Acoustic wave device and method for manufacturing same

Abstract

The invention provides an acoustic wave device and a manufacturing method thereof. The acoustic wave device may include a substrate, a bezel portion, a first electrode, a piezoelectric layer, and a second electrode. The substrate includes a first surface, a second surface, a reflective recess and a first recess. The second surface is opposite to the first surface. The reflective recess and the first recess are recessed from the first surface, and the first recess at least partially surrounds the reflective recess and is spaced apart from the reflective recess. The frame part is arranged in the first concave part of the substrate. The first electrode is disposed on the substrate and contacts the frame portion. The piezoelectric layer is at least partially disposed on the first electrode. The second electrode is at least partially disposed on the piezoelectric layer. In a vertical direction, the reflective recess, the first electrode, the piezoelectric layer, and the second electrode of the substrate at least partially overlap.

Description

Technical Field

[0001] The present invention relates to acoustic wave technology, and more particularly to an acoustic wave device and a method for manufacturing the same. Background Art

[0002] Bulk acoustic wave (BAW) devices can be used to convert and transmit electrical and acoustic signals. BAW devices are widely used in communications, global positioning systems (GPS), and military fields. BAW devices can be used in filters, which can filter noise and retain wireless signals in the required frequency band, provide low transmission loss and anti-electromagnetic interference, and are compact, so they are widely used in various communication products. In addition, BAW filters can also be used as resonators. Current BAW devices may produce spurious modes, causing unnecessary energy leakage and reducing circuit performance. Summary of the invention

[0003] The embodiment of the present invention discloses an acoustic wave device, comprising a substrate, a frame portion, a first electrode, a piezoelectric layer and a second electrode. The substrate comprises a first surface, a second surface, a reflective concave portion and a first concave portion. The second surface is opposite to the first surface. The reflective concave portion and the first concave portion are recessed from the first surface, and the first concave portion at least partially surrounds the reflective concave portion and is separated from the reflective concave portion. The frame portion is disposed in the first concave portion of the substrate. The first electrode is disposed on the substrate and contacts the frame portion. The piezoelectric layer is at least partially disposed on the first electrode. The second electrode is at least partially disposed on the piezoelectric layer. In the vertical direction, the reflective concave portion, the first electrode, the piezoelectric layer, and the second electrode of the substrate at least partially overlap.

[0004] The present invention also discloses a method for manufacturing an acoustic wave device, comprising: providing a substrate; forming a reflective portion in the substrate; forming a first recess in the substrate, the first recess at least partially surrounding the reflective portion and being separated from the reflective portion; forming a frame portion in the first recess; forming a first electrode on the substrate, the first electrode contacting the frame portion. The manufacturing method further comprises: forming a piezoelectric layer, the piezoelectric layer is at least partially located on the first electrode; forming a second electrode, the second electrode is at least partially located on the piezoelectric layer. In the vertical direction, the reflective portion of the substrate, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap.

[0005] The present invention also discloses a method for manufacturing an acoustic wave device, comprising: providing a substrate; forming a reflective concave portion in the substrate; filling a sacrificial material in the reflective concave portion; forming a first concave portion in the substrate, the first concave portion at least partially surrounding the reflective concave portion and being separated from the reflective concave portion; forming a frame portion in the first concave portion; forming a first electrode on the substrate, the first electrode being at least partially located on the sacrificial material and contacting the frame portion. The manufacturing method further comprises: forming a piezoelectric layer, the piezoelectric layer being at least partially located on the first electrode; forming a second electrode, the second electrode being at least partially located on the piezoelectric layer. In the vertical direction, the sacrificial material in the substrate, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 Schematic diagram of a cross-section of an acoustic wave device in an embodiment of the present invention.

[0007] Figure 2 yes Figure 1 A schematic top view of the configuration of the middle reflective recess and the first recess.

[0008] Figure 3 yes Figure 1 A schematic top view of another configuration of the middle reflective recess and the first recess.

