Acoustic wave device and method for manufacturing same

Abstract

A manufacturing method of an acoustic wave device includes providing a first substrate including a first body plate, a first frame, and a first electrode, a piezoelectric layer, and a second electrode stacked in sequence, and thinning the first substrate to expose the first electrode from a first surface of the first substrate. The first bezel is disposed in the first body plate and around the first electrode. The manufacturing method further includes providing a second substrate, the second substrate including a second body plate and a recess recessed from a second surface of the second substrate, and bonding the first surface of the first substrate and the second surface of the second substrate together such that in a vertical direction, the first body plate and the second body plate are bonded together. The recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region.

Description

Technical Field

[0001] This invention relates to an acoustic technology, and more particularly to an acoustic device and its manufacturing method, wherein the acoustic device may have a reduced parasitic mode. Background Technology

[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 applications. BAW devices can also be used as filters, filtering noise while preserving wireless signals in the desired frequency band, providing low transmission loss and immunity to electromagnetic interference, while maintaining a small size, thus finding wide application in various communication products. Furthermore, BAW filters can also be used as resonators. Current BAW devices may generate spurious modes, causing unnecessary energy leakage and reducing circuit efficiency. Summary of the Invention

[0003] This invention provides a method for manufacturing an acoustic wave device, including providing a first substrate. The first substrate includes a first body plate, a first frame, and a first electrode, a piezoelectric layer, and a second electrode stacked sequentially. The first frame is disposed in the first body plate and around the first electrode. The first substrate is thinned so that the first electrode is exposed from a first surface of the first substrate. A second substrate is provided, including a second body plate and a recess, the recess being recessed from a second surface of the second substrate. The first surface of the first substrate and the second surface of the second substrate are joined together such that, in the vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region.

[0004] This invention also provides an acoustic wave device, including a first substrate and a second substrate. The first substrate includes a first surface, a first body plate, a first electrode, a piezoelectric layer, a second electrode, and a first frame. The first electrode, the piezoelectric layer, and the second electrode are stacked sequentially. The first electrode is exposed from the first surface. The frame is disposed in the first body plate and around the first electrode. The second substrate includes a second surface, a second body plate, and a recess, the recess being disposed in the second body plate and recessed from the second surface. The first surface of the first substrate and the second surface of the second substrate are joined together. In the vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region. The first substrate and the second substrate form a sealed cavity at a position corresponding to the recess.

[0005] This invention also provides a method for manufacturing an acoustic wave device, comprising: providing a first body plate; forming a first electrode on the first body plate; forming a first frame on the first body plate, wherein the first frame is disposed around the first electrode and spaced apart from the first electrode. The manufacturing method further comprises: forming a piezoelectric layer at least on the first electrode; forming a second electrode at least on the piezoelectric layer; forming a contact hole penetrating the piezoelectric layer; forming a first contact portion in the contact hole, the first contact portion being electrically connected to the first electrode; forming a passivation layer, at least covering the second electrode, thereby forming a first substrate; applying an adhesion layer from a first side of the first substrate; fixing the first substrate to a carrier plate by the adhesion layer; reducing the thickness of the first substrate from a second side of the first substrate to a first surface using a planarization process, such that the first electrode is exposed from the first surface. The manufacturing method further comprises: providing a second substrate, the second substrate including a second body plate and a recess, the recess being recessed from a second surface of the second substrate; joining the first surface of the first substrate and the second surface of the second substrate together, such that in the vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region; and removing the carrier plate and the adhesion layer.

[0006] This invention also provides an acoustic wave device, including a first substrate and a second substrate. The first substrate includes a first surface, a first electrode, a piezoelectric layer, a second electrode, and a first frame. The first electrode, the piezoelectric layer, and the second electrode are stacked sequentially. The first electrode is exposed from the first surface. The first frame is disposed around the first electrode. The second substrate includes a second surface, a second body plate, a recess, and a second frame. The recess is disposed in the second body plate and recessed from the second surface. The second frame is disposed in the second body plate. The first surface of the first substrate and the second surface of the second substrate are joined together. In the vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region. The first substrate and the second substrate form a sealed cavity at a position corresponding to the recess. The second frame is disposed around the sealed cavity. Attached Figure Description

[0007] Figure 1A This is an exemplary cross-sectional view of an acoustic device according to an embodiment of the present invention.

[0008] Figure 1B This is an exemplary top view of a portion of an acoustic device according to an embodiment of the present invention.

[0009] Figure 2 This is an exemplary flowchart illustrating a method for manufacturing an acoustic device according to an embodiment of the present invention.

[0010] Figure 3A , 3B 3C and Figures 4 to 6 This diagram illustrates exemplary steps of a method for manufacturing an acoustic device according to an embodiment of the present invention.

[0011] Figure 7 This is an exemplary cross-sectional view of another acoustic device according to an embodiment of the present invention.

[0012] Figure 8 This is an exemplary cross-sectional view of another acoustic device according to an embodiment of the present invention.

[0013] Figure 9 This is an exemplary flowchart illustrating another method for manufacturing an acoustic device according to an embodiment of the present invention.

