Resonance filter and manufacturing method thereof

Abstract

The present application discloses a resonant filter and a method for manufacturing the same. The resonant filter includes: a first substrate; and a resonant filter structure formed on a first side of the first substrate, wherein the resonant filter structure includes a bulk acoustic wave resonant structure and a Lamb wave resonant structure, and the bulk acoustic wave resonant structure and the Lamb wave resonant structure are electrically connected. The bulk acoustic wave resonant structure includes a first electrode structure, and the Lamb wave resonant structure includes a second electrode structure, wherein the first electrode structure and the second electrode structure share the same first electrode layer; alternatively, the bulk acoustic wave resonant structure and the Lamb wave resonant structure share the same piezoelectric layer.

Description

Technical Field

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

[0002] BAW resonators have excellent bandpass performance, so they can be used to achieve the passband performance of filters. Lamb wave resonators have excellent stopband performance, so they can be used to achieve the stopband performance of filters. In this case, if BAW and Lamb wave resonators can be combined, the resulting resonant filter circuit can flexibly configure the stopband frequency of the resonant filter circuit while achieving excellent bandpass performance. Currently, BAW and Lamb wave resonators are independently formed using their own processes, so resonant filter circuits can only be constructed by combining independently formed BAW and Lamb wave resonators.

[0003] Since both the BAW resonator and the Lamb wave resonator are independent resonant filter devices, the integration of the resonant filter circuit is low. Moreover, since the BAW resonator and the Lamb wave resonator are formed through their own processes, the process cost of constructing the resonant filter circuit is also very high.

[0004] With respect to the technical problems in the prior art mentioned above, such as low integration and high process cost of the resonant filter circuit composed of a bulk acoustic wave resonator and a Lamb wave resonator, no effective solution has been proposed so far. Summary of the Invention

[0005] The present disclosure provides a resonant filter and a manufacturing method thereof, so as to at least solve the technical problems existing in the prior art of low integration and high process cost of a resonant filter circuit composed of a bulk acoustic wave resonator and a Lamb wave resonator.

[0006] According to one embodiment of the present application, a resonant filter is provided, comprising: a first substrate; and a resonant filter structure formed on a first side of the first substrate, wherein the resonant filter structure comprises a bulk acoustic wave resonator structure and a Lamb wave resonator structure, and the bulk acoustic wave resonator structure and the Lamb wave resonator structure are electrically connected. The bulk acoustic wave resonator structure comprises a first electrode structure, and the Lamb wave resonator structure comprises a second electrode structure, wherein the first electrode structure and the second electrode structure share the same first electrode layer; alternatively, the bulk acoustic wave resonator structure and the Lamb wave resonator structure share the same piezoelectric layer.

[0007] According to another embodiment of the present application, a method for manufacturing a resonant filter is provided, comprising: manufacturing a first substrate for use as a carrier and a resonant filter structure, wherein the resonant filter structure is formed on a first side of the first substrate, the resonant filter structure includes a bulk acoustic wave resonator structure and a Lamb wave resonator structure, and the bulk acoustic wave resonator structure and the Lamb wave resonator structure are electrically connected. Furthermore, the bulk acoustic wave resonator structure includes a first electrode structure, and the Lamb wave resonator structure includes a second electrode structure, wherein the first electrode structure and the second electrode structure share the same first electrode layer; alternatively, the bulk acoustic wave resonator structure and the Lamb wave resonator structure share the same piezoelectric layer.

[0008] Optionally, the second electrode structure comprises interdigitated electrodes, and the first side of the piezoelectric layer is adjacent to the first electrode layer.

[0009] Optionally, the process of fabricating the resonant filter structure further includes: fabricating a second electrode layer on the second side of the piezoelectric layer; and using the second electrode layer to form a third electrode structure of a bulk acoustic wave resonant structure and a fourth electrode structure of a Lamb wave resonant structure. The third electrode structure corresponds to the first electrode structure, and the fourth electrode structure corresponds to the second electrode structure.

[0010] Optionally, the process of manufacturing the resonant filter structure further includes: forming a first resonant cavity between the bulk acoustic wave resonant structure and the first substrate, and forming a second resonant cavity between the Lamb wave resonant structure and the first substrate.

[0011] Optionally, the method further includes: bonding a second substrate to the resonant filter structure using a bonding layer, wherein the second substrate includes a central region and an edge region, wherein the central region covers the bulk acoustic wave resonant structure and the Lamb wave resonant structure; and the bonding layer corresponds to the edge region of the first side of the second substrate.

[0012] Optionally, the method further includes forming a conductive electrode on the second side of the second substrate electrically connected to the BAW resonant structure and the Lamb wave resonant structure.

[0013] Optionally, the process of forming a conductive electrode electrically connected to the bulk acoustic wave resonator structure and the Lamb wave resonator structure on the second side of the second substrate further includes: forming a first conductive electrode and a second conductive electrode on the second side of the second substrate, wherein the first conductive electrode is electrically connected to the second electrode layer via a through-hole, and the second conductive electrode is electrically connected to the first interdigital electrode of the second electrode structure via a through-hole.

[0014] Optionally, the process of forming a conductive electrode electrically connected to the bulk acoustic wave resonator structure and the Lamb wave resonator structure on the second side of the second substrate further includes: forming a first conductive electrode, a second conductive electrode, and a third conductive electrode on the second side of the second substrate, wherein the first conductive electrode is electrically connected to the second electrode layer via a through-hole, the second conductive electrode is electrically connected to the first interdigital electrode of the second electrode structure via a through-hole, and the third conductive electrode is electrically connected to the second interdigital electrode of the first electrode structure and the second electrode structure via a through-hole.

[0015] Optionally, the method further includes forming a conductive electrode electrically connected to the bulk acoustic wave resonance structure and the Lamb wave resonance structure on the second side of the first substrate.

