Bulk acoustic wave resonator assembly and filter

Abstract

A bulk acoustic wave resonator assembly comprises at least two resonators arranged on the same substrate, each resonator comprises an acoustic mirror structure, a bottom electrode, a piezoelectric layer and a top electrode, and an overlapping area of the acoustic mirror structure, the bottom electrode, the piezoelectric layer and the top electrode in the direction perpendicular to the substrate forms an effective area of the resonator; the at least two resonators comprise a first resonator and a second resonator, the first resonator comprises an annular first effective area, and the second resonator comprises a second effective area; the second effective area is nested in the annular first effective area, the first effective area and the second effective area are connected in parallel through a plurality of groups of connecting parts, and each group of connecting parts comprises an input end and an output end. According to the bulk acoustic wave resonator, through nested connection of the two resonators, compared with conventional side-by-side connection, the occupied area is smaller, the heat dissipation effect of the nested resonator assembly is better, and nonlinearity of the resonators can be effectively reduced.

Description

Technical Field

[0001] The present application relates to the field of communication devices, and primarily to a bulk acoustic wave resonator component and a filter. Background Art

[0002] BAW filters, due to their low insertion loss, high squareness factor, and high power handling, are widely used in modern wireless communication systems. They are crucial components in determining the quality of RF signals entering and exiting these systems. BAW filters are constructed from BAW resonators connected in a cascaded fashion, so the performance of each resonator ultimately affects the performance of the filter.

[0003] Ideally, the performance of a bulk acoustic wave resonator is proportional to its input power. However, for higher powers, the ratio between power and resonator performance is no longer proportional, and the characteristic curve of the resonator becomes defective, i.e., it becomes nonlinear. If the resonator in the filter generates nonlinear components when an RF signal is input, the performance of the communication system will deteriorate. The nonlinear splitting structure in the prior art generally splits the resonator into two resonators and connects them in parallel to the circuit. The RF signal is input to the upper and lower electrodes of the two split resonators respectively, so that the nonlinear components of the two resonators with the same amplitude and opposite phase cancel each other out, thereby eliminating nonlinearity. However, due to the mutual influence between the two resonators, the nonlinear components cannot be completely offset. Utility Model Content

[0004] In order to solve the above technical problems existing in the prior art, the present invention proposes a bulk acoustic wave resonator component and a filter to solve the above problems.

[0005] One aspect of the present invention provides a bulk acoustic wave resonator assembly, comprising at least two resonators disposed on the same substrate, each resonator comprising: an acoustic mirror structure, a bottom electrode, a piezoelectric layer, and a top electrode, wherein the overlapping region of the acoustic mirror structure, the bottom electrode, the piezoelectric layer, and the top electrode in a direction perpendicular to the substrate constitutes an effective region of the resonator;

[0006] The at least two resonators include a first resonator and a second resonator. The first resonator includes a first annular active region, and the second resonator includes a second active region. The second active region is nested within the annular first active region. The first and second active regions are connected in parallel via multiple sets of connecting portions, each of which includes an input and an output. The nested arrangement of the two resonators' active regions and their parallel connection lays the structural foundation for subsequent performance reduction, such as minimizing nonlinearity and optimizing heat dissipation.

[0007] In some embodiments, the first effective area and the second effective area have different shapes in a direction parallel to the substrate and have the same area. By virtue of this arrangement, the mutual influence between the two resonators can be greatly reduced, thereby helping to eliminate the nonlinearity of the resonators and improve the performance stability of the resonators under different input powers.

[0008] In some embodiments, the outer edge of the second effective area is a circular structure, and the inner edge is an elliptical structure, or the inner edge and the outer edge are concentric or non-concentric. This particular shape design further enhances the difference between the two resonators and better achieves the effect of reducing mutual influence and nonlinearity.

[0009] In some embodiments, the inner and outer edges of the effective area of the first resonator are polygonal structures. More shape options are provided, increasing the flexibility of the design. Under the premise of meeting the same area and different shapes of the effective area, adjustments can be made according to different application requirements and manufacturing process conditions to further optimize the performance of the resonator.

[0010] In some embodiments, the connecting part includes at least three groups. By reasonably setting the number and connection method of the connecting part, the electrical interaction between the two resonators can be better balanced, and the increase in nonlinearity caused by unreasonable connection can be reduced.

