Bulk acoustic wave resonator assembly with acoustic decoupling layer, filter and electronic device

Abstract

The application relates to a bulk acoustic resonator assembly, comprising at least two bulk acoustic resonators stacked in the thickness direction of a substrate on one side of the substrate, the at least two resonators comprising a first and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode and a first acoustic mirror, the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode and a second acoustic mirror. The second top electrode is provided with a second wing bridge along the active area of the second resonator, an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the cavity acting as a second acoustic mirror, a second cavity is provided between the second wing bridge and the upper surface of the second piezoelectric layer; the boundary of the cavity is outside the non-electrode connection end of the first bottom electrode in the horizontal direction; the boundary of the cavity is outside the inner edge of the second wing bridge in the horizontal direction. The application also relates to a filter and an electronic device.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of semiconductor, and in particular, to a bulk acoustic wave resonator assembly, a filter having the resonator assembly, and an electronic device. BACKGROUND

[0002] With the rapid development of today's wireless communication technology, the application of small portable terminal devices is increasingly widespread, and thus the demand for high-performance, small-size radio frequency front-end modules and devices is increasingly urgent. In recent years, filter devices such as filters, duplexers, etc. based on, for example, film bulk acoustic resonators (FBAR) are increasingly favored by the market. On the one hand, this is because of their excellent electrical properties such as low insertion loss, steep transition characteristics, high selectivity, high power capacity, strong electrostatic discharge (ESD) resistance, etc., and on the other hand, this is because of their small size and ease of integration.

[0003] However, there is a need for further reduction in the size of filter devices in reality.

[0004] In addition, in existing designs, bulk acoustic wave resonators are combined in series and in parallel to form a filter, which requires multiple resonators to be formed on a substrate, with each resonator being separate at different horizontal positions on the substrate and being connected by horizontal metal leads, as shown in FIG. 1, where the top electrode 104 of the resonator 100 is connected to the bottom electrode 102 of the resonator 200 through the conductive via 10. In order to ensure electrical signal transmission and manufacturing process limitations, the connection width of the conductive via 10 to the top electrode 104 of the resonator 100, the width of the conductive via 10, the width of the top electrode 104 of the resonator 100, and the width of the bottom electrode 102 of the resonator 200 all have certain requirements, and the total length is generally > 5 μm, which leads to a large electrical loss introduced by the connection line, especially for high-frequency resonators, when the electrode thickness is < 1000 A, which can worsen the insertion loss by more than 0.1 dB. Figure 1 SUMMARY

[0005] To alleviate or solve at least one aspect of the above problems in the prior art, the present application is proposed.

[0006] According to an aspect of an embodiment of the present application, a bulk acoustic wave resonator assembly is proposed, comprising:

[0007] a substrate;

[0008] ​at least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked in a thickness direction of the substrate on one side of the substrate, the at least two resonators including a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror, the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror,

[0009] wherein:

[0010] the second top electrode is provided with a second wing bridge portion along an effective area of the second resonator, an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the cavity serving as the second acoustic mirror, a second cavity is provided between the second wing bridge portion and an upper surface of the second piezoelectric layer;

[0011] a boundary of the cavity is outside a non-electrode connecting end of the first bottom electrode in a horizontal direction and a first distance is present therefrom; and

[0012] a boundary of the cavity is outside an inner edge of the second wing bridge portion in the horizontal direction and a second distance is present therefrom.

[0013] Embodiments of the present application also relate to a bulk acoustic wave resonator assembly, comprising:

[0014] at least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked in a thickness direction of the substrate on one side of the substrate, the at least two resonators including a first resonator and a second resonator,

[0015] wherein:

[0016] an acoustic decoupling layer in the form of a cavity is provided between a top electrode of the first resonator and a bottom electrode of the second resonator, the cavity serving as an acoustic mirror of the second resonator;

[0017] a boundary of the cavity is outside a non-electrode connecting end of the bottom electrode of the first resonator in a horizontal direction; and

[0018] a boundary of the cavity is outside an inner edge of the second wing bridge portion in the horizontal direction.

[0019] Embodiments of the present application also relate to a filter, comprising the above-mentioned bulk acoustic wave resonator assembly.

[0020] Embodiments of the present application also relate to an electronic device, comprising the above-mentioned filter or the above-mentioned resonator assembly. BRIEF DESCRIPTION OF DRAWINGS

[0021] The following description and drawings are illustrative of the various embodiments of the present disclosure and are not intended to limit the scope of the present disclosure. Numerous variations and modifications will become apparent to those skilled in the art once the following description and drawings are reviewed. Those skilled in the art will readily appreciate that the various embodiments of the present disclosure can be implemented without resorting to any of the details of the following description and drawings. The same reference numbers in different drawings represent the same or similar elements.

[0022] Figure 1 schematic cross-sectional view of an electrical connection between two adjacent bulk acoustic wave resonators in an existing design;

[0023] Figure 2 schematic top view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present disclosure;

[0024] Figure 3A1 schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present disclosure taken along the line A-A' in Figure 2 Figure 3A2 schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present disclosure taken along the line A-A' in Figure 2

[0025] Figure 3B schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present disclosure taken along the line B-B' in Figure 2

[0026] Figure 3C1 schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present disclosure taken along the line C-C' in Figure 2 Figure 3C2 schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present disclosure taken along the line C-C' in Figure 2

[0027] Figure 3D graph showing an insertion loss curve comparison of the structure of FIG. 3A relative to the structure of FIG. 2A; Figure 1

[0028] schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present disclosure taken along the line A-A' in Figure 3E Figure 2 schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present disclosure taken along the line A-A' in

[0029] Figure 3F schematic cross-sectional view of a bulk acoustic wave resonator according to still another exemplary embodiment of the present disclosure taken along the line A-A' in Figure 2

[0030] schematic cross-sectional view of a bulk acoustic wave resonator according to yet another exemplary embodiment of the present disclosure taken along the line A-A' in Figure 3G Figure 2

[0031] ​​​​​​​​Figure 4 schematic top view of a bulk acoustic wave resonator assembly according to another exemplary embodiment of the present application, wherein only the acoustic mirror of the lower resonator, the bottom and top electrodes of the lower resonator, the electrode pair external leads of the lower resonator, and the bottom electrode external leads of the upper resonator are shown;

[0032] Figure 5A schematic cross-sectional view of a bulk acoustic wave resonator taken along the A-A' line in Figure 4

[0033] Figure 5B schematic cross-sectional view of a bulk acoustic wave resonator taken along the B-B' line in Figure 4

[0034] Figure 5C schematic cross-sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 4

[0035] Figure 5D schematic cross-sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 4

[0036] Figure 6 schematic top view of a bulk acoustic wave resonator assembly according to another exemplary embodiment of the present application, wherein only the acoustic mirror of the lower resonator, the bottom and top electrodes of the lower resonator, the electrode pair external leads of the lower resonator, and the bottom electrode external leads of the upper resonator are shown;

[0037] Figure 7A schematic cross-sectional view of a bulk acoustic wave resonator taken along the A-A' line in Figure 6

[0038] Figure 7B schematic cross-sectional view of a bulk acoustic wave resonator taken along the B-B' line in Figure 6

[0039] Figure 7C schematic cross-sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 6

[0040] Figure 7D schematic cross-sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 6

[0041] ​​​​​​​​Figure 8 schematic cross-sectional view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present application;

[0042] Figure 9 a cross-sectional view of a resonator assembly according to an exemplary embodiment of the present application, in which the upper and lower resonator active areas are acoustically isolated by a cavity, and Figure 9 in a left side view of FIG. 1, the upper and lower resonators are electrically isolated from each other, in a right side view of FIG. 1, the upper and lower resonators are electrically connected to each other. Figure 9 DETAILED DESCRIPTION

[0043] The technical solutions of the present application will be further described below by way of examples in conjunction with the accompanying drawings. In the description, identical or similar reference numerals indicate identical or similar components. The following description of the embodiments of the present application with reference to the accompanying drawings is intended to explain the general inventive concept of the present application, and should not be construed as limiting the present application to one of the embodiments. The present application is described by way of a part of the embodiments, but not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0044] The reference numerals in the present application are explained as follows:

[0045] 11: electrode external lead of bottom electrode of lower resonator.

