Filter and manufacturing method thereof

Abstract

The invention provides a filter and a manufacturing method thereof. The manufacturing method comprises the following steps: providing a substrate; manufacturing a piezoelectric body on a plane on one side of the substrate; a first electrode and a second electrode which are located on the two sides of the piezoelectric body are manufactured, and the first electrode, the piezoelectric body and the second electrode form a piezoelectric sensing structure; manufacturing a frequency modulation structure, wherein 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, wherein 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 an electric connection structure is manufactured, the electric connection structure comprises a first electric connection piece and a second electric connection piece, the first electric connection piece is electrically connected with the first electrode, and the second electric connection piece is electrically connected with the second electrode. According to the invention, the frequency of the filter can be adjusted more accurately by independently adjusting the frequency modulation blocks on one sides of different electrodes, the frequency adjustment range is enlarged, and the frequency stability and the control precision are improved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a filter and a manufacturing method thereof. Background Art

[0002] The filter includes two thin-film electrodes and a piezoelectric film layer disposed between the two thin-film electrodes. Its working principle is as follows: the thin-film electrode generates an electric field on the piezoelectric film layer by applying voltage, and the piezoelectric film layer generates periodic mechanical deformation under the action of the electric field, thereby generating sound waves of the corresponding frequency. When the sound wave propagates in the piezoelectric film layer and causes the piezoelectric film layer to deform, the thin-film electrode senses the charge change generated by the piezoelectric effect, thereby converting the mechanical vibration back into an electrical signal and completing the signal reception.

[0003] Commonly used filters are usually prepared by stacking a lower thin film electrode, a piezoelectric film and an upper thin film electrode along the thickness direction of the substrate. The upper thin film electrode and the lower thin film electrode need to undergo photolithography on both sides, and when preparing the upper thin film electrode, it is usually necessary to bond with a new silicon cover wafer to form a top cavity and seal it. The preparation process is complicated, and commonly used filters can only prepare the frequency modulation layer on the upper thin film electrode side. The frequency adjustment range is limited, the frequency modulation effect is poor, and the product quality cannot be controlled. Summary of the invention

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

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] In a first aspect, a method for manufacturing a filter is provided, comprising:

[0007] Providing a substrate, forming a piezoelectric material layer covering the surface of the substrate on a plane on one side of the substrate, and etching the piezoelectric material layer to form a piezoelectric body;

[0008] Manufacturing an electrode layer, wherein the electrode layer covers the piezoelectric body and the remaining surface of the substrate;

[0009] Etching the electrode layer to form a first electrode and a second electrode located on both sides of the piezoelectric body, wherein the first electrode, the piezoelectric body and the second electrode constitute a piezoelectric sensing structure;

[0010] Manufacturing a 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 the first electrode, and the second frequency modulation block being fixedly connected to the second electrode;

[0011] Manufacturing a housing structure, wherein the housing structure is covered and fixed on the substrate to form a first cavity for accommodating the piezoelectric sensing structure and the frequency modulation structure;

[0012] An electrical connection structure is manufactured, wherein the electrical connection structure includes a first electrical connection member and a second electrical connection member, wherein the first electrical connection member penetrates the shell structure and is electrically connected to the first electrode, and the second electrical connection member penetrates the shell structure and is electrically connected to the second electrode.

[0013] In addition to or instead of one or more features disclosed above, the first electrode includes a first part and a second part connected to the first part, the first part covers a portion of the piezoelectric body, a surface of a side of the piezoelectric body covered by the first part is exposed away from an area of ​​the substrate, the second part covers a portion of the remaining surface of the substrate, and the second electrode covers a portion of the piezoelectric body, a surface of a side of the piezoelectric body covered by the second electrode is exposed close to an area of ​​the substrate.

[0014] In addition to or as an alternative to one or more of the features disclosed above, before making the frequency modulation structure, the method further includes:

[0015] Depositing a first sacrificial material layer on a side plane of the substrate where the piezoelectric body is located, wherein 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 to expose an end of the piezoelectric sensing structure away from the substrate, and the remaining first sacrificial material layer forms a first sacrificial structure.

