Resonator, filter and radio frequency front-end module

Abstract

The utility model discloses a resonator, a filter and a radio frequency front end module, the resonator comprises a piezoelectric substrate, an interdigital transducer and a first dielectric layer, and the interdigital transducer is arranged on a first surface of the piezoelectric substrate; the first dielectric layer covers a partial region of the interdigital transducer. The interdigital transducer comprises two bus bars oppositely arranged on the piezoelectric substrate, a plurality of electrode finger pairs located between the two bus bars and a thickening layer arranged on at least one bus bar; wherein in the first direction, the side face, away from the piezoelectric substrate, of the thickening layer is higher than the side face, away from the piezoelectric substrate, of the first dielectric layer, and the first direction is the thickness direction of the piezoelectric substrate, so that the heat dissipation performance of the bus bar is improved, the heat dissipation efficiency is improved, and the power endurance capacity of the resonator is improved.

Description

Technical Field

[0001] The present application relates to the field of radio frequency filtering technology, and in particular to a resonator, a filter and a radio frequency front-end module. Background Art

[0002] SAW (Surface Acoustic Wave) resonator is the abbreviation of surface acoustic wave resonator. It is a special filtering device made by using its piezoelectric effect and the physical characteristics of surface acoustic wave propagation. It is widely used in various fields, such as the radio frequency field. Among them, the surface acoustic wave is an elastic wave with energy concentrated near the surface. With the increasing complexity of communication systems and application scenarios in today's society, the performance requirements for surface acoustic wave devices are also getting higher and higher.

[0003] Therefore, how to improve the power tolerance of surface acoustic wave resonators has become an urgent problem to be solved. Utility Model Content

[0004] In view of this, the present application proposes a resonator, a filter and a radio frequency front-end module.

[0005] A first aspect of the present application provides a resonator, comprising:

[0006] A piezoelectric substrate having a first surface;

[0007] an interdigital transducer, the interdigital transducer being disposed on the first surface of the piezoelectric substrate; and

[0008] A first dielectric layer, wherein the first dielectric layer covers a partial area of ​​the interdigital transducer;

[0009] The interdigital transducer comprises:

[0010] two bus bars disposed opposite to each other on the piezoelectric substrate;

[0011] a plurality of electrode finger pairs located between the two bus bars, the two bus bars being a first bus bar and a second bus bar, each of the electrode finger pairs comprising first electrode fingers and second electrode fingers alternately arranged at intervals from each other, the first electrode fingers being connected to the first bus bar and spaced from the second bus bar, and the second electrode fingers being connected to the second bus bar and spaced from the first bus bar; and

[0012] a thickening layer disposed on at least one of the bus bars;

[0013] Wherein, in a first direction, a side surface of the thickened layer away from the piezoelectric substrate is higher than a side surface of the first dielectric layer away from the piezoelectric substrate, and the first direction is a thickness direction of the piezoelectric substrate.

[0014] A second aspect of the present application provides a resonator, comprising:

[0015] A piezoelectric substrate having a first surface;

[0016] an interdigital transducer, the interdigital transducer being disposed on the first surface of the piezoelectric substrate; and

[0017] A temperature compensation layer, the temperature compensation layer covers a part of the IDT and is used to adjust the frequency temperature coefficient of the resonator;

[0018] The interdigital transducer comprises:

[0019] two bus bars disposed opposite to each other on the piezoelectric substrate;

[0020] a plurality of electrode finger pairs located between the two bus bars, the two bus bars being a first bus bar and a second bus bar, the electrode finger pairs comprising first electrode fingers and second electrode fingers alternately arranged at intervals from each other, the first electrode fingers being connected to the first bus bar and spaced from the second bus bar, the second electrode fingers being connected to the second bus bar and spaced from the first bus bar; and a thickening layer arranged on at least one of the bus bars;

[0021] The thickened layer includes a first layer abutting against the bus bar and a second layer arranged on a side of the first layer away from the piezoelectric substrate, and a projection area of ​​the second layer on the first surface is larger than a projection area of ​​the first layer on the first surface.

[0022] A third aspect of the present application provides a filter, comprising the above-mentioned resonator.

[0023] A fourth aspect of the present application provides a radio frequency front-end module, comprising the above-mentioned filter.

[0024] It can be seen from the above technical solution that the resonator proposed in the present application is provided with a thickened layer on the bus bar, and the side of the thickened layer away from the piezoelectric substrate is set higher than the side of the first dielectric layer away from the piezoelectric substrate, so as to improve the heat dissipation performance of the bus bar, improve the heat dissipation efficiency, and thus improve the power tolerance of the resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained like these drawings without paying any creative work.

[0026] Figure 1is a schematic diagram of the structure of the resonator proposed in the embodiment of the present application from a top view;

[0027] Figure 2 is a cross-sectional schematic diagram of a resonator proposed in an embodiment of the present application;

[0028] Figure 3 is a cross-sectional schematic diagram of a deformation mode of a resonator proposed in an embodiment of the present application;

[0029] Figure 4 is a schematic diagram of the structure of the resonator proposed in the embodiment of the present application;

[0030] Figure 5 is a schematic diagram of the structure of a resonator hiding a piezoelectric substrate proposed in an embodiment of the present application;

[0031] Figure 6 It is a structural schematic diagram of a first dielectric layer covering a partial area of ​​an IDT proposed in an embodiment of the present application.

[0032] Description of reference numerals:

[0033] 100, resonator; 10, piezoelectric substrate; 10a, first surface; 11, piezoelectric film; 12, substrate; 13, temperature compensation layer; 20, interdigital transducer; 21, bus bar; 21a, first bus bar; 21b, second bus bar; 211, first side; 212, second side; 22, electrode finger; 22a, first electrode finger; 22b, second electrode finger; 23, thickening layer; 23a, first layer; 23b, second layer; 231, first side; 2311, first edge; 2312, third edge; 232, second side; 2321, second edge; 2322, fourth edge; 24, piston structure; 25, first gap region; 26, second gap region; 30, first dielectric layer; 31, slot; 40, second dielectric layer; 50, solder ball. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0035] It should be understood that all directional indications in the embodiments of the present application (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0036] It should also be understood that when an element is referred to as being "fixed" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or it can be indirectly connected to the other element through an intermediate element.

[0037] The terms used in this specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. For example, the descriptions of "first", "second", etc. in the present application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0038] It should be further understood that the term “and / or” used in the specification and appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0039] See also Figures 1 to 3 The embodiment of the present application provides a resonator 100, comprising a piezoelectric substrate 10, an IDT 20 and a first dielectric layer 30. The piezoelectric substrate 10 has a first surface 10a; the IDT 20 is disposed on the first surface 10a of the piezoelectric substrate 10; and the first dielectric layer 30 covers a portion of the IDT 20. In order to facilitate observation of the IDT 20, Figure 1 The first dielectric layer 30 is hidden in FIG.

