Filter and method of manufacturing the same

Abstract

The application provides a filter and a manufacturing method thereof, wherein the manufacturing method comprises the following steps: providing a substrate; manufacturing a piezoelectric body on a plane of one side of the substrate; manufacturing a first electrode and a second electrode on two sides of the piezoelectric body, and the first electrode, the piezoelectric body and the second electrode form a piezoelectric sensing structure; manufacturing a frequency modulation structure, and the frequency modulation structure comprises a first frequency modulation block fixedly connected with the first electrode and a second frequency modulation block fixedly connected with the second electrode; manufacturing a shell structure, and the shell structure is fixed above the substrate to form a first cavity for accommodating the piezoelectric sensing structure and the frequency modulation structure; and manufacturing an electrical connection structure, and the electrical connection structure comprises a first electrical connecting member and a second electrical connecting member, the first electrical connecting member is electrically connected with the first electrode, and the second electrical connecting member is electrically connected with the second electrode. The application can realize more accurate frequency adjustment of the filter by independently adjusting the frequency modulation blocks on the sides of different electrodes, increase the frequency adjustment range, and improve the frequency stability and control precision.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, and in particular to a filter and its manufacturing method. Background Technology

[0002] The filter comprises two thin-film electrodes and a piezoelectric thin-film layer disposed between the two electrodes. Its working principle is as follows: The thin-film electrodes generate an electric field on the piezoelectric thin-film layer by applying a voltage. Under the influence of the electric field, the piezoelectric thin-film layer undergoes periodic mechanical deformation, thereby generating sound waves of the corresponding frequency. When the sound waves propagate through the piezoelectric thin-film layer and cause deformation, the thin-film electrodes sense the charge changes generated by the piezoelectric effect, thus converting the mechanical vibration back into an electrical signal, completing signal reception.

[0003] Commonly used filters typically involve stacking a lower thin-film electrode, a piezoelectric thin film, and an upper thin-film electrode along the thickness direction of the substrate. The upper and lower thin-film electrodes require photolithography on both sides. Furthermore, when fabricating the upper thin-film electrode, it is usually necessary to bond it with a new silicon cap wafer to form a top cavity and seal it. The fabrication process is complex. Moreover, commonly used filters can only fabricate a frequency modulation layer on the upper thin-film electrode side, which limits the frequency adjustment range, results in poor frequency modulation performance, and makes it difficult to control product quality. Summary of the Invention

[0004] The present invention aims to at least solve the technical problems existing in the prior art, and to provide a filter and its manufacturing method.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] Firstly, a method for manufacturing a filter is provided, comprising:

[0007] A substrate is provided, and a piezoelectric material layer covering the surface of the substrate is formed on a plane on one side of the substrate, and the piezoelectric material layer is etched to form a piezoelectric body;

[0008] An electrode layer is fabricated, which covers the piezoelectric body and the remaining surface of the substrate;

[0009] The electrode layer is etched to form a first electrode and a second electrode located on both sides of the piezoelectric body. The first electrode, the piezoelectric body, and the second electrode constitute a piezoelectric sensing structure.

[0010] A frequency modulation structure is fabricated, the frequency modulation structure including a first frequency modulation block and a second frequency modulation block, the first frequency modulation block being fixedly connected to a first electrode, and the second frequency modulation block being fixedly connected to a second electrode;

[0011] A housing structure is fabricated and fixed above the substrate to form a first cavity accommodating the piezoelectric sensing structure and the frequency modulation structure;

[0012] An electrical connection structure is fabricated, the electrical connection structure including a first electrical connector and a second electrical connector, the first electrical connector penetrating the housing structure and electrically connected to the first electrode, and the second electrical connector penetrating the housing structure and electrically connected to the second electrode.

[0013] In addition to one or more of the features disclosed above, or alternatively, the first electrode includes a first portion and a second portion connected to the first portion, the first portion covering a portion of the piezoelectric body, with a region of the piezoelectric body's side surface covered by the first portion exposed away from the substrate, the second portion covering a portion of the remaining surface of the substrate, and the second electrode covering a portion of the piezoelectric body, with a region of the piezoelectric body's side surface covered by the second electrode exposed near the substrate.

[0014] In addition to one or more of the features disclosed above, or alternatively, the method further includes, prior to the fabrication of the frequency modulation structure:

[0015] A first sacrificial material layer is deposited on one side plane of the substrate where the piezoelectric element is located. The first sacrificial material layer covers the remaining surface of the substrate and encapsulates the piezoelectric sensing structure.

[0016] The first sacrificial material layer is etched, exposing the end of the piezoelectric sensing structure away from the substrate, and the remaining first sacrificial material layer forms the first sacrificial structure.

