Bulk acoustic wave resonator assembly, filter, and electronic device

Abstract

The present application relates to a bulk acoustic wave resonator assembly including two bulk acoustic wave resonators. The bulk acoustic wave resonator includes a substrate, a resonator structure including a piezoelectric layer, a bottom electrode and a top electrode, a support layer disposed between the substrate and the resonator structure, and an acoustic mirror disposed between the support layer and the resonator structure. The material of the support layer is a material having a dielectric constant less than silicon. The present application also relates to a filter and an electronic device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the semiconductor field, and more particularly to a bulk acoustic wave resonator assembly, a filter including the bulk acoustic wave resonator assembly, and an electronic device including the bulk acoustic wave resonator assembly or the filter. Background Technology

[0002] With the rapid development of 5G communication technology, the requirements for communication frequency bands are becoming increasingly stringent. Traditional radio frequency filters, limited by their structure and performance, cannot meet the requirements of high-frequency communication. Thin-film bulk acoustic resonators (FBARs), as a novel MEMS device, have advantages such as small size, light weight, low insertion loss, wide bandwidth, and high quality factor, making them well-suited for the upgrading of wireless communication systems and making FBAR technology one of the research hotspots in the field of communication.

[0003] The main structure of a thin-film bulk acoustic resonator (FBAR) is a "sandwich" structure consisting of an electrode-piezoelectric thin film-electrode, that is, a piezoelectric material sandwiched between two layers of metal electrodes. By inputting a sinusoidal signal between the two electrodes, the FBAR uses the inverse piezoelectric effect to convert the input electrical signal into mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output.

[0004] For ease of use, multiple bulk acoustic wave resonators are usually manufactured on the same substrate to form a bulk acoustic wave resonator assembly.

[0005] Figure 16 This is a schematic cross-sectional view of a bulk acoustic resonator assembly in the prior art. Figure 16 In the existing bulk acoustic resonator assembly shown, the resonant structure, including the piezoelectric layer 109, bottom electrode 107, and top electrode 111, is directly supported on the substrate 101. That is, there is no support layer between the resonant structure and the substrate 101. The acoustic mirror 103 is a cavity embedded in the substrate 101. Figure 16 In the prior art shown, under ideal conditions, the linearity will be greatly improved after the two bulk acoustic resonators are connected in reverse; however, due to the parasitic capacitance Cp in the substrate of the bulk acoustic resonator, this connection structure cannot effectively suppress nonlinearity. Summary of the Invention

[0006] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.

[0007] According to one aspect of an embodiment of the present invention, a bulk acoustic resonator assembly is provided, comprising two bulk acoustic resonators, said bulk acoustic resonators comprising:

[0008] Base;

[0009] The resonant structure includes a piezoelectric layer, a bottom electrode, and a top electrode;

[0010] A support layer is disposed between the substrate and the resonant structure; and

[0011] An acoustic mirror is disposed between the support layer and the resonant structure.

[0012] in:

[0013] The material of the support layer is a material with a dielectric constant less than that of silicon.

[0014] According to another aspect of the embodiments of the present invention, a filter including the aforementioned bulk acoustic resonator assembly is also provided.

[0015] According to another aspect of the present invention, an electronic device including the aforementioned bulk acoustic resonator assembly or filter is also provided. Attached Figure Description

[0016] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:

[0017] Figure 1 A plan view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention;

[0018] Figure 2 for Figure 1 A cross-sectional view along the cutting line AA'.

[0019] Figure 3 for Figure 1-2 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0020] Figure 4 For the reason Figure 2 The schematic diagram of a filter circuit composed of a bulk acoustic resonator component is shown.

[0021] Figure 5 A schematic cross-sectional view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention;

[0022] Figure 6 A schematic cross-sectional view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention;

[0023] Figure 7 A schematic cross-sectional view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention;

[0024] Figure 8 A schematic cross-sectional view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention;

[0025] Figure 9 A plan view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention.

[0026] Figure 10 for Figure 9 A cross-sectional view along the cutting line AA'.

[0027] Figure 11 for Figure 9-10 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0028] Figure 12 A plan view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention;

[0029] Figure 13 for Figure 12 A cross-sectional view along the cutting line AA'.

[0030] Figure 14 for Figure 12 A cross-sectional view along the cutting line BB'.

[0031] Figure 15 for Figure 12-14 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0032] Figure 16 This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly in the prior art. Detailed Implementation

[0033] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0034] First, the reference numerals in the accompanying drawings of this invention are explained as follows:

[0035] 101: Substrate. Used to support and enclose acoustic devices; materials typically include single-crystal silicon, quartz, gallium arsenide, or sapphire, etc.