[0046] 12: electrode external lead of top electrode of lower resonator.

[0047] 13: electrode external lead of bottom electrode of upper resonator.

[0048] 14: electrode external lead of top electrode of upper resonator. The above electrode external leads 11-14 are connected to the corresponding electrodes,

[0049] S: substrate, which can be selected from single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.

[0050] 101, 201: acoustic mirror, which can be a cavity, or can be a Bragg reflection layer or other equivalent form. The acoustic mirror 201 is a cavity, which constitutes an acoustic decoupling layer.

[0051] 102, 202: bottom electrode, which can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite of the above metals or an alloy thereof, etc.

[0052] ​103, 203: piezoelectric layer, which can be a single-crystal piezoelectric material, optionally, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate (PZT), single-crystal potassium niobate, single-crystal quartz thin film, or single-crystal lithium tantalate, or a polycrystal piezoelectric material (as opposed to single-crystal, non-single-crystal material), optionally, such as polycrystal aluminum nitride, zinc oxide, PZT, or a rare earth element doped material containing the above materials in a certain atomic ratio, for example, doped aluminum nitride containing at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0053] 104, 204: top electrode, which can have the same material as the bottom electrode, and the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite or alloy thereof.

[0054] 105, 205: gap, which is defined between the wing bridge and the upper surface of the corresponding piezoelectric layer.

[0055] 106, 206: disconnection structure.

[0056] Figure 2 Fig. 1 is a schematic top view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present application, Fig. 2 is a schematic sectional view of the bulk acoustic wave resonator taken along the A-A' line in Fig. 1, Fig. 3 is a schematic sectional view of the bulk acoustic wave resonator taken along the B-B' line in Fig. 1, and Fig. 4 is a schematic sectional view of the bulk acoustic wave resonator taken along the C-C' line in Fig. 1. Figure 2 In Fig. 2, the A-A' line corresponds to a section passing through the non-electrode connection end of the top electrode of the upper resonator and the non-electrode connection end of the bottom electrode, the B-B' line corresponds to a section passing through the electrode connection end of the bottom electrode of the lower resonator and the electrode connection end of the top electrode of the lower resonator, and the C-C' line corresponds to a section passing through the electrode connection end of the bottom electrode of the upper resonator and the electrode connection end of the top electrode of the upper resonator.

[0057] Figure 3A1 and 3A2 are schematic sectional views of the bulk acoustic wave resonator taken along the A-A' line in Fig. 1, respectively, according to an exemplary embodiment of the present application, Figure 2 Figure 3A2 and Figure 3A1 differ in that, in Figure 3A2 , the top electrode 104 is not provided with a suspended wing.

[0058] Although not shown, a process layer can also be provided on the top electrode of the resonator, which can cover the top electrode, and the process layer can function as a mass adjustment load or a passivation layer. The material of the passivation layer can be a dielectric material, such as silicon dioxide, aluminum nitride, silicon nitride, or the like.​

[0059] Further, in the structure shown in Figure 3A1 and 3A2 two resonators are formed at the same horizontal position of the substrate S, and the spatial positions of the two resonators are different in the vertical direction or in the thickness direction of the substrate.

[0060] As will be understood by those skilled in the art, three resonators or more resonators can also be stacked. Figure 8 A schematic cross-sectional view of a bulk acoustic wave resonator assembly according to an exemplary embodiment of the present application. As shown in Figure 8 The resonator assembly includes a first resonator, a second resonator, and a third resonator stacked in the thickness direction, with an acoustic decoupling layer 201 (a cavity in this embodiment) between the top electrode 104 of the first resonator and the bottom electrode 202 of the second resonator, and an acoustic decoupling layer 301 (a cavity in this embodiment) between the top electrode 204 of the second resonator and the bottom electrode 302 of the third resonator, the acoustic decoupling layer 301 constituting an acoustic mirror of the third resonator. Optionally, as shown in Figure 8 The boundary of the acoustic decoupling layer 301 is outside the boundary of the acoustic decoupling layer 201 in the horizontal direction. As will be understood, the assembly structures shown in other embodiments of the present application can also be stacked.

[0061] In the structure shown in Figure 3A1 and 3A2 two resonators are shown, with the effective area of the upper resonator being the overlapping area in the thickness direction of the top electrode 204, the piezoelectric layer 203, the bottom electrode 202, and the cavity 201, denoted by A2. The effective area of the lower resonator is the overlapping area in the thickness direction of the cavity 201, the top electrode 104, the piezoelectric layer 103, the bottom electrode 102, and the acoustic mirror 101, denoted by Al.

[0062] Correspondingly, in Figure 8 the effective area of the uppermost third resonator is the overlapping area in the thickness direction of the top electrode 304, the piezoelectric layer 303, the bottom electrode 302, and the cavity 301, denoted by A3, the effective area of the middle second resonator is the overlapping area in the thickness direction of the cavity 301, the top electrode 204, the piezoelectric layer 203, the bottom electrode 202, and the cavity 201, denoted by A2, and the effective area of the lowermost first resonator is the overlapping area in the thickness direction of the cavity 201, the top electrode 104, the piezoelectric layer 103, the bottom electrode 102, and the cavity 101, denoted by Al.

[0063] In the structure shown in Figure 3A1 and 3A2In the structure shown, the upper resonator and the lower resonator are acoustically separated by the cavity 201, that is, the cavity 201 constitutes an acoustic decoupling layer between the upper and lower resonators, thereby completely avoiding the acoustic coupling problem that may be caused by the adjacent stacking of the upper and lower resonators.

[0064] Using the cavity 201 as an acoustic decoupling layer can achieve complete acoustic decoupling of the upper and lower resonators, so the performance of the resonator is better. Furthermore, the cavity 201 is directly surrounded by the top electrode 104 of the lower resonator and the bottom electrode 202 of the upper resonator (in other embodiments, the structure defining the position of the cavity also includes the piezoelectric layer of the upper resonator and / or the lower resonator), for example Figure 3A1-3C1 In the structure shown, the overall structure is stable and reliable and the processing technology is simple.

[0065] As those skilled in the art will appreciate, the cavity 201 is disposed between the bottom electrode of the upper resonator and the top electrode of the lower resonator in the thickness direction of the resonator. This includes not only the case where at least a portion of the upper and lower boundaries of the cavity are defined by the lower surface of the bottom electrode of the upper resonator and the upper surface of the top electrode of the lower resonator, but also the case where a process layer (e.g., a passivation layer) is disposed on the upper surface of the top electrode of the lower resonator, thereby defining at least a portion of the lower boundary of the cavity 201. All of these are within the scope of protection of the present invention.

[0066] exist Figure 3A1 In the structure shown, since multiple resonators are formed at the same horizontal position of the substrate S, the spatial positions of the multiple resonators in the vertical direction or in the thickness direction of the substrate are different. Therefore, the area of ​​the filter can be greatly reduced. For example, in the case of setting two resonators, the area of ​​the filter can be reduced from Figure 1 The area P1 shown in is reduced to Figure 3A1 The area P2 shown in .

[0067] like Figure 3A1 and 3A2 As shown, the bottom electrode 202 of the upper resonator and the top electrode 104 of the lower resonator are electrically connected to each other at the non-electrode connection end. In the case where the bottom electrode of the upper resonator is directly connected to the top electrode of the lower resonator, the bottom electrode of the upper resonator is directly electrically connected to the top electrode of the lower resonator, and the length of the connection portion is shorter than that of the top electrode of the lower resonator. Figure 1 The transmission path is shortened, which reduces the transmission loss. In addition, the thickness of the metal output of the electrical signal is the sum of the thickness of the top electrode of the lower resonator and the bottom electrode of the upper resonator, which further reduces the transmission loss. By reducing the electrical loss, the insertion loss of the filter is finally optimized. Figure 3A1 and 3A2 As shown, the length of the transmission path formed by the bottom electrode of the upper resonator and the top electrode of the lower resonator at the non-connected end of the electrodes is d0, which can be less than 5 μm.