[0016] Optionally, the process of forming a conductive electrode electrically connected to the bulk acoustic wave resonator structure and the Lamb wave resonator structure on the second side of the first substrate includes forming a fourth conductive electrode and a fifth conductive electrode on the second side of the first substrate, wherein the fourth conductive electrode is electrically connected to the second electrode layer via a through-hole, and the fifth conductive electrode is electrically connected to the first interdigital electrode of the second electrode structure via a through-hole.

[0017] Optionally, the process of forming conductive electrodes electrically connected to the bulk acoustic wave resonator structure and the Lamb wave resonator structure on the second side of the first substrate includes forming a fourth conductive electrode, a fifth conductive electrode, and a sixth conductive electrode on the second side of the first substrate. The fourth conductive electrode is electrically connected to the second electrode layer via a through-hole; the fifth conductive electrode is electrically connected to the first interdigital electrode of the second electrode structure via a through-hole; and the sixth conductive electrode is electrically connected to the second interdigital electrode of the first electrode structure and the second electrode structure via a through-hole.

[0018] Thus, according to an embodiment of the present application, in the resonant filter, the bulk acoustic wave resonant structure and the Lamb wave resonant structure share the same substrate, and the bulk acoustic wave resonant structure and the Lamb wave resonant structure also share the same electrode layer or piezoelectric layer. In this way, the present embodiment integrates the bulk acoustic wave resonant structure and the Lamb wave resonant structure into a resonant filter structure, and then integrates them into the same resonant filter device, thereby improving the integration of the resonant filter circuit. In addition, the method for manufacturing the resonant filter can simultaneously manufacture the bulk acoustic wave resonant structure and the Lamb wave resonant structure in the same set of processing steps, thereby reducing the process cost of constructing the resonant filter circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Hereinafter, some specific embodiments of the present application will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the drawings:

[0020] Figure 1 is a schematic diagram of the layer structure of the resonant filter according to Example 1 of the present application;

[0021] Figure 2 is a schematic top view of the resonant filter according to embodiment 1 of the present application;

[0022] Figure 3 is a circuit diagram of the resonant filter according to Example 1 of the present application;

[0023] Figures 4 to 6 is a schematic diagram of a resonant filter according to a modified example of embodiment 1 of the present application;

[0024] Figure 7 is a schematic diagram of a resonant filter according to another modified example of embodiment 1 of the present application;

[0025] Figure 8 is a schematic diagram of a resonant filter according to another modified example of embodiment 1 of the present application;

[0026] Figure 9 and Figure 10 is a schematic diagram of a resonant filter according to another modified example of embodiment 1 of the present application;

[0027] Figure 11 is a schematic diagram of a resonant filter according to another modified example of embodiment 1 of the present application;

[0028] Figures 12 to 31 1 is a schematic structural diagram corresponding to each step of the method for manufacturing a resonant filter according to embodiment 2 of the present application;

[0029] Figures 32 to 35 It is a structural schematic diagram corresponding to each step of the manufacturing method described in a modified example of Example 2 of the present application. DETAILED DESCRIPTION

[0030] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0031] In order to enable those skilled in the art to better understand the solutions of the present disclosure, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present disclosure.

[0032] It should be noted that the terms "first," "second," and the like in the specification and claims of the present disclosure and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate for the embodiments of the present disclosure described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatuses.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. Example 1

[0034] Figure 1 is a schematic diagram of the layer structure of the resonant filter according to Example 1 of the present application; Figure 2 is a schematic top view of the resonant filter according to embodiment 1 of the present application; Figure 3 This is a circuit diagram of the resonant filter according to Example 1 of the present application.

[0035] refer to Figure 1 As shown, the resonant filter according to this embodiment includes: a first substrate 210; and a resonant filter structure formed on a first side of the first substrate 210. Figure 1 In the embodiment, the first side of the first substrate 210 corresponds to the upper side of the first substrate 210, so that the resonant filter structure is formed on the upper side of the first substrate 210. However, the protection scope of the present invention is not limited thereto. For example, when Figure 1 When the device shown is flipped over, the first side of the first substrate 210 may also correspond to the lower side of the first substrate 210. Similar situations in this embodiment will not be described in detail.

[0036] refer to Figure 1 and Figure 2 As shown, the resonant filter structure includes a bulk acoustic wave resonator structure BAWR and a Lamb wave resonator structure LWR, and the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR are electrically connected. The bulk acoustic wave resonator structure BAWR includes a first electrode structure 131, and the Lamb wave resonator structure LWR includes a second electrode structure 132. Figure 1As shown, the first electrode structure 131 corresponds to the upper electrode of the bulk acoustic wave resonance structure BAWR, and the second electrode structure 132 corresponds to the upper electrode of the Lamb wave resonance structure LWR, and the first electrode structure 131 and the second electrode structure 132 share the same first electrode layer 130 .

[0037] As described in the background, if a bulk acoustic wave resonator (BAW) and a Lamb wave resonator can be combined, the resulting resonant filter circuit can flexibly configure the resonant filter circuit's stopband frequency while achieving excellent bandpass performance. Currently, BAW and Lamb wave resonators are independently formed using their own processes. Therefore, a resonant filter circuit can only be constructed by combining these independently formed BAW and Lamb wave resonators. Because both BAW and Lamb wave resonators are independent resonant filter devices, the resonant filter circuit has a low level of integration.

[0038] In view of this, in the resonant filter described in this embodiment, the BAW resonant structure and the Lamb wave resonant structure share the same substrate and the same electrode layer. Thus, this embodiment integrates the BAW resonant structure and the Lamb wave resonant structure into a single resonant filter structure, and then into a single resonant filter device, thereby improving the integration of the resonant filter circuit.

[0039] In addition, as another aspect of this embodiment, reference Figure 1 As shown, the resonant filter structure includes a piezoelectric layer 140, and the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR share the piezoelectric layer 140. In this way, since the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR share the same piezoelectric layer 140, the integration of the resonant filter structure can also be improved.