[0011] In some embodiments, the first resonator includes a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first cavity, and in a direction parallel to the substrate, the first top electrode, the first bottom electrode, and the first cavity are all ring-shaped structures. This ring-shaped structure is conducive to heat dissipation, greatly reducing the distance between the heat center of the ring-shaped resonator and the substrate, thereby improving the heat dissipation efficiency and further reducing the nonlinearity, while also facilitating process control and integration during the manufacturing process.

[0012] In some embodiments, the second resonator includes a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second cavity, and the second top electrode and the second cavity are ring-shaped structures. This structure design cooperates with the first resonator to meet the overall nested structure and performance requirements, facilitate manufacturing and integration, and is conducive to optimizing the electrical and thermal performance between the two resonators.

[0013] In some embodiments, the first cavity and the second cavity are connected to each other, and the sacrificial layer in the first cavity and the second cavity is released through a release channel provided on the substrate. This design can simplify the manufacturing process, reduce the complexity in the manufacturing process, improve production efficiency, and also help to ensure the consistency of the electrical and thermal performance of the two cavity structures.

[0014] In some embodiments, the first cavity and the second cavity are disconnected, and the sacrificial layers in the first and second cavities are released separately through release channels on the substrate adjacent to the first and second cavities. This arrangement allows for better control of the electrical and thermal properties of the two cavities and reduces mutual interference.

[0015] Another aspect of the present invention provides a filter, comprising the bulk acoustic wave resonator component as described above.

[0016] A bulk acoustic wave resonator assembly of the utility model can reduce the nonlinearity of the resonator assembly by nesting the effective areas of two resonators of equal area and reversely connecting multiple groups of connecting parts in parallel; the nested resonator assembly has a better heat dissipation effect, further reducing the nonlinear problem; further, multiple connecting parts are set between the two resonators, which can also further reduce the nonlinearity of the resonator; the nested resonator assembly occupies a smaller area than conventional structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate the embodiments and, together with the description, serve to explain the principles of the present invention. Other embodiments and many of the expected advantages of the embodiments will be readily apparent as they become better understood by reference to the following detailed description. The elements of the drawings are not necessarily to scale with respect to each other. Like reference numerals designate corresponding similar parts.

[0018] Figure 1 A schematic structural diagram of a bulk acoustic wave resonator with a nonlinear split structure in the prior art;

[0019] Figure 2 is a top view of a bulk acoustic wave resonator assembly according to an embodiment of the present invention;

[0020] Figure 3 This is a specific embodiment of the present invention Figure 2 BB' cross-sectional view of the bulk acoustic wave resonator assembly;

[0021] Figure 4 is a top view of a cavity structure of a resonator assembly according to a specific embodiment of the present invention;

[0022] Figure 5 is a top view of a bulk acoustic wave resonator assembly according to a second specific embodiment of the present invention;

[0023] Figure 6 It is a top view of a bulk acoustic wave resonator assembly according to a third specific embodiment of the present utility model. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely for the purpose of explaining the relevant utility model and are not intended to limit the utility model. It should also be noted that, for ease of description, only portions relevant to the relevant utility model are shown in the accompanying drawings.

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] Figure 1 The schematic diagram of the structure of the BAW resonator with nonlinear split structure in the prior art is shown as follows: Figure 1 As shown, the nonlinear splitting structure in the prior art splits the resonator S1 into resonator S2 and resonator S3, S2 and S3 are connected in parallel to the circuit, and the radio frequency signal is input to the upper and lower electrodes of the two split resonators respectively, so that the nonlinear components with the same amplitude and opposite phase generated by the resonators S2 and S3 are offset, thereby eliminating the nonlinearity. However, due to the mutual influence between the resonators S2 and S3, the nonlinear components cannot be completely offset.

[0027] This application proposes a nested resonator assembly structure. Figure 2 A top view of a bulk acoustic wave resonator assembly according to an embodiment of the present invention is shown. Figure 2 As shown, the first resonator S4 and the second resonator S5 are nested. The first resonator S4 is an annular structure arranged outside the second resonator S5. The first resonator S4 and the second resonator S5 are connected in parallel through multiple connecting parts. Specifically, the effective area A2 of the second resonator S5 is nested inside the annular effective area A1 of the first resonator S4. The effective area A1 and the effective area A2 are connected in parallel through multiple groups of connecting parts (in this embodiment, 3 groups of connecting parts are taken as an example), wherein each group of connecting parts includes an input end and an output end. The nested setting scheme of the effective areas of the two resonators and the parallel connection mode of multiple groups of connecting parts lay the structural foundation for the subsequent reduction of nonlinearity and optimization of heat dissipation and other performance.