[0017] In addition to one or more of the features disclosed above, or as an alternative, the fabrication of the frequency modulation structure, the frequency modulation structure comprising a first frequency modulation block and a second frequency modulation block, the first frequency modulation block being fixedly connected to a first electrode, and the second frequency modulation block being fixedly connected to a second electrode, comprising:

[0018] A frequency-modulated material layer is deposited on the first sacrificial structure, the frequency-modulated material layer covering the surface of the first sacrificial structure and partially covering the first electrode and a portion of the second electrode;

[0019] The frequency modulation material layer is etched to expose the surface of the end of the first sacrificial structure away from the piezoelectric sensing structure, in order to form the first frequency modulation block and the second frequency modulation block.

[0020] In addition to one or more of the features disclosed above, or alternatively, the method further includes, prior to the fabrication of the shell structure:

[0021] A second sacrificial structure is deposited on the first sacrificial structure, the second sacrificial structure covering the remaining surface of the first sacrificial structure and enclosing the exposed portion of the frequency modulation structure and the piezoelectric sensing structure;

[0022] The second sacrificial structure is etched to expose the surface of the substrate away from the edge of the piezoelectric sensing structure and to expose the end face of the piezoelectric body away from the substrate.

[0023] In addition to one or more of the features disclosed above, or alternatively, the fabrication of the housing structure, which covers and is fixed above the substrate to form a first cavity accommodating the piezoelectric sensing structure and the frequency modulation structure, includes:

[0024] A passivation material is deposited on the exposed surface of the substrate, the passivation material covering the first sacrificial structure, the second sacrificial structure, and the end face of the piezoelectric element away from the substrate, forming the shell structure.

[0025] In addition to one or more of the features disclosed above, or as an alternative, an electrical connection structure is fabricated, the electrical connection structure including a first electrical connector and a second electrical connector, the first electrical connector penetrating the housing structure and electrically connected to the first electrode, and the second electrical connector penetrating the housing structure and electrically connected to the second electrode, including:

[0026] The shell structure, the first sacrificial structure, and the second sacrificial structure are etched to form a first groove and a second groove, wherein the second portion of the first electrode is exposed at the bottom of the first groove and the second electrode is exposed at the bottom of the second groove;

[0027] A first conductive material is deposited, which fills the first groove and covers part of the housing to form the first electrical connector;

[0028] A second conductive material is deposited, which fills the second groove and covers part of the housing to form the second electrical connector.

[0029] In addition to one or more of the features disclosed above, or alternatively, the method may also include:

[0030] The shell structure is etched to form a first notch and a second notch, wherein, in the thickness direction of the substrate, the projection of the first notch is located within the projection range of the first frequency modulation block, and the projection of the second notch is located within the projection range of the second frequency modulation block;

[0031] The first sacrificial structure and the second sacrificial structure are removed through the first gap and the second gap.

[0032] In addition to one or more of the features disclosed above, or alternatively, the method may also include:

[0033] The frequency of the filter is adjusted by reducing the first and second frequency modulation blocks through ion beam bombardment, so that the frequency of the filter reaches the preset frequency.

[0034] The ion beam bombards the first frequency modulation block through the first notch, and the ion beam bombards the second frequency modulation block through the second notch.

[0035] Secondly, a filter is provided, including:

[0036] Substrate;

[0037] A shell structure, wherein the shell structure is fixedly connected to one side surface of the substrate to form a first cavity;

[0038] A piezoelectric sensing structure is located within the first cavity. The piezoelectric sensing structure includes a piezoelectric body fixed between the housing structure and the substrate, and a first electrode and a second electrode located on both sides of the piezoelectric body.

[0039] A frequency modulation structure is located within the first cavity. The frequency modulation structure includes a first frequency modulation block and a second frequency modulation block. The first frequency modulation block is fixedly connected to a first electrode, and the second frequency modulation block is fixedly connected to a second electrode.

[0040] An electrical connection structure, comprising a first electrical connector and a second electrical connector, which penetrate the housing and are electrically connected to a first electrode, and a second electrical connector that penetrates the housing and is electrically connected to a second electrode.

[0041] In addition to one or more of the features disclosed above, or alternatively, the first electrode includes a first portion and a second portion, the first portion covering a portion of the piezoelectric body, with a region of the piezoelectric body's side surface covered by the first portion exposed away from the substrate, the second portion covering the remaining surface of the substrate, and the second electrode covering a portion of the piezoelectric body, with a region of the piezoelectric body's side surface covered by the second electrode exposed near the substrate.