[0068] In the structure of, for example, FIGS. 3A1-3C2, the thickness of the top electrode 104 of the lower resonator and the thickness of the bottom electrode 202 of the upper resonator can be thinned, and the current transmission path to the lower resonator can be shortened, for example, to less than 5 μm, which reduces transmission loss, and this is advantageous for further miniaturization of the resonator. In the case where the bottom electrode of the upper resonator and the top electrode of the lower resonator are electrically connected to each other, the thickness of the electrode film layers of the bottom electrode of the upper resonator and the top electrode of the lower resonator can be further simultaneously reduced while reducing the current transmission path loss to the bottom electrode of the upper resonator and the current transmission path loss to the top electrode of the lower resonator. Accordingly, in the case where the resonant frequency of the lower resonator is greater than 0.5 GHz, the thickness of the top electrode 104 can be less than 0.5 μm, and in the case where the resonant frequency of the upper resonator is greater than 0.5 GHz, the thickness of the bottom electrode 202 can be less than 0.5 μm. and / or in the case where the resonant frequency of the upper resonator is greater than 0.5 GHz, the thickness of the bottom electrode 202 can be less than 0.5 μm. In further embodiments, in the case where the resonant frequency of the lower resonator is greater than 3 GHz, the thickness of the top electrode 104 can be designed to be less than 1 μm, and in the case where the resonant frequency of the upper resonator is greater than 3 GHz, the thickness of the bottom electrode 202 of the upper resonator can also be less than 1 μm. and / or in the case where the resonant frequency of the upper resonator is greater than 3 GHz, the thickness of the bottom electrode 202 of the upper resonator can also be less than 1 μm. As can be understood, in the present application, the thinning of the thickness of the electrodes refers to the thinning of the thickness of the portion of the electrodes within the effective area of the resonator.

[0069] Figure 3D For example, the structure of Figure 3A1 is compared with the insertion loss curve of the structure of Figure 1 . Figure 3D The insertion loss curve (solid line) of the structure of the present application Figure 3A1 after being applied to the 3.5G frequency band is compared with the insertion loss curve (dashed line) of the conventional structure of Figure 1 . It can be seen that, after the structure of the present application Figure 3A1 is applied, the insertion loss is improved by about 0.1 dB due to the reduction of electrode loss.

[0070] Figure 3B is a schematic sectional view of a bulk acoustic wave resonator taken along the B-B' line in Figure 2 , according to an exemplary embodiment of the present application, Figure 3C1 is a schematic sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 2 , according to an exemplary embodiment of the present application, Figure 3C2 is a schematic sectional view of a bulk acoustic wave resonator taken along the C-C' line in Figure 2 , according to an exemplary embodiment of the present application. It can be seen that, in the structure of Figure 3B and 3C1In 3C2, the top electrode of the lower resonator and the bottom electrode of the upper resonator are electrically connected to each other in the circumferential direction around the entire cavity 201.

[0071] For the case where the bottom electrode of the upper resonator and the top electrode of the lower resonator are electrically connected to each other, in Figure 3A1-3C2 the structure shown in FIG. 3C2, the non-electrically connected ends of the bottom electrode of the upper resonator and the top electrode of the lower resonator are connected to each other, i.e., electrically connected in the entire circumferential direction around the cavity 201. However, in addition to the connection mode as Figure 3A1-3C2 shown in FIG. 3C2, there can be other connection modes.

[0072] Figure 5B A schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present application taken along the line B-B' in FIG. 3A is shown in FIG. 3B. Figure 4 In FIG. 3B, the bottom electrode 202 of the upper resonator and the electrode-connected end of the top electrode 104 of the lower resonator are electrically connected to each other, i.e., the electrode-connected end of the bottom electrode 202 covers and is electrically connected to the electrode-connected end of the top electrode 104. However, unlike in Figure 5B FIG. 3B, in Figure 3B FIG. 3C, the non-electrode-connected end of the top electrode 104 is not connected to the non-electrode-connected end of the bottom electrode 202, as shown in Figure 5B FIG. 3C, the end of the non-electrode-connected end of the bottom electrode 202 of the upper resonator is outside (spaced apart in the horizontal direction from) the non-electrode-connected end of the top electrode 104 and is disposed on the upper surface of the piezoelectric layer 103 of the lower resonator. Figure 5B

[0073] A schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present application taken along the line B-B' in FIG. 3A is shown in FIG. 3B. Figure 7B In FIG. 3B, the bottom electrode 202 of the upper resonator and the electrode-connected end of the top electrode 104 of the lower resonator are electrically connected to each other, i.e., the electrode-connected end of the bottom electrode 202 covers and is electrically connected to the electrode-connected end of the top electrode 104. However, unlike in Figure 6 FIG. 3B, in Figure 7B FIG. 3C, the non-electrode-connected end of the top electrode 104 is not connected to the non-electrode-connected end of the bottom electrode 202, as shown in Figure 7B FIG. 3C, the end of the non-electrode-connected end of the bottom electrode 202 of the upper resonator is inside the boundary of the cavity 201 and is not disposed on the upper surface of the piezoelectric layer 103 of the lower resonator. Figure 7B

[0074] A schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present application taken along the line B-B' in FIG. 3A is shown in FIG. 3B. Figure 9 In FIG. 3B, the bottom electrode 202 of the upper resonator and the electrode-connected end of the top electrode 104 of the lower resonator are electrically connected to each other, i.e., the electrode-connected end of the bottom electrode 202 covers and is electrically connected to the electrode-connected end of the top electrode 104. However, unlike in Figure 9 FIG. 3B, in FIG. 3C, the non-electrode-connected end of the top electrode 104 is not connected to the non-electrode-connected end of the bottom electrode 202, as shown in

[0075] like Figure 9 As shown in the right side cross-sectional view, the top electrode 104 covers the piezoelectric layer 103, and the bottom electrode 202 is connected to the top electrode 104 at both the electrode connection end and the non-electrode connection end. Figure 9 In the right side view of , the electrode connection end of the bottom electrode 202 covers the electrode connection end of the top electrode 104 , and the non-electrode connection end of the bottom electrode 202 covers the non-electrode connection end of the top electrode 104 .

[0076] In the present invention Figure 9 In the structure shown, since the second electrode layer where the bottom electrode 202 is located covers the first electrode layer where the top electrode 104 is located, the metal thickness of the electrode connection part between the bottom electrode of the upper resonator and the top electrode of the lower resonator can be increased, which is beneficial to reducing electrical loss.

[0077] When the maximum width of the resonator effective area is larger than the cavity height, the upper and lower resonators may come into contact in the cavity due to bending or other reasons. For example, when the cavity height is When the maximum width of the effective area of ​​the resonator is greater than 100 μm, in order to ensure the complete formation of the cavity 201 within the effective areas of the upper and lower resonators, the stress of the lower resonator can be controlled to bend toward the lower air cavity, and / or the stress of the upper resonator can be controlled to bend toward the upper air cavity. The top electrode of the lower resonator finally formed is concave downward, and / or the bottom electrode of the upper resonator is convex upward.

[0078] In the above embodiments, the bottom electrode of the upper resonator and the top electrode of the lower resonator are electrically connected to each other, but the present invention is not limited to this. In the case where two stacked BAW resonators share an acoustic decoupling layer, the bottom electrode of the upper resonator and the top electrode of the lower resonator can also be electrically isolated from each other.

[0079] Figure 5A According to an exemplary embodiment of the present invention Figure 4 Schematic cross-sectional view of the bulk acoustic wave resonator taken along line A-A' in FIG. Figure 5A In the figure, the bottom electrode 202 of the upper resonator is not electrically connected to the top electrode 104 of the lower resonator, and the end of the non-electrode connection end of the bottom electrode 202 of the upper resonator is located outside the non-electrode connection end of the top electrode 104 of the lower resonator and is both arranged on the upper surface of the piezoelectric layer 103 of the lower resonator.

[0080] Figure 5C According to an exemplary embodiment of the present invention Figure 4a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line C-C' in FIG. 10, in which the non-electrode connecting end of the bottom electrode 202 of the upper resonator and the non-electrode connecting end of the top electrode 104 of the lower resonator are not electrically connected, and the electrode connecting end of the bottom electrode 202 of the upper resonator and the electrode connecting end of the top electrode 104 of the lower resonator are not electrically connected. In Figure 5C the end of the non-electrode connecting end of the bottom electrode 202 of the upper resonator is outside the non-electrode connecting end of the top electrode 104 of the lower resonator and is disposed on the upper surface of the piezoelectric layer 103 of the lower resonator.