[0040] Optionally, refer to Figure 2 As shown, the second electrode structure 132 includes interdigitated electrodes. Figure 1 As shown, the resonant filter structure includes a piezoelectric layer 140, and the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR share the piezoelectric layer 140. In addition, the first electrode structure 131 and the second electrode structure 132 are located on the first side of the piezoelectric layer 140, wherein the first side of the piezoelectric layer 140 is away from the first substrate 210. Figure 1 As shown, the first side of the piezoelectric layer 140 corresponds to the upper side of the piezoelectric layer 140, so in this embodiment, the first electrode structure 131 and the second electrode structure 132 are located on the upper side of the piezoelectric layer 140. In this way, because the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR share the same piezoelectric layer 140, the integration of the resonant filter structure is further improved.

[0041] Optionally, refer to Figure 1 As shown, the bulk acoustic wave resonance structure BAWR further includes a third electrode structure 150a located on the second side (i.e., the lower side) of the piezoelectric layer 140, wherein the third electrode structure 150a corresponds to the first electrode structure 131. The Lamb wave resonance structure LWR further includes a fourth electrode structure 150b located on the second side of the piezoelectric layer 140, wherein the fourth electrode structure 150b corresponds to the second electrode structure 132. Furthermore, the third electrode structure 150a and the fourth electrode structure 150b share the same second electrode layer 150.

[0042] In this way, the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR not only share the same first electrode layer, but also share the same second electrode layer, thereby further improving the integration of the resonant filter structure.

[0043] In addition, further reference Figure 1 As shown, the resonant filtering structure further includes: a first resonant cavity 1801, wherein the first resonant cavity 1801 is formed between the bulk acoustic wave resonator structure BAWR and the first substrate 210; and a second resonant cavity 1802, wherein the second resonant cavity 1802 is formed between the Lamb wave resonator structure LWR and the first substrate 210.

[0044] Specifically, refer to Figure 1 As shown, a first support structure SUP1, a second support structure SUP2, and a third support structure SUP3 are formed on the first side of the first substrate 210. The first support structure SUP1 is used to support the piezoelectric layer 140, while the second support structure SUP2 and the third support structure SUP3 are used to support the second electrode layer 150. The third electrode structure 150a has one end supported by the second support structure SUP2 and the other end is free. The fourth electrode structure 150b is supported by both the second support structure SUP2 and the third support structure SUP3. Thus, a first resonant cavity 1801 is formed between the first support structure SUP1 and the second support structure SUP2, and a second resonant cavity 1802 is formed between the second support structure SUP2 and the third support structure SUP3.

[0045] In this way, this embodiment integrates the BAW resonator structure and the Lamb wave resonator structure into the same resonant filter structure. Based on their structural characteristics, electrode support structures and resonant cavities suitable for the BAW resonator structure and the Lamb wave resonator structure are respectively constructed. This allows both the BAW resonator structure and the Lamb wave resonator structure integrated into the same resonant filter structure to function properly and leverage the performance of their respective resonant structures.

[0046] Optionally, refer to Figure 1As shown, the resonant filter also includes: a second substrate 250, wherein the second substrate 250 includes a central area and an edge area, wherein the central area covers the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR; and a second bonding layer 240, the second bonding layer 240 corresponds to the edge area of ​​the first side of the second substrate 250, and is used to bond the second substrate 250 to the resonant filter structure.

[0047] Thus refer to Figure 1 As shown, a third resonant cavity 2400 is formed between the resonant filter structure and the second substrate 250. The bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR share the third resonant cavity 2400.

[0048] Therefore, this embodiment protects the resonant filter structure through the second substrate on the one hand, and uses the second substrate and the bonding layer to form a resonant cavity shared by the bulk acoustic wave resonant structure and the Lamb wave resonant structure, thereby further improving the integration of the resonant filter.

[0049] refer to Figure 1 As shown, a conductive electrode electrically connected to the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR is provided on the second side of the second substrate 250. Thus, the resonant filter structure of the resonant filter is electrically connected to the outside through the conductive electrode.

[0050] Furthermore, the conductive electrode includes a first conductive electrode 270a and a second conductive electrode 270b. The first conductive electrode 270a is electrically connected to the second electrode layer 150 via a through-hole conduction; and the second conductive electrode 270b is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole conduction. Figure 3 As shown, through this electrical connection, a series structure between the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR is realized.

[0051] also, Figures 4 to 6 A schematic diagram for describing a modified example of the resonant filter described in Example 1. Figure 4 and Figure 5 As shown, in this modified example, the conductive electrodes include a first conductive electrode 270a, a second conductive electrode 270b, and a third conductive electrode 260a. The first conductive electrode 270a is electrically connected to the second electrode layer 150 via a through-hole; the second conductive electrode 270b is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole; and the third conductive electrode 260a is electrically connected to the second interdigital electrode 132a of the first electrode structure 131 and the second electrode structure 132 via a through-hole.

[0052] Thus refer to Figure 6As shown, through this electrical connection, a parallel structure between the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR is achieved.

[0053] also, Figure 7 and Figure 8 A schematic diagram for describing another modified example of the resonant filter described in Example 1. Figure 7 and Figure 8 As shown, in this modification, the second side of the first substrate 210 is provided with a conductive electrode electrically connected to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR. Figure 7 and Figure 8 In FIG. 2 , the resonant filter is turned upside down so that the second side of the first substrate 210 corresponds to the upper side of the first substrate 210 .

[0054] Thus, a through-hole conductive structure for connecting the conductive electrode and the bulk acoustic wave resonator structure BAWR and a through-hole conductive structure for connecting the conductive electrode and the bulk acoustic wave resonator structure LWR are formed on the first substrate 210. In addition to penetrating the bonding layer, they also penetrate the cutoff boundary layer, the sacrificial layer, the dielectric layer, the piezoelectric layer and other solid material layers in sequence. Since these layers are mainly composed of solid materials with high mechanical strength and toughness, the risk of fracture caused by weak material connection (such as the bonding layer) can be significantly reduced during perforation, and the local stress concentration that may be introduced by the perforation operation is reduced, which greatly reduces the fracture of the filter device caused by perforation during the manufacturing and use process, and improves the reliability and stability of the filter device.