[0042] In addition to one or more of the features disclosed above, or alternatively, the distance between the end face of the first portion away from the substrate and the end face of the piezoelectric body away from the substrate is 0.1µm-0.5µm;

[0043] The distance between the end face of the second electrode near the substrate and the surface of the substrate is 0.1um-0.5um.

[0044] In addition to one or more of the features disclosed above, or as an alternative, the housing structure has a first notch and a second notch that penetrate the housing structure, wherein, in the thickness direction of the substrate, the projection of the first notch is located within the projection range of the first frequency modulation block, and the projection of the second notch is located within the projection range of the second frequency modulation block.

[0045] In addition to one or more of the features disclosed above, or alternatively, in the thickness direction of the substrate, the distance between the projection of the first notch and the projection of the first electrode is 0.1-1 μm, and the distance between the projection of the second notch and the projection of the second electrode is 0.1-1 μm.

[0046] In addition to one or more of the features disclosed above, or alternatively, the projection of the piezoelectric body in the substrate thickness direction is a closed loop or an open loop.

[0047] In addition to one or more of the features disclosed above, or alternatively, one side surface of the substrate includes a plurality of the piezoelectric elements, with a spacing greater than 1 μm between adjacent piezoelectric elements.

[0048] The filter and its manufacturing method provided by this invention involve stacking the first electrode, piezoelectric element, and second electrode along the planar direction of the substrate in the piezoelectric sensing structure. Compared to a piezoelectric sensing structure where the lower electrode, piezoelectric element, and upper electrode are stacked along the thickness direction of the substrate, the fabrication process of this application is simpler. For example, the former requires etching the substrate connected to the lower electrode to form the lower movable cavity of the piezoelectric sensing structure, and etching the substrate connected to the upper electrode to form the upper movable cavity of the piezoelectric sensing structure, while this application does not require such a complex process. Furthermore, when fabricating the frequency modulation structure, this application can fabricate a first frequency modulation block connected to the first electrode on the side where the first electrode is located, and a second frequency modulation block connected to the second electrode on the side where the second electrode is located. This allows for more accurate adjustment of the filter frequency by independently adjusting the frequency modulation blocks on different electrode sides, increasing the frequency adjustment range, improving frequency stability and control accuracy, and enabling the filter to better adapt to different application requirements. Attached Figure Description

[0049] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other implementation methods can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic flowchart of a filter manufacturing method according to an embodiment of the present invention.

[0051] Figure 2-17 This is a schematic diagram of the manufacturing process of a filter according to an embodiment of the present invention.

[0052] Figure 18 This is a schematic projection of a piezoelectric element provided according to an embodiment of the present invention.

[0053] Figure label:

[0054] 10. Substrate;

[0055] 20. Piezoelectric sensing structure; 201. Piezoelectric element; 202. First electrode; 2021. First part; 2022. Second part; 203. Second electrode;

[0056] 30. Frequency modulation structure; 301. First frequency modulation block; 302. Second frequency modulation block;

[0057] 40. First sacrificial structure; 41. Second sacrificial structure;

[0058] 50. Shell structure;

[0059] 60. Electrical connection structure; 601. First electrical connector; 602. Second electrical connector;

[0060] 020, Piezoelectric material layer; 021, Electrode layer; 040, First sacrificial material layer;

[0061] 030, First groove; 031, Second groove; 033, First notch; 034, Second notch. Detailed Implementation

[0062] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described in detail below with reference to the accompanying drawings.

[0063] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "depth" will be used to indicate the extension of each component element of the pressure sensor in the embodiments of the present invention along the first axis Z of the Cartesian reference system XYZ, and the terms "length" and "width" will respectively indicate the extension of each component element of the pressure sensor in the embodiments of the present invention along the second axis X and the third axis Y of the Cartesian coordinate system XYZ. The terms "installed," "connected," and "linked" should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. When referring to method steps, the order shown in the illustrations represents an exemplary scheme but does not imply a limitation on the order. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0064] To make the objectives, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0065] This invention provides a method for manufacturing a filter, referring to... Figure 1 The method for manufacturing this filter includes:

[0066] S100. Provides a substrate;

[0067] S200. A piezoelectric material layer covering the surface of the substrate is fabricated on a plane on one side of the substrate, and the piezoelectric material layer is etched to form a piezoelectric body;

[0068] S300. Fabricate an electrode layer, which covers the piezoelectric material and the remaining surface of the substrate;

[0069] S400. Etch the electrode layer to form a first electrode and a second electrode located on both sides of the piezoelectric body. The first electrode, the piezoelectric body, and the second electrode constitute a piezoelectric sensing structure.

[0070] S500. Fabricate a frequency modulation structure, which includes a first frequency modulation block and a second frequency modulation block. The first frequency modulation block is fixedly connected to the first electrode, and the second frequency modulation block is fixedly connected to the second electrode.