[0081] Figure 5D a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line Figure 4 in FIG. 10 according to another exemplary embodiment of the present application. Figure 5D which is different from Figure 5C in that, in Figure 5D the electrode connecting end of the bottom electrode 202 is disposed below the electrode connecting end of the top electrode 104 in the same layer to increase the electrode thickness of the electrode connecting end of the bottom electrode 202, thereby reducing the electrical loss.

[0082] Figure 7A a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line Figure 6 in FIG. 10 according to an exemplary embodiment of the present application, in which the non-electrode connecting end of the bottom electrode 202 of the upper resonator and the non-electrode connecting end of the top electrode 104 of the lower resonator are not electrically connected, and the end of a part of the non-electrode connecting end of the bottom electrode 202 of the upper resonator is disposed on the upper surface of the piezoelectric layer 103 of the lower resonator (see the left side in Figure 7A and the end of the other part is inside the boundary of the cavity 201 in the lateral direction (see the right side in Figure 7A ).

[0083] Figure 5A a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line Figure 7A in FIG. 10 according to an exemplary embodiment of the present application, in which the non-electrode connecting end of the bottom electrode 202 of the upper resonator and the non-electrode connecting end of the top electrode 104 of the lower resonator are not electrically connected, and the electrode connecting end of the bottom electrode 202 of the upper resonator and the electrode connecting end of the top electrode 104 of the lower resonator are not electrically connected. The non-electrode connecting end of the bottom electrode 202 is inside the boundary of the cavity 201 in the horizontal direction.

[0084] Figure 7B the left side view of Figure 6In the left side view of FIG. 1A, the top electrode 104 is in the first electrode layer, which, as mentioned above, includes the top electrode 104 and the non-top electrode layer (i.e., the portion of the first electrode layer to the right of the break structure 106) that is electrically isolated from the non-electrode-connected end of the top electrode 104 via the break structure 106. In the left side view of FIG. 1A, the electrode-connected end of the top electrode 104 covers the non-top electrode layer. Figure 7B In the left side view of FIG. 1A, the bottom electrode 202 is in the second electrode layer, which, as shown in the left side view of FIG. 1A, includes the bottom electrode 202 and the non-bottom electrode layer (i.e., the portion of the second electrode layer to the left of the break structure 206) that is electrically isolated from the non-electrode-connected end of the bottom electrode 202 via the break structure 206. In the left side view of FIG. 1A, the electrode-connected end of the bottom electrode 202 covers the non-bottom electrode layer. Figure 7B In the left side view of FIG. 1A, the bottom electrode 202 is in the second electrode layer, which, as shown in the left side view of FIG. 1A, includes the bottom electrode 202 and the non-bottom electrode layer (i.e., the portion of the second electrode layer to the left of the break structure 206) that is electrically isolated from the non-electrode-connected end of the bottom electrode 202 via the break structure 206. In the left side view of FIG. 1A, the electrode-connected end of the bottom electrode 202 covers the non-bottom electrode layer. Figure 5B In the left side view of FIG. 1A, the bottom electrode 202 is in the second electrode layer, which, as shown in the left side view of FIG. 1A, includes the bottom electrode 202 and the non-bottom electrode layer (i.e., the portion of the second electrode layer to the left of the break structure 206) that is electrically isolated from the non-electrode-connected end of the bottom electrode 202 via the break structure 206. In the left side view of FIG. 1A, the electrode-connected end of the bottom electrode 202 covers the non-bottom electrode layer. Figure 5B In the left side view of FIG. 1A, the bottom electrode 202 is in the second electrode layer, which, as shown in the left side view of FIG. 1A, includes the bottom electrode 202 and the non-bottom electrode layer (i.e., the portion of the second electrode layer to the left of the break structure 206) that is electrically isolated from the non-electrode-connected end of the bottom electrode 202 via the break structure 206. In the left side view of FIG. 1A, the electrode-connected end of the bottom electrode 202 covers the non-bottom electrode layer. Figure 7B In the left side view of FIG. 1A, the electrode-connected end of the top electrode 104 covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode-connected end of the top electrode 104.

[0085] In addition, the control of stress can reduce the probability of the upper and lower resonators contacting each other, but when the resonator area is large, a support can be added, which can be in contact with the top or top electrode of the lower resonator, and the height of the support is less than or equal to the height of the cavity, equal means that the top end of the support is in contact with the bottom or bottom electrode of the upper resonator, and the height of the support is less than the height of the cavity means that the top end of the support is not in contact with the upper resonator, and the top end of the support is in contact with the upper resonator when the local thickness of the cavity is reduced due to the bending of the resonator, which serves as a support.

[0086] In Figure 5B , 3B , 3C1 and 3E-3G, the first top electrode 104 and the second top electrode 204 are both provided with a wing bridge portion (i.e., the non-connected end of the electrode includes a wing or bridge portion, or the electrode-connected end of the electrode includes a bridge portion, or both), but the present application is not limited thereto, for example, the wing bridge portion can be provided only on the uppermost top electrode of the resonator along the effective area, as shown in Figure 7C , 3C2 , 5A-5D, 7A-7D, 8 and 9.

[0087] The following exemplary describes the position relationship between the wing bridge portion of the electrode of the upper and lower resonators, especially the wing bridge portion of the second top electrode 204 and the first top electrode 104 and the cavity 201 in the lateral direction, with reference to the accompanying drawings.

[0088] Figure 6 and Figure 7C is a schematic cross-sectional view of the bulk acoustic wave resonator taken along the A-A' line in Figure 7C .

[0089] Figure 5C and Figure 5CBoth show two resonators, an upper resonator and a lower resonator, wherein the cavity 101, the bottom electrode 102, the piezoelectric layer 103, the top electrode 104 constitute the lower resonator (the passivation layer, the load layer, etc. are omitted), and the cavity 201, the bottom electrode 202, the piezoelectric layer 203, the top electrode 204 constitute the upper resonator. The cavity 201 is a common cavity for the upper and lower resonators.

[0090] As shown in Figure 7C , the non-electrode connecting end of the top electrode 104 and the non-electrode connecting end of the top electrode 204 are both provided with a suspension wing, as shown in Figure 5C , the suspension wing and the piezoelectric layer form a gap 105 and a gap 205, respectively.

[0091] Figure 7D In the structure shown, the effective area of the lower resonator is determined by the overlapping area of the cavity 101, the bottom electrode 102, the piezoelectric layer 103, and the top electrode 104 in the thickness direction, A1 corresponds to the effective area of the lower resonator (in the embodiment shown in Figure 6 , the inner edge of the gap 105 defines the boundary of the effective area A1 of the lower resonator); the effective area of the upper resonator is determined by the overlapping area of the cavity 201, the bottom electrode 202, the piezoelectric layer 203, and the top electrode 204 in the thickness direction, A2 corresponds to the effective area of the upper resonator (in the embodiment shown in Figure 7D , the inner edge of the gap 205 defines the boundary of the effective area A2 of the upper resonator).

[0092] Figure 7C In the structure shown, the effective area of the lower resonator is determined by the overlapping area of the cavity 101, the bottom electrode 102, the piezoelectric layer 103, and the top electrode 104 in the thickness direction, A1 corresponds to the effective area of the lower resonator; the effective area of the upper resonator is determined by the overlapping area of the cavity 201, the bottom electrode 202, the piezoelectric layer 203, and the top electrode 204 in the thickness direction, A2 corresponds to the effective area of the upper resonator (in the embodiment shown in Figure 7D , the inner edge of the gap 205 defines the boundary of the effective area A2 of the upper resonator).

[0093] In the following description with reference to the accompanying ​ , the above statements for the effective areas A1 and A2 also apply, and will not be repeated hereinafter.