[0036] 103: Acoustic Mirror. The acoustic mirror is located on the upper surface of the substrate or embedded inside the substrate. In the illustrated embodiment, the acoustic mirror is a cavity located on the upper surface of the substrate and embedded in the support layer, but any other acoustic mirror structure, such as a Bragg reflector layer, is equally applicable.

[0037] 105: Support layer. The material is a material with a dielectric constant less than that of silicon, including but not limited to one or more combinations of ALN or doped ALN, silicon oxide or doped silicon dioxide, PSG, BPSG, BSG, silicon nitride, silicon carbide, porous silica, fluorinated amorphous carbon, fluoropolymer, parylene, polyarylene ether, silsesquioxane (HSQ), cross-linked polyphenylene polymer (SiLK), bis(phenylcyclobutene) (BCB), fluorinated silicon dioxide, carbon doped oxide, or diamond-like carbon.

[0038] 105A: Support rib, a component of the support layer.

[0039] 107: Bottom electrode. The bottom electrode material can be formed from: gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), titanium-tungsten (TiW), aluminum (Al), titanium (Ti), osmium (Os), magnesium (Mg), gold (Au), tungsten (W), molybdenum (Mo), platinum (Pt), ruthenium (Ru), iridium (Ir), germanium (Ge), copper (Cu), aluminum (Al), chromium (Cr), arsenic-doped gold, and similar metals.

[0040] 109: Piezoelectric layer. The piezoelectric layer can be a single-crystal piezoelectric layer, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate, single-crystal potassium niobate, single-crystal quartz film, or single-crystal lithium tantalate, etc. It can also be a polycrystalline piezoelectric layer, such as polycrystalline aluminum nitride, zinc oxide, PZT, etc. It can also contain rare earth element doping materials with a certain atomic ratio of the above materials, such as doped aluminum nitride, which contains 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), lutetium (Lu), etc.

[0041] 111: Top electrode. Materials can include molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or composites or alloys of these metals. The top and bottom electrodes are generally made of the same material, but they can also be different.

[0042] 113: External leads. The material is generally a high-conductivity metal, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite or alloy of the above metals.

[0043] 113': Electrical connection lead. The material is generally a high-conductivity metal, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or a composite or alloy of these metals. In the illustrated embodiment, the electrical connection lead and the external lead are formed by etching the same electrical connection layer.

[0044] 115: Adhesive layer. Its material is a material with a dielectric constant less than that of silicon, including but not limited to one or more combinations of ALN or doped ALN, silicon oxide or doped silicon dioxide, PSG, BPSG, BSG, silicon nitride, silicon carbide, porous silica, fluorinated amorphous carbon, fluoropolymer, parylene, Su-8, polyarylene ether, silsesquioxane (HSQ), cross-linked polyphenylene polymer (SiLK), bis(phenylcyclobutene) (BCB), fluorinated silicon dioxide, carbon doped oxide, or diamond-like carbon.

[0045] Figure 1 A plan view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention;

[0046] Figure 2 for Figure 1 A schematic diagram of the cross section along the cutting line AA'.

[0047] like Figure 1 and Figure 2 As shown in the illustrated embodiment, the bulk acoustic wave resonator assembly includes two bulk acoustic wave resonators connected in series. Each bulk acoustic wave resonator mainly includes a substrate 101, a piezoelectric layer 109, a bottom electrode 107, a top electrode 111, an acoustic mirror 103, and a support layer 105. The bottom electrode 107 and the top electrode 111 are respectively disposed on the upper and lower sides of the piezoelectric layer 109, such that the piezoelectric layer 109 is sandwiched between the bottom electrode 107 and the top electrode 111, forming a sandwich-structured resonant structure.

[0048] like Figure 1 and Figure 2 As shown, in the illustrated embodiment, a support layer 105 is disposed on a substrate 101, and the aforementioned resonant structure is supported on the substrate 101.

[0049] like Figure 2 As shown, a support rib 105A is provided between the acoustic mirrors of the two bulk acoustic resonators, and the support rib 105A is provided between the bottom electrode 107 and the substrate 101.

[0050] Figure 3 for Figure 1-2 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0051] like Figures 1 to 3 As shown in the illustrated embodiment, in addition to the original parasitic capacitance Cp in the substrate 101, a parasitic capacitance Cp' also exists in the support layer 105. In the illustrated embodiment, the two parasitic capacitances Cp and Cp' are connected in series, thereby reducing the total parasitic capacitance of the bulk acoustic wave resonator assembly.

[0052] In an exemplary embodiment of the present invention, in order to minimize the total parasitic capacitance of the bulk acoustic wave resonator assembly, the material of the support layer 105 is selected as a material with a low dielectric constant; for example, the material of the support layer 105 can be selected as a material with a dielectric constant less than that of silicon. Therefore, the parasitic capacitance Cp' will be smaller than the parasitic capacitance when the support material is silicon, thereby reducing the total parasitic capacitance.