[0040] The interdigital transducer 20 includes two bus bars 21 arranged relatively on the piezoelectric substrate 10, a plurality of electrode finger pairs located between the two bus bars 21, and a thickened layer 23 arranged on at least one of the bus bars 21; the two bus bars 21 are respectively a first bus bar 21a and a second bus bar 21b, each electrode finger pair includes two electrode fingers 22, respectively a first electrode finger 22a and a second electrode finger 22b arranged alternately and spaced from each other, the first electrode finger 22a is connected to the first bus bar 21a and spaced from the second bus bar 21b, the second electrode finger 22b is connected to the second bus bar 21b and spaced from the first bus bar 21a; wherein, in a first direction, a side of the thickened layer 23 away from the piezoelectric substrate 10 is higher than a side of the first dielectric layer 30 away from the piezoelectric substrate 10, and the first direction is the thickness direction of the piezoelectric substrate 10.

[0041] Among them, the resonator 100 of the present application is a surface acoustic wave (SAW) resonator, and the resonator 100 also includes two reflectors, which are arranged on both sides of the interdigital transducer 20 (IDT) along the propagation direction of the sound wave, wherein the propagation direction of the sound wave is perpendicular to the first direction and the second direction. The reflector is used to constrain the surface acoustic wave in the interdigital transducer 20. The piezoelectric substrate 10 can be made of piezoelectric materials such as lithium niobate, lithium tantalate or quartz, so that it has a piezoelectric effect, that is, when an electric field or mechanical stress is applied, charge distribution and mechanical deformation will be generated. As an important component of the resonator 100, the function of the interdigital transducer 20 is to complete the conversion of electrical energy and mechanical energy, that is, to generate and detect surface acoustic waves. The structure of the interdigital transducer 20 is usually manufactured on the piezoelectric substrate 10 using a photolithography process. When a voltage signal is applied to the piezoelectric substrate 10, the interdigital transducer 20 excites acoustic waves in the piezoelectric material. The changing voltage causes the piezoelectric substrate 10 to deform, thereby exciting surface acoustic waves. The surface acoustic waves are generated and propagated on the surface of the piezoelectric substrate 10 by utilizing the piezoelectric effect, thereby realizing signal processing and transmission.

[0042] Specifically, the first dielectric layer 30 may be an insulating material, so as to achieve electrical isolation, improve safety, and prevent electromagnetic fields from interfering with the working signal of the IDT 20 .

[0043] Specifically, the electrode fingers 22 of the IDT 20 are used to excite and detect surface acoustic waves on the surface of the piezoelectric substrate 10 to achieve mutual conversion between electrical signals and acoustic signals. The bus bar 21 of the IDT 20 is used to connect the electrode fingers 22 and transmit electrical signals. For example, when a plurality of IDTs 20 are provided in the resonator 100, different IDTs 20 can be electrically connected through the bus bar 21 and the wiring.

[0044] The thickened layer 23 and the bus bar 21 of the IDT 20 are both made of metal, thus having good thermal conductivity.

[0045] The resonator 100 proposed in the embodiment of the present application is provided with a thickened layer 23 on the bus bar 21, and the side of the thickened layer 23 away from the piezoelectric substrate 10 is set higher than the side of the first dielectric layer 30 away from the piezoelectric substrate 10, so as to improve the heat dissipation performance of the bus bar 21 and improve the heat dissipation efficiency, thereby improving the power tolerance of the resonator 100.

[0046] It should be noted that if the resonator 100 is not provided with the thickened layer 23, the first dielectric layer 30 will cover the surface of the bus bar 21. When the resonator 100 is working, the heat generated on the surface of the bus bar 21 needs to be dissipated through the first dielectric layer 30, affecting the heat dissipation efficiency.

[0047] In addition, the first dielectric layer 30 is usually made of insulating material, which has poor heat dissipation performance. If the thickened layer 23 is not provided, the heat dissipation effect of the resonator 100 is poor, which affects the power tolerance of the resonator 100.

[0048] Specifically, the first dielectric layer 30 covers a partial area of ​​the interdigital transducer 20, which means that the first dielectric layer 30 covers the area other than the thickened layer 23. The area covered by the first dielectric layer 30 includes at least the area where the plurality of electrode finger pairs are located. Optionally, the area covered by the first dielectric layer 30 may also include a partial area of ​​the bus bar 21. For example, the thickened layer 23 may cover all or part of the bus bar 21. When the thickened layer 23 only covers a partial area of ​​the bus bar 21, the area on the bus bar 21 that is not covered by the thickened layer 23 may be covered by the first dielectric layer 30, and the first dielectric layer 30 and the thickened layer 23 may be connected.

[0049] See also Figures 4 to 5 In some embodiments, the side of the thickened layer 23 away from the piezoelectric substrate 10 is the first side 231, and the side of the thickened layer 23 abutting the bus bar 21 is the second side 232; wherein the length of the first side 231 in the second direction is greater than the length of the second side 232 in the second direction, the second direction is the arrangement direction of the two bus bars 21, that is, the extension direction of the electrode fingers 22, and the second direction is perpendicular to the first direction. Therefore, the length of the first side 231 in the second direction is set to be greater than the length of the second side 232 in the second direction, so that the area of ​​the first side 231 is greater than the area of ​​the second side 232, which can increase the heat dissipation area and improve the heat dissipation efficiency, thereby improving the power tolerance of the resonator 100.

[0050] In some embodiments, the thickened layer 23 may include a first layer 23a abutting against the bus bar 21 and a second layer 23b disposed on the side of the first layer 23a away from the piezoelectric substrate 10, wherein the first side surface 231 is located on the side of the second layer 23b away from the bus bar 21, that is, the top surface of the second layer 23b, and the second side surface 232 is located on the side of the first layer 23a close to the bus bar 21, that is, the bottom surface of the first layer 23a, and the areas of any cross-sections of the first layer 23a parallel to the second side surface 232 are equal, and the areas of any cross-sections of the second layer 23b parallel to the first side surface 231 are equal, and the cross-section of the second layer 23b is larger than the cross-sectional area of ​​the first layer 23a, so as to increase the heat dissipation area of ​​the bus bar 21 and improve the heat dissipation efficiency, thereby improving the power tolerance of the resonator 100. Optionally, the first layer 23a and the second layer 23b of the thickened layer 23 can be integrally formed, that is, formed in the same process procedure, so as to simplify the process flow and improve the manufacturing efficiency.

