15 The provided method for fabricating piezoelectric MEMS sensors produces piezoelectric MEMS sensors.

[0121] This invention also discloses an electronic device, which is provided with such... Figure 7 , Figure 8 , Figure 14 or Figure 15 The piezoelectric MEMS sensor shown.

[0122] The various embodiments in this specification are described in a progressive, parallel, or combined manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referred to each other.

[0123] It should be noted that, in the description of this application, the drawings and embodiments are illustrative rather than restrictive. The same reference numerals throughout the embodiments identify the same structures. Additionally, for ease of understanding and description, the thicknesses of some layers, films, panels, regions, etc., may be exaggerated in the drawings. It is also understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element or there may be intermediate elements. Furthermore, "on" means positioning an element on or below another element, but does not inherently mean positioning it above another element according to the direction of gravity.

[0124] The terms "upper," "lower," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be a component positioned centrally in the middle.

[0125] It should also be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or apparatus comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or apparatus that includes the aforementioned element.

[0126] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for fabricating a piezoelectric MEMS sensor, characterized in that, The preparation method includes: Provide a substrate layer; An electrode of a predetermined thickness is formed at the location of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer; A bottom electrode, a piezoelectric layer, and a top electrode are deposited on the upper surfaces of the electrode and the substrate layer; A photolithography process is performed to form the bottom electrode pad opening and the thin film end.

2. The method according to claim 1, characterized in that, An electrode of a predetermined thickness is formed at the location of a predetermined bottom electrode Pad opening on the upper surface of the substrate, including: One or more electrode films are deposited at the location of the bottom electrode Pad opening on the upper surface of the substrate layer, and the one or more electrode films are patterned to obtain an electrode with a predetermined thickness. or, At the location of the predetermined bottom electrode Pad opening on the upper surface of the substrate, a trench of predetermined depth is etched. An electrode is deposited in the trench and CMP is performed so that the upper surface of the electrode is at the same level as the upper surface of the substrate.

3. The method according to claim 2, characterized in that, Patterning the one or more electrode films includes: The one or more electrode films are patterned according to single-step, polygonal, or right-angled trapezoidal shapes.

4. A piezoelectric MEMS sensor, characterized in that, The piezoelectric MEMS sensor includes: Substrate layer; An electrode of a predetermined thickness is disposed at the position of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer; A bottom electrode, a piezoelectric layer, and a top electrode are deposited on the upper surfaces of the electrode and the substrate layer; The bottom electrode Pad opening and the thin film end are formed simultaneously by photolithography after depositing a bottom electrode, a piezoelectric layer and a top electrode on the upper surface of the substrate. The bottom electrode end, the piezoelectric layer end and the top electrode end at the thin film end position are aligned.

5. The piezoelectric MEMS sensor according to claim 4, characterized in that, The substrate layer includes a semiconductor substrate layer.

6. The piezoelectric MEMS sensor according to claim 4, characterized in that, The width of the electrode with the preset thickness is greater than the width of the opening of the bottom electrode Pad.

7. The piezoelectric MEMS sensor according to claim 4, characterized in that, The thickness of the electrode with the preset thickness is greater than the thickness of the bottom electrode.

8. The piezoelectric MEMS sensor according to claim 4, characterized in that, The thickness of the electrode with the preset thickness is greater than 20% of the thickness of the bottom electrode.

9. The piezoelectric MEMS sensor according to any one of claims 4 to 8, characterized in that, The electrode with the preset thickness is a patterned electrode composed of one or more electrode films; The patterned electrode is positioned at the location of the pre-set bottom electrode Pad opening on the upper surface of the substrate.

10. The piezoelectric MEMS sensor according to claim 9, characterized in that, The width of the patterned electrode is greater than the width of the opening of the bottom electrode Pad.

11. The piezoelectric MEMS sensor according to claim 9, characterized in that, The patterned electrode is a single-stage stepped electrode, a polygonal electrode, or a right-angled trapezoidal electrode; If it is a right-angled trapezoidal electrode, the inclined waist of the right-angled trapezoidal electrode faces the end of the thin film.

12. The piezoelectric MEMS sensor according to any one of claims 4 to 8, characterized in that, A groove of a predetermined depth is formed at the position of the predetermined bottom electrode Pad opening on the upper surface of the substrate layer; An electrode is deposited in the trench, and the upper surface of the electrode is at the same level as the upper surface of the substrate.

13. The piezoelectric MEMS sensor according to claim 12, characterized in that, The groove opening width is greater than the opening width of the bottom electrode Pad.

14. An electronic device, characterized in that, The electronic device is provided with a piezoelectric MEMS sensor prepared using the piezoelectric MEMS sensor preparation method according to any one of claims 1 to 3; or, the electronic device is provided with a piezoelectric MEMS sensor according to any one of claims 4 to 13.

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