[0055] Alternatively, refer to Figure 7 As shown, the conductive electrodes include a fourth conductive electrode 270c and a fifth conductive electrode 270d. The fourth conductive electrode 270c is electrically connected to the second electrode layer 150 via a through-hole; and the fifth conductive electrode 270d is electrically connected to the first interdigitated electrode 132b of the second electrode structure 132 via a through-hole. Thus, through this electrical connection, a series structure is achieved between the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR (see FIG. 1 ). Figure 3 shown).

[0056] Alternatively, refer to Figure 8As shown, the conductive electrodes include a fourth conductive electrode 270c, a fifth conductive electrode 270d, and a sixth conductive electrode 260b. The fourth conductive electrode 270c is electrically connected to the second electrode layer 150 via a through-hole conduction; the fifth conductive electrode 270d is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole conduction; and the sixth conductive electrode 260b is electrically connected to the second interdigital electrode 132a of the first electrode structure 131 and the second electrode structure 132 via a through-hole conduction. Thus, through this electrical connection, a parallel structure between the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR is achieved (see FIG. 1 ). Figure 6 shown).

[0057] In addition, reference Figure 9 As shown, the resonant filter structure described in this embodiment includes multiple bulk acoustic wave resonant structures BAWR and multiple Lamb wave resonant structures LWR. Therefore, in this embodiment, not only one bulk acoustic wave resonant structure and one Lamb wave resonant structure are integrated into one resonant filter structure, but also multiple bulk acoustic wave resonant structures and multiple Lamb wave resonant structures can be integrated into one resonant filter structure. This further improves the integration of the resonant filter. In addition, referring to Figure 10 As shown, further optionally, a plurality of bulk acoustic wave resonance structures BAWR and a plurality of Lamb wave resonance structures LWR form a ladder filter structure.

[0058] In addition, further reference Figure 11 As shown, the Lamb wave resonance structure LWR can be a dual-mode filter structure. Therefore, the second electrode structure 132 of the Lamb wave resonance structure LWR is Figure 11 The electrode structure shown.

[0059] In summary, in the resonant filter described in this embodiment, the BAW resonant structure and the Lamb wave resonant structure share the same substrate and the same electrode layer or piezoelectric layer. Thus, this embodiment integrates the BAW resonant structure and the Lamb wave resonant structure into a single resonant filter structure, and then into a single resonant filter device, thereby improving the integration of the resonant filter circuit. Example 2

[0060] also, Figures 12 to 31 It is a schematic diagram of the layer structure in each manufacturing process of the resonant filter described in Example 2 of the present application.

[0061] Embodiment 2 provides a method for manufacturing a resonant filter. The resonant filter corresponds to the resonant filter described in Embodiment 1. Specifically, the method includes: manufacturing a first substrate for use as a carrier and a resonant filter structure, wherein the resonant filter structure is formed on a first side of the first substrate, the resonant filter structure includes a bulk acoustic wave resonant structure and a Lamb wave resonant structure, and the bulk acoustic wave resonant structure and the Lamb wave resonant structure are electrically connected. Furthermore, the bulk acoustic wave resonant structure includes a first electrode structure, the Lamb wave resonant structure includes a second electrode structure, and the first electrode structure and the second electrode structure share the same first electrode layer; or, the bulk acoustic wave resonant structure and the Lamb wave resonant structure share the same piezoelectric layer.

[0062] Specifically, the method for manufacturing the resonant filter described in Embodiment 2 includes:

[0063] like Figure 12 As shown, a transition layer 110, a seed layer 120, a first electrode layer 130, a piezoelectric layer 140, and a second electrode layer 150 are sequentially formed on a temporary substrate 100 used as a temporary substrate. Optionally, the temporary substrate 100 is a silicon substrate, a silicon-on-insulator substrate, a glass substrate, a silicon carbide substrate, or a gallium arsenide (GaAs) substrate; the transition layer 110 can be a silicon oxide (SiO2) layer or a silicon nitride (SiNx) layer, and can be formed by a thermal oxidation process, a physical vapor deposition (PVD) process, or a chemical vapor deposition (CVD) process; the seed layer 120 can be an aluminum nitride (AlN) layer, and can be formed by a physical vapor deposition (PVD) process, specifically a magnetron sputtering process; the first electrode layer 130 can be an Al layer, a Cu layer, a Mo layer, or a Cu layer. layer, Au layer or Pt layer, which can be formed by physical vapor deposition (PVD) process; similarly, the second electrode layer 150 can be an Al layer, a Cu layer, a Mo layer, an Au layer or a Pt layer, which can be formed by physical vapor deposition (PVD) process; the piezoelectric layer 140 can be an AlN layer, a scandium-doped aluminum nitride (AlxSc1-xN) layer, a lithium niobate (LiNbO3) layer, a lithium tantalate (LiTaO3) layer or a quartz layer, etc., and can be a polycrystalline layer or a single crystal layer, and can be formed by PVD or metal organic chemical vapor deposition (MOCVD), etc.

[0064] like Figure 13 As shown, the first region of the second electrode layer 150 is etched to form a step structure 151 in the second electrode layer 150 to improve the performance of the resonant filter structure. Specifically, in one embodiment of the present application, the process for etching the second electrode layer 150 can be a dry etching process or a wet etching process, but this application does not limit this and the specific process depends on the specific situation.