[0014] Figures 10 to 12 A schematic diagram illustrating exemplary steps of another method for manufacturing an acoustic device according to an embodiment of the present invention is shown.

[0015] Figure 13 This is an exemplary cross-sectional view of another acoustic device according to an embodiment of the present invention.

[0016] Symbol explanation:

[0017] 1,7,8,13: Acoustic wave device

[0018] 11: First substrate

[0019] 12: Second substrate

[0020] 112: First electrode

[0021] 113: Piezoelectric layer

[0022] 114: Second electrode

[0023] 115: First Contact Section

[0024] 116: Passivation layer

[0025] 11BP, 12BP: Main board

[0026] 12R: concave part

[0027] 11S, 12S: Surface

[0028] 11F, 12F, 13F, 14F: Border

[0029] 200,900: Method

[0030] S201, S203, S205, S207: Steps

[0031] S201a to S201i, S203a to S203c, S205a to S205c: Steps 901 to 914: Step 112R: First electrode receiving portion

[0032] 11FR, 12FR: Frame housing

[0033] 118: Adhesion layer

[0034] 119: Carrier plate

[0035] H: Contact hole

[0036] X, Y, Z: Direction

[0037] L1, L2, L3, L4: Horizontal distance

[0038] d1, d2, d3, d4, d5: Depth

[0039] OS: Overlapping region Detailed Implementation

[0040] The directional terms "up," "down," "left," and "right" used in this invention are merely illustrative of structures or methods and are not intended to limit the invention. They may have different meanings in different descriptions of the same drawing or in different drawings with the same description. In this document, some features, elements, structures, materials, configurations, etc., may be described illustratively in one embodiment, but are not limited to that embodiment. For example, elements described in one embodiment may be omitted from that embodiment or may be applied to another embodiment.

[0041] Figure 1A This is an exemplary cross-sectional view of an acoustic device 1 according to an embodiment of the present invention.

[0042] In some embodiments, the acoustic device 1 may include a bulk acoustic wave (BAW) device, which may be used, for example, as a resonator, filter, or for other purposes. In some embodiments, the acoustic device 1 may be used as a BAW resonator, which may receive an input signal to generate a standing sound wave and then convert the standing sound wave into a resonant signal. In other embodiments, the acoustic 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 signals of a specific frequency to pass through. The uses of the acoustic device 1 are merely illustrative herein, and the invention is not limited thereto. For example, the bulk acoustic wave device may include a thin film bulk acoustic resonator (FBAR).

[0043] In some embodiments, the acoustic device 1 may include a first substrate 11 and a second substrate 12. The first substrate 11 may include a first body plate 11BP and a first frame 11F disposed in the first body plate 11BP. The first substrate 11 may also include a first electrode 112, a piezoelectric layer 113, and a second electrode 114 stacked in sequence, wherein the first electrode 112 may be exposed from a surface of the first substrate 11 (e.g., a first surface 11S), and the first frame 11F may be disposed around the first electrode 112, for example, the first frame 11F may at least partially surround the first electrode 112.

[0044] Furthermore, the second substrate 12 may include a second main body plate 12BP and a recess 12R disposed in the second main body plate 12BP, wherein the recess 12R is recessed from a surface (e.g., the second surface 12S) of the second substrate 12. Figure 1A As shown, the first surface 11S of the first substrate 11 and the second surface 12S of the second substrate 12 are joined such that, in the vertical direction, for example, in the direction Z perpendicular to the first surface 11S, the recess 12R, the first electrode 112, the piezoelectric layer 113, and the second electrode 114 at least partially overlap to form an overlapping region OS. After joining, the first substrate 11 and the second substrate 11 form a cavity at the position corresponding to the recess 12R, which can be, for example, a sealed cavity. For example, the cavity can be used as a sound wave reflector, which can help reduce sound wave leakage in the vertical direction.

[0045] In some embodiments, the material of the first body plate 11BP and the material of the second body plate 12BP may be the same or different.

[0046] In some embodiments, the first substrate 11 may further include a first contact portion 115 and a passivation layer 116. The first contact portion 115 is electrically connected to the first electrode 112, and the passivation layer 116 may at least cover the second electrode 114, as further described below. In other embodiments, the first substrate 11 may further include a second contact portion (not shown) that is electrically connected to the second electrode 114. In some embodiments, the material of the second electrode 114 may be the same as or different from the material of the first electrode 112.

[0047] In some embodiments, for example, the materials of the first substrate 11BP and / or the substrate 12BP may include silicon, glass, ceramic, gallium arsenide, and / or silicon carbide. The materials of the first electrode 112 and / or the second electrode 114 may include conductive materials, 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 113 may include, for example, at least one of the following: zinc oxide (ZnO), aluminum nitride (AlN), lithium niobate (LiTaO3, LT), lithium niobate (LN), quartz (QZ), lead titanate (PTO), lead zirconate titanate (PZT), and combinations thereof. In some embodiments, the piezoelectric layer 113 may be doped with rare earth elements, such as scandium (Sc). The materials of the first contact portion 115 and / or the second contact portion may include conductive materials, such as molybdenum (Mo), copper (Cu), aluminum (Al), gold (Au), platinum (Pt), tungsten (W), other suitable metals, and combinations thereof. The material of the passivation layer 116 may include silicon dioxide (SiO2), silicon nitride (SiN), or other suitable materials. It should be noted that the above materials are merely illustrative and are not intended to limit the invention.