[0051] Of course, in other embodiments, the thickened layer 23 may not be limited to the above-mentioned setting of the first layer 23a and the second layer 23b. For example, it can also be set to gradually increase in length from the second side 232 to the first side 231, or be set to other regular or irregular structures, so that the area of ​​the first side 231 can be larger than the area of ​​the second side 232, so as to increase the heat dissipation area of ​​the bus bar 21 and improve the heat dissipation efficiency.

[0052] See also Figures 1 to 3 as well as Figure 5 In some embodiments, in the second direction, the side opposite to the two bus bars 21 is the first side 211, and the side opposite to the two bus bars 21 is the second side 212; in the second direction, the first side surface 231 has a first edge 2311 facing the first side 211, and the second side surface 232 has a second edge 2321 facing the first side 211; the distance between the first edge 2311 and the edge of the bus bar 21 located on the first side 211 is D1, and the distance between the second edge 2321 and the edge of the bus bar 21 located on the first side 211 is D2, wherein D2>D1>0. Thus, the extension length of the first side surface 231 of the thickened layer 23 toward the first side 211 is greater than the extension length of the second side surface 232 toward the first side 211, and does not exceed the edge of the first side 211 of the bus bar 21, thereby increasing the heat dissipation area while avoiding affecting the performance of the resonator 100.

[0053] In some embodiments, the first side surface 231 further has a third edge 2312 opposite to the first edge 2311, and the second side surface 232 further has a fourth edge 2322 opposite to the second edge 2321, the distance between the third edge 2312 and the edge of the bus bar 21 located on the second side 212 is D3, and the distance between the fourth edge 2322 and the edge of the bus bar 21 located on the second side 212 is D4, wherein D4≥D3≥0. Thus, the extension length of the first side surface 231 of the thickened layer 23 toward the second side 212 can be set to be greater than or equal to the extension length of the second side surface 232 toward the second side 212, and is limited to not exceed the edge of the second side 212 of the bus bar 21, so as to increase the heat dissipation area while avoiding affecting the performance of the resonator 100.

[0054] Exemplarily, when the extension length of the first side 231 toward the first side 211 is greater than the extension length of the second side 232 toward the first side 211, and the extension length of the first side 231 toward the second side 212 is greater than the extension length of the second side 232 toward the second side 212, the bus bar 21 and the thickened layer 23 form an I-shaped structure.

[0055] See also Figures 4 to 6In some embodiments, the first dielectric layer 30 is provided with a slot 31 penetrating along the first direction to the surface of the bus bar 21, and the thickened layer 23 is filled in the slot 31 and protrudes above the slot 31. Thus, the slot 31 is provided to facilitate the formation of the thickened layer 23, so that the thickened layer 23 can fully contact the surface of the bus bar 21 and protrude above the slot 31, so that the side of the thickened layer 23 away from the piezoelectric substrate 10 is higher than the side of the first dielectric layer 30 away from the piezoelectric substrate 10, so as to improve the heat dissipation performance of the bus bar 21, improve the heat dissipation efficiency, and thus improve the power tolerance of the resonator 100.

[0056] In some application scenarios, the grooves 31 may be formed in the first dielectric layer 30 by photolithography, etching or other processes.

[0057] In some embodiments, the portion of the thickened layer 23 protruding above the groove 31 extends along the second direction to a side of the first dielectric layer 30 away from the piezoelectric substrate 10. Thus, the heat dissipation area can be increased while protecting the first dielectric layer 30 to a certain extent.

[0058] As an implementation mode, the portion of the thickened layer 23 protruding above the slot 31 extends along the second direction to meet the edge of the first dielectric layer 30 , thereby increasing the heat dissipation area and providing a certain degree of protection to the first dielectric layer 30 .

[0059] As another embodiment, the portion of the thickened layer 23 protruding above the slot 31 extends along the second direction to overlap with a portion of the first dielectric layer 30 , further increasing the heat dissipation area while providing a certain degree of protection to the first dielectric layer 30 .

[0060] In some embodiments, the first dielectric layer 30 covers a partial area of ​​the bus bar 21, and in the second direction, a gap is provided between the edge of the thickened layer 23 and the edge of the bus bar 21. The first dielectric layer 30 covers a partial area of ​​the bus bar 21, which means that the first dielectric layer 30 covers an area of ​​the bus bar 21 where the thickened layer 23 is not provided. Among them, the portion of the thickened layer 23 protruding above the slot 31 extends along the second direction to overlap with a partial area of ​​the first dielectric layer 30, and does not exceed the edge of the bus bar 21, which can further increase the heat dissipation area without affecting the performance of the resonator 100, and at the same time provide a certain protection for the first dielectric layer 30.

[0061] In some embodiments, in the second direction, the side opposite to the two bus bars 21 is the first side 211, the side opposite to the two bus bars 21 is the second side 212, and the distance between the edge of the slot 31 facing the first side 211 and the first side 211 is D5, D5>3μm; wherein the second direction is the arrangement direction of the two bus bars 21, and the second direction is perpendicular to the first direction. Specifically, since the thickened layer 23 is formed at the slot 31, the distance D2 between the second edge 2321 of the thickened layer 23 and the first side 211 is also D5. By setting D5>3μm, it is possible to prevent energy leakage of the resonator 100 located in the electrode finger 22 area, thereby avoiding affecting the quality factor of the resonator 100.

[0062] In some embodiments, in order to better prevent energy leakage of the resonator 100 in the electrode finger 22 region, D5>7 μm may be further defined.

[0063] In some embodiments, the thickness of the thickened layer 23 is 1 μm-5 μm. Limiting the thickness of the thickened layer 23 within the above range can not only improve the heat dissipation effect, but also control the cost at a suitable level. For example, the thickness of the thickened layer 23 can be 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, etc.

[0064] In some embodiments, in order to better balance the heat dissipation effect and the use cost, the thickness of the thickened layer 23 may be further limited to 2 μm-3 μm.

[0065] In some embodiments, the thickening layer 23 is mainly composed of titanium, aluminum or aluminum-copper alloy. It is understandable that the main component can be understood as the metal with the highest content in the layer structure, for example, it can be the metal with the highest weight. Exemplarily, the material of the thickening layer 23 can be a combination of one or more metal materials such as titanium, aluminum or aluminum-copper alloy. It is understandable that the thickening layer 23 of the present application can also be made of other metal materials, which can be a single metal, an alloy, or a structure formed by stacking multiple metals. It is not limited here, as long as the required performance can be achieved.

[0066] In some embodiments, the first dielectric layer 30 is a temperature compensation layer for adjusting the frequency temperature coefficient of the resonator 100. Thus, by coating or bonding the temperature compensation layer to improve performance, the device temperature coefficient of frequency (TCF) is reduced, thereby improving temperature characteristics.