[0094] d1 corresponds to, at the non-electrode connecting end of the bottom electrode 102, the distance (first distance) in the horizontal direction from the outer boundary of the cavity 201 to the non-electrode connecting end of the bottom electrode 102 of the lower resonator, d1 should be greater than 0, that is, the boundary of the cavity 201 is outside the bottom electrode 102 in the horizontal direction. Thus, in ​ , the acoustic energy leakage area formed by the overlapping of the bottom electrode 102, the piezoelectric layer 103, the suspension wing 105, and the top electrode 104 without the cavity structure is avoided, and in ​In this way, the acoustic energy leakage area formed by the bottom electrode 102, the piezoelectric layer 103, the top electrode 104 overlapping and no cavity structure above and below is avoided, which can cause a large amount of acoustic energy to be conducted to the substrate and non-effective area, thereby reducing the Q value of the resonator.

[0095] In the following description with reference to the accompanying drawings, the above statements for d1 also apply, and will not be repeated hereinafter. ​

[0096] In ​ and 3A2 It can be seen that the end of the non-electrode connecting end of the bottom electrode 202 covers the end of the non-electrode connecting end of the top electrode 104 connected by the electrode. In ​ and 3A2, d21 corresponds to the fourth distance d21 that the boundary of the cavity 201 is outside the outer edge of the wing in the horizontal direction in the case that the non-electrode connecting end of the top electrode 204 is provided with a wing.

[0097] In ​ , in the case that d21 is greater than 0, the acoustic energy leakage area formed by the bottom electrode 202, the piezoelectric layer 203, the top electrode 204, the gap 205 overlapping or the bottom electrode 202, the piezoelectric layer 203, the top electrode 204 overlapping and no cavity structure below can be avoided, which can cause a large amount of acoustic energy to be conducted to the substrate and non-effective area, thereby reducing the Q value of the resonator.

[0098] In the following description with reference to the accompanying drawings, the above statements for d21 also apply, and will not be repeated hereinafter. ​

[0099] In ​ and 3A2, d2 corresponds to the second distance d2 that the boundary of the cavity 201 is outside the inner edge of the wing in the horizontal direction in the case that the non-electrode connecting end of the top electrode 204 is provided with a wing.

[0100] In ​ , in the case that d2 is greater than 0, the acoustic energy leakage area formed by the bottom electrode 202, the piezoelectric layer 203, the top electrode 204, the gap 205 overlapping or the bottom electrode 202, the piezoelectric layer 203, the top electrode 204 overlapping and no cavity structure below can be avoided, which can cause a large amount of acoustic energy to be conducted to the substrate and non-effective area, thereby reducing the Q value of the resonator.

[0101] In the following description with reference to the accompanying drawings, the above statements for d2 also apply, and will not be repeated hereinafter. ​

[0102] ​​​d3 corresponds to the distance (third distance) from the outer edge of the acoustic energy leakage region formed by the lower cavity-free structure of the lower resonator, where the bottom electrode 102, the piezoelectric layer 103, and the top electrode 104 overlap, at the non-electrode connection end of the bottom electrode 102 to the boundary of the acoustic mirror 101. In other words, the outer edge of the portion of the bottom electrode 102 horizontally between the boundary of the acoustic mirror 101 and the boundary of the cavity 201 is at a third distance d3 from the boundary of the acoustic mirror 101 in the horizontal direction. This structure forming the acoustic energy leakage region causes a large amount of acoustic energy to be conducted to the substrate and the inactive area, reducing the Q value of the resonator. In an optional embodiment, d3 is less than or equal to 10 μm.

[0103] Refer to the attached ​ In the description of , the above statement about d3 also applies and will not be repeated hereafter.

[0104] ​ For the ​ The schematic cross-sectional view of the bulk acoustic wave resonator taken along line BB' in FIG. 1 shows the bottom electrode of the lower resonator and the external lead 11, and the top electrode of the lower resonator and the external lead 12.

[0105] ​ d1, d2, d21 and d3, as well as A1 and A2 are shown in FIG.

[0106] exist ​ In the figure, d5 corresponds to the horizontal distance between the outer edge of the non-electrode connection end of the bottom electrode 202 outside the boundary of the cavity 201 and the boundary of the cavity 201. At the electrode connection end of the bottom electrode 102, the acoustic energy leakage area formed by the overlap of the bottom electrode 102, the piezoelectric layer 103, the gap 105, and the top electrode 104 of the lower resonator and the absence of a cavity structure will cause a large amount of acoustic energy to be conducted to the substrate and the ineffective area, reducing the Q value of the resonator. The area corresponding to d5 is at the non-electrode connection end of the top electrode 104. In order to reduce its impact on performance, in an optional embodiment, d5 is less than or equal to 10μm.

[0107] Refer to the attached ​ In the description of , the above statement about d5 is also applicable and will not be repeated hereafter.

[0108] exist ​In the figure, d11 corresponds to the distance from the gap 105 formed by the bridge portion of the electrode connection end of the top electrode 104 at the non-electrode connection end of the bottom electrode 102 to the end of the non-electrode connection portion of the bottom electrode 102. In other words, the outer edge of the gap 105 is located horizontally outside the non-electrode connection end of the bottom electrode 102 and is separated from it by a seventh distance d11. d11 should be greater than 0 to avoid an acoustic energy leakage region formed by the overlap of the bottom electrode 102, the piezoelectric layer 103, and the top electrode 104 without a cavity above or below. This structure causes a large amount of acoustic energy to be conducted to the substrate and the inactive area, thereby reducing the Q value of the lower resonator.

[0109] Refer to the attached ​ In the description of , the above statement about d11 is also applicable and will not be repeated hereafter.

[0110] exist ​ In the embodiment, d12 corresponds to the case where a cantilever is provided at the non-electrode connection end of the top electrode 204 (forming a gap 205) and a wing bridge portion is provided at the top electrode 104 (forming a gap 205). ​ On the right side of the diagram, the top electrode 104 is provided with a bridge portion at the electrode connection end. ​ In the case of the left side of the top electrode 104 (where a cantilever is provided at the non-electrode connection end), the outer edge of the bridge portion of the top electrode 104 is horizontally located outside the outer edge of the cantilever of the top electrode 204 and is separated therefrom by an eighth distance d12. d12 should be greater than 0 to avoid an acoustic energy leakage region formed by the overlapping structure of the bottom electrode 202, the piezoelectric layer 203, the gap 205, and the top electrode 204, without a cavity underneath. This structure can cause a large amount of acoustic energy to be transferred to the substrate and inactive areas, reducing the Q value of the upper resonator.

[0111] Refer to the attached ​ In the description of , the above statement about d12 is also applicable and will not be repeated hereafter.

[0112] ​ and 3C2 Along ​ The schematic cross-sectional view of the bulk acoustic wave resonator taken along line CC' in FIG. 1 shows the bottom electrode of the upper resonator and the external lead 13, and the top electrode of the upper resonator and the external lead 14.

[0113] ​ and 3C2 d1, d2, d21, d3, as well as A1 and A2 are shown in FIG.

[0114] exist ​ and 3C2 In the embodiment, the electrode connection end of the top electrode 204 is provided with a bridge portion, and the outer edge of the bridge portion is located outside the non-electrode connection end of the bottom electrode 202 in the horizontal direction and has a sixth distance d6 therefrom.

[0115] In ​ , in the case where the overhang is not provided to the top electrode 104 or the bridge portion is provided to the non-electrode connecting end of the top electrode 104, d6 should be greater than 0 to avoid a structure in which the bottom electrode 202, the piezoelectric layer 203, and the top electrode 204 of the upper resonator overlap and a cavity-free region is formed, which causes a large amount of acoustic energy to be conducted to the substrate and an ineffective region, thereby reducing the Q value of the resonator.

[0116] In the following description with reference to the accompanying ​ , the above statements for d6 are equally applicable, and the following will not be described again.

[0117] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present application taken along the A-A' line in ​ . As shown in ​ , the non-electrode connecting end of the top electrode 204 is provided with a bridge portion to define the gap 205, and the non-electrode connecting end of the top electrode 104 is provided with an overhang to define the gap 105.

[0118] In ​ , d1, d2, d21, d3, d11, and d21, and A1 and A2 are shown.

[0119] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present application taken along the A-A' line in ​ . As shown in ​ , the non-electrode connecting end of the top electrode 204 is provided with an overhang to define the gap 205, and the non-electrode connecting end of the top electrode 104 is provided with a bridge portion to define the gap 105. In ​ , the outer edge of the gap 205 is outside the boundary of the cavity 201 in the horizontal direction.