[0048] In some embodiments, during operation, the second electrode 114 can receive an input signal via a second contact (not shown), and the first electrode 112 can be grounded via a first contact 115, thereby generating an acoustic wave propagating in the vertical Z direction. The piezoelectric layer 113 can be used to convert the acoustic wave into a resonant signal with a resonant frequency. The resonant frequency can depend on many parameters of the acoustic device 1, such as the material and thickness of the piezoelectric layer 113, and the size and thickness of the first electrode 112 and the second electrode 114. For example, the resonant frequency can range from 100 MHz (megahertz) to 20 GHz (gigahertz).

[0049] In the prior art, to form a cavity in an acoustic wave device, it may be necessary to first fill a sacrificial material at a specific location, and then form a through-hole leading to the sacrificial material. The sacrificial material is removed through the through-hole, thereby forming the cavity. However, the through-hole may need to be formed in the first substrate or the second substrate, which may increase the process complexity and / or weaken the structural strength of the acoustic wave device, thus hindering the optimization of the acoustic wave device's performance. In some embodiments of the present invention, when forming the acoustic wave device 1, it is not necessary to form a through-hole connecting to the recess 12R, that is, the through-hole passing through the first substrate 11 or the second substrate 12 can be omitted, thereby reducing the process complexity and improving the structural strength of the acoustic wave device.

[0050] Figure 1BThis is an exemplary top view of a portion of an acoustic device according to an embodiment of the present invention. In some embodiments, the overlapping region OS may be referred to as the effective region, within which acoustic waves can propagate in the vertical direction Z. A first border 11F may be further disposed around the overlapping region OS. As shown, the first border 11F may at least partially surround the overlapping region OS.

[0051] In some embodiments, such as Figure 1B As shown, the outline of the overlapping region OS can be oval, but in other embodiments, the outline of the overlapping region OS can also be other shapes, such as a chamfered oval, square, circular, pentagonal, or other regular or irregular shapes. The first border 11F can be configured to substantially continuously surround the overlapping region OS, for example, surrounding more than 50% of the perimeter of the overlapping region OS. For example, the first border 11F can continuously surround the narrower end and side of the oval-shaped overlapping region OS, and have an opening at the wider end of the overlapping region OS to partially surround the overlapping region OS. In other embodiments, the opening of the first border 11F can also have different positions and sizes; for example, the outline of the first border 11F can have an opening at the narrow end or at the side of the oval shape. In a further embodiment, the first border 11F can also continuously and completely surround the entire overlapping region OS.

[0052] In other embodiments, the first border 11F may be configured to substantially discontinuously surround the overlapping region OS. For example, the first border 11F may be a segmented border, comprising a plurality of discontinuous portions disposed around the overlapping region OS. In other words, the outline of the first border 11F may include a plurality of openings, such as three openings. For example, the first opening may be positioned near the narrower end of the overlapping region OS, and the second and third openings may be positioned near the side or wider end of the overlapping region OS. In the above embodiments, the shapes are for illustrative purposes only and are not intended to limit the invention.

[0053] Figure 2 This is an exemplary flowchart of a method for manufacturing an acoustic device according to an embodiment of the present invention, 200. Figures 3A to 3C and Figure 4 Steps 6 to 6 show exemplary steps of a method 200 for manufacturing an acoustic device according to an embodiment of the present invention. The following is in conjunction with… Figure 1A and Figure 2 and Figure 3A , 3B 3C and Figures 4 to 6 An exemplary embodiment of manufacturing method 200 is described.

[0054] In some embodiments, manufacturing method 200 may include steps S201 to S207. Any reasonable technical changes or adjustments to the steps are within the scope of this invention. The steps S201 to S207 are briefly described as follows: Step S201: A first substrate 11 is provided, including a first main plate 11BP, a first frame 11F, and a first electrode 112, a piezoelectric layer 113, and a second electrode 114 stacked in sequence, wherein the first frame 11F is disposed in the first main plate 11BP and around the first electrode 112; Step S203: The first substrate 11 is thinned so that the first electrode 112 is exposed from the first surface 11S of the first substrate 11; Step S205: A second substrate 12 is provided, including a second main plate 12BP and a recess 12R, the recess 12R being recessed from the second surface 12S of the second substrate 12; Step S207: The first surface 11S of the first substrate 11 and the second surface 12S of the second substrate 12 are joined together so that in the vertical direction, the recess 12R, the first electrode 112, the piezoelectric layer 113, and the second electrode 114 at least partially overlap to form an overlapping region OS.

[0055] In some embodiments, please refer to Figure 3A , 3B And 3C, the step S201 of providing the first substrate 11 may include steps S201a to S201j.