[0065] like Figure 14As shown, a dielectric layer 160 is formed on the side of the second electrode layer 150 away from the temporary substrate 100. Optionally, the dielectric layer 160 is formed by a deposition process, specifically PVD or CVD, and the material of the dielectric layer 160 can be SiO2, SiNx, or AlN, etc. This application does not limit this, and the specific method depends on the specific situation. It should be noted that in the embodiment of the present application, the dielectric layer 160 is a protective layer for the second electrode layer 150 to prevent the second electrode layer 150 from being oxidized. Optionally, the dielectric layer 160 also serves as the dielectric layer of the capacitor formed subsequently.

[0066] like Figure 15 As shown, the second region of the second electrode layer 150 and the portion of the dielectric layer 160 located on the surface of the second region of the second electrode layer are etched to obtain the second electrode layer 150. The second electrode layer 150 includes the remaining portion of the second electrode layer 150 and the portion of the dielectric layer 160 located on the surface of the second electrode layer 150. In a plane parallel to the temporary substrate 100, the second region is located on the first side of the stepped structure. Optionally, the process for etching the dielectric layer 160 and the second electrode layer 150 can be a wet etching process or a dry etching process.

[0067] like Figure 16 As shown, a capacitor electrode 170 is formed in a third region on the surface of the dielectric layer 160, that is, in a third region on the surface of the dielectric layer 160 away from the piezoelectric layer 140. In a plane parallel to the temporary substrate 100, the third region is located on the second side of the step structure 151, where the second side is opposite to the first side. It should be noted that in this embodiment, the capacitor electrode 170 forms a capacitor with the dielectric layer 160 and the second electrode layer 150. Optionally, the material of the capacitor electrode 170 can be Al, Cu, Mo, Au, or Pt, etc., which is not limited in this application and depends on the specific circumstances.

[0068] like Figure 17 As shown, a sacrificial layer 180 is formed, which covers the exposed part of the piezoelectric layer 140, the dielectric layer 160 and the capacitor electrode 170. Optionally, the material of the sacrificial layer 180 can be SiO2, PSG, USG, a-Si or photoresist, etc.; the formation process of the sacrificial layer 180 can be PVD, CVD or spin coating, etc.

[0069] like Figure 18 As shown, the sacrificial layer 180 is etched to form first through holes 181 to third through holes 183 in the sacrificial layer 180. The first through hole 181 exposes a portion of the surface of the piezoelectric layer 140, and the second through hole 182 and the third through hole 183 expose a portion of the surface of the dielectric layer 160. Specifically, the etching process of the sacrificial layer 180 can be dry etching or wet etching.

[0070] like Figure 19 As shown, a cutoff boundary layer 190 is formed on the side of the sacrificial layer 180 away from the dielectric layer 160. The cutoff boundary layer 190 also fills the first through-holes 181 to the third through-holes 183. It should be noted that in this embodiment, the portion of the cutoff boundary layer corresponding to the first through-hole 181 contacts the piezoelectric layer 140, while the portions of the cutoff boundary layer corresponding to the second through-hole 182 and the third through-hole 183 contact the dielectric layer 160.

[0071] It should also be noted that in this embodiment, the cutoff boundary layer 190 and the sacrificial layer 180 are made of different materials so that the chemicals used to etch the sacrificial layer 180 will not damage the cutoff boundary layer 190. Alternatively, the cutoff boundary layer 190 may be made of SiO2 or polycrystalline silicon (poly-Si), and may be formed using PVD, CVD, or the like.

[0072] like Figure 20 As shown, a first bonding layer 200 is formed on the side of the cutoff boundary layer 190 away from the piezoelectric layer 140. The first bonding layer 200 covers the surface of the cutoff boundary layer 190 and also fills the first through-holes 181 to the third through-holes 183. Thus, the first bonding layer 200 and the cutoff boundary layer 190 corresponding to the first through-holes 181 to the third through-holes 183 form the first support structure SUP1, the second support structure SUP2, and the third support structure SUP3. Optionally, the material of the first bonding layer 200 can be SiO2, and the formation process can be PVD or CVD, etc. This application does not limit this, and the specific process depends on the circumstances.

[0073] like Figure 21 As shown, a first substrate 210 serving as a carrier is bonded to the side of the first bonding layer 200 away from the stop boundary layer 190 .

[0074] like Figure 22 As shown, the wafer composed of the various structures obtained above is flipped over to remove the temporary substrate 100 and the transition layer 110. Optionally, the removal process of the temporary substrate 100 and the transition layer 110 can be grinding or chemical mechanical polishing (CMP). This application does not limit this and it depends on the specific situation.

[0075] like Figure 23 As shown, the seed layer 120 and the first electrode layer 130 are etched to form a first electrode structure 131 and a second electrode structure 132. The second electrode structure 132 includes interdigitated electrodes. Optionally, the etching process for the seed layer 120 and the first electrode layer 130 can be wet etching or dry etching. In addition, the seed layer 120 is also etched into a first seed layer portion 121 corresponding to the first electrode structure 131 and a second seed layer portion 122 corresponding to the second electrode structure 132.

[0076] like Figure 24 As shown, a fourth through hole 1401 is formed in the exposed portion of the piezoelectric layer 140, and a fifth through hole 1201 is formed in the seed layer 120. The fourth through hole 1401 penetrates the piezoelectric layer 140, exposing a portion of the surface of the second electrode layer 150 to facilitate the extraction of the second electrode layer 150. The fifth through hole 1201 penetrates the seed layer 120 (e.g., the second seed layer portion 122), exposing the second electrode structure 132 (e.g., the first interdigitated electrode 132b). Optionally, the fifth through hole 1201 and the fourth through hole 1401 can be formed by either a wet or dry etching process.

[0077] like Figure 25 As shown, a first conductive layer 230 is formed in the fifth through hole 1201. The first conductive layer 230 covers the sidewalls and the bottom of the fifth through hole 1201, and also extends to cover a portion of the surface of the seed layer 120. A second conductive layer 220 is formed in the fourth through hole 1401. The second conductive layer 220 covers the sidewalls and the bottom of the fourth through hole 1401, and also extends to cover a portion of the surface of the piezoelectric layer 140. Optionally, in one embodiment of the present application, the material of the second conductive layer 220 and the first conductive layer 230 can be Au, Cu, or Al, and can be formed by PVD or electroplating.