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

[0018] Depositing a frequency modulation material layer on the first sacrificial structure, wherein the frequency modulation material layer covers a surface of the first sacrificial structure and partially covers the first electrode and a portion of the second electrode;

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

[0020] In addition to or as an alternative to one or more of the features disclosed above, before manufacturing the housing structure, the method further includes:

[0021] Depositing a second sacrificial structure on the first sacrificial structure, wherein the second sacrificial structure covers the remaining surface of the first sacrificial structure and encapsulates the frequency modulation structure and the exposed portion of the piezoelectric sensing structure;

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

[0023] In addition to or as an alternative to one or more of the features disclosed above, the manufacturing of the housing structure, the housing structure being disposed and fixed above the substrate to form a first cavity accommodating the piezoelectric sensing structure and the frequency modulation structure, comprises:

[0024] A passivation material is deposited on the exposed surface of the substrate, and the passivation material covers the first sacrificial structure, the second sacrificial structure, and the end surface of the piezoelectric body away from the substrate to form the shell structure.

[0025] In addition to or as an alternative to one or more of the features disclosed above, manufacturing an electrical connection structure, the electrical connection structure comprising a first electrical connection member and a second electrical connection member, the first electrical connection member passing through the housing structure and being electrically connected to the first electrode, the second electrical connection member passing through the housing structure and being electrically connected to the second electrode comprises:

[0026] Etching the housing structure, the first sacrificial structure and the second sacrificial structure 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] Depositing a first conductive material, wherein the first conductive material fills the first groove and covers a portion of the housing to form the first electrical connector;

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

[0029] In addition to or as an alternative to one or more of the features disclosed above, the method further comprises:

[0030] Etching the shell structure 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 notch and the second notch.

[0032] In addition to or as an alternative to one or more of the features disclosed above, the method further comprises:

[0033] The first frequency modulation block and the second frequency modulation block are reduced by ion beam bombardment to adjust the frequency of the filter so that the frequency of the filter reaches a preset frequency;

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

[0035] In a second aspect, a filter is provided, comprising:

[0036] substrate;

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

[0038] A piezoelectric sensing structure, the piezoelectric sensing structure is located in the first cavity, the piezoelectric sensing structure comprises 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, the frequency modulation structure is located in the first cavity, the frequency modulation structure comprises 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;

[0040] The electrical connection structure includes a first electrical connection member and a second electrical connection member, which penetrates the shell and is electrically connected to the first electrode, and a second electrical connection member, which penetrates the shell and is electrically connected to the second electrode.

[0041] In addition to or instead of one or more features disclosed above, the first electrode includes a first part and a second part, the first part covers a portion of the piezoelectric body, a surface of a side of the piezoelectric body covered by the first part is exposed away from an area of ​​the substrate, the second part covers a portion of the remaining surface of the substrate, and the second electrode covers a portion of the piezoelectric body, a surface of a side of the piezoelectric body covered by the second electrode is exposed close to an area of ​​the substrate.

[0042] In addition to or as an alternative to one or more of the features disclosed above, the distance between the end surface of the first portion away from the substrate and the end surface of the piezoelectric body away from the substrate is: 0.1um-0.5um;

[0043] The distance between the end surface of the second electrode close to one end of 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 shell structure is provided with a first notch and a second notch that penetrate the shell structure, and 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 or instead of one or more features disclosed above, in the thickness direction of the substrate, the spacing between the projection of the first notch and the projection of the first electrode is 0.1-1um, and the spacing between the projection of the second notch and the projection of the second electrode is 0.1-1um.

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

[0047] In addition to or as an alternative to one or more of the features disclosed above, one side surface of the substrate includes a plurality of the piezoelectric bodies, and a spacing between adjacent piezoelectric bodies is greater than 1 um.