[0056] In step S201a, a first body plate 11BP is provided; in step S201b, a first electrode receiving portion 112R is formed in the first body plate 11BP, which can subsequently be used to receive the first electrode 112; in step S201c, a first frame receiving portion 11FR is formed in the first body plate 11BP, wherein the first frame receiving portion 11FR is spaced apart from the first electrode receiving portion 112R, and the first frame receiving portion 11FR can subsequently be used to form a first frame 11F. Further, the first frame receiving portion 11FR can be disposed around the first electrode receiving portion 112R, thereby at least partially surrounding the first electrode receiving portion 112R. It should be noted that steps S201b and S201c can be performed simultaneously, or their order can be interchanged. For example, the steps of forming the first electrode receiving portion 112R and / or the first frame receiving portion 11FR include dry etching and / or wet etching. Further, as... Figure 3A As shown, the first electrode receiving portion 112R may have a depth d1, the first frame receiving portion 11FR may have a depth d2, and the depth d2 may be equal to or less than the depth d1.

[0057] In step S201d, a first electrode 112 is formed in the first electrode receiving portion 112R. For example, the step of forming the first electrode 112 may include depositing a conductive material layer (e.g., molybdenum (Mo)) on the first substrate 11 and patterning the conductive material layer to form the first electrode 112. In step S201e, a first border 11F is formed using the first border receiving portion 11FR. For example, the first border receiving portion 11FR may be filled with a conductive material (e.g., molybdenum (Mo) or tungsten (W)) or a dielectric material (e.g., SiO2) to form the first border 11F. The material used to form the first border 11F may be the same as or different from the material used to form the first electrode 112. If the same material is used, the first electrode 112 and the first border 11F may be formed in the same step. If different materials are used, the first electrode 112 and the first border 11F may be formed in different steps. In other words, steps S201d and S201e may be performed simultaneously or in an interchangeable order. It should be noted that the first frame 11F may not contain any filling material. That is, in the above step S201e, the first frame receiving portion 11FR may not be filled with material.

[0058] In some embodiments, the material forming the first frame 11F may be selected to have a density greater than that of the first electrode 112, thereby reducing or preventing sound wave leakage along the horizontal direction (e.g., directions X and Y parallel to the first surface 11S), thus suppressing parasitic modes, also known as secondary wave modes or stray modes. Material density can be defined, for example, as the mass of material per unit volume; for example, aluminum has a density of approximately 2.9 grams per cubic centimeter (g / cm³). 3 The density of molybdenum is approximately 10.2 g / cm³. 3 The density of tungsten is approximately 19.25 g / cm³. 3 .

[0059] In some embodiments, please refer to Figure 3B and 3CStep S201, which provides the first substrate 11, may further include steps S201f to S201j. In step S201f, a piezoelectric layer 113 is formed on the first electrode 112, such that the piezoelectric layer 113 is at least partially disposed on the first electrode 112. In step S201g, a second electrode 114 is formed on the piezoelectric layer 113, such that the second electrode 114 is at least partially disposed on the piezoelectric layer 113. In step S201h, a contact hole H is formed penetrating the piezoelectric layer 113. In step S201i, a first contact portion 115 is formed in the contact hole H, which is electrically connected to the first electrode 112. Specifically, the first contact portion 115 fills the contact hole H and contacts the first electrode 112. In step S201j, a passivation layer 116 is formed to protect the surface of the acoustic wave device. The passivation layer 116 may at least cover the second electrode 114 and may expose the first contact portion 115.

[0060] In some embodiments, please refer to Figure 4 The step S203 of thinning the first substrate 11 may include steps S203a to S203c.

[0061] In step S203a, from the first side of the first substrate 11 (e.g. Figure 4 An adhesion layer 118 is applied to the upper side shown; in step S203b, the first substrate 11 is fixed to the carrier plate 119 by the adhesion layer 118; and in step S203c, a planarization process is used to apply an adhesion layer 118 to the second side of the first substrate 11 (as shown above); Figure 4 The thickness of the first substrate 11 is reduced to the first surface 11S (shown on the lower side). For example, the planarization process may include chemical mechanical polishing and smart cut. For example, smart cut may include using ion implantation and wafer bonding to precisely cut the semiconductor substrate.

[0062] In the above embodiment, the thickness of the first substrate 11 is reduced to the first surface 11S, so that the first electrode 112 is exposed from the first surface 11S. Further, in this step, the first frame portion 11F may or may not be exposed from the first surface 11S. For example, please simultaneously... Figure 3A In the case where the depth d2 of the first frame receiving portion 11FR is less than the depth d1 of the first electrode receiving portion 112R, the first frame portion 11F may not be exposed from the first surface 11S.

[0063] In some embodiments, please refer to Figure 5 The step S205 of providing the second substrate 12 may include steps S205a to S205c.

[0064] In step S205a, a second main body plate 12BP is provided; in step S205b, a recess 12R is formed in the second main body plate; in a further embodiment, step S205 of providing the second substrate 12 may further include step S205c, wherein a second frame receiving portion 12FR is formed in the second main body plate 12BP, and the second frame receiving portion 12FR is spaced apart from the recess 12R. Further, the second frame receiving portion 12FR may be disposed around the recess 12R, thereby at least partially surrounding the recess 12R. Specifically, the recess 12R and / or the second frame receiving portion 12FR may be recessed from the second surface 12S of the second substrate 12; it should be noted that steps S205b and S205c may be performed simultaneously, or their order may be interchanged. For example, the step of forming the recess 12R and / or the second frame receiving portion 12FR includes dry etching and / or wet etching. Furthermore, as... Figure 5 As shown, the recess 12R may have a depth d3, the second frame receiving portion 12FR may have a depth d4, and the depth d4 may be less than, equal to, or greater than the depth d3.