[0009] Figure 4 It is a partial cross-sectional schematic diagram of another acoustic wave device in an embodiment of the present invention.

[0010] Figure 5 yes Figure 1 Flowchart of an exemplary method for manufacturing an acoustic wave device in FIG.

[0011] Figures 6 to 9 show Figure 5 Schematic diagram of exemplary steps of an exemplary method for manufacturing an acoustic wave device in FIG. Fig.10 is a flow chart of another exemplary method for manufacturing an acoustic wave device in an embodiment of the present invention.

[0012] Explanation of symbols:

[0013] 1,4: Sound wave device

[0014] 10: Base

[0015] 100: Reflective recess

[0016] 102,411,412: concave part

[0017] 1021, 1022 and 1023: Part

[0018] 104: Through hole

[0019] 12,16: Electrode

[0020] 122,421,422: Border

[0021] 14: Piezoelectric layer

[0022] 140: Contact hole

[0023] 18,28: Electrode contact area

[0024] 19: Passivation layer

[0025] 500,1000: Manufacturing method

[0026] S501 to S523, steps S1001 to S1013: steps

[0027] 70: Sacrificial Materials

[0028] dr,d1,d2: depth

[0029] h: height

[0030] S1, S2: Surface

[0031] s1,s2: distance

[0032] Wr, W1, W2: Dimensions

[0033] X,Y,Z: Direction DETAILED DESCRIPTION

[0034] Figure 1 is a cross-sectional schematic diagram of an acoustic wave device 1 in an embodiment of the present invention. The acoustic wave device 1 may include a bulk acoustic wave (BAW) device, which may be used, for example, for a resonator, a filter, or other purposes. In some embodiments, the acoustic wave device 1 may be used as a BAW resonator, which may receive an input signal to generate a standing acoustic wave, and then convert the standing acoustic wave into a resonant signal. In other embodiments, the acoustic wave device 1 may be used as a BAW filter, which may receive an input signal from, for example, an antenna, and filter the received signal based on its frequency selectivity, thereby allowing a signal of a specific frequency to pass through. The use of the acoustic wave device 1 is only exemplified here, but the present invention is not limited thereto.

[0035] In some embodiments, the acoustic wave device 1 may include a substrate 10, a frame portion 122, an electrode 12, a piezoelectric layer 14, and an electrode 16. During operation, the electrode 16 may receive an input signal, the electrode 12 may be grounded, thereby generating an acoustic wave transmitted along the vertical direction Y, and the piezoelectric layer 14 may convert the acoustic wave into a resonant signal having a resonant frequency. The resonant frequency may depend on many parameters of the acoustic wave device 1, such as the material and thickness of the piezoelectric layer 14, the weight of the electrode 12 and the electrode 16, etc. For example, the resonant frequency may range from 100 megahertz (MHz) to 20 gigahertz (GHz). The material of the substrate 10 may be silicon, glass, ceramic, gallium arsenide, and / or silicon carbide.

[0036] In some embodiments, the substrate 10 may include a surface S1, a surface S2, a reflective concave portion 100, and a first concave portion 102. Figure 1 As shown, the surface S1 and the surface S2 of the substrate 10 are opposite to each other. The reflective concave portion 100 and the first concave portion 102 are recessed from the surface S1 , wherein the first concave portion 102 may at least partially surround the reflective concave portion 100 and be spaced apart from the reflective concave portion 100 .

[0037] Figure 2 and Figure 3 1 is a top view schematic diagram of two exemplary configurations of the reflective concave portion 100 and the first concave portion 102. As shown in the figure, the outline of the reflective concave portion 100 may be egg-shaped, but in other embodiments, the outline of the reflective concave portion 100 may also be other shapes, such as square, circular, pentagonal, or other regular or irregular shapes.