[0028] In a specific embodiment, Figure 1 Compared with the prior art, the total area before and after the split remains unchanged, but in the prior art, the two resonators are placed horizontally, which increases the lateral width of the resonator assembly and occupies a larger area when forming a filter. However, in the nested resonator assembly of the present application, the lateral width of the resonator is slightly increased due to the addition of the first resonator S4 on the outside of the second resonator S5, and the filter is more convenient to adjust when arranged.

[0029] In a specific embodiment, the active area A1 of the first resonator S4 is connected to the active area A2 of the second resonator S5. A1 is an annular active area with irregular polygonal inner and outer edges, while A2 is an annular active area with circular inner and outer edges. This creates a nested split resonator assembly, with active areas A1 and A2 having the same area. The different shapes of A1 and A2 significantly minimize the influence between the two resonators, thereby eliminating resonator nonlinearity.

[0030] Continue to refer Figure 3 , Figure 3 A specific embodiment of the present invention is shown. Figure 2 The BAW resonator assembly BB' cross-sectional view is as shown in FIG. Figure 3 As shown, the first resonator S4 includes a first top electrode 51, a first piezoelectric layer 41, a first bottom electrode 31 and a first cavity 21, and the first top electrode 51, the first bottom electrode 31 and the first cavity 21 are all annular structures. The distance between the heating center of the annular resonator and the substrate is greatly reduced, so that the heat dissipation effect of the annular resonator is better, the performance of the resonator is more stable, and the nonlinear components generated are greatly reduced. The second resonator S5 includes a second top electrode 52, a second piezoelectric layer 42, a second bottom electrode 32 and a second cavity 22. Preferably, the second top electrode 52 and the second cavity 22 are annular structures. Through the above arrangement, the annular structure of the first resonator S4 is conducive to heat dissipation, so that the distance between the heating center of the annular resonator and the substrate is greatly reduced, thereby improving the heat dissipation efficiency and further reducing nonlinearity. The structure of the second resonator S5 cooperates with the first resonator S4 to meet the overall nested structure and performance requirements, and also facilitates process control and integration during the manufacturing process.

[0031] Figure 4 FIG. 1 shows a top view of a cavity structure of a resonator assembly according to a specific embodiment of the present invention, as shown in FIG. Figure 4 As shown, the resonator assembly includes substrates 1a, 1b, and 1c, forming two cavities 2a and 2b, where cavity 2a corresponds to Figure 3 The ring structure of the cavity 21 of the first resonator S4, the cavity 2b corresponds to Figure 3The annular structure of the cavity 22 of the second resonator S5. The two cavities can be interconnected or disconnected, that is, the sacrificial layers in the two cavities can be released simultaneously or separately. In this embodiment, it is in a disconnected state, including two release channels 6a and 6b, wherein the release channel 6a is arranged on the side wall of the substrate 1b, and the release channel 6a extends from the cavity 2a to the direction of the substrate 1b, and passes through the side wall of the substrate 1b in the longitudinal direction of the substrate, and above the release channel 6a, the release hole 7a passes through the membrane layer (including the piezoelectric layer or the piezoelectric layer and the bottom electrode) and is connected to the release channel 6a for releasing the sacrificial layer in the cavity. The release channel 6b is arranged on the substrate 1c, and its structure is the same as 6a, and a release hole 7b is provided above the release channel 6b. The separate release of the sacrificial layers in the disconnected state can better control the electrical and thermal properties of the two cavities and reduce mutual interference.

[0032] In other embodiments, cavities 2a and 2b can also be interconnected, with a release channel extending parallel to the substrate 1b, allowing cavities 2a and 2b to communicate and simultaneously releasing the sacrificial layer. This design can simplify the manufacturing process, reduce complexity, and improve production efficiency. It also helps ensure consistency in the electrical and thermal performance of the two cavity structures.

[0033] In a specific embodiment, at least three groups of connection parts are provided between the first resonator S4 and the second resonator S5, and each group of connection parts has two connection points (i.e., one input end and one output end). This arrangement can reduce the nonlinearity of the resonator. Figure 1 and 2 The first resonator S4 and the second resonator S5 are connected in parallel via three sets of connections (EE', FF', and GG'). Taking one set of connections EE' as an example, connection E connects the first top electrode 51 of the first resonator S4 to the second bottom electrode 32 of the second resonator S5. Connection E' connects the first bottom electrode 31 of the first resonator S4 to the second top electrode 52 of the second resonator S5. The connection relationship between FF' and GG' is the same as that between EE'. RF signals are input from the first bottom electrode 31 of the first resonator S4 and output from the first top electrode 51 of the first resonator S4.