[0078] like Figure 26 As shown, the sacrificial layer 180 is released between the first support structure SUP1 and the second support structure SUP2, and between the second support structure SUP2 and the third support structure SUP3, forming a first resonant cavity 1801 located between the first support structure SUP1 and the second support structure SUP2, and a second resonant cavity 1802 located between the second support structure SUP2 and the third support structure SUP3. Thus, a resonant filter structure is formed, which includes a bulk acoustic wave resonator structure BAWR and a Lamb wave resonator structure LWR.

[0079] As described above, the method described in this embodiment includes fabricating a first substrate 210 serving as a carrier and a resonant filter structure, wherein the resonant filter structure is formed on a first side of the first substrate 210. The resonant filter structure includes a bulk acoustic wave resonator structure BAWR and a Lamb wave resonator structure LWR, and the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR are electrically connected. Furthermore, the bulk acoustic wave resonator structure BAWR includes a first electrode structure 131, and the Lamb wave resonator structure LWR includes a second electrode structure 132, wherein the second electrode structure 132 includes interdigitated electrodes, and the first electrode structure 131 and the second electrode structure 132 share the same first electrode layer 130.

[0080] As described in the background, because BAW resonators and Lamb wave resonators are formed using separate processes, the cost of constructing a resonant filter circuit is also very high. In view of this, the resonant filter fabrication method described in this embodiment enables the simultaneous fabrication of both the BAW resonant structure and the Lamb wave resonant structure using the same set of fabrication processes, thereby reducing the cost of constructing the resonant filter circuit.

[0081] Optionally, the second electrode structure 132 includes interdigitated electrodes. Figures 12 to 26 The process of fabricating the resonant filter structure includes fabricating a piezoelectric layer 140 shared by the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR, wherein a first side of the piezoelectric layer 140 is adjacent to the first electrode layer 130. This allows the piezoelectric layers of the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR to be formed simultaneously in the same process, thereby reducing the process cost of constructing the resonant filter circuit.

[0082] Alternatively, refer to Figures 12 to 26 The process of fabricating the resonant filter structure also includes: forming a second electrode layer 150 on the second side of the piezoelectric layer 140; and using the second electrode layer 150 to form a third electrode structure 150a of the bulk acoustic wave resonator structure and a fourth electrode structure 150b of the Lamb wave resonator structure, wherein the third electrode structure 150a corresponds to the first electrode structure 131, and the fourth electrode structure 150b corresponds to the second electrode structure 132. Thus, the third electrode structure 150a of the bulk acoustic wave resonator structure BAWR and the fourth electrode structure 150b of the Lamb wave resonator structure LWR can be formed simultaneously in the same process, thereby reducing the process cost of constructing the resonant filter circuit.

[0083] In addition, reference Figure 26 The process of manufacturing the resonant filter structure also includes forming a first resonant cavity 1801 between the bulk acoustic wave resonator structure BAWR and the first substrate 210, and forming a second resonant cavity 1802 between the Lamb wave resonator structure LWR and the first substrate 210. Thus, the first resonant cavity 1801 of the bulk acoustic wave resonator structure BAWR and the second resonant cavity 1802 of the Lamb wave resonator structure LWR can be formed simultaneously in the same process, thereby reducing the process cost of constructing the resonant filter circuit.

[0084] Optionally, the method further includes: bonding a second substrate to the resonant filter structure using a bonding layer, wherein the second substrate includes a central region and an edge region, wherein the central region covers the bulk acoustic wave resonant structure and the Lamb wave resonant structure; and the bonding layer corresponds to the edge region of the first side of the second substrate.

[0085] Specifically, if Figure 27As shown, the method includes forming a second bonding layer 240, which is located on the side of the first electrode layer 130 away from the piezoelectric layer 140, that is, the second bonding layer 240 is located on the side of the seed layer 120 away from the piezoelectric layer 140, and the second bonding layer 240 also covers the exposed surface of the piezoelectric layer 140.

[0086] Optionally, the material of the second bonding layer 240 is SiO2 or SiNx, etc., and the formation process can be PVD or CVD, etc.; in another embodiment of the present application, the second bonding layer 240 is a photoresist-like dry film material, which is formed by spin coating, photolithography and other processes. This application does not limit this, and it depends on the specific situation.

[0087] Further, if Figure 28 As shown, the second bonding layer 240 is etched to form a space in the central area for constructing the third resonant cavity 2400 .

[0088] Then as Figure 29 As shown, a second substrate 250 is bonded to the second bonding layer 240. Thus, the central area of ​​the second substrate 250 covers the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR, and the second bonding layer 240 corresponds to the edge area of ​​the first side of the second substrate 250. Thus, a third resonant cavity 2400 is formed between the resonant filter structure and the second substrate 250. And the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR share the third resonant cavity 2400. Therefore, on the one hand, this embodiment protects the resonant filter structure through the second substrate, and forms a resonant cavity shared by the bulk acoustic wave resonator structure and the Lamb wave resonator structure in the same process, thereby further reducing the process cost of constructing the resonant filter circuit.

[0089] Optionally, the method further includes forming a conductive electrode on the second side of the second substrate electrically connected to the BAW resonant structure and the Lamb wave resonant structure.

[0090] Specifically, if Figure 30 As shown, a sixth through hole 2501 and a seventh through hole 2502 are formed penetrating the second substrate 250 and the second bonding layer 240 , wherein the sixth through hole 2501 exposes the first conductive layer 230 , and the seventh through hole 2502 exposes the second conductive layer 220 .