[0038] exist Figure 2 In the embodiment, the reflective concave portion 100 may be, for example, egg-shaped, and the first concave portion 102 may be arranged to substantially and continuously surround the reflective concave portion 100, for example, surround more than 50% of the circumference of the reflective concave portion 100. For example, the first concave portion 102 may continuously surround the narrower end and the side of the egg-shaped reflective concave portion 100, and have an opening at the wider end of the reflective concave portion 100, thereby partially surrounding the reflective concave portion 100. In other embodiments, the opening of the first concave portion 102 may also have different positions and sizes, for example, the first concave portion 102 may have an opening at a position corresponding to the narrower end of the reflective concave portion 100, or may have an opening at a position corresponding to the side of the reflective concave portion 100. In further embodiments, the first concave portion 102 may also completely surround the entire egg-shaped reflective concave portion 100.

[0039] exist Figure 3In the embodiment, the reflective concave portion 100 may be, for example, egg-shaped, and the first concave portion 102 may be arranged to substantially discontinuously surround the reflective concave portion 100, for example, the first concave portion 102 may include three portions 1021, 1022, and 1023. For example, portion 1021 may be arranged to be close to the narrower end of the reflective concave portion 100, and portions 1022 and 1023 may be arranged to be close to the side or wider end of the reflective concave portion. In some embodiments, the first concave portion 102 may also include a greater number of portions to partially surround the reflective concave portion 100. In the above embodiments, the shapes are only used for illustrative purposes and are not used to limit the present invention. In some embodiments not shown, the reflective concave portion may also have other shapes.

[0040] like Figure 1 As shown, the frame portion 122 is disposed in the first concave portion 102 of the substrate 10. For example, the frame portion 122 may fill the first concave portion 102 of the substrate 10. The electrode 12 may be disposed on the surface S1 of the substrate 10 and may contact the frame portion 122. Further, the piezoelectric layer 14 may be at least partially disposed on the electrode 12, and the electrode 16 may be at least partially disposed on the piezoelectric layer 14. Figure 1 As shown, the reflective concave portion 100 of the substrate 10 forms a cavity below the electrode 12, and the cavity can be used as a reflector of the acoustic wave device 1. For example, the material of the electrode 12 and the electrode 16 may include a conductive material, such as molybdenum (Mo), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), tungsten (W), other suitable metals, and combinations thereof. The material of the piezoelectric layer 14 may include, for example, at least one of the following: zinc oxide (ZnO), aluminum nitride (AlN), lithium niobate (LiTaO 3 , LT), lithium niobate (LN), quartz (QZ), lead titanate (PTO), lead zirconate titanate (PZT), etc. or a combination thereof. In some embodiments, the piezoelectric layer 14 may be doped with a rare earth element, such as scandium (Sc).

[0041] Further, the material of the frame portion 122 may be a conductive material or a non-conductive material. In some embodiments, the material of the frame portion 122 may be the same as the material of the electrode 12, such as Mo. In this embodiment, the frame portion 122 and the electrode 12 may be formed as one body, for example, the frame portion 122 and the electrode 12 are formed in the same process step. In other embodiments, the material of the frame portion 122 may also be different from the material of the electrode 12, for example, the material of the frame portion 122 may be W, and the material of the electrode 12 may be Mo. For example, the material of the frame portion 122 may be selected to have a density greater than the material density of the electrode 12, so as to reduce or prevent the leakage of the sound wave along the horizontal direction X, thereby suppressing the side wave mode. In other embodiments, the material of the frame portion 122 may be a dielectric material. In detail, the horizontal direction X may be, for example, a direction parallel to the surface S1, and the material density may be, for example, defined as the mass of the material per unit volume, for example, the density of aluminum is about 2.9 grams per cubic centimeter (g / cm3), the density of molybdenum is about 10.2g / cm3, and the density of tungsten is about 19.25g / cm 3 .

[0042] exist Figure 1 In the embodiment of the present invention, in the vertical direction Y (e.g., the direction perpendicular to the surface S1), the reflective concave portion 100 of the substrate 10, the electrode 12, the piezoelectric layer 14, and the electrode 16 may at least partially overlap. Further, the overlapping area of ​​the reflective concave portion 100, the electrode 12, the piezoelectric layer 14, and the electrode 16 may be referred to as an effective area, and the sound wave may be transmitted along the vertical direction Y in the effective area.