[0048] Using the filter and its manufacturing method provided by the present invention, the first electrode, piezoelectric body and second electrode included in the piezoelectric sensing structure are stacked along the plane direction of the substrate. Compared with the piezoelectric sensing structure in which the lower electrode, piezoelectric body and upper electrode are stacked along the thickness direction of the substrate, the preparation process of the present application is simple. For example, the former needs to etch the substrate connected to the lower electrode to form the lower active cavity of the piezoelectric sensing structure, and needs to etch the substrate connected to the upper electrode to form the upper active cavity of the piezoelectric sensing structure, while the present application does not require such a complicated process. And when preparing the frequency modulation structure, the present application can make a first frequency modulation block connected to the first electrode on the side where the first electrode is located, and make a second frequency modulation block connected to the second electrode on the side where the second electrode is located. In this way, the frequency of the filter can be more accurately adjusted by independently adjusting the frequency modulation blocks on different sides of the electrodes, which increases the frequency adjustment range, improves the frequency stability and control accuracy, and enables the filter to better adapt to different application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other implementation methods can be obtained based on these drawings without paying any creative work.

[0050] Figure 1 It is a schematic flow chart of a method for manufacturing a filter provided according to an embodiment of the present invention.

[0051] Figure 2-17 It is a schematic diagram of the process of the method for manufacturing the filter provided in an embodiment of the present invention.

[0052] Fig.18 It is a schematic projection diagram of a piezoelectric body provided according to an embodiment of the present invention.

[0053] Reference numerals:

[0054] 10. Substrate;

[0055] 20. Piezoelectric sensing structure; 201. Piezoelectric body; 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. a first sacrificial structure; 41. a second sacrificial structure;

[0058] 50. Shell structure;

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

[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 DESCRIPTION

[0062] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following specifically cites a preferred embodiment and describes it in detail with the accompanying drawings as follows.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the term "depth" will be used to indicate that each component element of the pressure sensor in the embodiment of the present invention extends in the direction of the first axis Z of the Cartesian reference system XYZ, and the terms "length" and "width" respectively indicate that each component element of the pressure sensor in the embodiment of the present invention extends in the direction of the second axis X and the third axis Y of the Cartesian coordinate system XYZ. The terms "installation", "connection" and "connection" 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 mechanical connection, an electrical connection or mutual communication; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. When it comes to method steps, the sequence illustrated in this article represents an exemplary scheme, but does not represent a limitation on the sequence. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0064] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0065] The embodiment of the present invention provides a method for manufacturing a filter, referring to Figure 1 , the manufacturing method of the filter comprises:

[0066] S100. Providing a substrate;

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

[0068] S300. Fabricating an electrode layer, the electrode layer covering the piezoelectric body and the remaining surface of the substrate;

[0069] S400. Etching 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 forming a piezoelectric sensing structure;

[0070] S500. Making a frequency modulation structure, 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 the first electrode, and the second frequency modulation block is fixedly connected to the second electrode;

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

[0072] S700. Make an electrical connection structure, the electrical connection structure comprising a first electrical connection member and a second electrical connection member, the first electrical connection member passes through the shell structure and is electrically connected to the first electrode, the second electrical connection member passes through the shell structure and is electrically connected to the second electrode.

[0073] Specifically, in step S100, a substrate 10 is provided as Figure 2 In some embodiments, the 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 the substrate 10 is formed on a plane on one side of the substrate 10, and then referring to Figure 4 , the piezoelectric material layer 020 is etched to form a 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 side wall of the formed piezoelectric body 201 and the plane of the substrate 10 is approximately vertical. The vertical sidewalls can enhance the mechanical stability and strength of the piezoelectric body 201, avoiding deformation or fracture during subsequent processing or use. At the same time, in surface acoustic wave devices, the vertical sidewalls can ensure that the path and mode of sound wave propagation are consistent. And the vertical sidewalls help reduce the reflection and diffraction of sound waves during propagation. Inclined or irregular sidewalls may cause scattering of sound waves and deviation of the path, thereby affecting the performance and efficiency of the device.