[0065] In some embodiments, please refer to Figure 5 Step S205, which provides the second substrate 12, may further include filling the second frame receiving portion 12FR with a conductive or dielectric material to form the second frame 12F, as will be described further below. In some embodiments, step S201, which provides the first substrate 11, and step S205, which provides the second substrate 12, may be performed simultaneously, or their order may be interchanged.

[0066] In some embodiments, please refer to Figure 6 In step S207, the first surface 11S of the first substrate 11 is bonded to the second surface 12S of the second substrate 12. Further, step S207 may include flipping the first substrate 11 or the second substrate 12 so that the second surface 12S of the second substrate 12 is bonded to the first surface 11S of the first substrate 11, and then removing the carrier plate 119 and / or the attachment layer 118. After bonding in step S207, a sealed cavity is formed between the first substrate 11 and the second substrate 12 at a location corresponding to the recess 12R. Further, this cavity can be used as a reflector in an acoustic wave device. In some embodiments, the bonding of the second substrate 12 and the first substrate 11 may be achieved using an adhesive and by applying pressure to bond the second surface 12S of the second substrate 12 and the surface 11S of the first substrate 11 to each other. The larger the bonding area between the first surface 11S of the first substrate 11 and the second surface 12S of the second substrate 12, the more stable the bonding between the first substrate 11 and the second substrate 12.

[0067] In manufacturing method 200, a second substrate 12 having a recess 12R is bonded to a first substrate 11 to form a sealed cavity. This bonding method eliminates the need for through holes in the first substrate 11 or the second substrate 12 to communicate with the recess 12R, thereby improving the efficiency of sound wave transmission, reducing process complexity, or improving the structural strength of the sound wave device.

[0068] Figure 7 This is an exemplary cross-sectional view of another acoustic wave device 7 according to an embodiment of the present invention. The acoustic wave device 7 is similar to the acoustic wave device 1, and will not be described in detail here; only some differences are described below. The second substrate 12 of the acoustic wave device 7 further includes a second frame 12F. Please refer to... Figure 5 and Figure 7 As described above, a second frame receiving portion 12FR can be formed in the second body plate 12BP, and optionally, the second frame receiving portion 12FR can be further filled with, for example, a conductive or dielectric material to form a second frame 12F. After engagement in step S207, the second frame receiving portion 12FR forms the second frame 12F around the cavity. In other words, the second frame 12F can at least partially surround the cavity, wherein the second frame 12F can be disposed in the second body plate 12BP.

[0069] In some embodiments, the first border 11F and the second border 12F may be at least partially aligned. For example... Figure 7 As shown, the first border 11F and the second border 12F can be perfectly aligned. However, the present invention is not limited to this; in other embodiments not shown, the first border 11F and the second border 12F may also be misaligned.

[0070] In other embodiments, a plurality of stacked layers may be provided in the recess 12R. For example, the plurality of stacked layers may include at least a first layer having a first acoustic impedance and a second layer stacked on the first layer having a second acoustic impedance, wherein the first acoustic impedance may be less than the second acoustic impedance. In this embodiment, the plurality of stacked layers may form a Bragg reflector, which can be used to reduce or prevent sound wave leakage in the vertical direction, thereby suppressing parasitic modes. Specifically, the first and second layers of the plurality of stacked layers may, for example, be layers of different materials. Alternatively, the first and second layers may be substantially the same material but with different dopants or dopant concentrations to achieve different refractive indices for sound waves.

[0071] In a further embodiment, the first substrate 11 may include a plurality of borders, and the second substrate 12 may also include a plurality of borders. Figure 8 This is an exemplary cross-sectional view of another acoustic device 8 according to an embodiment of the present invention. Acoustic device 8 is similar to acoustic device 1, and will not be described in detail here, except for some differences.

[0072] In some embodiments, the first substrate 11 of the acoustic device 8 may further include a third frame 13F, which may be disposed in the first main body plate 11BP and around the first electrode 112. Specifically, the horizontal distance L3 between the third frame 13F and the overlapping region OS may be greater than the horizontal distance L1 between the first frame 11F and the overlapping region OS. In other words, in the XY plane, the third frame 13F is farther from the overlapping region OS than the first frame 11F.

[0073] In some embodiments, such as Figure 8 As shown, the dimensions of the third border 13F along the horizontal direction, such as the dimension along the Y direction (e.g., width), may be the same as or different from the dimension of the first border 11F along the Y direction. Furthermore, the dimensions of the third border 13F along the vertical direction Z (e.g., depth) may be the same as or different from the dimension of the first border 11F along the vertical direction Z. For example, the formation steps of the third border 13F may be similar to those of the first border 11F, and will not be described in detail here, except that the filler material used for the third border 13F (if used) may be different from the filler material used for the first border 11F (if used). For example, the filler material used for the third border 13F may be a dielectric material, while the filler material used for the first border 11F may be a metallic material.