[0043] As shown in the figure, in the substrate 10, the first concave portion 102 may have a dimension W1 along the horizontal direction X and a depth d1 along the vertical direction Y, and the reflective concave portion 100 may have a dimension Wr along the horizontal direction X (e.g., referred to as the reflection dimension) and a depth dr along the vertical direction Y (e.g., referred to as the reflection depth). For example, the depth d1 of the first concave portion 102 or the depth dr of the reflective concave portion 100 may be, for example, a distance measured from the surface S1 of the substrate 10 to the bottom. Furthermore, the dimension W1 of the first concave portion 102 may be smaller than the dimension Wr of the reflective concave portion 100. Figure 1 In the embodiment, the depth d1 of the first concave portion 102 and the depth dr of the reflective concave portion 100 may be the same (d1=dr), but the present invention is not limited thereto. In other embodiments, the depth d1 of the first concave portion 102 may not be equal to the depth dr of the reflective concave portion 100 (d1≠dr). For example, the depth d1 of the first concave portion 102 is greater than the depth dr of the reflective concave portion 100 (d1>dr). In other words, the first concave portion 102 may be deeper than the reflective concave portion 100, thereby forming a deeper frame portion 122 around the reflective concave portion 100, thereby better suppressing the side wave mode.

[0044] like Figure 1As shown, the substrate 10 may further include a through hole 104, and the through hole 104 may be connected from the surface S2 of the substrate 10 to the reflective concave portion 100. The height h of the through hole 104 may be between 150 microns and 200 microns. As described in further detail below, during the manufacturing process, the through hole 104 can be used to remove sacrificial materials. Disposing the through hole 104 on the bottom surface of the substrate 10 (e.g., the surface S2) can avoid affecting the routing and layout of the material layer above the surface S1, thereby avoiding or reducing the impact on the resonant frequency of the acoustic wave device 1.

[0045] As described above, the reflective concave portion 100 of the substrate 10 may form an air cavity, which may be used as a reflective portion of the acoustic wave device 1. In other embodiments, the reflective portion may be implemented in other forms, for example, a plurality of stacks may be provided at the location of the reflective concave portion 100, for example, the plurality of stacks may at least include a first layer having a first acoustic wave impedance, and a second layer stacked on the first layer and having a second acoustic wave impedance, wherein the first acoustic wave impedance may be less than the second acoustic wave impedance. In this embodiment, the reflector formed by the plurality of stacks may also be called a Bragg reflector, which may be used to reduce or prevent acoustic wave leakage and suppress side wave modes. In detail, the first layer and the second layer of the plurality of stacks may be, for example, layers of different materials. Alternatively, the first layer and the second layer may be substantially the same material, but have different dopants or dopant concentrations, so as to achieve different refractive indices for acoustic waves.

[0046] In some embodiments, the acoustic wave device 1 may further include a passivation layer 19, which may at least partially cover the upper electrode, such as the electrode 16, to protect the upper electrode and the materials below. For example, the material of the passivation layer 19 may be silicon oxide (e.g., silicon dioxide) or silicon nitride (e.g., silicon nitride). Furthermore, the acoustic wave device 1 may further include an electrode contact portion 18, which may be electrically connected to a lower electrode, such as the electrode 12, via a contact hole 140 in the piezoelectric layer 14. Figure 1 As shown, the contact hole 140 may pass through the piezoelectric layer 14, and the electrode contact portion 18 may cover the piezoelectric layer 14 and contact the electrode 12 through the contact hole 140 in the piezoelectric layer 14. In this embodiment, the material of the electrode contact portion 18 may be a conductive material, such as tin, gold, or aluminum-copper alloy (Al-Cu). In some embodiments, the contact hole 140 of the piezoelectric layer 14 may be omitted, and the electrode contact portion 18 may be electrically connected to the electrode 12 in other ways. Further, as Figure 1 As shown, the passivation layer 19 may also partially cover the electrode contact 18 and the piezoelectric layer 14. As discussed further below, the acoustic wave device 1 may additionally include an electrode contact 28 electrically connected to the electrode 16.