[0120] In ​ , d1, d2, d3, d6, and A1 and A2 are shown.

[0121] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator according to another exemplary embodiment of the present application taken along the A-A' line in ​ . As shown in ​ , the non-electrode connecting end of the top electrode 204 is provided with a bridge portion to define the gap 205, and the non-electrode connecting end of the top electrode 104 is provided with a bridge portion to define the gap 105. In ​ , the outer edge of the gap 205 is outside the boundary of the cavity 201 in the horizontal direction.

[0122] In ​ d1, d21, d3, d6, and A1 and A2 are shown.

[0123] To eliminate the acoustic energy leakage area formed by the overlapping of the bottom electrode 102, the piezoelectric layer 103, and the top electrode 104 of the lower resonator without the cavity structure below, the top electrode of the lower resonator is not connected to the bottom electrode of the upper resonator. The structure is described in detail below. ​

[0124] A schematic top view of the bulk acoustic wave resonator assembly according to another exemplary embodiment of the present application, in which only the three layers of the acoustic mirror 101 of the lower resonator, the bottom electrode 102 and the top electrode 104 of the lower resonator, the electrode pair external leads 11, 12 of the lower resonator, and the bottom electrode external lead 13 of the upper resonator are shown for highlighting the key points. ​ In ​ the boundary of the non-electrode connecting end of the top electrode 104 is inside the boundary of the acoustic mirror 101, and the boundary of the acoustic mirror 101 is inside the boundary of the piezoelectric layer 102.

[0125] ​ A schematic cross-sectional view of the bulk acoustic wave resonator taken along the A-A' line in ​ . ​ d1, d2, d21, d4, and A1 and A2 are shown. In ​ , the non-electrode connecting ends on the left and right sides of the bottom electrode 202 are spaced apart from and outside the non-electrode connecting end of the top electrode 104 in the lateral direction.

[0126] d4 corresponds to the distance (fourth distance) in the horizontal direction between the outer edge of the portion of the non-electrode connecting end of the bottom electrode 202 that is in electrical contact with the upper surface of the piezoelectric layer 103 and the non-electrode connecting end of the bottom electrode 102. In other words, at least a portion of the non-electrode connecting end of the bottom electrode 202 in the circumferential direction is outside the non-electrode connecting end of the bottom electrode 102 in the horizontal direction and in electrical contact with the upper surface of the piezoelectric layer 103, and there is a distance d4 in the horizontal direction between the outer edge of the non-electrode connecting end of the bottom electrode 202 and the non-electrode connecting end of the bottom electrode 102.

[0127] In the area corresponding to d4, although there is no bottom electrode 102 directly below, a weak electrical coupling is formed with the edge (bottom electrode 102 in the area corresponding to d3), which affects the performance of the resonator. In optional embodiments, d4 is less than or equal to 10 μm.

[0128] In the following description with reference to the accompanying ​ , the above statements for d4 also apply and are not repeated hereinafter.

[0129] ​ is taken along the line B-B' in ​ is a schematic cross-sectional view of a bulk acoustic resonator taken along the line B-B' in ​ d1, d2, d21, d3, d5, and A1 and A2 are shown in ​ In

[0130] ​ is taken along the line C-C' in ​ is a schematic cross-sectional view of a bulk acoustic resonator taken along the line C-C' in ​ d1, d2, d21, d4, and A1 and A2 are shown in ​ In

[0131] ​ is taken along the line C-C' in ​ is a schematic cross-sectional view of a bulk acoustic resonator taken along the line C-C' in ​ d1, d2, d21, d4, and A1 and A2 are shown in ​ is different from the structure shown in ​ In ​ In

[0132] ​ is a schematic top view of a bulk acoustic resonator assembly according to yet another exemplary embodiment of the present application, in which mainly the position relationship between the bottom electrode 202 of the upper resonator and the cavity 201, and the top electrode external lead 12 of the lower resonator and the bottom electrode external lead 13 of the upper resonator are shown.

[0133] ​ is taken along the line A-A' in ​ is a schematic cross-sectional view of a bulk acoustic resonator taken along the line A-A' in ​ d1, d2, d21, d4, and A1 and A2 are shown in

[0134] It should be noted that, ​ The difference between the structures shown in ​ is that, ​ The structure corresponding to d4 on the right side disappears, thus reducing the influence of the existence of the area corresponding to d4 on the performance of the resonator.

[0135] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line B-B' in ​ , showing the lower resonator bottom electrode pair outer lead 11, and the lower resonator top electrode pair outer lead 12. ​ d1, d2, d21, d3, and A1 and A2 are shown in ​ The difference between the structures shown in ​ is that, in ​ , the non-electrode connecting end (the area where d5 is located) on the left side of the bottom electrode 202 is outside and spaced apart from the non-electrode connecting end of the top electrode 104 in the lateral direction, while in ​ , the non-electrode connecting end of the bottom electrode 202 is not outside the boundary of the cavity 201, thus eliminating the influence of the area corresponding to d5 in ​ on the performance of the resonator.

[0136] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator taken along the line C-C' in ​ , showing the upper resonator bottom electrode pair outer lead 13, and the upper resonator top electrode pair outer lead 14. ​ d1, d2, d21, and A1 and A2 are shown in ​ The difference between the structures shown in ​ is that, in ​ , the non-electrode connecting end on the left side of the bottom electrode 202 is outside and spaced apart from the non-electrode connecting end of the top electrode 104 in the lateral direction, while in ​ , the non-electrode connecting end of the bottom electrode 202 is not outside the boundary of the cavity 201, thus eliminating the influence of the corresponding area in ​ on the performance of the resonator.

[0137] ​ is a schematic cross-sectional view of a bulk acoustic wave resonator similar to that taken along the line C-C' in ​ . ​ On the basis of ​ , a layer of metal of the lower resonator top electrode is added at the electrode lead 13 of the upper resonator bottom electrode to reduce lead resistance loss. ​ d1, d2, d21, and A1 and A2 are shown in

[0138] In the above embodiment, the boundary of the cavity 201 is laterally outside the non-electrode connection end of the top electrode 204 or the bottom electrode 102, but the present invention is not limited thereto. In other embodiments, the boundary of the cavity 201 is horizontally inside the non-electrode connection end of the bottom electrode 102, and the distance thereto is within a range of 0 to -10 μm; and / or the boundary of the cavity 201 is horizontally inside the inner edge of the wing bridge portion of the top electrode 204, and the distance thereto is within a range of 0 to -10 μm.

[0139] It should be pointed out that in the present invention, each numerical range, except for those explicitly stated to not include endpoint values, can be not only endpoint values ​​but also the median of each numerical range, all of which are within the protection scope of the present invention.

[0140] In the present invention, the terms "up" and "down" are relative to the bottom surface of the base of the resonator. For a component, the side close to the bottom surface is the lower side, and the side away from the bottom surface is the upper side.

[0141] In the present invention, "inside" and "outside" are relative to the center of the effective area of ​​the resonator (i.e., the center of the effective area) in the lateral direction or radial direction. The side or end of a component closer to the center of the effective area is the inner side or inner end, while the side or end of the component farther from the center of the effective area is the outer side or outer end. For a reference position, being located inside the position means being between the position and the center of the effective area in the lateral direction or radial direction, and being located outside the position means being farther from the center of the effective area in the lateral direction or radial direction than the position.

[0142] As those skilled in the art will appreciate, the BAW resonator according to the present invention can be used to form filters or electronic devices. These electronic devices include, but are not limited to, intermediate products such as RF front-ends and filter amplifier modules, as well as end products such as mobile phones, Wi-Fi, and drones.

[0143] Based on the above, the present invention proposes the following technical solutions:

[0144] 1. A bulk acoustic wave resonator assembly, comprising:

[0145] substrate;

[0146] At least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked on one side of a substrate in a thickness direction of the substrate, the at least two resonators including a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror, and the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror,

[0147] in:

[0148] The second top electrode is provided with a second wing bridge along the effective area of the second resonator, an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the cavity serves as the second acoustic mirror, a second cavity is provided between the second wing bridge and the upper surface of the second piezoelectric layer;

[0149] The boundary of the cavity is outside the non-electrode connecting end of the first bottom electrode in the horizontal direction and has a first distance therefrom; and

[0150] The boundary of the cavity is outside the inner edge of the second wing bridge in the horizontal direction and has a second distance therefrom.