[0074] In some embodiments, the second substrate 12 of the acoustic device 8 may further include a fourth frame 14F, which may be disposed in the second main body plate 12BP. Further, the fourth frame 14F may be disposed around the cavity formed by the recess 12R, and may further be disposed around the second frame 12F (if present). In other words, the fourth frame 14F may at least partially surround the cavity, and may further at least partially surround the second frame 12F (if present). For example, the horizontal distance L4 between the fourth frame 14F and the overlapping region OS may be greater than the horizontal distance L2 between the second frame 12F and the overlapping region OS. In other words, in the XY plane, the fourth frame 14F is farther away from the overlapping region OS than the second frame 12F.

[0075] In some embodiments, such as Figure 8 As shown, the dimension (e.g., width) of the fourth frame 14F along the Y direction may be the same as or different from the dimension of the second frame 12F along the Y direction. Furthermore, the dimension (e.g., depth) of the fourth frame 14F along the vertical Z direction may be the same as or different from the dimension of the first frame 11F along the vertical Z direction. For example, the formation steps of the fourth frame 14F may be similar to those of the second frame 12F. For instance, a fourth frame receiving portion may be formed in the second body plate 12BP, spaced apart from the recess 12R and spaced apart from the second frame receiving portion 12FR. In a subsequent joining step, the fourth frame 14F may be formed using the fourth frame receiving portion. The filler material used for the fourth frame 14F (if used) may be different from the filler material used for the second frame 12F (if used).

[0076] In some embodiments, the depth of the second border 12F and / or the fourth border 14F may be the same as or different from the depth of the recess 12R. For example, the depth d5 ​​of the fourth border 14F may be greater than the depth d4 of the second border 12F, and the depth d4 of the second border 12F may be greater than the depth d3 of the recess 12R.

[0077] exist Figure 8 In the illustrated embodiment, the horizontal distance is shown as being measured from the right edge of the border (e.g., the right edge of the first border 11F), for example, to the left edge of the overlapping region OS. However, this is only for illustration. In other embodiments, the horizontal distance may also be measured from the vertical center axis of the border and / or may also be measured to the vertical center axis of the overlapping region OS.

[0078] In some embodiments, multiple borders may form additional border structures (e.g., additional reflective structures and / or weight loads) around the overlapping region OS (e.g., the effective region) to further reduce or prevent sound wave leakage in the horizontal direction, thereby suppressing parasitic modes.

[0079] Figure 9 This is an exemplary flowchart of another method for manufacturing an acoustic device according to an embodiment of the present invention, 900. Figures 10 to 12 This diagram illustrates exemplary steps of another method 900 for manufacturing an acoustic device according to an embodiment of the present invention. The following is in conjunction with... Figure 9 and Figures 10 to 12 An exemplary embodiment of manufacturing method 900 is described.

[0080] In some embodiments, the manufacturing method 900 may include steps S901 to S914. Any reasonable technical changes or adjustments to the steps are within the scope of this invention. Steps S901 to S914 are briefly described as follows: Step 901: Provide a first main body plate 11BP; Step 902: Form a first electrode 112 on the first main body plate 11BP; Step 903: Form a first frame 11F on the first main body plate 11BP, wherein the first frame 11F is disposed around the first electrode 112 and spaced apart from the first electrode 112; Step 904: Form a piezoelectric layer 113 at least on the first electrode 112; Step 905: Form a second electrode 114 at least on the piezoelectric layer 113; Step 906: Form a contact hole H penetrating the piezoelectric layer 113; Step 907: Form a first contact portion 115 in the contact hole H, which is electrically connected to the first electrode 112; Step 908: Form a passivation layer 116, which at least covers the second electrode 114, thereby forming a first substrate 11; Step 909: From the first substrate 1... Step 910: Apply an adhesion layer 118 to the first side of the substrate 11; Step 911: Fix the first substrate 11 to the carrier plate 119 by means of the adhesion layer 118; Step 912: Reduce the thickness of the first substrate 11 from the second side of the first substrate 11 to the first surface 11S using a planarization process, so that the first electrode 112 is exposed from the first surface 11S; Step 913: Provide a second substrate 12, which includes a second body plate 12BP and a recess 12R, the recess 12R being recessed from the second surface 12S of the second substrate 12; Step 914: Join the first surface 11S of the first substrate 11 to the second surface 12S of the second substrate 12, such that in the vertical direction, the recess 12R, the first electrode 112, the piezoelectric layer 113, and the second electrode 114 at least partially overlap to form an overlapping region; and Step 915: Remove the carrier plate 119 and / or the adhesion layer 118.

[0081] Figure 13 This is an exemplary cross-sectional view of another acoustic device 13 according to an embodiment of the present invention. The acoustic device 13 can utilize... Figure 9 The manufacturing method 900 shown is used to form the device. In detail, the acoustic device 13 may include a first substrate 11, which includes a first frame 11F, a first electrode 112, a piezoelectric layer 113, and a second electrode 114, wherein the first electrode 112, the piezoelectric layer 113, and the second electrode 114 are stacked sequentially, and the first electrode 112 is exposed from a first surface 11S of the first substrate 11, and the first frame 11F may be disposed around the first electrode 112.