[0071] S600. Fabricate a housing structure, which is covered and fixed above the substrate to form a first cavity for accommodating the piezoelectric sensing structure and the frequency modulation structure;

[0072] S700. Fabricate an electrical connection structure, the electrical connection structure including a first electrical connector and a second electrical connector, the first electrical connector penetrates the housing structure and is electrically connected to a first electrode, and the second electrical connector penetrates the housing structure and is electrically connected to a second electrode.

[0073] Specifically, in step S100, the provided substrate 10 is as follows: Figure 2 As shown. In some embodiments, substrate 10 may be a silicon substrate. Further, in step S200, first refer to Figure 3 A piezoelectric material layer 020 covering the surface of substrate 10 is fabricated on a plane on one side of substrate 10, and then referred to... Figure 4 The piezoelectric material layer 020 is etched to form the piezoelectric body 201. In some embodiments, the etching angle of the piezoelectric material layer 020 is 85-90 degrees, so that the angle between the sidewalls of the formed piezoelectric body 201 and the plane of the substrate 10 is approximately perpendicular. The vertical sidewalls can enhance the mechanical stability and strength of the piezoelectric body 201, preventing deformation or breakage during subsequent processing or use. Furthermore, in surface acoustic wave devices, the vertical sidewalls can ensure consistent propagation paths and modes of sound waves. Vertical sidewalls also help reduce reflection and diffraction of sound waves during propagation. Tilted or irregular sidewalls can lead to scattering and path deviation of sound waves, thereby affecting the performance and efficiency of the device.

[0074] In some embodiments, the piezoelectric material layer 020 can be a single-crystal piezoelectric material or a polycrystalline piezoelectric material. Specifically, the piezoelectric material can be nitride (ALN), sodium aluminate scandium (ALScN), quartz, etc. These materials exhibit the piezoelectric effect, that is, charge separation or mechanical deformation occurs when pressure or an electric field is applied, thereby realizing the piezoelectric effect. Different piezoelectric materials have different properties and characteristics, and in practical applications, a suitable material can be selected for deposition according to specific application requirements. It should be noted that in some embodiments, the piezoelectric body 201 can be etched into different film structures, referring to... Figure 18 In the thickness direction of the substrate 10, the projection of the piezoelectric body 201 is either a closed loop or an open loop. The closed loop can be a circular loop, an elliptical loop, a rectangular loop, or other closed rings, while the open loop can be a curve or other open line. It should be noted that... Figure 18 The linewidths of the closed-loop and open-loop lines shown represent the thickness of the piezoelectric element 201. The etched piezoelectric element 201 is a film structure. As a film structure, the piezoelectric element 201 has a relatively small thickness, therefore its projection in the thickness direction of the substrate 10 is approximately equivalent to a line. Furthermore, in some embodiments, multiple piezoelectric elements 201 may be etched on a single substrate. (Continuing to refer to...) Figure 18When etching multiple piezoelectric elements 201 on a substrate, the shapes of the multiple piezoelectric elements 201 can be inconsistent; they can be either circular or rectangular ring-shaped. However, the spacing between adjacent piezoelectric elements 201 needs to be greater than 1 μm (inclusive). Figure 18 For example, in the diagram, the distance A is greater than 1 μm, to facilitate the subsequent deposition of other structures on both sides of the piezoelectric body 201. Similarly, when multiple piezoelectric bodies 201 are nested ring structures, the spacing between the nested ring structures also needs to be greater than 1 μm (for example, the distance A in the diagram is greater than 1 μm). Figure 18 For example, in the diagram, the distance C is greater than 1 μm. Simultaneously, the distance between opposite faces within a single ring structure also needs to be greater than 1 μm. Figure 18 For example, the distance B in the diagram is greater than 1µm.

[0075] Step S300: An electrode layer 021 is fabricated on a plane on one side of the substrate 10, referring to... Figure 5 In some embodiments, an electrode layer 021 is formed by depositing electrode material on one side plane of the substrate 10 on which the piezoelectric element 201 is fabricated, thereby covering the piezoelectric element 201 and the remaining surface of the substrate 10. It should be noted that the electrode material can be molybdenum (Mo), tungsten (W), or other materials that can be used to fabricate electrodes.