[0034] Figure 5 FIG. 4 shows a top view of a bulk acoustic wave resonator assembly according to a second specific embodiment of the present invention, Figure 6 FIG1 shows a top view of a bulk acoustic wave resonator assembly according to a third specific embodiment of the present invention, and shows two schematic structural diagrams of the effective area A2 of the second resonator S5, as shown in FIG1. Figure 5 As shown, in the aforementioned embodiment, the outer edge of the effective area A2 of the second resonator S5 is a circular structure, and the inner edge is a circular structure concentric with the outer edge. Figure 5 In the embodiment of the present invention, the inner edge of the effective area A2 of the second resonator S5 is set to a circular structure that is not concentric with the outer edge. Figure 6 In the embodiment, the inner edge of the effective area A2 of the second resonator S5 is set to an elliptical structure. The present application provides a variety of shape options, which increases the flexibility of the design. On the premise that the effective area is the same and the shape is different, it can be adjusted according to different application requirements and manufacturing process conditions to further optimize the performance of the resonator.

[0035] The BAW resonator assembly of the present application is split into two resonators of equal area, nested and connected in reverse parallel, which can reduce the nonlinearity of the resonator assembly. The shapes of the inner and outer resonators are different, effectively reducing the nonlinearity of each resonator. Furthermore, at least three groups of six connecting parts are provided between the two resonators, further reducing the nonlinearity of the resonator. The nested resonators have better heat dissipation effect, further reducing nonlinear problems. The nested resonator assembly occupies a smaller area than conventional structures. The present application also proposes a filter including the above-mentioned BAW resonator assembly, which has the corresponding characteristics of the above-mentioned BAW resonator assembly.

[0036] The above describes the specific embodiments 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 this 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.

[0037] In the description of this application, it should be understood that the terms "upper", "lower", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limiting this application. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of multiple such elements. The simple fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used for improvement. Any reference signs in the claims should not be interpreted as limiting the scope.

Claims

1. A bulk acoustic wave resonator assembly comprising at least two resonators disposed on a common substrate, each resonator comprising: an acoustic mirror structure, a bottom electrode, a piezoelectric layer, and a top electrode, wherein the overlapping area of ​​the acoustic mirror structure, the bottom electrode, the piezoelectric layer, and the top electrode in a direction perpendicular to the substrate constitutes an effective area of ​​the resonator; It is characterized in that at least two resonators include a first resonator and a second resonator, the first resonator includes a first annular effective area, and the second resonator includes a second effective area; the second effective area is nested inside the first annular effective area, and the first effective area and the second effective area are connected in parallel through multiple groups of connecting parts, wherein each group of the connecting parts includes an input end and an output end.

2. The BAW resonator assembly according to claim 1, wherein: The first active region and the second active region have different shapes in a direction parallel to the substrate and have the same area.

3. The BAW resonator assembly according to claim 2, wherein: The outer edge of the second effective area is a circular structure; the inner edge is an elliptical structure, or the inner edge and the outer edge are concentric circle structures or non-concentric circle structures.

4. The BAW resonator assembly according to claim 2, wherein: The inner and outer edges of the effective area of ​​the first resonator are both polygonal structures.

5. The BAW resonator assembly according to claim 1, wherein: The connecting parts include at least three groups.

6. The BAW resonator assembly according to claim 1, wherein: The first resonator includes a first top electrode, a first piezoelectric layer, a first bottom electrode and a first cavity. In a direction parallel to the substrate, the first top electrode, the first bottom electrode and the first cavity are all annular structures.

7. The BAW resonator assembly according to claim 6, wherein: The second resonator includes a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second cavity. The second top electrode and the second cavity are ring structures.

8. The BAW resonator assembly according to claim 7, wherein: The first cavity and the second cavity are communicated with each other, and the sacrificial layers in the first cavity and the second cavity are released simultaneously through a release channel provided on the substrate.

9. The BAW resonator assembly according to claim 7, wherein: The first cavity and the second cavity are not connected, and the sacrificial layers of the first cavity and the second cavity are released respectively through release channels on the substrate adjacent to the first cavity and the second cavity.

10. A filter, characterized in that: The device comprises a bulk acoustic wave resonator assembly according to any one of claims 1 to 9.

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