[0067] In some embodiments, the first dielectric layer 30 is mainly composed of silicon dioxide or silicon nitride. Exemplarily, the material of the first dielectric layer 30 can be a combination of one or more materials such as silicon dioxide or silicon nitride. It can be understood that the temperature compensation layer of the present application can also be made of other materials, which are not limited here, as long as they can achieve the required performance.

[0068] See also Figures 2 to 4 In some embodiments, the resonator 100 further includes a second dielectric layer 40, and the second dielectric layer 40 covers the thickened layer 23 and the first dielectric layer 30. Exemplarily, the second dielectric layer 40 can be a frequency modulation layer, and the frequency modulation layer can be a single layer or a multi-layer, and different materials can be used between the multiple layers. The frequency modulation layer can be used to adjust the resonant frequency of the resonator 100. The frequency modulation layer can also play a passivation role to protect the interdigital transducer 20, which helps to prevent the interdigital transducer 20 from being damaged or corroded.

[0069] In some embodiments, the second dielectric layer 40 is mainly composed of silicon nitride or silicon oxynitride. Exemplarily, the material of the second dielectric layer 40 can be a combination of one or more materials such as silicon nitride or silicon oxynitride. It can be understood that the second dielectric layer 40 of the present application can also be made of other materials, which are not limited here, as long as they can achieve the required performance.

[0070] In some embodiments, the thickness of the second dielectric layer 40 is 10 nm-200 nm. For example, the thickness of the second dielectric layer 40 can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, etc.

[0071] In some embodiments, in order to better improve the performance of the resonator 100 , the thickness of the second dielectric layer 40 may be further limited to 20 nm-70 nm.

[0072] See also Figures 1 to 3 In some embodiments, thickened layers 23 are provided on both bus bars 21, and one of the thickened layers 23 is used to set the solder ball 50. Therefore, thickened layers 23 are provided on both bus bars 21, which can better improve the heat dissipation effect. At the same time, one of the thickened layers 23 can also be used as a metal layer to support the solder ball 50, so as to facilitate the connection between the resonator 100 and the circuit board.

[0073] In some embodiments, the thickened layers 23 on the two bus bars 21 are symmetrically arranged. Thus, the two thickened layers 23 can be symmetrically arranged, that is, the projection areas of the two thickened layers 23 on the first surface 10a are equal. The first side surfaces 231 of the two thickened layers 23 can both extend along the second direction, so that the length of the first side surfaces 231 of the two thickened layers 23 in the second direction is greater than the length of the second side surfaces 232 thereof in the second direction, so as to improve the heat dissipation effect.

[0074] Of course, in other embodiments, the projection area of ​​the thickened layer 23 provided with the solder balls 50 on the first surface 10a may be larger than the projection area of ​​another thickened layer 23 on the first surface 10a (eg Figure 2 It is also possible to design the projection area of ​​the thickened layer 23 provided with the solder ball 50 on the first surface 10a to be smaller than the projection area of ​​another thickened layer 23 on the first surface 10a (as shown in Figure 3 Specifically, the thickness of the thickened layer 23 and the length in the second direction may be set in combination with heat dissipation requirements and the thickness and surface area of ​​the thickened layer 23 required to support the solder ball 50 .

[0075] The thickness of the thickened layer 23 is set to 1 μm-5 μm, so that the thickness of the thickened layer 23 can meet the requirement of protecting the bus bar 21 during ball implantation.

[0076] Optionally, when both bus bars 21 are provided with thickened layers 23, and one of the thickened layers 23 is used to set the solder ball 50, the thickness of the two thickened layers 23 may be the same or different. The thickness of the thickened layer 23 used to set the solder ball 50 is greater than or equal to the thickness of the other thickened layer 23, so as to ensure that the bus bar 21 and the electrode fingers 22 near the bus bar 21 can be protected during ball planting.

[0077] When the thicknesses of the two thickened layers 23 are the same, the two thickened layers 23 can be produced in the same process.

[0078] When the thicknesses of the two thickened layers 23 are different, the two thickened layers 23 can be formed separately through different processes; or, two thickened layers 23 with the same thickness are formed first, and then one of the thickened layers 23 is further thickened to form two thickened layers 23 with different thicknesses.

[0079] In some application scenarios, a pad area can be set in the thickened layer 23. In order to avoid affecting the performance of the resonator 100, the pad area can be positioned away from the first side 211 of the bus bar 21. For example, the pad area is set at a position close to the second side 212, and a portion of the second dielectric layer 40 in the pad area is removed by processes such as photolithography and etching to expose the metal of the thickened layer 23 in the pad area, thereby being used for electrical connection ball implantation in the pad area. By way of example, the solder ball 50 can be a tin ball or a gold ball.

[0080] In an optional embodiment, the piezoelectric substrate 10 may be a single-layer piezoelectric structure, that is, the piezoelectric substrate 10 is composed of one piezoelectric material. Of course, in other embodiments, the piezoelectric substrate 10 may also be a multi-layer piezoelectric structure, composed of piezoelectric layers of different materials or the same material but with different properties, and these layers are stacked together in a specific manner to achieve the desired performance.

[0081] See also Figure 4 , Figure 4 The multilayer structure of the piezoelectric substrate 10 is shown in FIG. In some embodiments, the multilayer piezoelectric structure includes a piezoelectric film 11 and a substrate 12, the interdigital transducer 20 is arranged on the piezoelectric film 11, and the substrate 12 is arranged on the side of the piezoelectric film 11 facing away from the interdigital transducer 20. The piezoelectric film 11 is the core part of the piezoelectric substrate 10, and is made of a piezoelectric material, such as a piezoelectric material with lithium niobate, lithium tantalate or quartz as the main component. The piezoelectric film 11 has a good piezoelectric effect and can convert mechanical stress into an electrical signal or convert an electrical signal into mechanical stress. The substrate 12 is a supporting layer of the piezoelectric film 11, and its main function is to provide mechanical support and protect the piezoelectric film 11, while ensuring that the piezoelectric film 11 can be uniformly stressed when subjected to external force. In addition, the substrate 12 can also form a specific acoustic structure together with the piezoelectric film 11 to optimize the performance of the resonator 100.

[0082] In some embodiments, the substrate 12 may be an insulating substrate 12 such as silicon material, sapphire, or spinel having high resistivity.

[0083] In some embodiments, the multilayer piezoelectric structure may further include a temperature compensation layer 13, which is disposed between the piezoelectric film 11 and the substrate 12. The temperature compensation layer 13 is used to compensate for the effect of temperature changes on the performance of the piezoelectric substrate 10 through its specific thermal expansion coefficient and mechanical properties. This helps to maintain the stability and reliability of the device under different temperature conditions.

[0084] It can be understood that the material or structure of the piezoelectric substrate 10 of the present application is not limited here, as long as it can achieve the required performance.