[0047] Figure 44 is a partial cross-sectional schematic diagram of another acoustic wave device 4 in an embodiment of the present invention. The difference between the acoustic wave device 4 and the acoustic wave device 1 is that the base 10 of the acoustic wave device 4 includes two recesses 411 and 412, and the two frame portions 421 and 422 are respectively arranged in the two recesses 411 and 412. The following is an explanation of the difference between the acoustic wave device 4 and the acoustic wave device 1. The other structures of the acoustic wave device 4 are similar to those of the acoustic wave device 1, and their description is not repeated here.

[0048] As shown in the figure, the substrate 10 may include a first and a second recess 411, 412, which may be recessed from the surface S1 of the substrate 10 and at least partially surround the reflective recess 100. The first and the second recess 411, 412 may be separated from the reflective recess 100. Further, the first recess 411 and the second recess 412 may also be separated from each other. For example, in the horizontal direction X, the first recess 411 may be separated from the reflective recess 100 by a first distance s1, and the second recess 412 may be separated from the reflective recess 100 by a second distance s2, wherein s2 may be greater than s1. The acoustic wave device 1 may include a first and a second frame portion 421, 422, wherein the first frame portion 421 may be filled in the first recess 411, and the second frame portion 422 may be filled in the second recess 412. In this embodiment, both the first and the second frame portions 421, 422 contact the electrode 12. However, the present invention is not limited thereto, and in other embodiments, the second frame portion 422 may not contact the electrode 12 but may contact the electrode 16 . Alternatively, the second frame portion 422 may not contact the electrode 12 or the electrode 16 .

[0049] In some embodiments, the first and second frame portions 421 and 422 may be made of different materials. For example, the first frame portion 421 may be made of a metal material, and the second frame portion 422 may be made of a dielectric material. Figure 1 In the embodiment shown, Figure 4 A second frame portion 422 is additionally provided in the middle, which forms an additional frame structure (eg, additional weight load) around the effective area to further reduce or prevent the leakage of sound waves along the horizontal direction X, thereby suppressing the side wave mode.

[0050] In detail, in the substrate 10, the first recess 411 may have a dimension W1 along the horizontal direction X and a depth d1 along the vertical direction Y, and the second recess 412 may have a dimension W2 along the horizontal direction X and a depth d2 along the vertical direction Y. In some embodiments, the depth d1 of the first recess 411 and the depth d2 of the second recess 412 may be the same (d1=d2). In other embodiments, the depth d1 of the first recess 411 and the depth d2 of the second recess 412 may be different (d1≠d2), for example, d1 may be smaller than d2. In some embodiments, the dimension W1 of the first recess 411 and the dimension W2 of the second recess 412 may be the same (W1=W2). In other embodiments, the dimension W1 of the first recess 411 and the dimension W2 of the second recess 412 may be different (W1≠W2), for example, W1 may be larger than W2.

[0051] Although Figure 4 Two recesses and two frame portions are shown, but those skilled in the art can adjust the number and / or position of the recesses and frame portions according to the spirit of the present invention to meet actual needs. For example, three recesses and three frame portions can also be set in the acoustic wave device. Figure 4 and Figure 2 In the illustrated embodiment, the number of recesses is the same as the frame portion, but the present invention is not limited thereto. In other unillustrated embodiments, the number of recesses may be greater than the frame portion. In other words, there may be at least one recess in which no frame portion is provided.