[0074] In some embodiments, the piezoelectric material layer 020 can be a piezoelectric material of a single crystal structure, or a piezoelectric material of a polycrystalline material. Specifically, the piezoelectric material can be nitride (ALN), sodium aluminum scandate (ALScN), quartz, etc. These materials have a piezoelectric effect, that is, when pressure or an electric field is applied, charge separation or mechanical deformation will occur, thereby achieving a piezoelectric effect. Different piezoelectric materials have different properties and characteristics. In practical applications, suitable materials 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, refer to Fig.18 In the thickness direction of the substrate 10, the projection of the piezoelectric body 201 is a closed loop or an open loop. The closed loop can be a circular loop, an elliptical loop, a rectangular loop or other closed loops, and the open loop can be a curve or other open loop. It should be noted that Fig.18 The line width of the closed loop linear shape and the open loop linear shape shown is the thickness of the piezoelectric body 201. The piezoelectric body 201 after etching is a membrane structure. The thickness of the piezoelectric body 201 as a membrane structure is small, so the projection in the thickness direction of the substrate 10 is approximately equivalent to a line. Further, in some embodiments, multiple piezoelectric bodies 201 may be etched on one substrate. Fig.18When etching multiple piezoelectric bodies 201 on a substrate, the shapes of the multiple piezoelectric bodies 201 may be different, and may be circular or rectangular. However, the spacing between adjacent piezoelectric bodies 201 needs to be greater than 1 um (in terms of Fig.18 For example, the distance A in the figure is greater than 1um), so that other structures can be deposited 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 1um (with Fig.18 For example, the distance C in the figure is greater than 1um). At the same time, the distance between the opposite surfaces in a single ring structure also needs to be greater than 1um (with Fig.18 For example, the distance B in the figure is greater than 1um).

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

[0076] Step S400 forms a first electrode 202 and a second electrode 203 located on both sides of the piezoelectric body 201 by etching the electrode layer 021, so that the first electrode 202, the piezoelectric body 201 and the second electrode 203 together constitute the 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 a surface of the piezoelectric body 201 covered by the first portion 2021 is exposed in an area away from the substrate 10, and the second portion 2022 covers a portion of the remaining surface of the substrate 10. The second electrode 203 covers a portion of the piezoelectric body 201, and a surface of the piezoelectric body 201 covered by the second electrode 203 is exposed in an area close to the substrate 10. Specifically, the first electrode 202 and the second electrode 203 can be completed by the following process: first refer to Figure 6 , etching the portion of the electrode layer 021 covering the end face of the piezoelectric body 201 so that the end face of the piezoelectric body 201 away from the substrate 10 is exposed, and at the same time etching the portion of the electrode layer 021 covering the substrate 10 so that the surface of the substrate 10 on one side of the piezoelectric body 201 is completely exposed, and the surface of the substrate 10 on the other side is partially exposed (in some embodiments, the thickness of the electrode layer 021 covering part of the surface of the substrate 10 is also reduced in this process); refer to Figure 7, the electrode layer 021 covering the two side surfaces of the piezoelectric body 201 is etched to form the first electrode 202 and the second electrode 203 described above.

[0077] Reference Fig.10 The frequency modulation structure 30 produced in step S500 is as follows: Fig.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 the above step S500, it is necessary to do some preparatory steps before making the frequency modulation structure 30, specifically including: first refer to Figure 8 , a first sacrificial material layer 040 is deposited on a side plane of the substrate 10 where the piezoelectric body 201 is located, and the first sacrificial material layer 040 covers the remaining surface of the substrate 10 and covers the piezoelectric sensing structure 20; referring to Fig. 9 , the first sacrificial material layer 040 is etched, and the end of the piezoelectric sensing structure 20 away from the substrate 10 is exposed, and the remaining first sacrificial material layer 040 forms a first sacrificial structure 40. In some embodiments, the first sacrificial material can be undoped silicate glass (USG), phosphorus silicate glass (PSG), silicon nitride (SIN), etc. The first sacrificial material layer 040 can be etched by wet etching, and the damage to the electrode by wet etching can be ignored. Moreover, the thickness of the first sacrificial structure 40 is greater than the thickness of the second part 2022. In some embodiments, the thickness of the first sacrificial structure 40 is 0.3um-1um, and the thickness of the first sacrificial structure 40 is 0.1um-0.5um greater than the thickness of the second part 2022.