[0085] Exemplarily, one IDT 20 may be disposed on the piezoelectric substrate 10, or a plurality of IDTs 20 may be disposed to form a plurality of resonators 100. When a plurality of IDTs 20 are disposed on the piezoelectric substrate 10, the thickening layer 23 may be disposed only on the bus bars 21 of some of the IDTs 20, or may be disposed on the bus bars 21 of all the IDTs 20.

[0086] See also Figures 1 to 6In some embodiments, the interdigital transducer 20 further includes a piston structure 24 (the electrode finger 22 is widened and / or thickened), and the first electrode finger 22a and the second electrode finger 22b of the plurality of electrode finger pairs have an overlapping area along the propagation direction of the sound wave, and the piston structure 24 is located on opposite sides of the overlapping area along the second direction, the second direction is the arrangement direction of the two bus bars 21, and the second direction is perpendicular to the first direction. Thus, the mass load of the electrode finger 22 on opposite sides of the overlapping area can be increased by setting the piston structure 24, so as to suppress the transverse mode of the resonator 100. Specifically, the propagation direction of the sound wave is perpendicular to both the first direction and the second direction, and the mass load of the corresponding area can be increased by the piston structure 24, and the sound velocity on opposite sides of the overlapping area along the second direction is reduced, so that a piston mode can be formed to further reduce the lateral loss of the sound wave, which helps to further suppress the noise mode.

[0087] In some embodiments, the overlapping area may be a working area, and it can be understood that the sound waves mainly propagate in the overlapping area.

[0088] In some embodiments, the piston structure 24 is mainly composed of chromium, copper, titanium, silver, molybdenum or gold. For example, the material of the piston structure 24 can be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It can be understood that the piston structure 24 of the present application can also be made of other metal materials, which are not limited here, as long as they can achieve the required performance.

[0089] In some embodiments, the busbar 21 is mainly composed of chromium, copper, titanium, silver, molybdenum or gold. Exemplarily, the material of the busbar 21 can be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It can be understood that the busbar 21 of the present application can also be made of other metal materials, which can be a single metal, an alloy, or a structure formed by stacking multiple metals. It is not limited here, as long as it can achieve the required performance.

[0090] In some embodiments, the electrode fingers 22 and the bus bar 21 may be made of the same or different metal materials. Exemplarily, the material of the electrode fingers 22 may be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It is understandable that the electrode fingers 22 of the present application may also be made of other metal materials, which may be a single metal, an alloy, or a structure formed by stacking multiple metals. This is not limited here, as long as the required performance can be achieved.

[0091] In some embodiments, the bus bar 21 has a thickness of 5 nm to 1000 nm. For example, the bus bar 21 may have a thickness of 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm.

[0092] In some embodiments, the thickness of the electrode fingers 22 is the same as the thickness of the bus bar 21. Exemplarily, the electrode fingers 22 and the bus bar 21 may be integrally formed, that is, formed in the same process.

[0093] In some embodiments, in order to improve the performance of the resonator, it can be further limited that the thickness of the bus bar 21 is between 100 nm and 500 nm. At the same time, within the above thickness range, the bus bar 21 is also more convenient to manufacture.

[0094] See also Figures 5 and 6 In some embodiments, the gap between the first bus bar 21a and the second electrode finger 22b forms a first gap region 25, and the gap between the second bus bar 21b and the first electrode finger 22a forms a second gap region 26. The first gap region 25 and the second gap region 26 are both defined as D6, D6>0.5*λ, λ is the wavelength of the sound wave. Therefore, by defining D6>0.5*λ, the performance of the resonator 100 can be improved.

[0095] In some embodiments, in order to better improve the performance of the resonator 100 , it can be further defined that 2.0*λ>D6>1.0*λ.

[0096] See also Figures 1 to 3 The embodiment of the present application also proposes a resonator 100, including a piezoelectric substrate 10, an IDT 20 and a first dielectric layer 30, wherein the first dielectric layer 30 is a temperature compensation layer, and the piezoelectric substrate 10 has a first surface 10a; the IDT 20 is arranged on the first surface 10a of the piezoelectric substrate 10; the temperature compensation layer covers a partial area of ​​the IDT 20, and is used to adjust the frequency temperature coefficient of the resonator 100.

[0097] The interdigital transducer 20 includes two bus bars 21 arranged on a piezoelectric substrate 10, a plurality of electrode finger pairs located between the two bus bars 21, and a thickening layer 23 arranged on at least one of the bus bars 21; the two bus bars 21 are respectively a first bus bar 21a and a second bus bar 21b, the electrode finger pairs include first electrode fingers 22a and second electrode fingers 22b arranged alternately and spaced apart from each other, the first electrode fingers 22a are connected to the first bus bar 21a and spaced apart from the second bus bar 21b, the second electrode fingers 22b are connected to the second bus bar 21b and spaced apart from the first bus bar 21a, and the first electrode fingers 22a and the second electrode fingers 22b of the plurality of electrode finger pairs are arranged alternately and spaced apart from each other; wherein the thickening layer 23 includes a first layer 23a abutting the bus bar 21 and a second layer 23b arranged on a side of the first layer 23a away from the piezoelectric substrate 10, and the projection area of ​​the second layer 23b on the first surface 10a is larger than the projection area of ​​the first layer 23a on the first surface 10a.

[0098] The resonator 100 proposed in the embodiment of the present application is provided with a thickened layer 23 on the bus bar 21, and the projection area of ​​the second layer 23b of the thickened layer 23 on the first surface 10a is set to be larger than the projection area of ​​the first layer 23a on the first surface 10a, so as to increase the heat dissipation area of ​​the bus bar 21 and improve the heat dissipation efficiency, thereby enhancing the power tolerance capability of the resonator 100.

[0099] It should be noted that if the resonator 100 is not provided with the thickened layer 23, the first dielectric layer 30 will cover the surface of the bus bar 21. When the resonator 100 is working, the heat generated on the surface of the bus bar 21 needs to be dissipated through the first dielectric layer 30, affecting the heat dissipation efficiency.

[0100] In addition, the first dielectric layer 30 is usually made of insulating material, which has poor heat dissipation performance. If the thickened layer 23 is not provided, the heat dissipation effect of the resonator 100 is poor, which affects the power tolerance of the resonator 100.

[0101] Specifically, the first dielectric layer 30 covers a partial area of ​​the interdigital transducer 20, which means that the first dielectric layer 30 covers the area other than the thickened layer 23. The area covered by the first dielectric layer 30 includes at least the area where the plurality of electrode finger pairs are located. Optionally, the area covered by the first dielectric layer 30 may also include a partial area of ​​the bus bar 21. For example, the thickened layer 23 may cover all or part of the bus bar 21. When the thickened layer 23 only covers a partial area of ​​the bus bar 21, the area on the bus bar 21 that is not covered by the thickened layer 23 may be covered by the first dielectric layer 30, and the first dielectric layer 30 and the thickened layer 23 may be connected.