[0053] See also Figure 3 In the illustrated embodiment, the bulk acoustic resonators on the left and right vibrate in opposite directions, and their nonlinear effects cancel each other out. However, due to the presence of parasitic capacitance Cp, the degree of cancellation of their nonlinear effects is relatively weak. Introducing parasitic capacitance Cp' reduces the influence of the total parasitic capacitance, significantly offsetting the nonlinear effects.

[0054] like Figures 1 to 3 As shown in the illustrated embodiment, the bottom electrodes 107 of the two bulk acoustic wave resonators are integrated, meaning that the two bulk acoustic wave resonators share the same bottom electrode 107. However, the invention is not limited to the illustrated embodiment. For example, the two bulk acoustic wave resonators may each have a separate bottom electrode 107, and the bottom electrodes 107 of the two bulk acoustic wave resonators may be electrically connected to each other via electrical connection leads.

[0055] like Figures 1 to 3 As shown in the illustrated embodiment, each of the two bulk acoustic wave resonators has a separate top electrode 111. The bulk acoustic wave resonator also includes an external lead 113 electrically connected to the top electrode 111. Thus, each top electrode 111 can be connected to an external circuit via a separate external lead 113.

[0056] Figure 4 For the reason Figure 2 The schematic diagram of the filter circuit composed of the bulk acoustic resonator components is shown.

[0057] like Figure 4 As shown in the illustrated embodiment, the filter circuit includes multiple series-connected bulk acoustic wave (BAW) resonators Zs and multiple parallel-connected BAW resonators Zp. Two adjacent BAW resonators can form a BAW resonator assembly, and each BAW resonator assembly can include two BAW resonators Zs and Zp. A parasitic capacitance Cp exists between the two BAW resonators Zs and Zp, which will lead to a significant difference between the actual fabricated filter test results and the simulation results. Introducing the parasitic capacitance Cp' can reduce the influence of the total parasitic capacitance, thereby reducing the difference between the actual fabricated filter test results and the simulation results, and improving the filter performance.

[0058] like Figure 2 As shown in the illustrated embodiment, the acoustic mirror 103 is disposed between the support layer 105 and the bottom electrode 107. Based on the support rib 105A, each of two adjacent bulk acoustic resonators has a separate acoustic mirror 103. If the two separate acoustic mirrors 103 are cavities, they can be either non-communicating cavities or interconnected cavities, both of which are within the scope of protection of this invention. In the illustrated embodiment, the acoustic mirror 103 is a cavity embedded in the support layer 105. However, this invention is not limited to the illustrated embodiment; for example, the acoustic mirror 103 can also be a Bragg reflector layer embedded in the support layer 105. Furthermore, in Figure 2 In one embodiment, the lower side of the acoustic mirror is defined by a support layer 105; however, in an alternative embodiment, it may also be defined by a substrate 101, for example, see [link to relevant documentation]. Figure 6 (If it can be understood, if the substrate 101 also includes an adhesive layer 115, then it is defined by the adhesive layer 115).

[0059] like Figure 2 As shown in the illustrated embodiment, the acoustic mirror 103 of one of the two bulk acoustic resonators is identical to that of the other bulk acoustic resonator. That is, the acoustic mirrors 103 of the two bulk acoustic resonators are exactly the same in size and shape. However, the invention is not limited to the illustrated embodiment, and the acoustic mirrors 103 of the two bulk acoustic resonators may also be different.

[0060] like Figure 2 As shown in the illustrated embodiment, the two bulk acoustic wave resonators share the same substrate 101, the same piezoelectric layer 109, or the same support layer 105. The advantage of this shared structure is that it simplifies the fabrication process of the bulk acoustic wave resonator assembly and reduces manufacturing costs.

[0061] Figure 5This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention.

[0062] Figure 5 The bulk acoustic resonator assembly shown is... Figure 2 The only difference in the bulk acoustic resonator assembly shown is the addition of an adhesive layer 115. The adhesive layer 115 is disposed between the substrate 101 and the support layer 105. Therefore, in Figure 5 In the illustrated embodiment, a parasitic capacitance Cp” exists within the adhesive layer 115. Therefore, the total parasitic capacitance is further reduced when the three parasitic capacitances Cp, Cp’, and Cp” are connected in series. It should be noted that in this invention, the adhesive layer 115 is not necessary; the support layer 105 can be directly disposed on the substrate 101 without being bonded to the substrate 101 through the adhesive layer 115.