[0078] Furthermore, the frequency modulation structure 30 is completed by the following steps: first, a frequency modulation material layer is deposited on the first sacrificial structure 40, the frequency modulation material layer covers the surface of the first sacrificial structure 40, and partially covers 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 away from the piezoelectric sensing structure 20, so as to form a Fig.10The first frequency modulation block 301 and the second frequency modulation block 302 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, in the thickness direction of the substrate 10, the size of the first frequency modulation block 301 and the second frequency modulation block 302 is 0.1um-1um. In some embodiments, the distance between the side surface of the first frequency modulation block 301 away from the substrate 10 and the side surface of the second frequency modulation block 302 away from the substrate 10 and the side surface of the first part 2021 away from the substrate 10 is 0.1um-0.5um. In some embodiments, the distance between the end surface of the first frequency modulation block 301 away from one end of the first part 2021 and the side surface of the first part 2021 is 1um-5um, and the distance between the end surface of the second frequency modulation block 302 away from one end of the second electrode 203 and the side surface of the second electrode 203 is 1um-5um.

[0079] Reference Fig.13 The shell structure 50 manufactured in step S600 is as follows Fig.13 As shown, the housing structure 50 is covered and fixed on the substrate 10 to form a first cavity for accommodating the piezoelectric sensing structure 20 and the frequency modulation structure 30. Specifically, in some embodiments, in order to prepare the housing structure 50 in the above step S600, some preparatory steps need to be performed before making the housing structure 50, specifically including: first referring to Fig.11 , a second sacrificial structure 41 is deposited on the first sacrificial structure 40, the second sacrificial structure 41 covers the remaining surface of the first sacrificial structure 40, and covers the exposed portion of the frequency modulation structure 30 and the piezoelectric sensing structure 20; and referring to Fig.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 surface 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), phosphorus silicate glass (PSG), etc.

[0080] Furthermore, the shell structure 50 is completed by the following steps: a passivation material is deposited on the exposed surface of the substrate 10, and the passivation material covers the first sacrificial structure 40, the second sacrificial structure 41, and the end surface of the piezoelectric body 201 away from the substrate 10, thereby forming a Fig.13 The housing structure 50 is shown.

[0081] Reference Fig.15 In step S700, the electrical connection structure 60 is made as Fig.15As shown, the electrical connection structure 60 includes a first electrical connection member 601 and a second electrical connection member 602. The first electrical connection member 601 penetrates the shell structure 50 and is electrically connected to the first electrode 202. The second electrical connection member 602 penetrates the shell structure 50 and is electrically connected to the second electrode 203. In some embodiments, the electrical connection structure 60 is completed by the following process. Fig.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 portion 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; referring to Fig.15 , depositing a first conductive material, the first conductive material fills the first groove 030 and covers part of the shell to form a first electrical connector 601; depositing a second conductive material, the second conductive material fills the second groove 031 and covers 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 1um-3um.

[0082] In some embodiments, the filter manufacturing method further includes the following steps: firstly 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; and then referring to Fig.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, when the first groove 030 and the second groove 031 are formed, the first notch 033 and the second notch 034 are formed simultaneously. Fig.14 and Fig.15 shown.

[0083] In some embodiments, the filter manufacturing method further includes the following steps: Fig.17 , the first frequency modulation block 301 and the second frequency modulation block 302 are reduced by ion beam bombardment. The frequency of the filter is adjusted by changing the thickness of the first frequency modulation block 301 and the thickness of the second frequency modulation block 302, so that the frequency of the filter reaches a preset frequency. The ion beam bombards the first frequency modulation block 301 through the first notch 033, and the ion beam bombards the second frequency modulation block 302 through the second notch 034.

[0084] The embodiment of the present invention provides a filter, referring to Fig.17, which includes a substrate 10, a shell structure 50, a piezoelectric sensing structure 20, a frequency modulation structure 30 and an electrical connection structure 60. Specifically, the shell structure 50 is fixedly connected to a surface of one side of the substrate 10 to form a first cavity. The piezoelectric sensing structure 20 is located in the first cavity, and the piezoelectric sensing structure 20 includes a piezoelectric body 201 fixed between the shell structure 50 and the substrate 10, and a first electrode 202 and a second electrode 203 located on both sides of the piezoelectric body 201. The frequency modulation structure 30 is located in the first cavity, and 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. The electrical connection structure 60 includes a first electrical connector 601 and a second electrical connector 602, which penetrate the shell and are electrically connected to the first electrode 202, and a second electrical connector 602, which penetrates the shell 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, and the above disclosed filter manufacturing method can 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, and the surface of the piezoelectric body 201 covered by the first portion 2021 is exposed in an area away from the substrate 10, the second portion 2022 covers the remaining surface of the substrate 10, and the second electrode 203 covers a portion of the piezoelectric body 201, and the surface of the piezoelectric body 201 covered by the second electrode 203 is exposed in an area close to the substrate 10. Further, the distance between the end surface of the first portion 2021 away from the substrate 10 and the end surface of the piezoelectric body 201 away from the substrate 10 is: 0.1um-0.5um. The distance between the end surface of the second electrode 203 close to the substrate 10 and the surface of the substrate 10 is: 0.1um-0.5um.