[0052] Figure 5 yes Figure 1 Flow chart of an exemplary manufacturing method 500 of the acoustic wave device 1 in FIG. The manufacturing method 500 may include steps S501 to S523 for manufacturing, for example, the acoustic wave device 1. Any reasonable technical changes or step adjustments fall within the scope of the present invention. The details of steps S501 to S523 are as follows:

[0053] Step S501: providing a substrate 10, and forming a reflective concave portion 100 in the substrate 10;

[0054] Step S503: filling the reflective concave portion 100 with a sacrificial material 70;

[0055] Step S505: performing a planarization process so that the sacrificial material 70 and the substrate 10 are coplanar;

[0056] Step S507: forming a concave portion 102 in the substrate 10 , wherein the concave portion 102 at least partially surrounds the reflective concave portion 100 and is spaced apart from the reflective concave portion 100 ;

[0057] Step S509: forming a frame portion 122 in the recess 102 , and forming a first electrode 12 , wherein the first electrode 12 contacts the frame portion 122 , and the first electrode 12 is at least partially located on the sacrificial material 70 ;

[0058] Step S511: forming a piezoelectric layer 14, wherein the piezoelectric layer 14 is at least partially located on the first electrode 12;

[0059] Step S513: forming a second electrode 16, wherein the second electrode 16 is at least partially located on the piezoelectric layer 14;

[0060] Step S515: forming a first contact hole 140 in the piezoelectric layer 14;

[0061] Step S517: forming a first electrode contact portion 18 , wherein the first electrode contact portion 18 is electrically connected to the first electrode 12 through the first contact hole 140 ;

[0062] Step S519: forming a passivation layer 19, wherein the passivation layer 19 at least partially covers the second electrode 16;

[0063] Step S520: forming a second electrode contact portion 28, wherein the second electrode contact portion 28 may be electrically connected to the second electrode 16 through a second contact hole 240, wherein the second contact hole 240 may be formed in the passivation layer 19;

[0064] Step S521: grinding the substrate 10 thin from the back side of the substrate 10;

[0065] Step S523 : drilling a hole from the surface S2 of the substrate 10 to form a through hole 104 , wherein the through hole 104 is connected from the lower surface S2 to the reflective concave portion 100 , and removing the sacrificial material 70 through the through hole 104 .

[0066] The following references Figure 6-Figure 9 The manufacturing method 500 is further described.

[0067] Figure 6 A schematic diagram showing steps S501 to S505 is shown. In step S501, a substrate 10 is provided and the substrate 10 is etched, for example, to form a reflective concave portion 100. In step S503, a sacrificial material 70 is filled in the reflective concave portion 100. The sacrificial material 70 may be, for example, silicon dioxide. In step S503, a planarization process, such as chemical mechanical polishing / planarization (CMP), is performed on the sacrificial material 70 to make the remaining sacrificial material 70 coplanar with the substrate 10.

[0068] Figure 7A schematic diagram showing steps S507 to S513. In step S507, a recess 102 is formed in the substrate 10. For example, the substrate 10 may be etched a second time to form the recess 102, wherein the recess 102 at least partially surrounds the reflective recess 100 and is spaced apart from the reflective recess 100. Next, in step S509, a material (e.g., a deposited metal) is filled in the recess 102 to form a frame portion 122, and a metal layer may be deposited on the sacrificial material 70 at the same time to form the electrode 12. For example, the frame portion 122 and the electrode 12 may be formed as one body. The electrode 12 may include a portion covering the sacrificial material 70, a portion covering the surface S1 of the substrate 10, and a portion contacting the frame portion 122. In other embodiments, the frame portion 122 and the electrode 12 may also be formed separately. For example, a first metal layer is first deposited in the recess 102 to form the frame portion 122, and then a second metal layer is deposited on the frame portion 122, the sacrificial material 70, and the substrate 10 to form the electrode 12. The materials of the first metal layer and the second metal layer can be different. In step S511, a piezoelectric material is deposited on the substrate 10, the electrode 12, and the sacrificial material 70 to form the piezoelectric layer 14. In step S513, a metal layer is deposited on the piezoelectric layer 14 to form the electrode 16.