[0102] See also Figures 4 to 5In some embodiments, the side of the thickened layer 23 away from the piezoelectric substrate 10 is the first side 231, and the side of the thickened layer 23 abutting the bus bar 21 is the second side 232; wherein the first side 231 is located on the side of the second layer 23b away from the bus bar 21, that is, the top surface of the second layer 23b, and the second side 232 is located on the side of the first layer 23a close to the bus bar 21, that is, the bottom surface of the first layer 23a, and the length of the first side 231 in the second direction is greater than the length of the second side 232 in the second direction. The second direction is the arrangement direction of the two bus bars 21, that is, the extension direction of the electrode fingers 22, and the second direction is perpendicular to the first direction. Therefore, the length of the first side 231 in the second direction is set to be greater than the length of the second side 232 in the second direction, so that the area of ​​the first side 231 is greater than the area of ​​the second side 232, which can increase the heat dissipation area and improve the heat dissipation efficiency, thereby improving the power tolerance of the resonator 100.

[0103] In some embodiments, the areas of any cross sections of the first layer 23a parallel to the second side 232 are equal, the areas of any cross sections of the second layer 23b parallel to the first side 231 are equal, and the cross section of the second layer 23b is larger than the cross section of the first layer 23a, so as to increase the heat dissipation area of ​​the bus bar 21 and improve the heat dissipation efficiency, thereby improving the power tolerance of the resonator 100. Optionally, the first layer 23a and the second layer 23b of the thickened layer 23 can be integrally formed, that is, formed in the same process procedure, so as to simplify the process flow and improve the manufacturing efficiency.

[0104] See also Figures 1 to 3 as well as Figure 5 In some embodiments, in the second direction, the side opposite to the two bus bars 21 is the first side 211, and the side opposite to the two bus bars 21 is the second side 212; in the second direction, the first side surface 231 has a first edge 2311 facing the first side 211, and the second side surface 232 has a second edge 2321 facing the first side 211; the distance between the first edge 2311 and the edge of the bus bar 21 located on the first side 211 is D1, and the distance between the second edge 2321 and the edge of the bus bar 21 located on the first side 211 is D2, wherein D2>D1>0. Thus, the extension length of the first side surface 231 of the thickened layer 23 toward the first side 211 is greater than the extension length of the second side surface 232 toward the first side 211, and does not exceed the edge of the first side 211 of the bus bar 21, thereby increasing the heat dissipation area while avoiding affecting the performance of the resonator 100.

[0105] In some embodiments, the first side surface 231 further has a third edge 2312 opposite to the first edge 2311, and the second side surface 232 further has a fourth edge 2322 opposite to the second edge 2321, the distance between the third edge 2312 and the edge of the bus bar 21 located on the second side 212 is D3, and the distance between the fourth edge 2322 and the edge of the bus bar 21 located on the second side 212 is D4, wherein D4≥D3≥0. Thus, the extension length of the first side surface 231 of the thickened layer 23 toward the second side 212 can be set to be greater than or equal to the extension length of the second side surface 232 toward the second side 212, and is limited to not exceed the edge of the second side 212 of the bus bar 21, so as to increase the heat dissipation area while avoiding affecting the performance of the resonator 100.

[0106] Exemplarily, when the extension length of the first side 231 toward the first side 211 is greater than the extension length of the second side 232 toward the first side 211, and the extension length of the first side 231 toward the second side 212 is greater than the extension length of the second side 232 toward the second side 212, the bus bar 21 and the thickened layer 23 form an I-shaped structure.

[0107] See also Figures 4 to 6 In some embodiments, the first dielectric layer 30 is provided with a groove 31 penetrating along the first direction to the surface of the bus bar 21, the first layer 23a of the thickened layer 23 is filled in the groove 31, and the second layer 23b of the thickened layer 23 protrudes above the groove 31. Thus, the groove 31 is provided to facilitate the formation of the thickened layer 23, so that the thickened layer 23 can fully contact the surface of the bus bar 21 and protrude above the groove 31, so that the side of the thickened layer 23 away from the piezoelectric substrate 10 is higher than the side of the first dielectric layer 30 away from the piezoelectric substrate 10, so as to improve the heat dissipation performance of the bus bar 21, improve the heat dissipation efficiency, and thus improve the power tolerance of the resonator 100.

[0108] In some application scenarios, the grooves 31 may be formed in the first dielectric layer 30 by photolithography, etching or other processes.

[0109] In some embodiments, the portion of the thickened layer 23 protruding above the groove 31, that is, the second layer 23b, extends along the second direction to a side of the first dielectric layer 30 away from the piezoelectric substrate 10. Thus, the heat dissipation area can be increased while protecting the first dielectric layer 30 to a certain extent.

[0110] As an implementation mode, the portion of the thickened layer 23 protruding above the slot 31, that is, the second layer 23b, extends along the second direction to meet the edge of the first dielectric layer 30, thereby increasing the heat dissipation area and protecting the first dielectric layer 30 to a certain extent.

[0111] As another embodiment, the portion of the thickened layer 23 protruding above the groove 31, that is, the second layer 23b, extends along the second direction to overlap with a portion of the first dielectric layer 30, further increasing the heat dissipation area while providing a certain degree of protection for the first dielectric layer 30.

[0112] In some embodiments, the first dielectric layer 30 covers a partial area of ​​the bus bar 21, and in the second direction, a gap is provided between the edge of the thickened layer 23 and the edge of the bus bar 21. The first dielectric layer 30 covers a partial area of ​​the bus bar 21, which means that the first dielectric layer 30 covers an area of ​​the bus bar 21 where the thickened layer 23 is not provided. Among them, the portion of the thickened layer 23 protruding above the slot 31 extends along the second direction to overlap with a partial area of ​​the first dielectric layer 30, and does not exceed the edge of the bus bar 21, which can further increase the heat dissipation area without affecting the performance of the resonator 100, and at the same time provide a certain protection for the first dielectric layer 30.

[0113] In some embodiments, in the second direction, the side opposite to the two bus bars 21 is the first side 211, the side opposite to the two bus bars 21 is the second side 212, and the distance between the edge of the slot 31 facing the first side 211 and the first side 211 is D5, D5>3μm; wherein the second direction is the arrangement direction of the two bus bars 21, and the second direction is perpendicular to the first direction. Specifically, since the thickened layer 23 is formed at the slot 31, the distance D2 between the second edge 2321 of the thickened layer 23 and the first side 211 is also D5. By setting D5>3μm, it is possible to prevent energy leakage of the resonator 100 located in the electrode finger 22 area, thereby avoiding affecting the quality factor of the resonator 100.