[0063] like Figure 2 and Figure 5 As shown in the illustrated embodiment, both ends of the bottom electrode 107 are placed within the support layer 105 and held between the support layer 105 and the piezoelectric layer 109. The bottom surface and boundary sides of the bottom electrode 107 are in contact with and surrounded by the support layer 105, resulting in a relatively large parasitic capacitance from the support layer 105. Therefore, in this invention, a support layer material with a low dielectric constant is required to significantly reduce the parasitic capacitance effect.

[0064] Figure 6 This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention. Figure 7 This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention.

[0065] Figure 6 and Figure 7 The bulk acoustic resonator assembly shown is... Figure 2 The only difference between the bulk acoustic wave resonator assemblies shown is the acoustic mirror 103 of the two bulk acoustic wave resonators. This difference in acoustic mirror 103 is determined by the manufacturing process; for example, for... Figure 6 The structure in the middle can be constructed by first forming a sacrificial material layer corresponding to the cavity of the acoustic mirror 103, then forming a support layer, and finally etching or releasing the sacrificial material layer; while for Figure 7 The structure shown can be formed by first creating a support material layer, and then etching it to form the cavity of the acoustic mirror 103. Figure 6 and Figure 7 The acoustic mirror 103 shown is a cavity embedded in the support layer 105. However, the present invention is not limited to the illustrated embodiment; for example, the acoustic mirror 103 may also be a Bragg reflector layer embedded in the support layer 105.

[0066] like Figure 6 and Figure 7 As shown, in the illustrated embodiment, the acoustic mirror 103 of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator. Figure 6 In the illustrated embodiment, the shape of the acoustic mirror 103 of one of the two bulk acoustic resonators is approximately the same as that of the acoustic mirror 103 of the other bulk acoustic resonator, but their dimensions differ. Figure 7 In the embodiment shown, the shape and size of the acoustic mirror 103 of one of the two bulk acoustic resonators are different from those of the acoustic mirror 103 of the other bulk acoustic resonator.

[0067] Figure 8 This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention.

[0068] like Figure 8 As shown in the illustrated embodiment, the acoustic mirror 103 is disposed between the support layer 105 and the bottom electrode 107, and the two bulk acoustic resonators share the same acoustic mirror 103, which simplifies the manufacturing process of the bulk acoustic resonator assembly and reduces manufacturing costs. Figure 8 The acoustic mirror 103 shown is a cavity embedded in the support layer 105. However, the present invention is not limited to the illustrated embodiment; for example, the acoustic mirror 103 may also be a Bragg reflector layer embedded in the support layer 105.

[0069] like Figure 8 As shown in the illustrated embodiment, the dielectric constant of the air in the cavity of the acoustic mirror 103 is very small, thus further reducing the parasitic capacitance Cp' and ultimately minimizing the total parasitic capacitance.

[0070] Figure 9 A plan view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention. Figure 10 for Figure 9 A schematic diagram of the cross section along the cutting line AA'.

[0071] like Figure 9 and Figure 10 As shown in the illustrated embodiment, the bulk acoustic wave resonator assembly includes two bulk acoustic wave resonators connected in series. Each bulk acoustic wave resonator mainly includes a substrate 101, a piezoelectric layer 109, a bottom electrode 107, a top electrode 111, an acoustic mirror 103, and a support layer 105. The bottom electrode 107 and the top electrode 111 are respectively disposed on the upper and lower sides of the piezoelectric layer 109, such that the piezoelectric layer 109 is sandwiched between the bottom electrode 107 and the top electrode 111, forming a sandwich-structured resonant structure.

[0072] like Figure 9 and Figure 10As shown, in the illustrated embodiment, a support layer 105 is disposed on a substrate 101, and the aforementioned resonant structure is supported on the substrate 101.

[0073] Figure 11 for Figure 9-10 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0074] like Figures 9 to 11 As shown in the illustrated embodiment, in addition to the original parasitic capacitance Cp in the substrate 101, a parasitic capacitance Cp' also exists in the support layer 105. In the illustrated embodiment, the two parasitic capacitances Cp and Cp' are connected in series, thereby reducing the total parasitic capacitance of the bulk acoustic wave resonator assembly.

[0075] In an exemplary embodiment of the present invention, in order to minimize the total parasitic capacitance of the bulk acoustic wave resonator assembly, the support layer 105 is made of a material with a low dielectric constant; for example, the support layer 105 can be made of a material with a dielectric constant less than that of silicon. Therefore, the parasitic capacitance Cp' will be smaller than the parasitic capacitance if the support material is silicon, thus reducing the total parasitic capacitance.

[0076] See also Figure 11 In the illustrated embodiment, the bulk acoustic resonators on the left and right vibrate in opposite directions, and their nonlinear effects cancel each other out. However, due to the presence of parasitic capacitance Cp, the degree of cancellation of their nonlinear effects is relatively weak. Introducing parasitic capacitance Cp' can reduce the influence of the total parasitic capacitance and significantly cancel out the nonlinear effects.