[0069] Figure 8 A schematic diagram showing steps S515 and S517 is shown. In step S515, a first contact hole 140 is formed in the piezoelectric layer 14. For example, the piezoelectric layer 14 may be plasma etched to form the first contact hole 140. Next, in step S517, a metal material is deposited to form a first electrode contact portion 18. The first electrode contact portion 18 may be electrically connected to the electrode 12 through the first contact hole 140 and is separated from the electrode 16 and is not electrically connected to the electrode 16.

[0070] Fig. 9 A schematic diagram showing steps S519 to S523. In steps S519 to S520, a passivation layer 19 is formed, which at least partially covers the electrode 16; a second contact hole 240 is formed in the passivation layer 19, and a second electrode contact portion 28 is formed, wherein the second electrode contact portion 28 is electrically connected to the electrode 16 through the second contact hole 240. In step S521, the substrate 10 is ground thin from the back side of the substrate 10 so that the material thickness of the substrate 10 below the reflective concave portion 100 is reduced from H to h, wherein h may be between 150 microns and 200 microns. In step S523, a through hole 104 is formed by drilling from the back side of the substrate 10, wherein the through hole 104 may be connected to the reflective concave portion 100, and the sacrificial material 70 located in the reflective concave portion 100 is removed through the through hole 104.

[0071] Fig.101 is a flow chart of another exemplary manufacturing method 1000 of an acoustic wave device 1 in an embodiment of the present invention. The manufacturing method 1000 includes steps S1001 to S1013, which are used to manufacture the acoustic wave device 1. Any reasonable technical changes or step adjustments fall within the scope of the present invention. The details of steps S1001 to S1013 are as follows:

[0072] Step S1001: providing a substrate 10, forming a reflective portion 100 in the substrate 10, wherein the reflective portion 100 may include a cavity or a plurality of stacked layers;

[0073] Step S1007: forming a concave portion 102 in the substrate 10, wherein the concave portion 102 at least partially surrounds the reflective portion and is spaced apart from the reflective portion;

[0074] Step S1009: forming a frame portion 122 in the recess 102 , and forming a first electrode 12 , wherein the first electrode 12 contacts the frame portion 122 ;

[0075] Step S1011: forming a piezoelectric layer 14, wherein the piezoelectric layer 14 is at least partially located on the first electrode 12;

[0076] Step S1013 : forming a second electrode 16 , where the second electrode 16 is at least partially located on the piezoelectric layer 14 .

[0077] The present invention discloses an acoustic wave device and a manufacturing method thereof, wherein a frame portion is formed at the edge of an electrode to reduce or prevent acoustic wave leakage along the horizontal direction X, suppress the side wave mode, and improve circuit performance. The above description is only a preferred embodiment of the present invention, and any equivalent changes and modifications made according to the claims of the present invention shall fall within the scope of the present invention.

Claims

1. An acoustic wave device, characterized in that: Include: A substrate, comprising a first surface, a second surface, a reflective concave portion, and a first concave portion, wherein the second surface is opposite to the first surface, the reflective concave portion is recessed from the first surface, the first concave portion is recessed from the first surface, and the first concave portion at least partially surrounds the reflective concave portion and is spaced apart from the reflective concave portion; A first frame portion, disposed in the first recessed portion of the base; A first electrode is disposed on the substrate and contacts the first frame portion; a piezoelectric layer at least partially disposed on the first electrode; and A second electrode is at least partially disposed on the piezoelectric layer, wherein in a vertical direction, the reflective concave portion of the substrate, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap.

2. The acoustic wave device according to claim 1, characterized in that The invention also comprises a reflective portion disposed in the reflective concave portion, wherein the reflective portion comprises at least one of a cavity and a plurality of stacked layers.

3. The acoustic wave device according to claim 1, characterized in that The first concave portion has a first dimension along the horizontal direction and a first depth along the vertical direction, the reflective concave portion has a reflective dimension along the horizontal direction and a reflective depth along the vertical direction, and the first dimension of the first concave portion is smaller than the reflective dimension of the reflective concave portion.