[0082] In some embodiments, the acoustic wave device 13 may further include a second substrate 12, which includes a second main body plate 12BP and a recess 12R. The recess 12R may be disposed in the second main body plate 12BP and recessed from the second surface 12S of the second substrate 12. It should be noted that the second substrate 12 of the acoustic wave device 13 also includes a second frame 12F disposed in the second main body plate 12BP. The second frame 12F can be achieved by adjusting the above-described step 912. In detail, the second substrate 12 may further include a second frame receiving portion 12FR for forming the second frame 12F.

[0083] In some embodiments, the first surface 11S of the first substrate 11 is bonded to the second surface 12S of the second substrate 12, and in the vertical direction, the recess 12R, the first electrode 112, the piezoelectric layer 113, and the second electrode 114 at least partially overlap to form an overlapping region OS. The first substrate 11 and the second substrate 12 form a closed cavity at a position corresponding to the recess 12R, and a second frame 12F may be disposed around the cavity.

[0084] Compared to manufacturing method 200, manufacturing method 900 omits the first electrode receiving portion 112R and / or the first frame receiving portion 11FR. In other words, in manufacturing method 900, the first substrate 11 is not etched, and the first electrode 112 and / or the first frame 11F are formed directly on the first body plate 11BP. The step of forming the first electrode 112 and / or the first frame 11F on the first body plate 11BP includes depositing a conductive material layer on the process surface of the first substrate 11 and patterning the conductive material layer. This step can simultaneously form the first electrode 112 and the first frame 11F.

[0085] This invention provides an acoustic wave device and a method for manufacturing the acoustic wave device, which forms a sealed cavity and does not include a through hole connecting to the recess 12R, thereby improving the efficiency of sound wave conduction and strengthening the structure. Furthermore, the acoustic wave device and its manufacturing method in this invention further form a frame structure around the effective area to reduce or prevent sound wave leakage in the horizontal direction, thereby suppressing parasitic modes.

[0086] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention shall fall within the scope of the present invention.

Claims

1. A method for manufacturing an acoustic device, characterized in that, include: A first substrate is provided, the first substrate including a first body plate, a first frame, and a first electrode, a piezoelectric layer and a second electrode stacked in sequence, wherein the first frame is disposed in the first body plate and around the first electrode; Thinning the first substrate causes the first electrode to be exposed from a first surface of the first substrate; A second substrate is provided, the second substrate including a second body plate and a recess, the recess being recessed from a second surface of the second substrate; and The first surface of the first substrate is joined to the second surface of the second substrate such that the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap in a vertical direction to form an overlapping region.

2. The method for manufacturing the acoustic device according to claim 1, characterized in that, The provision of the first substrate includes: providing the first main body plate; A first electrode receiving portion is formed in the first main body plate; A first frame receiving portion is formed in the first main body plate, wherein the first frame receiving portion is spaced apart from the first electrode receiving portion; The first electrode is formed in the first electrode receiving portion; The first border is formed using the first border receiving portion; The piezoelectric layer is formed on the first electrode; and The second electrode is formed on the piezoelectric layer.

3. The method for manufacturing the acoustic device according to claim 2, characterized in that, Forming the first frame using the first frame receiving portion includes filling the first frame receiving portion with a conductive material or a dielectric material.

4. The method for manufacturing the acoustic device according to claim 2, characterized in that, The first substrate further includes: A contact hole is formed that penetrates the piezoelectric layer; A first contact portion is formed in the contact hole, and the first contact portion is electrically connected to the first electrode; and A passivation layer is formed, at least covering the second electrode.

5. The method for manufacturing the acoustic device according to claim 4, characterized in that, The step of thinning the first substrate includes: An adhesion layer is applied from a first side of the first substrate; The first substrate is fixed to a carrier plate by the adhesion layer; and A planarization process is used to reduce the thickness of the first substrate from a second side to the first surface.

6. The method for manufacturing the acoustic device according to claim 5, characterized in that, The step of bonding the first surface of the first substrate to the second surface of the second substrate includes: Flip the second substrate or the first substrate such that the second surface of the second substrate is bonded to the first surface of the first substrate; and Remove the carrier plate and the adhesive layer.

7. The method for manufacturing the acoustic device according to claim 2, characterized in that, The first electrode receiving portion has a first depth, and the first frame receiving portion has a second depth, the second depth being equal to or less than the first depth.

8. The method for manufacturing the acoustic device according to claim 7, characterized in that, The step of thinning the first substrate causes the first frame portion to be exposed or not exposed from the first surface.

9. The method for manufacturing the acoustic device according to claim 1, characterized in that, The provision of the second substrate includes: providing the second body plate; and The recess is formed in the second main body plate.

10. The method for manufacturing the acoustic device according to claim 9, characterized in that, The second substrate further includes: A second frame receiving portion is formed in the second main body plate, wherein the second frame receiving portion is spaced apart from the recess.