[0151] 2. The assembly according to 1, wherein:

[0152] The second wing bridge comprises a second wing provided at the non-electrode connecting end of the second top electrode, and the boundary of the cavity is outside the outer edge of the second wing in the horizontal direction and has a fourth distance therefrom.

[0153] 3. The assembly according to 1, wherein:

[0154] The second wing bridge comprises a non-connecting end second bridge provided at the non-electrode connecting end of the second top electrode, and the boundary of the cavity is between the inner edge and the outer edge of the non-connecting end second bridge in the horizontal direction.

[0155] 4. The assembly according to 1, wherein:

[0156] The second wing bridge comprises a connecting end second bridge provided at the electrode connecting end of the second top electrode, and the boundary of the cavity is between the inner edge and the outer edge of the connecting end second bridge in the horizontal direction.

[0157] 5. The assembly according to 1, wherein:

[0158] The outer edge of the portion of the first bottom electrode between the boundary of the first acoustic mirror and the boundary of the cavity has a third distance from the boundary of the first acoustic mirror in the horizontal direction.

[0159] 6. The assembly according to 1, wherein:

[0160] The outer edge of the portion of the second bottom electrode outside the boundary of the cavity at the non-electrode connecting end has a fifth distance from the boundary of the cavity in the horizontal direction.

[0161] 7. The assembly according to 1, wherein:

[0162] An edge of the non-electrode connecting end of the second bottom electrode is located inside and at a sixth distance from an outer edge of the second cavity in the horizontal direction.

[0163] 8. The assembly according to any one of 1-7, wherein:

[0164] The first top electrode is provided with a first wing bridge portion along an active area of the first resonator, an inner edge of the first wing bridge portion is located inside a boundary of the cavity in the horizontal direction, and a first cavity is provided between the first wing bridge portion and an upper surface of the first piezoelectric layer.

[0165] 9. The assembly according to 8, wherein:

[0166] The first wing bridge portion includes a first wing provided at a non-electrode connecting end of the first top electrode, and a boundary of the cavity is located between an inner edge and an outer edge of the first wing in the horizontal direction.

[0167] 10. The assembly according to 8, wherein:

[0168] The first wing bridge portion includes a non-connecting end first bridge portion provided at a non-electrode connecting end of the first top electrode, and a boundary of the cavity is located between an inner edge and an outer edge of the non-connecting end first bridge portion in the horizontal direction.

[0169] 11. The assembly according to 8, wherein:

[0170] An outer edge of the first cavity is located outside and at a seventh distance from a non-electrode connecting end of the first bottom electrode in the horizontal direction.

[0171] 12. The assembly according to 11, wherein:

[0172] An inner edge of the first cavity is located inside a boundary of the first acoustic mirror in the horizontal direction.

[0173] 13. The assembly according to any one of 8-12, wherein:

[0174] The first wing bridge portion includes a connecting end first bridge portion provided at an electrode connecting end of the first top electrode, and a boundary of the cavity is located between an inner edge and an outer edge of the connecting end first bridge portion in the horizontal direction.

[0175] 14. The assembly according to 8, wherein:

[0176] The second wing bridge portion includes a second wing provided at a non-electrode connecting end of the second top electrode; and

[0177] An outer edge of the first cavity is located outside and at an eighth distance from an outer edge of the second wing in the horizontal direction.

[0178] 15. The assembly according to 1, wherein:

[0179] the resonance frequency of the first resonator is greater than 0.5 GHz and the thickness of the first top electrode is less than and / or

[0180] the resonance frequency of the second resonator is greater than 0.5 GHz and the thickness of the second bottom electrode is less than

[0181] 16. The assembly according to 15, wherein:

[0182] the resonance frequency of the first resonator is greater than 3 GHz and the thickness of the first top electrode is less than and / or

[0183] the resonance frequency of the second resonator is greater than 3 GHz and the thickness of the second bottom electrode is less than

[0184] 17. The assembly according to any one of 1-16, wherein:

[0185] the first top electrode and the second bottom electrode are electrically connected to each other.

[0186] 18. The assembly according to 17, wherein:

[0187] the assembly is the assembly according to any one of 8-14;

[0188] the first wing bridge portion comprises a horizontal portion above the first cavity, the second bottom electrode at least partially covering and electrically connected to the horizontal portion.

[0189] 19. The assembly according to 18, wherein:

[0190] the length of the connection path at which the first top electrode and the second bottom electrode are electrically connected to each other at the electrode non-connection end is less than 5 pm.

[0191] the first top electrode and the second bottom electrode are electrically isolated from each other.

[0192] 21. The assembly according to 20, wherein:

[0193] the assembly comprises a first electrode layer and a second electrode layer;

[0194] the first electrode layer comprises the first top electrode and a non-top electrode layer electrically isolated from the first top electrode outside the non-electrode connection end of the first top electrode;

[0195] The second electrode layer includes a second bottom electrode and a non-bottom electrode layer electrically isolated from the non-electrode connection end of the second bottom electrode and located outside the non-electrode connection end of the second bottom electrode;

[0196] The electrode connection end of the second bottom electrode covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode connection end of the first top electrode.

[0197] 22. The assembly of 20, wherein:

[0198] An end portion of at least a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is disposed on the upper surface of the first piezoelectric layer, and the end portion is located inside the non-electrode connection end of the first top electrode in the horizontal direction.

[0199] 23. The assembly of 22, wherein:

[0200] An end portion of a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is disposed on the upper surface of the first piezoelectric layer, and an end portion of another portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is located inside the boundary of the acoustic decoupling layer in the horizontal direction.

[0201] 24. A bulk acoustic wave resonator assembly, comprising:

[0202] a substrate;

[0203] at least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked in a thickness direction of the substrate on one side of the substrate, the at least two resonators including a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror, the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror,

[0204] wherein:

[0205] the second top electrode is provided with a wing bridge portion along an effective area of the second resonator, an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the acoustic decoupling layer serving as the second acoustic mirror;

[0206] a boundary of the cavity is located inside the non-electrode connection end of the first bottom electrode in the horizontal direction, and a distance present is in a range of 0 to -10 μm; and

[0207] the boundary of the cavity is located inside an inner edge of the wing bridge portion in the horizontal direction, and a distance present is in a range of 0 to -10 μm.

[0208] 25. A bulk acoustic wave resonator assembly, comprising:

[0209] at least two resonators adjacent and stacked from bottom to top in a thickness direction of the assembly, the at least two resonators being bulk acoustic wave resonators, the at least two resonators including a first resonator and a second resonator,

[0210] wherein:

[0211] a first acoustic decoupling layer in a form of a cavity is provided between the top electrode of the first resonator and the bottom electrode of the second resonator, the cavity serving as an acoustic mirror for the second resonator;

[0212] a boundary of the cavity is outside a non-electrode-connection end of the bottom electrode of the first resonator in a horizontal direction; and

[0213] a boundary of the cavity is outside an inner edge of the second wing bridge portion in the horizontal direction.

[0214] 26. The assembly according to 1 or 24 or 25, wherein:

[0215] the at least two resonators include a first resonator, a second resonator and a third resonator stacked in the thickness direction;

[0216] the first acoustic decoupling layer is between the top electrode of the first resonator and the bottom electrode of the second resonator, a second acoustic decoupling layer in a form of a cavity is between the top electrode of the second resonator and the bottom electrode of the third resonator, the second acoustic decoupling layer constituting an acoustic mirror for the third resonator;

[0217] the top electrode of the third resonator is provided with a third wing bridge portion along an effective area of the third resonator.

[0218] 27. A filter comprising the bulk acoustic wave resonator assembly according to any one of 1-26.

[0219] 28. An electronic device comprising the filter according to 27 or the bulk acoustic wave resonator assembly according to any one of 1-26.

[0220] While embodiments of the present application have been shown and described with reference to a few embodiments, it will be understood by those skilled in the art that various changes in form and details can be made therein without departing from the spirit and scope of the application which is defined by the appended claims and their equivalents.