[0077] like Figures 9 to 11 As shown in the illustrated embodiment, the top electrodes 111 of the two bulk acoustic wave resonators are integrated, meaning that the two bulk acoustic wave resonators share the same top electrode 111. However, the invention is not limited to the illustrated embodiment. For example, the two bulk acoustic wave resonators may each have a separate top electrode 111, and the top electrodes 111 of the two bulk acoustic wave resonators may be electrically connected to each other via electrical connection leads.

[0078] like Figures 9 to 11 As shown in the illustrated embodiment, each of the two bulk acoustic wave resonators has a separate bottom electrode 107. The bulk acoustic wave resonator also includes an external lead 113 electrically connected to the bottom electrode 107. Thus, each bottom electrode 107 can be connected to an external circuit via a separate external lead 113. Figure 10 In the embodiment shown, the external lead 113 is a conductive connection structure that penetrates the piezoelectric layer 109.

[0079] like Figure 10As shown, in the illustrated embodiment, the acoustic mirror 103 is disposed between the support layer 105 and the bottom electrode 107, and each of the two bulk acoustic resonators has a separate acoustic mirror 103. In the illustrated embodiment, the acoustic mirror 103 is a cavity embedded in the support layer 105. However, the invention is not limited to the illustrated embodiment; for example, the acoustic mirror 103 may also be a Bragg reflector layer embedded in the support layer 105.

[0080] like Figure 10 As shown in the illustrated embodiment, the acoustic mirror 103 of one of the two bulk acoustic resonators is identical to that of the other bulk acoustic resonator. That is, the acoustic mirrors 103 of the two bulk acoustic resonators are exactly the same in size and shape. However, the invention is not limited to the illustrated embodiment, and the acoustic mirrors 103 of the two bulk acoustic resonators may also be different.

[0081] like Figure 10 As shown in the illustrated embodiment, the two bulk acoustic wave resonators share the same substrate 101, the same piezoelectric layer 109, or the same support layer 105. The advantage of this shared structure is that it simplifies the fabrication process of the bulk acoustic wave resonator assembly and reduces manufacturing costs.

[0082] like Figure 10 As shown in the illustrated embodiment, both ends of the bottom electrode 107 are placed within the support layer 105 and held between the support layer 105 and the piezoelectric layer 109. The bottom surface and boundary sides of the bottom electrode 107 are in contact with and surrounded by the support layer 105, resulting in a relatively large parasitic capacitance from the support layer 105. Therefore, in this invention, a support layer material with a low dielectric constant is required to significantly reduce the parasitic capacitance effect.

[0083] Figure 12 A plan view of a bulk acoustic resonator assembly according to another exemplary embodiment of the present invention. Figure 13 for Figure 12 A schematic diagram of the cross section along the cutting line AA'. Figure 14 for Figure 12 A cross-sectional view along the cutting line BB'.

[0084] like Figures 12 to 14 As shown in the illustrated embodiment, the bulk acoustic wave resonator assembly includes two bulk acoustic wave resonators connected in parallel. Each bulk acoustic wave resonator mainly includes a substrate 101, a piezoelectric layer 109, a bottom electrode 107, a top electrode 111, an acoustic mirror 103, and a support layer 105. The bottom electrode 107 and the top electrode 111 are respectively disposed on the upper and lower sides of the piezoelectric layer 109, such that the piezoelectric layer 109 is sandwiched between the bottom electrode 107 and the top electrode 111, forming a sandwich-structured resonant structure.

[0085] like Figures 12 to 14 As shown, in the illustrated embodiment, a support layer 105 is disposed on a substrate 101, and the aforementioned resonant structure is supported on the substrate 101.

[0086] Figure 15 for Figure 12-14 The circuit diagram of the bulk acoustic resonator assembly is shown.

[0087] like Figures 12 to 15 As shown in the illustrated embodiment, in addition to the original parasitic capacitance Cp in the substrate 101, a parasitic capacitance Cp' also exists in the support layer 105. In the illustrated embodiment, the two parasitic capacitances Cp and Cp' are connected in series, thereby reducing the total parasitic capacitance of the bulk acoustic wave resonator assembly.

[0088] In an exemplary embodiment of the present invention, in order to minimize the total parasitic capacitance of the bulk acoustic wave resonator assembly, the support layer 105 is made of a material with a low dielectric constant; for example, the support layer 105 can be made of a material with a dielectric constant less than that of silicon. Therefore, the parasitic capacitance Cp' will be smaller than the parasitic capacitance if the support material is silicon, thus reducing the total parasitic capacitance.