11. The method for manufacturing the acoustic device according to claim 10, characterized in that, The recess has a third depth, and the second frame receiving portion has a fourth depth, the fourth depth being equal to or greater than the third depth.

12. The method for manufacturing the acoustic device according to claim 10, characterized in that, The second substrate further includes: The second frame receiving portion is filled with a conductive material or a dielectric material.

13. The method for manufacturing the acoustic device according to claim 10, characterized in that, The first surface of the first substrate and the second surface of the second substrate are joined together, such that the first substrate and the second substrate form a sealed cavity at a position corresponding to the recess.

14. The method for manufacturing the acoustic device according to claim 13, characterized in that, The first surface of the first substrate is joined to the second surface of the second substrate to form a second frame using the second frame receiving portion. The second frame is disposed in the second main body plate and around the sealed cavity.

15. The method for manufacturing the acoustic device according to claim 14, characterized in that, The first border and the second border are at least partially aligned.

16. The method for manufacturing the acoustic device according to claim 14, characterized in that, The first substrate further includes a third frame disposed in the first main plate and around the first electrode, wherein a horizontal distance between the third frame and the overlapping area is greater than a horizontal distance between the first frame and the overlapping area.

17. The method for manufacturing the acoustic device according to claim 1, characterized in that, The second substrate further includes: A fourth frame receiving portion is formed in the second main body plate, wherein the fourth frame receiving portion is spaced apart from the recess and also spaced apart from the second frame receiving portion. The first surface of the first substrate is joined to the second surface of the second substrate, thereby forming a fourth frame using the fourth frame receiving portion. The fourth frame is disposed within the second main body plate and around the sealed cavity. The horizontal distance between the fourth border and the overlapping area is greater than the horizontal distance between the second border and the overlapping area.

18. An acoustic device, characterized in that, include: A first substrate, comprising: The first surface; The first main body panel; A first electrode, a piezoelectric layer, and a second electrode, wherein the first electrode, the piezoelectric layer, and the second electrode are stacked sequentially, and the first electrode is exposed from the first surface; and A first frame is disposed within the first main body plate and surrounding the first electrode; and A second substrate, comprising: A second surface; A second main body panel; and A recess is provided in the second main body plate and recessed from the second surface; The first surface of the first substrate is bonded to the second surface of the second substrate; In a vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region; and The first substrate and the second substrate form a sealed cavity at a position corresponding to the recess.

19. The acoustic device according to claim 18, characterized in that, The second substrate further includes a second frame disposed in the second main body plate and around the sealed cavity.

20. The acoustic device according to claim 19, characterized in that, The first border and the second border are at least partially aligned.

21. The acoustic device according to claim 19, characterized in that, The first substrate further includes a third frame disposed in the first main plate and around the first electrode, wherein a horizontal distance between the third frame and the overlapping area is greater than a horizontal distance between the first frame and the overlapping area.

22. The acoustic device according to claim 21, characterized in that, The second substrate further includes a fourth frame, which is disposed in the second main body plate and around the sealed cavity, wherein a horizontal distance between the fourth frame and the overlapping area is greater than a horizontal distance between the second frame and the overlapping area.

23. The acoustic device according to claim 22, characterized in that, The first border, the second border, the third border, and the fourth border shall each contain a filling material, the filling material being a conductive material or a dielectric material.

24. A method for manufacturing an acoustic device, characterized in that, include: Provide a primary main board; A first electrode is formed on the first main body plate; A first frame is formed on the first main body plate, wherein the first frame is disposed around the first electrode and is spaced apart from the first electrode system; At least one piezoelectric layer is formed on the first electrode; At least one second electrode is formed on the piezoelectric layer; A contact hole is formed that penetrates the piezoelectric layer; A first contact portion is formed in the contact hole, and the first contact portion is electrically connected to the first electrode; A passivation layer is formed to at least cover the second electrode, thereby forming the first substrate; An adhesion layer is applied from a first side of the first substrate; The first substrate is fixed to a carrier plate by the adhesion layer; A planarization process is used to reduce the thickness of the first substrate from a second side of the first substrate to a first surface, such that the first electrode is exposed from the first surface; A second substrate is provided, the second substrate including a second body plate and a recess, the recess being recessed from a second surface of the second substrate; The first surface of the first substrate is joined to the second surface of the second substrate such that the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap in a vertical direction to form an overlapping region. as well as Remove the carrier plate and the adhesive layer.

25. An acoustic device, characterized in that, include: A first substrate, comprising: The first surface; A first electrode, a piezoelectric layer, and a second electrode, wherein the first electrode, the piezoelectric layer, and the second electrode are stacked sequentially, and the first electrode is exposed from the first surface; and A first frame is disposed around the first electrode; and A second substrate, comprising: A second surface; A second main body panel; A recess is provided in the second main body plate and recessed from the second surface; and A second frame is set in the second main body plate. The first surface of the first substrate is bonded to the second surface of the second substrate; In a vertical direction, the recess, the first electrode, the piezoelectric layer, and the second electrode at least partially overlap to form an overlapping region; The first substrate and the second substrate form a sealed cavity at a position corresponding to the recess; The second frame is disposed around the sealed cavity.

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