[0076] Step S400 involves etching the electrode layer 021 to form a first electrode 202 and a second electrode 203 located on both sides of the piezoelectric body 201, such that the first electrode 202, the piezoelectric body 201, and the second electrode 203 together constitute a piezoelectric sensing structure 20. Specifically, in some embodiments, refer to... Figure 7 The first electrode 202 formed by etching the electrode layer 021 includes a first portion 2021 and a second portion 2022 connected to the first portion 2021. The first portion 2021 covers a portion of the piezoelectric body 201, and the area of ​​the piezoelectric body 201 covered by the first portion 2021 away from the substrate 10 is exposed. The second portion 2022 covers the remaining surface of the substrate 10. The second electrode 203 covers a portion of the piezoelectric body 201, and the area of ​​the piezoelectric body 201 covered by the second electrode 203 near the substrate 10 is exposed. Specifically, the first electrode 202 and the second electrode 203 can be completed by the following process: First refer to... Figure 6 The electrode layer 021 is etched to cover a portion of the end face of the piezoelectric body 201, exposing the end face of the piezoelectric body 201 away from the substrate 10. Simultaneously, the portion of the electrode layer 021 covering the substrate 10 is etched, so that the entire surface of the substrate 10 on one side of the piezoelectric body 201 is exposed, and a portion of the surface of the substrate 10 on the other side is exposed (in some embodiments, the thickness of the electrode layer 021 covering a portion of the substrate 10 surface is also thinned in this step); then refer to... Figure 7The electrode layer 021 covering both sides of the piezoelectric body 201 is etched to form the first electrode 202 and the second electrode 203 described above.

[0077] Reference Figure 10 The frequency modulation structure 30 fabricated in step S500 is as follows: Figure 10 As shown, the frequency modulation structure 30 includes a first frequency modulation block 301 and a second frequency modulation block 302. The first frequency modulation block 301 is fixedly connected to the first electrode 202, and the second frequency modulation block 302 is fixedly connected to the second electrode 203. Specifically, in some embodiments, in order to prepare the frequency modulation structure 30 in step S500 above, some preparatory steps need to be performed before fabricating the frequency modulation structure 30, specifically including: first referring to... Figure 8 A first sacrificial material layer 040 is deposited on one side plane of the substrate 10 where the piezoelectric body 201 is located. The first sacrificial material layer 040 covers the remaining surface of the substrate 10 and encapsulates the piezoelectric sensing structure 20; then refer to Figure 9 The first sacrificial material layer 040 is etched, exposing the end of the piezoelectric sensing structure 20 away from the substrate 10, and the remaining first sacrificial material layer 040 forms the first sacrificial structure 40. In some embodiments, the first sacrificial material can be undoped silicate glass (USG), silicon phosphosilicate glass (PSG), silicon nitride (SIN), etc. The first sacrificial material layer 040 can be etched using a wet etching method, and the damage to the electrode caused by wet etching is negligible. Furthermore, the thickness of the first sacrificial structure 40 is greater than the thickness of the second portion 2022. In some embodiments, the thickness of the first sacrificial structure 40 is 0.3µm-1µm, which is 0.1µm-0.5µm greater than the thickness of the second portion 2022.

[0078] Furthermore, the aforementioned frequency modulation structure 30 is completed through the following steps: first, a frequency modulation material layer is deposited on the first sacrificial structure 40, covering the surface of the first sacrificial structure 40 and partially covering the first electrode 202 and part of the second electrode 203; then, the frequency modulation material layer is etched to expose the surface of the first sacrificial structure 40 at the end away from the piezoelectric sensing structure 20, so as to form a structure as described above. Figure 10The first frequency modulation block 301 and the second frequency modulation block 302 are shown. It should be noted that the frequency modulation material can be molybdenum (Mo), tungsten (W), nitride (ALN), silicon nitride (SIN), etc. In some embodiments, the dimensions of the first frequency modulation block 301 and the second frequency modulation block 302 in the thickness direction of the substrate 10 are 0.1µm-1µm. In some embodiments, the distance between the surface of the first frequency modulation block 301 away from the substrate 10 and the surface of the first portion 2021 away from the substrate 10 is 0.1µm-0.5µm. In some embodiments, the distance between the end face of the first frequency modulation block 301 away from the first portion 2021 and the side surface of the first portion 2021 is 1µm-5µm, and the distance between the end face of the second frequency modulation block 302 away from the second electrode 203 and the side surface of the second electrode 203 is 1µm-5µm.

[0079] Reference Figure 13 The shell structure 50 fabricated in step S600 is as follows Figure 13 As shown, the housing structure 50 is covered and fixed above the substrate 10 to form a first cavity accommodating the piezoelectric sensing structure 20 and the frequency modulation structure 30. Specifically, in some embodiments, in order to fabricate the housing structure 50 in step S600 above, some preparatory steps need to be performed before fabricating the housing structure 50, specifically including: first referring to... Figure 11 A second sacrificial structure 41 is deposited on the first sacrificial structure 40, covering the remaining surface of the first sacrificial structure 40 and enclosing the exposed portions of the frequency modulation structure 30 and the piezoelectric sensing structure 20; then refer to Figure 12 The second sacrificial structure 41 is etched to expose the surface of the substrate 10 away from the edge of the piezoelectric sensing structure 20, and to expose the end face of the piezoelectric body 201 away from the substrate 10. It should be noted that the second sacrificial material can be undoped silicate glass (USG), phosphosilicate glass (PSG), etc.