4. The acoustic wave device according to claim 3, characterized in that The first depth of the first concave portion is different from the reflection depth of the reflection concave portion.

5. The acoustic wave device according to claim 1, characterized in that The substrate further comprises: a second recessed portion, recessed from the first surface, the second recessed portion at least partially surrounding the reflective recessed portion and spaced apart from the reflective recessed portion, wherein In a horizontal direction, the first concave portion is separated from the reflective concave portion by a first distance, and the second concave portion is separated from the reflective concave portion by a second distance, wherein the second distance is greater than the first distance.

6. The acoustic wave device according to claim 5, characterized in that The first recess has a first dimension in the horizontal direction and a first depth in the vertical direction, the second recess has a second dimension in the horizontal direction and a second depth in the vertical direction, and the first depth of the first recess is different from the second depth of the second recess.

7. The acoustic wave device according to claim 6, characterized in that The first size of the first recess is different from the second size of the second recess.

8. The acoustic wave device according to claim 1, characterized in that The material of the first frame portion is different from the material of the first electrode.

9. The acoustic wave device according to claim 1, characterized in that The material density of the first frame portion is greater than the material density of the first electrode.

10. The acoustic wave device according to claim 1, characterized in that The first frame portion and the first electrode are formed as one body.

11. The acoustic wave device according to claim 1, characterized in that The substrate further comprises a through hole which is connected from the second surface of the substrate to the reflective concave portion.

12. The acoustic wave device according to claim 1, characterized in that Also includes: A first electrode contact portion covers the piezoelectric layer and is electrically connected to the first electrode through a contact hole in the piezoelectric layer.

13. A method for manufacturing an acoustic wave device, characterized in that: Include: providing a substrate; forming a reflective portion in the substrate; A first concave portion is formed in the substrate, the first concave portion at least partially surrounds the reflective portion and is spaced apart from the reflective portion; a first frame portion is formed in the first concave portion; forming a first electrode on the substrate, the first electrode contacting the first frame portion; forming a piezoelectric layer, the piezoelectric layer being at least partially located on the first electrode; and forming a second electrode, the second electrode being at least partially located on the piezoelectric layer; In a vertical direction, the reflective portion of the substrate, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap.

14. A method for manufacturing an acoustic wave device, characterized in that: Include: providing a substrate; forming a reflective recess in the substrate; Filling a sacrificial material in the reflective concave portion; A first concave portion is formed in the substrate, the first concave portion at least partially surrounding the reflective concave portion and being spaced apart from the reflective concave portion; A first frame portion is formed in the first recess; Forming a first electrode on the substrate, wherein the first electrode is at least partially located on the sacrificial material and contacts the first frame portion; forming a piezoelectric layer, the piezoelectric layer being at least partially located on the first electrode; and forming a second electrode, the second electrode being at least partially located on the piezoelectric layer; In a vertical direction, the sacrificial material in the substrate, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap.

15. The method according to claim 14, characterized in that Also includes: After filling the sacrificial material, a planarization process is performed to make the sacrificial material coplanar with the substrate.

16. The method according to claim 14, characterized in that Also includes: grinding the substrate thin from the back side of the substrate; drilling a hole in the substrate to form a through hole, the through hole communicating with the reflective concave portion; and The sacrificial material is removed through the through hole.

17. The method according to claim 14, characterized in that Also includes: forming a second recess in the substrate, the second recess at least partially surrounding the reflective recess and spaced apart from the reflective recess; In a horizontal direction, the first concave portion is separated from the reflective concave portion by a first distance, and the second concave portion is separated from the reflective concave portion by a second distance, wherein the second distance is greater than the first distance.

18. The method according to claim 14, characterized in that Also includes: A first electrode contact portion is formed, which is electrically connected to the first electrode.

19. The method according to claim 14, characterized in that Also includes: A second electrode contact portion is formed, which is electrically connected to the second electrode.

20. The method according to claim 14, characterized in that Also includes: A passivation layer is formed to at least partially cover the second electrode.

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