[0089] See also Figure 15 In the illustrated embodiment, the bulk acoustic resonators on the left and right vibrate in opposite directions, and their nonlinear effects cancel each other out. However, due to the presence of parasitic capacitance Cp, the degree of cancellation of their nonlinear effects is relatively weak. Introducing parasitic capacitance Cp' can reduce the influence of the total parasitic capacitance and significantly cancel out the nonlinear effects.

[0090] like Figures 12 to 15 As shown in the illustrated embodiment, the two bulk acoustic wave resonators each have a separate bottom electrode 107 and a separate top electrode 111. The bottom electrode 107 and top electrode 111 of one of the bulk acoustic wave resonators are electrically connected to the top electrode 111 and bottom electrode 107 of the other bulk acoustic wave resonator, respectively.

[0091] like Figure 13 As shown, the bottom electrode 107 of a bulk acoustic wave resonator on the left is electrically connected to the top electrode 111 of a bulk acoustic wave resonator on the right via an electrical connection 113'. Figure 14 As shown, the bottom electrode 107 of the bulk acoustic wave resonator on the right is electrically connected to the top electrode 111 of the bulk acoustic wave resonator on the left through the electrical connection part 113'.

[0092] like Figures 12 to 15As shown in the illustrated embodiment, the bulk acoustic resonator also includes an external lead 113 electrically connected to the bottom electrode 107. Thus, each bottom electrode 107 can be connected to an external circuit via a separate external lead 113.

[0093] like Figure 13 and Figure 14 As shown in the illustrated embodiment, the external lead 113 and the electrical connection portion 113' can be conductive connection structures formed by etching the same electrical connection layer. In the illustrated embodiment, the external lead 113 is a conductive connection structure covering one end of the top electrode 111, and the electrical connection portion 113' is a conductive connection structure penetrating the piezoelectric layer 109.

[0094] like Figure 13 and Figure 14 As shown, in the illustrated embodiment, the acoustic mirror 103 is disposed between the support layer 105 and the bottom electrode 107, and each of the two bulk acoustic resonators has a separate acoustic mirror 103. In the illustrated embodiment, the acoustic mirror 103 is a cavity embedded in the support layer 105. However, the invention is not limited to the illustrated embodiment; for example, the acoustic mirror 103 may also be a Bragg reflector layer embedded in the support layer 105.

[0095] like Figure 13 and Figure 14 As shown in the illustrated embodiment, the acoustic mirror 103 of one of the two bulk acoustic resonators is identical to that of the other bulk acoustic resonator. That is, the acoustic mirrors 103 of the two bulk acoustic resonators are exactly the same in size and shape. However, the invention is not limited to the illustrated embodiment, and the acoustic mirrors 103 of the two bulk acoustic resonators may also be different.

[0096] like Figure 13 and Figure 14 As shown in the illustrated embodiment, the two bulk acoustic wave resonators share the same substrate 101, the same piezoelectric layer 109, or the same support layer 105. The advantage of this shared structure is that it simplifies the fabrication process of the bulk acoustic wave resonator assembly and reduces manufacturing costs.

[0097] like Figure 13 and Figure 14 As shown in the illustrated embodiment, both ends of the bottom electrode 107 are placed within the support layer 105 and held between the support layer 105 and the piezoelectric layer 109. The bottom surface and boundary sides of the bottom electrode 107 are in contact with and surrounded by the support layer 105, resulting in a relatively large parasitic capacitance from the support layer 105. Therefore, in this invention, a support layer material with a low dielectric constant is required to significantly reduce the parasitic capacitance effect.

[0098] In the aforementioned embodiments of the present invention, a support layer using a support structure material with a low dielectric constant is selected. In addition to the original parasitic capacitance Cp, a parasitic capacitance Cp' existing in the support structure material is added. The two parasitic capacitances are connected in series, thereby reducing the total parasitic capacitance. The selected support material has a lower dielectric constant than silicon; therefore, the parasitic capacitance Cp' is smaller than the parasitic capacitance when the support material is silicon, thus reducing the total parasitic capacitance. The reduction in total parasitic capacitance can alleviate the impact of parasitic capacitance on the deterioration of the filter's electrical performance, especially improving the filter's nonlinearity.

[0099] In the foregoing embodiments of the present invention, for bulk acoustic resonators, reducing parasitic capacitance can improve the Rp value and the effective electromechanical coupling coefficient. For filters, reducing parasitic capacitance can make the test results closer to the simulated structure; by adding multiple resonators in series or parallel reverse connection to the filter, reducing parasitic capacitance can improve the linearity of the filter, especially suppressing the second-order resonance, second-order intermodulation and third-order intermodulation of the filter.