[0080] Furthermore, the aforementioned shell structure 50 is completed through the following process: depositing a passivation material on the exposed surface of the substrate 10, the passivation material covering the first sacrificial structure 40, the second sacrificial structure 41, and the end face of the piezoelectric body 201 away from the substrate 10, forming... Figure 13 The shell structure 50 shown.

[0081] Reference Figure 15 The electrical connection structure 60, fabricated in step S700, is as follows: Figure 15As shown, the electrical connection structure 60 includes a first electrical connector 601 and a second electrical connector 602. The first electrical connector 601 penetrates the housing structure 50 and is electrically connected to the first electrode 202. The second electrical connector 602 penetrates the housing structure 50 and is electrically connected to the second electrode 203. In some embodiments, the electrical connection structure 60 is completed through the following steps, referring first to... Figure 14 The shell structure 50, the first sacrificial structure 40, and the second sacrificial structure 41 are etched to form a first groove 030 and a second groove 031, wherein the second part 2022 of the first electrode 202 is exposed at the bottom of the first groove 030, and the second electrode 203 is exposed at the bottom of the second groove 031; then refer to Figure 15 A first conductive material is deposited, filling the first groove 030 and covering part of the shell to form a first electrical connector 601; a second conductive material is deposited, filling the second groove 031 and covering part of the shell to form a second electrical connector 602. Specifically, dry etching can be used when etching the shell structure 50 to form the first groove 030 and the second groove 031. In the thickness direction of the substrate 10, the distance between the projection of the first groove 030 and the projection of the first frequency modulation block 301 is 1µm-3µm.

[0082] In some embodiments, the filter manufacturing method further includes the following steps: first, etching the housing structure 50 to form a first notch 033 and a second notch 034, wherein, in the thickness direction of the substrate 10, the projection of the first notch 033 is located within the projection range of the first frequency modulation block 301, and the projection of the second notch 034 is located within the projection range of the second frequency modulation block 302; then referring to... Figure 16 The first sacrificial structure 40 and the second sacrificial structure 41 are removed through the first notch 033 and the second notch 034. Specifically, in some embodiments, the first notch 033 and the second notch 034 are formed simultaneously when the first notch 030 and the second notch 031 are formed, and the first notch 033 and the second notch 034 are as follows: Figure 14 and Figure 15 As shown.

[0083] In some embodiments, the method of manufacturing the filter further includes the following steps: (Refer to...) Figure 17 The first frequency modulation block 301 and the second frequency modulation block 302 are reduced by bombardment with an ion beam. The frequency of the filter is adjusted by changing the thickness of the first frequency modulation block 301 and the second frequency modulation block 302 to achieve a preset frequency. Specifically, the ion beam bombards the first frequency modulation block 301 through the first notch 033 and the second frequency modulation block 302 through the second notch 034.

[0084] This invention provides a filter, with reference to... Figure 17The system includes a substrate 10, a housing structure 50, a piezoelectric sensing structure 20, a frequency modulation structure 30, and an electrical connection structure 60. Specifically, the housing structure 50 is fixedly connected to one surface of the substrate 10 to form a first cavity. The piezoelectric sensing structure 20 is located within the first cavity and includes a piezoelectric element 201 fixed between the housing structure 50 and the substrate 10, a first electrode 202, and a second electrode 203 located on both sides of the piezoelectric element 201. The frequency modulation structure 30 is located within the first cavity and includes a first frequency modulation block 301 and a second frequency modulation block 302. The first frequency modulation block 301 is fixedly connected to the first electrode 202, and the second frequency modulation block 302 is fixedly connected to the second electrode 203. The electrical connection structure 60 includes a first electrical connector 601 and a second electrical connector 602, which penetrate the housing and are electrically connected to the first electrode 202. The second electrical connector 602 also penetrates the housing and is electrically connected to the second electrode 203.

[0085] It should be noted that the filter provided in this embodiment can be a bulk acoustic wave filter or a surface acoustic wave filter. The above-disclosed filter manufacturing method can be used to manufacture both bulk acoustic wave filters and surface acoustic wave filters.