[0114] In some embodiments, in order to better prevent energy leakage of the resonator 100 in the electrode finger 22 region, D5>7 μm may be further defined.

[0115] In some embodiments, the thickness of the thickened layer 23 is 1 μm-5 μm. Limiting the thickness of the thickened layer 23 within the above range can not only improve the heat dissipation effect, but also control the cost at a suitable level. For example, the thickness of the thickened layer 23 can be 1 μm, 2 μm, 3 μm, 4 μm or 5 μm, etc.

[0116] In some embodiments, in order to better balance the heat dissipation effect and the use cost, the thickness of the thickened layer 23 may be further limited to 2 μm-3 μm.

[0117] In some embodiments, the thickening layer 23 is mainly composed of titanium, aluminum or aluminum-copper alloy. It is understandable that the main component can be understood as the metal with the highest content in the layer structure, for example, it can be the metal with the highest weight. Exemplarily, the material of the thickening layer 23 can be a combination of one or more metal materials such as titanium, aluminum or aluminum-copper alloy. It is understandable that the thickening layer 23 of the present application can also be made of other metal materials, which can be a single metal, an alloy, or a structure formed by stacking multiple metals. It is not limited here, as long as the required performance can be achieved.

[0118] In some embodiments, the first dielectric layer 30 is mainly composed of silicon dioxide or silicon nitride. Exemplarily, the material of the first dielectric layer 30 can be a combination of one or more materials such as silicon dioxide or silicon nitride. It can be understood that the temperature compensation layer of the present application can also be made of other materials, which are not limited here, as long as they can achieve the required performance.

[0119] See also Figures 2 to 4 In some embodiments, the resonator 100 further includes a second dielectric layer 40, and the second dielectric layer 40 covers the thickened layer 23 and the first dielectric layer 30. Exemplarily, the second dielectric layer 40 can be a frequency modulation layer, and the frequency modulation layer can be a single layer or a multi-layer, and different materials can be used between the multiple layers. The frequency modulation layer can be used to adjust the resonant frequency of the resonator 100. The frequency modulation layer can also play a passivation role to protect the interdigital transducer 20, which helps to prevent the interdigital transducer 20 from being damaged or corroded.

[0120] In some embodiments, the second dielectric layer 40 is mainly composed of silicon nitride or silicon oxynitride. Exemplarily, the material of the second dielectric layer 40 can be a combination of one or more materials such as silicon nitride or silicon oxynitride. It can be understood that the second dielectric layer 40 of the present application can also be made of other materials, which are not limited here, as long as they can achieve the required performance.

[0121] In some embodiments, the thickness of the second dielectric layer 40 is 10 nm-200 nm. For example, the thickness of the second dielectric layer 40 can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm or 200 μm, etc.

[0122] In some embodiments, in order to better improve the performance of the resonator 100 , the thickness of the second dielectric layer 40 may be further limited to 20 nm-70 nm.

[0123] See also Figures 1 to 3In some embodiments, thickened layers 23 are provided on both bus bars 21, and solder balls 50 are provided on one of the thickened layers 23. Thus, thickened layers 23 are provided on both bus bars 21, which can better improve the heat dissipation effect. At the same time, one of the thickened layers 23 can also be used as a metal layer to support the solder balls 50, so as to facilitate the connection between the resonator 100 and the circuit board.

[0124] In some embodiments, the thickened layers 23 on the two bus bars 21 are symmetrically arranged. Thus, the two thickened layers 23 can be symmetrically arranged, that is, the projection areas of the two thickened layers 23 on the first surface 10a are equal. The first side surfaces 231 of the two thickened layers 23 can both extend along the second direction, so that the length of the first side surfaces 231 of the two thickened layers 23 in the second direction is greater than the length of the second side surfaces 232 thereof in the second direction, so as to improve the heat dissipation effect.

[0125] Of course, in other embodiments, the projection area of ​​the thickened layer 23 provided with the solder balls 50 on the first surface 10a may be larger than the projection area of ​​another thickened layer 23 on the first surface 10a (eg Figure 2 It is also possible to design the projection area of ​​the thickened layer 23 provided with the solder ball 50 on the first surface 10a to be smaller than the projection area of ​​another thickened layer 23 on the first surface 10a (as shown in Figure 3 Specifically, the thickness of the thickened layer 23 and the length in the second direction may be set in combination with heat dissipation requirements and the thickness and surface area of ​​the thickened layer 23 required to support the solder ball 50 .

[0126] The thickness of the thickened layer 23 is set to 1 μm-5 μm, so that the thickness of the thickened layer 23 can meet the requirement of protecting the bus bar 21 during ball implantation.

[0127] Optionally, when both bus bars 21 are provided with thickened layers 23, and one of the thickened layers 23 is used to set the solder ball 50, the thickness of the two thickened layers 23 may be the same or different. The thickness of the thickened layer 23 used to set the solder ball 50 is greater than or equal to the thickness of the other thickened layer 23, so as to ensure that the bus bar 21 and the electrode fingers 22 near the bus bar 21 can be protected during ball planting.

[0128] When the thicknesses of the two thickened layers 23 are the same, the two thickened layers 23 can be produced in the same process.

[0129] When the thicknesses of the two thickened layers 23 are different, the two thickened layers 23 can be formed separately through different processes; or, two thickened layers 23 with the same thickness are formed first, and then one of the thickened layers 23 is further thickened to form two thickened layers 23 with different thicknesses.

[0130] In some application scenarios, a pad area can be set in the thickened layer 23. In order to avoid affecting the performance of the resonator 100, the pad area can be positioned away from the first side 211 of the bus bar 21. For example, the pad area is set at a position close to the second side 212, and a portion of the second dielectric layer 40 in the pad area is removed by processes such as photolithography and etching to expose the metal of the thickened layer 23 in the pad area, thereby being used for electrical connection ball implantation in the pad area. By way of example, the solder ball 50 can be a tin ball or a gold ball.

[0131] In an optional embodiment, the piezoelectric substrate 10 may be a single-layer piezoelectric structure, that is, the piezoelectric substrate 10 is composed of one piezoelectric material. Of course, in other embodiments, the piezoelectric substrate 10 may also be a multi-layer piezoelectric structure, composed of piezoelectric layers of different materials or the same material but with different properties, and these layers are stacked together in a specific manner to achieve the desired performance.