[0091] Then, if Figure 31As shown, a first conductive electrode 270a and a second conductive electrode 270b are formed on the second side of the second substrate 250, electrically connected to the second conductive layer 220 and the first conductive layer 230. The first conductive electrode 270a and the second conductive electrode 270b are thereby electrically connected to the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR. Optionally, the second conductive layer 220 and the first conductive layer 230 may be made of Au, Cu, or Al, and may be formed by PVD or electroplating.

[0092] Alternatively, as Figure 31 As shown, the process of forming conductive electrodes electrically connected to the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR on the second side of the second substrate 250 also includes forming a first conductive electrode 270a and a second conductive electrode 270b on the second side of the second substrate 250. The first conductive electrode 270a is electrically connected to the second electrode layer 150 via a through-hole, and the second conductive electrode is electrically connected to the first interdigital electrode 132b of the second electrode structure via a through-hole. In this way, a series structure is achieved between the bulk acoustic wave resonator structure BAWR and the Lamb wave resonator structure LWR.

[0093] In addition, according to a modification of the present embodiment, the process of forming conductive electrodes electrically connected to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR on the second side of the second substrate 250 further includes: forming a first conductive electrode 270a, a second conductive electrode 270b, and a third conductive electrode 260a on the second side of the second substrate 250. The first conductive electrode 270a is electrically connected to the second electrode layer 150 via a through-hole conduction, the second conductive electrode 270b is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole conduction, and the third conductive electrode 260a is electrically connected to the second interdigital electrode 132a of the first electrode structure 131 and the second electrode structure 132 via a through-hole conduction. The resonant filter formed specifically is as follows. Figure 4 and Figure 5 The specific formation process can be Figures 24 to 31 Based on the process shown, the third conductive electrode 260a and the corresponding through hole and conductive layer can be adjusted, which will not be repeated here. In this way, a parallel structure between the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR is achieved.

[0094] In addition, according to a modification of this embodiment, the method further includes forming a conductive electrode electrically connected to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR on the second side of the first substrate 210 .

[0095] Specific reference Figures 32-35 As shown. Figure 322 is a schematic diagram of the layer structure according to this modification after bonding the second substrate 250. Part of the second electrode layer 150 in the edge region is also etched, and the etched region is covered by the sacrificial layer 180 to form a through hole and a conductive electrode.

[0096] Then refer to Figure 33 As shown, the resonator filter is turned upside down so that the first substrate 210 is located on the upper side of the device.

[0097] Then refer to Figure 34 As shown, eighth through holes 2101 to tenth through holes 2103 are formed from the first substrate 210. The eighth through hole 2101 penetrates the first substrate 210, the first bonding layer 200, the cut-off boundary layer 190, the sacrificial layer 180, and the piezoelectric layer 140, thereby exposing the first electrode structure 131. The ninth through hole 2102 penetrates the first substrate 210, the first bonding layer 200, the cut-off boundary layer 190, the sacrificial layer 180, and the dielectric layer 160, thereby exposing the second electrode layer 150. The tenth through hole 2103 penetrates the first substrate 210, the first bonding layer 200, the cut-off boundary layer 190, the sacrificial layer 180, and the piezoelectric layer 140, thereby exposing the first interdigitated electrodes 132b of the second electrode structure.

[0098] Then, refer to Figure 35 As shown, a sixth conductive electrode 260b, a fourth conductive electrode 270c and a fifth conductive electrode 270d are formed on the second side of the first substrate 210, thereby electrically connecting to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR through vias.

[0099] Thus, the through-hole conductive structure for connecting the conductive electrode and the bulk acoustic wave resonator structure BAWR and the through-hole conductive structure for connecting the conductive electrode and the bulk acoustic wave resonator structure LWR are formed on the first substrate 210, and sequentially penetrate the cutoff boundary layer, the sacrificial layer, the dielectric layer, the piezoelectric layer and other solid material layers. Since these layers are mainly composed of solid materials with high mechanical strength and toughness, the risk of fracture caused by weak material connection (such as the bonding layer) can be significantly reduced during perforation, and the local stress concentration that may be introduced by the perforation operation is reduced, which greatly reduces the fracture of the filter device caused by perforation during the manufacturing and use process, and improves the reliability and stability of the filter device.

[0100] Optionally, refer to Figure 34 and Figure 35As shown, the process of forming conductive electrodes electrically connected to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR on the second side of the first substrate 210 includes forming a fourth conductive electrode 270c, a fifth conductive electrode 270d, and a sixth conductive electrode 260b on the second side of the first substrate 210. The fourth conductive electrode 270c is electrically connected to the second electrode layer 150 via a through-hole conduction; the fifth conductive electrode 270d is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole conduction; and the sixth conductive electrode 260b is electrically connected to the second interdigital electrode 132a of the first electrode structure 131 and the second electrode structure 132 via a through-hole conduction. Thus, through this electrical connection, a parallel structure between the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR is realized (refer to Figure 6 shown).

[0101] Alternatively, as Figure 7 As shown, the process of forming conductive electrodes electrically connected to the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR on the second side of the first substrate 210 includes forming a fourth conductive electrode 270c and a fifth conductive electrode 270d on the second side of the first substrate 210. The fourth conductive electrode 270c is electrically connected to the second electrode layer 150 via a through-hole; and the fifth conductive electrode 270d is electrically connected to the first interdigital electrode 132b of the second electrode structure 132 via a through-hole. Thus, through this electrical connection, a series structure between the bulk acoustic wave resonance structure BAWR and the Lamb wave resonance structure LWR is achieved (see Figure 3 shown).

[0102] The manufacturing method of the resonant filter described in this embodiment can simultaneously manufacture a bulk acoustic wave resonant structure and a Lamb wave resonant structure in the same set of processing steps, thereby reducing the process cost of constructing a resonant filter circuit.