[0086] In some embodiments, the first electrode 202 includes a first portion 2021 and a second portion 2022. The first portion 2021 covers a portion of the piezoelectric body 201, with the area of ​​the piezoelectric body 201 covered by the first portion 2021 away from the substrate 10 exposed. The second portion 2022 covers the remaining surface of the substrate 10. A second electrode 203 covers a portion of the piezoelectric body 201, with the area of ​​the piezoelectric body 201 covered by the second electrode 203 near the substrate 10 exposed. Further, the distance between the end face of the first portion 2021 away from the substrate 10 and the end face of the piezoelectric body 201 away from the substrate 10 is 0.1µm-0.5µm. The distance between the end face of the second electrode 203 near the substrate 10 and the surface of the substrate 10 is 0.1µm-0.5µm.

[0087] In some embodiments, the housing structure 50 has a first notch 033 and a second notch 034 that penetrate the housing structure 50. In the thickness direction of the substrate 10, the projection of the first notch 033 is located within the projection range of the first frequency modulation block 301, and the projection of the second notch 034 is located within the projection range of the second frequency modulation block 302. Further, in the thickness direction of the substrate 10, the distance between the projection of the first notch 033 and the projection of the first electrode 202 is 0.1-1 μm, and the distance between the projection of the second notch 034 and the projection of the second electrode 203 is 0.1-1 μm.

[0088] Meanwhile, in some embodiments, the projection of the piezoelectric body 201 in the thickness direction of the substrate 10 is a closed loop or an open loop. In some embodiments, one side surface of the substrate 10 includes a plurality of piezoelectric bodies 201, and the spacing between adjacent piezoelectric bodies 201 is greater than 1 μm.

[0089] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0090] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for manufacturing a filter, characterized in that, include: A substrate is provided, and a piezoelectric material layer covering the surface of the substrate is formed on a plane on one side of the substrate, and the piezoelectric material layer is etched to form a piezoelectric body; An electrode layer is fabricated, which covers the piezoelectric body and the remaining surface of the substrate; The electrode layer is etched to form a first electrode and a second electrode located on both sides of the piezoelectric body, such that the first electrode, the piezoelectric body and the second electrode are stacked along the planar direction of the substrate to form a piezoelectric sensing structure. A frequency modulation structure is fabricated, the frequency modulation structure including a first frequency modulation block and a second frequency modulation block, the first frequency modulation block being fixedly connected to a first electrode, and the second frequency modulation block being fixedly connected to a second electrode; A housing structure is fabricated and fixed above the substrate to form a first cavity accommodating the piezoelectric sensing structure and the frequency modulation structure; An electrical connection structure is fabricated, the electrical connection structure including a first electrical connector and a second electrical connector, the first electrical connector penetrating the housing structure and being electrically connected to the first electrode, and the second electrical connector penetrating the housing structure and being electrically connected to the second electrode; The shell structure is etched to form a first notch and a second notch, wherein, in the thickness direction of the substrate, the projection of the first notch is located within the projection range of the first frequency modulation block, and the projection of the second notch is located within the projection range of the second frequency modulation block.

2. The method for manufacturing a filter as described in claim 1, characterized in that, The first electrode includes a first portion and a second portion connected to the first portion. The first portion covers a portion of the piezoelectric body, and the area of ​​the piezoelectric body on the side surface covered by the first portion away from the substrate is exposed. The second portion covers the remaining surface of the substrate. The second electrode covers a portion of the piezoelectric body, and the area of ​​the piezoelectric body on the side surface covered by the second electrode near the substrate is exposed.

3. The method for manufacturing a filter as described in claim 2, characterized in that, Prior to fabricating the frequency modulation structure, the manufacturing method further includes: A first sacrificial material layer is deposited on one side plane of the substrate where the piezoelectric element is located. The first sacrificial material layer covers the remaining surface of the substrate and encapsulates the piezoelectric sensing structure. The first sacrificial material layer is etched, exposing the end of the piezoelectric sensing structure away from the substrate, and the remaining first sacrificial material layer forms the first sacrificial structure.

4. The method for manufacturing a filter as described in claim 3, characterized in that, The fabrication of the frequency modulation structure includes a first frequency modulation block and a second frequency modulation block. The first frequency modulation block is fixedly connected to a first electrode, and the second frequency modulation block is fixedly connected to a second electrode. A frequency-modulated material layer is deposited on the first sacrificial structure, the frequency-modulated material layer covering the surface of the first sacrificial structure and partially covering the first electrode and a portion of the second electrode; The frequency modulation material layer is etched to expose the surface of the end of the first sacrificial structure away from the piezoelectric sensing structure, in order to form the first frequency modulation block and the second frequency modulation block.