[0100] In this invention, "upper" and "lower" are relative to the bottom surface of the resonator's base. For a component, the side closer to the bottom surface is the lower side, and the side farther from the bottom surface is the upper side.

[0101] In this invention, "inner" and "outer" are relative to the center (i.e., the center of the effective region) of the resonator (the overlapping area of ​​the piezoelectric layer, top electrode, bottom electrode, and acoustic mirror in the thickness direction of the resonator constitutes the effective region) in the lateral or radial direction. A component's side or end closer to the center of the effective region is called the inner side or inner end, while the side or end of the component farther from the center of the effective region is called the outer side or outer end. For a reference position, being inside the position means being between that position and the center of the effective region in the lateral or radial direction, while being outside the position means being farther from the center of the effective region in the lateral or radial direction than that position.

[0102] As will be understood by those skilled in the art, the bulk acoustic resonator assembly according to the present invention can be used to form filters or electronic devices.

[0103] Based on the above, the present invention proposes the following technical solution:

[0104] 1. A bulk acoustic wave resonator assembly, comprising at least two bulk acoustic wave resonators, wherein the bulk acoustic wave resonator includes:

[0105] Base;

[0106] The resonant structure includes a piezoelectric layer, a bottom electrode, and a top electrode;

[0107] A support layer is disposed between the substrate and the resonant structure; and

[0108] An acoustic mirror is disposed between the support layer and the resonant structure.

[0109] in:

[0110] The material of the support layer is a material with a dielectric constant less than that of silicon.

[0111] 2. The component according to 1, wherein:

[0112] The bottom electrodes of the two bulk acoustic resonators are connected or integrated, and each of the two bulk acoustic resonators has a separate top electrode.

[0113] 3. The component according to 2, wherein:

[0114] A support rib is provided between the acoustic mirrors of the two bulk acoustic resonators, and the support rib is located between the bottom electrode and the substrate.

[0115] 4. The component according to 3, wherein:

[0116] The bottom side of the acoustic mirror is defined by the support layer; or

[0117] The bottom side of the acoustic mirror is defined by the substrate.

[0118] 5. The component according to 4, wherein:

[0119] The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

[0120] 6. The component according to claim 2, wherein:

[0121] The acoustic mirror is disposed between the support layer and the bottom electrode, and the two bulk acoustic resonators share the same acoustic mirror.

[0122] 7. The component according to 2, wherein:

[0123] The substrate includes a substrate body and an adhesive layer disposed on the upper side of the substrate body, the adhesive layer being disposed between the substrate body and the support layer.

[0124] 8. The component according to 2, wherein:

[0125] The bulk acoustic resonator also includes an external lead electrically connected to the top electrode.

[0126] 9. The component according to claim 1, wherein:

[0127] The top electrodes of the two bulk acoustic resonators are connected or integrated, and each of the two bulk acoustic resonators has a separate bottom electrode.

[0128] 10. The component according to 9, wherein:

[0129] A support rib is provided between the acoustic mirrors of the two bulk acoustic wave resonators. The support rib is located between the piezoelectric layer and the substrate and separates the bottom electrodes of the two bulk acoustic wave resonators in the horizontal direction.

[0130] 11. The component according to 10, wherein:

[0131] The bottom side of the acoustic mirror is defined by the support layer; or

[0132] The bottom side of the acoustic mirror is defined by the substrate.

[0133] 12. The component according to 11, wherein:

[0134] The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

[0135] 13. The component according to claim 1, wherein:

[0136] The two bulk acoustic resonators each have a separate bottom electrode and a separate top electrode;

[0137] The bottom and top electrodes of one of the two bulk acoustic resonators are electrically connected to the top and bottom electrodes of the other bulk acoustic resonator, respectively.

[0138] 14. The component according to 13, wherein:

[0139] A support rib is provided between the acoustic mirrors of the two bulk acoustic wave resonators. The support rib is located between the bottom electrode and the substrate and separates the bottom electrodes of the two bulk acoustic wave resonators in the horizontal direction.

[0140] 15. The component according to 14, wherein:

[0141] The bottom side of the acoustic mirror is defined by the support layer; or

[0142] The bottom side of the acoustic mirror is defined by the substrate.

[0143] 16. The component according to 15, wherein:

[0144] The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

[0145] 17. The component according to claim 1, wherein:

[0146] The acoustic mirror is either a cavity defined by the support layer with at least a portion of its boundary or a Bragg reflector layer.

[0147] 18. The component according to any one of 1-17, wherein:

[0148] The material of the support layer is one or a combination of two or more of the following: ALN or doped ALN, silicon dioxide or doped silicon dioxide, PSG, BPSG, BSG, silicon nitride, silicon carbide, porous silicon, fluorinated amorphous carbon, fluoropolymer, parylene, polyarylene ether, silsesquioxane, cross-linked polyphenylene polymer, diphenylcyclobutene, fluorinated silicon dioxide, carbon-doped oxide, or diamond.