Claims

1. A bulk acoustic wave resonator assembly, comprising: substrate; At least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked on one side of a substrate in a thickness direction of the substrate, the at least two resonators including a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror, and the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror, in: The second top electrode is provided with a second wing bridge portion along the effective area of ​​the second resonator, an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the cavity serves as the second acoustic mirror, and a second cavity is provided between the second wing bridge portion and the upper surface of the second piezoelectric layer; The boundary of the cavity is located outside the non-electrode connection end of the first bottom electrode in the horizontal direction and has a first distance therefrom; and The boundary of the cavity is located outside the inner edge of the second wing bridge portion in the horizontal direction and has a second distance therefrom; The first top electrode is provided with a first wing bridge portion along the effective area of ​​the first resonator, the inner edge of the first wing bridge portion is located on the inner side of the boundary of the cavity in the horizontal direction, and a first cavity is provided between the first wing bridge portion and the upper surface of the first piezoelectric layer.

2. The assembly according to claim 1, wherein: The second wing bridge portion includes a second cantilevered wing provided at the non-electrode connection end of the second top electrode, and the boundary of the cavity is located outside the outer edge of the second cantilevered wing in the horizontal direction and has a fourth distance therefrom.

3. The assembly of claim 1 , wherein: The second wing bridge portion includes a non-connection end second bridge portion provided at the non-electrode connection end of the second top electrode, and the boundary of the cavity is located between the inner edge and the outer edge of the non-connection end second bridge portion in the horizontal direction.

4. The assembly of claim 1 , wherein: The second wing bridge portion includes a second bridge portion of the connection end provided at the electrode connection end of the second top electrode, and the boundary of the cavity is located between the inner edge and the outer edge of the outer edge of the second bridge portion of the connection end in the horizontal direction.

5. The assembly of claim 1 , wherein: An outer edge of a portion of the first bottom electrode between a boundary of the first acoustic mirror and a boundary of the cavity in the horizontal direction has a third distance from the boundary of the first acoustic mirror in the horizontal direction.

6. The assembly of claim 1 , wherein: At the electrode connection end of the first bottom electrode, an outer edge of a portion of the non-electrode connection end of the second bottom electrode outside the boundary of the cavity is at a fifth distance from the boundary of the cavity in the horizontal direction.

7. The assembly of claim 1 , wherein: The edge of the non-electrode connection end of the second bottom electrode is located on the inner side of the outer edge of the second cavity in the horizontal direction and has a sixth distance therefrom.

8. The assembly of claim 1 , wherein: The first wing bridge portion includes a first cantilever provided at the non-electrode connection end of the first top electrode, and the boundary of the cavity is located between the inner edge and the outer edge of the first cantilever in the horizontal direction.

9. The assembly of claim 1 , wherein: The first wing bridge portion includes a non-connection end first bridge portion provided at the non-electrode connection end of the first top electrode, and the boundary of the cavity is located between the inner edge and the outer edge of the non-connection end first bridge portion in the horizontal direction.

10. The assembly of claim 1, wherein: The outer edge of the first cavity is located outside the non-electrode connection end of the first bottom electrode in the horizontal direction and is at a seventh distance therefrom.

11. The assembly of claim 10, wherein: The inner edge of the first cavity is located inside the boundary of the first acoustic mirror in the horizontal direction.

12. The assembly of claim 8, wherein: The first wing bridge portion includes a first bridge portion of a connection end provided at the electrode connection end of the first top electrode, and the boundary of the cavity is located between the inner edge and the outer edge of the outer edge of the first bridge portion of the connection end in the horizontal direction.

13. The assembly of claim 1 , wherein: The second wing bridge portion includes a second cantilevered wing provided at a non-electrode connection end of the second top electrode; and The outer edge of the first cavity is located outside the outer edge of the second cantilever in the horizontal direction and has an eighth distance (d12) therefrom.

14. The assembly of claim 1, wherein: The resonant frequency of the first resonator is greater than 0.5 GHz, the thickness of the first top electrode is less than 5000 Å and / or The resonant frequency of the second resonator is greater than 0.5 GHz, and the thickness of the second bottom electrode is less than 5000 Å.

15. The assembly of claim 14, wherein: The resonant frequency of the first resonator is greater than 3 GHz, the thickness of the first top electrode is less than 2000 Å and / or The resonant frequency of the second resonator is greater than 3 GHz, and the thickness of the second bottom electrode is less than 2000 Å.

16. The assembly according to any one of claims 1 to 15, wherein: The first top electrode and the second bottom electrode are electrically connected to each other.

17. An assembly according to any one of claims 8 to 13, wherein: The first wing bridge portion includes a horizontal portion above the first cavity, and the second bottom electrode at least partially covers and is electrically connected to the horizontal portion.

18. The assembly of claim 17, wherein: The length of a connection path electrically connecting the first top electrode and the second bottom electrode to each other at the electrode non-connection end is less than 5 μm.

19. The assembly of claim 1, wherein: The first top electrode and the second bottom electrode are electrically isolated from each other.

20. The assembly of claim 19, wherein: The assembly includes a first electrode layer and a second electrode layer; The first electrode layer includes a first top electrode and a non-top electrode layer electrically isolated from the non-electrode connection end of the first top electrode and located outside the non-electrode connection end of the first top electrode; The second electrode layer includes a second bottom electrode and a non-bottom electrode layer electrically isolated from the non-electrode connection end of the second bottom electrode and located outside the non-electrode connection end of the second bottom electrode; The electrode connection end of the second bottom electrode covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode connection end of the first top electrode.

21. The assembly of claim 19, wherein: At least a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is disposed on the upper surface of the first piezoelectric layer, and the end is located outside the non-electrode connection end of the first top electrode in the horizontal direction.

22. The assembly of claim 21, wherein: An end portion of a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is arranged on the upper surface of the first piezoelectric layer, and an end portion of another portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is located on the inner side of the boundary of the acoustic decoupling layer in the horizontal direction.

23. The assembly of claim 1, wherein: The at least two resonators include a first resonator, a second resonator, and a third resonator stacked in a thickness direction; A first acoustic decoupling layer is provided between the top electrode of the first resonator and the bottom electrode of the second resonator, a second acoustic decoupling layer in the form of a cavity is provided between the top electrode of the second resonator and the bottom electrode of the third resonator, and the second acoustic decoupling layer constitutes an acoustic mirror of the third resonator; The top electrode of the third resonator is provided with a third wing bridge portion along the active area of ​​the third resonator.

24. A bulk acoustic wave resonator assembly comprising: substrate; At least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked on one side of a substrate in a thickness direction of the substrate, the at least two resonators including a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror, and the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror, in: The second top electrode is provided with a second wing bridge portion along the effective area of ​​the second resonator, and an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, and the acoustic decoupling layer serves as the second acoustic mirror; The boundary of the cavity is located inside the non-electrode connection end of the first bottom electrode in the horizontal direction, and the distance therebetween is in the range of 0 to 10 μm; and The boundary of the cavity is located on the inner side of the inner edge of the second wing bridge portion in the horizontal direction, and the distance therebetween is in the range of 0 to 10 μm; The first top electrode is provided with a first wing bridge portion along the effective area of ​​the first resonator, the inner edge of the first wing bridge portion is located on the inner side of the boundary of the cavity in the horizontal direction, and a first cavity is provided between the first wing bridge portion and the upper surface of the first piezoelectric layer.

25. The assembly of claim 24, wherein: The at least two resonators include a first resonator, a second resonator, and a third resonator stacked in a thickness direction; A first acoustic decoupling layer is provided between the top electrode of the first resonator and the bottom electrode of the second resonator, a second acoustic decoupling layer in the form of a cavity is provided between the top electrode of the second resonator and the bottom electrode of the third resonator, and the second acoustic decoupling layer constitutes an acoustic mirror of the third resonator; The top electrode of the third resonator is provided with a third wing bridge portion along the active area of ​​the third resonator.

26. A filter comprising the BAW resonator assembly according to any one of claims 1 to 25.

27. An electronic device comprising the filter according to claim 26 or the BAW resonator assembly according to any one of claims 1 to 25.

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