[0103] Unless otherwise specifically stated, the relative arrangement of the parts and steps, the numerical expressions and the numerical values ​​set forth in these embodiments do not limit the scope of the present disclosure. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to actual proportional relationships. The techniques, methods and equipment known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, the techniques, methods and equipment should be considered as part of the authorization specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as being merely exemplary and not as limitations. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0104] For ease of description, spatially relative terms such as "above," "above," "on the upper surface of," and "upper" may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in a drawing is inverted, a device described as "above" or "on top of" another device or structure would then be positioned as "below" or "below" the other device or structure. Thus, the exemplary term "above" can include both the "above" and "below" orientations. The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0105] In the description of the present disclosure, it should be understood that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present disclosure; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0106] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A resonant filter, characterized in that: include: a first substrate (210); as well as A resonant filter structure is formed on the first side of the first substrate (210), wherein the resonant filter structure comprises a bulk acoustic wave resonator structure (BAWR) and a Lamb wave resonator structure (LWR), and the bulk acoustic wave resonator structure (BAWR) and the Lamb wave resonator structure (LWR) are electrically connected, wherein The bulk acoustic wave resonator (BAWR) structure includes a first electrode structure (131), and the Lamb wave resonator (LWR) structure includes a second electrode structure (132), wherein the first electrode structure (131) and the second electrode structure (132) share the same first electrode layer (130); or, the bulk acoustic wave resonator (BAWR) structure and the Lamb wave resonator (LWR) structure share the same piezoelectric layer (140), and wherein, The second electrode structure (132) comprises a first interdigitated electrode (132b) and a second interdigitated electrode (132a), wherein the first interdigitated electrode (132b) is electrically connected to the outside, and the second interdigitated electrode (132a) is electrically connected to the first electrode structure (131).

2. The resonant filter according to claim 1, wherein The second electrode structure (132) includes interdigitated electrodes, and the first electrode structure (131) and the second electrode structure (132) are located on a first side of the piezoelectric layer (140), wherein the first side of the piezoelectric layer (140) is opposite to the first substrate (210).

3. The resonant filter according to claim 2, wherein: The bulk acoustic wave resonance (BAWR) structure further includes a third electrode structure (150a) located on a second side of the piezoelectric layer (140), wherein the third electrode structure (150a) corresponds to the first electrode structure (131); The Lamb wave resonator (LWR) structure further includes a fourth electrode structure (150b) located on a second side of the piezoelectric layer (140), wherein the fourth electrode structure (150b) corresponds to the second electrode structure (132), and wherein The third electrode structure (150a) and the fourth electrode structure (150b) share the same second electrode layer (150).

4. The resonant filter according to claim 2, wherein The resonant filter structure further includes: a first resonant cavity (1801), wherein the first resonant cavity (1801) is formed between the bulk acoustic wave resonator (BAWR) structure and the first substrate (210); and A second resonant cavity (1802), wherein the second resonant cavity (1802) is formed between the Lamb wave resonant structure (LWR) and the first substrate (210).

5. The resonant filter according to claim 3, wherein Also includes: a second substrate (250), wherein the second substrate (250) comprises a central region and an edge region, wherein the central region covers the bulk acoustic wave resonator structure (BAWR) and the Lamb wave resonator structure (LWR); and A bonding layer (240), the bonding layer (240) corresponding to an edge region of the first side of the second substrate (250), and used for bonding the second substrate (250) to the resonant filtering structure.

6. The resonant filter according to claim 5, wherein: A conductive electrode electrically connected to the bulk acoustic wave resonance structure (BAWR) and the Lamb wave resonance structure (LWR) is provided on the second side of the second substrate (250).

7. The resonant filter according to claim 6, wherein: The conductive electrodes include a first conductive electrode (270a) and a second conductive electrode (270b), and wherein The first conductive electrode (270a) is electrically connected to the second electrode layer (150) via a through-hole; and The second conductive electrode (270b) is electrically connected to the first interdigitated electrode (132b) of the second electrode structure (132) via a through-hole.

8. The resonant filter according to claim 7, wherein The conductive electrodes include a first conductive electrode (270a), a second conductive electrode (270b) and a third conductive electrode (260a), and wherein The first conductive electrode (270a) is electrically connected to the second electrode layer (150) via a through-hole; The second conductive electrode (270b) is electrically connected to the first interdigitated electrode (132b) of the second electrode structure (132) via a through-hole conduction; and The third conductive electrode (260a) is electrically connected to the first electrode structure (131) and the second interdigitated electrode (132a) of the second electrode structure (132) via a through hole.

9. The resonant filter according to claim 5, wherein A conductive electrode electrically connected to the bulk acoustic wave resonance structure (BAWR) and the Lamb wave resonance structure (LWR) is provided on the second side of the first substrate (210).

10. The resonant filter according to claim 9, wherein The conductive electrodes include a fourth conductive electrode (270c) and a fifth conductive electrode (270d), and wherein The fourth conductive electrode (270c) is electrically connected to the second electrode layer (150) via a through-hole conduction; and The fifth conductive electrode (270d) is electrically connected to the first interdigitated electrode (132b) of the second electrode structure (132) via a through-hole.

11. The resonant filter according to claim 9, wherein The conductive electrodes include a fourth conductive electrode (270c), a fifth conductive electrode (270d) and a sixth conductive electrode (260b), and wherein The fourth conductive electrode (270c) is electrically connected to the second electrode layer (150) via a through-hole; The fifth conductive electrode (270d) is electrically connected to the first interdigitated electrode (132b) of the second electrode structure (132) via a through-hole conduction; and The sixth conductive electrode (260b) is electrically connected to the first electrode structure (131) and the second interdigitated electrode (132a) of the second electrode structure (132) via a through hole.

12. The resonant filter according to claim 1, wherein The resonant filter structure includes a plurality of the bulk acoustic wave resonator structures (BAWR) and a plurality of the Lamb wave resonator structures (LWR), and wherein A plurality of said bulk acoustic wave resonator structures (BAWR) and a plurality of said Lamb wave resonator structures (LWR) constitute a ladder filter structure, and wherein, The Lamb wave resonance structure (LWR) is a dual-mode filter structure.

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