[0087] In some embodiments, the housing structure 50 is provided with 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 spacing between the projection of the first notch 033 and the projection of the first electrode 202 is 0.1-1um, and the spacing between the projection of the second notch 034 and the projection of the second electrode 203 is 0.1-1um.

[0088] Meanwhile, in some embodiments, the projection of the piezoelectric body 201 is a closed loop line or an open loop line in the thickness direction of the substrate 10. 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 um.

[0089] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for manufacturing a filter, characterized in that: include: Providing a substrate, forming a piezoelectric material layer covering the surface of the substrate on a plane on one side of the substrate, and etching the piezoelectric material layer to form a piezoelectric body; Manufacturing an electrode layer, wherein the electrode layer covers the piezoelectric body and the remaining surface of the substrate; Etching the electrode layer to form a first electrode and a second electrode located on both sides of the piezoelectric body, wherein the first electrode, the piezoelectric body and the second electrode constitute a piezoelectric sensing structure; Manufacturing a 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 the first electrode, and the second frequency modulation block being fixedly connected to the second electrode; Manufacturing a housing structure, wherein the housing structure is covered and fixed on the substrate to form a first cavity for accommodating the piezoelectric sensing structure and the frequency modulation structure; An electrical connection structure is manufactured, wherein the electrical connection structure includes a first electrical connection member and a second electrical connection member, wherein the first electrical connection member penetrates the shell structure and is electrically connected to the first electrode, and the second electrical connection member penetrates the shell structure and is electrically connected to the second electrode.

2. The method for manufacturing a filter according to claim 1, wherein: The first electrode includes a first part and a second part connected to the first part, the first part covers a portion of the piezoelectric body, and a surface of the piezoelectric body covered by the first part is exposed in an area away from the substrate, the second part covers a portion of the remaining surface of the substrate, and the second electrode covers a portion of the piezoelectric body, and a surface of the piezoelectric body covered by the second electrode is exposed in an area close to the substrate.

3. The method for manufacturing a filter according to claim 2, wherein: Before manufacturing the frequency modulation structure, the manufacturing method further includes: Depositing a first sacrificial material layer on a side plane of the substrate where the piezoelectric body is located, wherein 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 to expose an end of the piezoelectric sensing structure away from the substrate, and the remaining first sacrificial material layer forms a first sacrificial structure.

4. The method for manufacturing a filter according to claim 3, wherein: The manufacturing of the frequency modulation structure, wherein the frequency modulation structure includes a first frequency modulation block and a second frequency modulation block, wherein 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, comprises: Depositing a frequency modulation material layer on the first sacrificial structure, wherein the frequency modulation material layer covers a surface of the first sacrificial structure and partially covers the first electrode and a portion of the second electrode; The frequency modulation material layer is etched to expose a surface of an end of the first sacrificial structure away from the piezoelectric sensing structure, so as to form the first frequency modulation block and the second frequency modulation block.

5. The method for manufacturing a filter according to claim 3, wherein: Before manufacturing the shell structure, the method further includes: Depositing a second sacrificial structure on the first sacrificial structure, wherein the second sacrificial structure covers the remaining surface of the first sacrificial structure and encapsulates the frequency modulation structure and the exposed portion of the piezoelectric sensing structure; The second sacrificial structure is etched to expose a surface of the substrate away from an edge of the piezoelectric sensing structure and an end surface of the piezoelectric body away from one end of the substrate.