5. The method for manufacturing a filter as described in claim 3, characterized in that, Before fabricating the shell structure, the method further includes: A second sacrificial structure is deposited on the first sacrificial structure, the second sacrificial structure covering the remaining surface of the first sacrificial structure and enclosing the exposed portion of the frequency modulation structure and the piezoelectric sensing structure; The second sacrificial structure is etched to expose the surface of the substrate away from the edge of the piezoelectric sensing structure and to expose the end face of the piezoelectric body away from the substrate.

6. The method for manufacturing a filter as described in claim 5, characterized in that, The fabrication of the housing structure, which is covered and fixed above the substrate to form a first cavity accommodating the piezoelectric sensing structure and the frequency modulation structure, includes: A passivation material is deposited on the exposed surface of the substrate, the passivation material covering the first sacrificial structure, the second sacrificial structure, and the end face of the piezoelectric element away from the substrate, forming the shell structure.

7. The method for manufacturing a filter as described in claim 5, characterized in that, Fabricating an electrical connection structure, the electrical connection structure including a first electrical connector and a second electrical connector, the first electrical connector penetrating the housing structure and electrically connected to the first electrode, and the second electrical connector penetrating the housing structure and electrically connected to the second electrode, comprising: The shell structure, the first sacrificial structure, and the second sacrificial structure are etched to form a first groove and a second groove, wherein the second portion of the first electrode is exposed at the bottom of the first groove and the second electrode is exposed at the bottom of the second groove; A first conductive material is deposited, which fills the first groove and covers part of the housing to form the first electrical connector; A second conductive material is deposited, which fills the second groove and covers part of the housing to form the second electrical connector.

8. The method for manufacturing a filter as described in claim 5, characterized in that, The method further includes: The first sacrificial structure and the second sacrificial structure are removed through the first gap and the second gap.

9. The method for manufacturing a filter as described in claim 6, characterized in that, The method further includes: The frequency of the filter is adjusted by reducing the first and second frequency modulation blocks through ion beam bombardment, so that the frequency of the filter reaches the preset frequency. The ion beam bombards the first frequency modulation block through the first notch, and the ion beam bombards the second frequency modulation block through the second notch.

10. A filter, characterized in that, include: Substrate (10); A housing structure (50) is fixedly connected to one side surface of the substrate (10) to form a first cavity; A piezoelectric sensing structure (20) is located in the first cavity. The piezoelectric sensing structure (20) includes a piezoelectric body (201) fixed between the housing structure (50) and the substrate (10), a first electrode (202) and a second electrode (203) located on both sides of the piezoelectric body (201). A frequency modulation structure (30) is located in the first cavity. The frequency modulation structure (30) includes a first frequency modulation block (301) and a second frequency modulation block (302). The first frequency modulation block (301) is fixedly connected to the first electrode (202), and the second frequency modulation block (302) is fixedly connected to the second electrode (203). An electrical connection structure (60) includes a first electrical connector (601) and a second electrical connector (602), which penetrate the housing and are electrically connected to the first electrode (202), and the second electrical connector (602) penetrates the housing and is electrically connected to the second electrode (203). The shell structure (50) has a first notch (033) and a second notch (034) that penetrate the shell structure (50). In the thickness direction of the substrate (10), the projection of the first notch (033) is located within the projection range of the first frequency modulation block (301), and the projection of the second notch (034) is located within the projection range of the second frequency modulation block (302).

11. The filter as claimed in claim 10, characterized in that, The first electrode (202) includes a first portion (2021) and a second portion (2022). The first portion (2021) covers a portion of the piezoelectric body (201), and the area of ​​the piezoelectric body (201) covered by the first portion (2021) away from the substrate (10) is exposed. The second portion (2022) covers the remaining surface of the substrate (10). The second electrode (203) covers a portion of the piezoelectric body (201), and the area of ​​the piezoelectric body (201) covered by the second electrode (203) near the substrate (10) is exposed.

12. The filter as claimed in claim 11, characterized in that, The distance between the end face of the first portion (2021) away from the substrate (10) and the end face of the piezoelectric body (201) away from the substrate (10) is 0.1um-0.5um; The distance between the end face of the second electrode (203) near the substrate (10) and the surface of the substrate (10) is 0.1um-0.5um.

13. The filter as described in claim 10, characterized in that, In the thickness direction of the substrate (10), the distance between the projection of the first notch (033) and the projection of the first electrode (202) is 0.1-1 μm, and the distance between the projection of the second notch (034) and the projection of the second electrode (203) is 0.1-1 μm.

14. The filter as described in claim 10, characterized in that, In the thickness direction of the substrate (10), the projection of the piezoelectric body (201) is either a closed loop or an open loop.

15. The filter as described in claim 14, characterized in that, One side surface of the substrate (10) includes a plurality of piezoelectric elements (201), and the spacing between adjacent piezoelectric elements (201) is greater than 1 μm.

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