[0149] 19. The component according to any one of 1-17, wherein:

[0150] The piezoelectric layer is a single-crystal piezoelectric layer;

[0151] The piezoelectric layer is arranged roughly parallel to the substrate.

[0152] 20. A filter comprising any one of the components according to 1-19.

[0153] 21. An electronic device comprising the component according to any one of 1-19, or the filter according to 20.

[0154] The electronic devices mentioned here include, but are not limited to, intermediate products such as radio frequency front-ends and filtering and amplification modules, as well as terminal products such as mobile phones, WIFI, and drones.

[0155] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bulk acoustic wave resonator assembly, comprising at least two bulk acoustic wave resonators, wherein the bulk acoustic wave resonators include: Base; The resonant structure includes a piezoelectric layer, a bottom electrode, and a top electrode; A support layer is disposed between the substrate and the resonant structure; and An acoustic mirror is disposed between the support layer and the resonant structure. in: The material of the support layer is a material with a dielectric constant less than that of silicon; The bottom electrodes of the two bulk acoustic resonators are connected or made into one piece, and each of the two bulk acoustic resonators has a separate top electrode. A support rib is provided between the acoustic mirrors of the two bulk acoustic resonators, and the support rib is located between the bottom electrode and the substrate.

2. The component according to claim 1, wherein: The bottom side of the acoustic mirror is defined by the support layer; or The bottom side of the acoustic mirror is defined by the substrate.

3. The component according to claim 2, wherein: The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

4. The component according to claim 1, wherein: The acoustic mirror is disposed between the support layer and the bottom electrode, and the two bulk acoustic resonators share the same acoustic mirror.

5. The component according to claim 1, wherein: The substrate includes a substrate body and an adhesive layer disposed on the upper side of the substrate body, the adhesive layer being disposed between the substrate body and the support layer.

6. The component according to claim 1, wherein: The bulk acoustic resonator also includes an external lead electrically connected to the top electrode.

7. The component according to claim 1, wherein: The top electrodes of the two bulk acoustic resonators are connected or integrated, and each of the two bulk acoustic resonators has a separate bottom electrode.

8. The component according to claim 7, wherein: A support rib is provided between the acoustic mirrors of the two bulk acoustic wave resonators. The support rib is located between the piezoelectric layer and the substrate and separates the bottom electrodes of the two bulk acoustic wave resonators in the horizontal direction.

9. The component according to claim 8, wherein: The bottom side of the acoustic mirror is defined by the support layer; or The bottom side of the acoustic mirror is defined by the substrate.

10. The component of claim 9, wherein: The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

11. The component according to claim 1, wherein: The two bulk acoustic resonators each have a separate bottom electrode and a separate top electrode; The bottom and top electrodes of one of the two bulk acoustic resonators are electrically connected to the top and bottom electrodes of the other bulk acoustic resonator, respectively.

12. The component of claim 11, wherein: A support rib is provided between the acoustic mirrors of the two bulk acoustic wave resonators. The support rib is located between the bottom electrode and the substrate and separates the bottom electrodes of the two bulk acoustic wave resonators in the horizontal direction.

13. The component of claim 12, wherein: The bottom side of the acoustic mirror is defined by the support layer; or The bottom side of the acoustic mirror is defined by the substrate.

14. The component of claim 13, wherein: The acoustic mirror of one of the two bulk acoustic resonators is different from that of the other bulk acoustic resonator.

15. The component according to claim 1, wherein: The acoustic mirror is either a cavity defined by the support layer with at least a portion of its boundary or a Bragg reflector layer.

16. The component according to any one of claims 1-15, wherein: The material of the support layer is one or a combination of two or more of the following: ALN or doped ALN, silicon dioxide or doped silicon dioxide, PSG, BPSG, BSG, silicon nitride, silicon carbide, porous silicon, fluorinated amorphous carbon, fluoropolymer, parylene, polyarylene ether, silsesquioxane, cross-linked polyphenylene polymer, diphenylcyclobutene, fluorinated silicon dioxide, carbon-doped oxide, or diamond.

17. The component according to any one of claims 1-15, wherein: The piezoelectric layer is a single-crystal piezoelectric layer; The piezoelectric layer is arranged roughly parallel to the substrate.

18. The component according to any one of claims 1-15, wherein: The bottom surface and boundary sides of the bottom electrode are in contact with and surrounded by the support layer.

19. A filter comprising the components according to any one of claims 1-18.

20. An electronic device comprising the component according to any one of claims 1-18, or the filter according to claim 19.

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