6. The method for manufacturing a filter according to claim 5, wherein: The manufacturing of the housing structure, wherein the housing structure is covered and fixed above the substrate to form a first cavity for accommodating the piezoelectric sensing structure and the frequency modulation structure, comprises: A passivation material is deposited on the exposed surface of the substrate, and the passivation material covers the first sacrificial structure, the second sacrificial structure, and the end surface of the piezoelectric body away from the substrate to form the shell structure.

7. The method for manufacturing a filter according to claim 5, wherein: Producing an electrical connection structure, the electrical connection structure comprising a first electrical connection member and a second electrical connection member, the first electrical connection member passing through the shell structure and being electrically connected to the first electrode, the second electrical connection member passing through the shell structure and being electrically connected to the second electrode comprises: Etching the housing structure, the first sacrificial structure and the second sacrificial structure 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; Depositing a first conductive material, wherein the first conductive material fills the first groove and covers a portion of the housing to form the first electrical connector; A second conductive material is deposited, where the second conductive material fills the second groove and covers a portion of the housing to form the second electrical connector.

8. The method for manufacturing a filter according to claim 5, wherein: The method further comprises: Etching the shell structure 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; The first sacrificial structure and the second sacrificial structure are removed through the first notch and the second notch.

9. The method for manufacturing a filter according to claim 6, wherein: The method further comprises: The first frequency modulation block and the second frequency modulation block are reduced by ion beam bombardment to adjust the frequency of the filter so that the frequency of the filter reaches a preset frequency; The ion beam bombards the first frequency modulation block through the first gap, and the ion beam bombards the second frequency modulation block through the second gap.

10. A filter, characterized in that: include: A substrate (10); A shell structure (50), the shell structure (50) being fixedly connected to a surface of one side of the substrate (10) to form a first cavity; A piezoelectric sensing structure (20), the piezoelectric sensing structure (20) being located in the first cavity, the piezoelectric sensing structure (20) comprising a piezoelectric body (201) fixed between the housing structure (50) and the substrate (10), and a first electrode (202) and a second electrode (203) located on both sides of the piezoelectric body (201); A frequency modulation structure (30), the frequency modulation structure (30) being located in the first cavity, the frequency modulation structure (30) comprising a first frequency modulation block (301) and a second frequency modulation block (302), the first frequency modulation block (301) being fixedly connected to the first electrode (202), and the second frequency modulation block (302) being fixedly connected to the second electrode (203); An electrical connection structure (60), the electrical connection structure (60) comprising a first electrical connection member (601) and a second electrical connection member (602), which penetrate the shell and are electrically connected to the first electrode (202), and a second electrical connection member (602) which penetrates the shell and is electrically connected to the second electrode (203).

11. The filter according to claim 10, characterized in that The first electrode (202) comprises a first part (2021) and a second part (2022), wherein the first part (2021) covers a portion of the piezoelectric body (201), and a surface of a side of the piezoelectric body (201) covered by the first part (2021) is exposed in an area away from the substrate (10), and the second part (2022) covers a portion of the remaining surface of the substrate (10), and the second electrode (203) covers a portion of the piezoelectric body (201), and a surface of a side of the piezoelectric body (201) covered by the second electrode (203) is exposed in an area close to the substrate (10).

12. The filter according to claim 11, characterized in that The distance between the end surface of the first part (2021) away from the substrate (10) and the end surface of the piezoelectric body (201) away from the substrate (10) is 0.1um-0.5um; The distance between the end surface of the second electrode (203) close to one end of the substrate (10) and the surface of the substrate (10) is 0.1 um-0.5 um.

13. The filter according to claim 10, characterized in that The shell structure (50) is provided with a first notch (033) and a second notch (034) which pass through 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).

14. The filter according to claim 13, 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 0.1-1um, and the distance between the projection of the second notch (034) and the projection of the second electrode (203) is 0.1-1um.

15. The filter according to claim 10, characterized in that In the thickness direction of the substrate (10), the projection of the piezoelectric body (201) is a closed loop line or an open line.

16. The filter according to claim 15, characterized in that One side surface of the substrate (10) comprises a plurality of piezoelectric bodies (201), and the spacing between adjacent piezoelectric bodies (201) is greater than 1 um.

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