[0132] See also Figure 4 , Figure 4 The multilayer structure of the piezoelectric substrate 10 is shown in FIG. In some embodiments, the multilayer piezoelectric structure includes a piezoelectric film 11 and a substrate 12, the interdigital transducer 20 is arranged on the piezoelectric film 11, and the substrate 12 is arranged on the side of the piezoelectric film 11 facing away from the interdigital transducer 20. The piezoelectric film 11 is the core part of the piezoelectric substrate 10, and is made of a piezoelectric material, such as a piezoelectric material with lithium niobate, lithium tantalate or quartz as the main component. The piezoelectric film 11 has a good piezoelectric effect and can convert mechanical stress into an electrical signal or convert an electrical signal into mechanical stress. The substrate 12 is a supporting layer of the piezoelectric film 11, and its main function is to provide mechanical support and protect the piezoelectric film 11, while ensuring that the piezoelectric film 11 can be uniformly stressed when subjected to external force. In addition, the substrate 12 can also form a specific acoustic structure together with the piezoelectric film 11 to optimize the performance of the resonator 100.

[0133] In some embodiments, the substrate 12 may be an insulating substrate 12 such as silicon material, sapphire, or spinel having high resistivity.

[0134] In some embodiments, the multilayer piezoelectric structure may further include a temperature compensation layer 13, which is disposed between the piezoelectric film 11 and the substrate 12. The temperature compensation layer 13 is used to compensate for the effect of temperature changes on the performance of the piezoelectric substrate 10 through its specific thermal expansion coefficient and mechanical properties. This helps to maintain the stability and reliability of the device under different temperature conditions.

[0135] It can be understood that the material or structure of the piezoelectric substrate 10 of the present application is not limited here, as long as it can achieve the required performance.

[0136] Exemplarily, one IDT 20 may be disposed on the piezoelectric substrate 10, or a plurality of IDTs 20 may be disposed to form a plurality of resonators 100. When a plurality of IDTs 20 are disposed on the piezoelectric substrate 10, the thickening layer 23 may be disposed only on the bus bars 21 of some of the IDTs 20, or may be disposed on the bus bars 21 of all the IDTs 20.

[0137] See also Figures 1 to 6 In some embodiments, the interdigital transducer 20 further includes a piston structure 24 (the electrode finger 22 is widened and / or thickened), and the first electrode finger 22a and the second electrode finger 22b of the plurality of electrode finger pairs have an overlapping area along the propagation direction of the sound wave, and the piston structure 24 is located on opposite sides of the overlapping area along the second direction, the second direction is the arrangement direction of the two bus bars 21, and the second direction is perpendicular to the first direction. Thus, the mass load of the electrode finger 22 on opposite sides of the overlapping area can be increased by setting the piston structure 24, so as to suppress the transverse mode of the resonator 100. Specifically, the propagation direction of the sound wave is perpendicular to both the first direction and the second direction, and the mass load of the corresponding area can be increased by the piston structure 24, and the sound velocity on opposite sides of the overlapping area along the second direction is reduced, so that a piston mode can be formed to further reduce the lateral loss of the sound wave, which helps to further suppress the noise mode.

[0138] In some embodiments, the overlapping area may be a working area, and it can be understood that the sound waves mainly propagate in the overlapping area.

[0139] In some embodiments, the piston structure 24 is mainly composed of chromium, copper, titanium, silver, molybdenum or gold. For example, the material of the piston structure 24 can be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It can be understood that the piston structure 24 of the present application can also be made of other metal materials, which are not limited here, as long as they can achieve the required performance.

[0140] In some embodiments, the busbar 21 is mainly composed of chromium, copper, titanium, silver, molybdenum or gold. Exemplarily, the material of the busbar 21 can be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It can be understood that the busbar 21 of the present application can also be made of other metal materials, which can be a single metal, an alloy, or a structure formed by stacking multiple metals. It is not limited here, as long as it can achieve the required performance.

[0141] In some embodiments, the electrode fingers 22 and the bus bar 21 may be made of the same or different metal materials. Exemplarily, the material of the electrode fingers 22 may be a combination of one or more metal materials such as chromium, copper, titanium, silver, molybdenum or gold. It is understandable that the electrode fingers 22 of the present application may also be made of other metal materials, which may be a single metal, an alloy, or a structure formed by stacking multiple metals. This is not limited here, as long as the required performance can be achieved.

[0142] In some embodiments, the bus bar 21 has a thickness of 5 nm to 1000 nm. For example, the bus bar 21 may have a thickness of 5 nm, 10 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, or 1000 nm.

[0143] In some embodiments, the thickness of the electrode fingers 22 is the same as the thickness of the bus bar 21. Exemplarily, the electrode fingers 22 and the bus bar 21 may be integrally formed, that is, formed in the same process.

[0144] In some embodiments, in order to improve the performance of the resonator, it can be further limited that the thickness of the bus bar 21 is between 100 nm and 500 nm. At the same time, within the above thickness range, the bus bar 21 is also more convenient to manufacture.

[0145] See also Figures 5 and 6 In some embodiments, the gap between the first bus bar 21a and the second electrode finger 22b forms a first gap region 25, and the gap between the second bus bar 21b and the first electrode finger 22a forms a second gap region 26. The first gap region 25 and the second gap region 26 are both defined as D6, D6>0.5*λ, λ is the wavelength of the sound wave. Therefore, by defining D6>0.5*λ, the performance of the resonator 100 can be improved.

[0146] In some embodiments, in order to better improve the performance of the resonator 100 , it can be further defined that 2.0*λ>D6>1.0*λ.

[0147] The embodiment of the present application also provides a filter, which includes the resonator 100 in any of the above embodiments. Since the resonator 100 increases the heat dissipation area by providing the thickened layer 23, the power tolerance of the filter can be improved.

[0148] See also Figures 1 to 3 In some embodiments, the filter further comprises a solder ball 50, which is disposed on the thickened layer 23 of the IDT 20 of the resonator 100. Specifically, a thickened layer 23 is disposed on each of the two bus bars 21, and a solder ball 50 is disposed on one of the thickened layers 23.

[0149] In some embodiments, the number of resonators 100 may be multiple, and the multiple resonators 100 may be arranged as required, and the multiple resonators 100 may be two, three, four, and so on.

[0150] In some embodiments, the filter may be a ladder structure filter, which may include a plurality of series arm resonators 100 and a plurality of parallel arm resonators 100, wherein at least one of the plurality of series arm resonators 100 and the plurality of parallel arm resonators 100 is the resonator 100 in the above-mentioned embodiment.

[0151] In some other embodiments, the filter may also be other types of filters.

[0152] In addition, since the filter includes the resonator 100 , the filter has all the beneficial effects of the resonator 100 , which will not be described in detail here.

[0153] The present application also provides a radio frequency front-end module, which includes the filter in the above embodiment. Since the resonator 100 increases the heat dissipation area by setting the thickened layer 23, the power tolerance of the filter can be improved, and the power tolerance of the radio frequency front-end module can be improved.

[0154] In some embodiments, the RF front-end module can be applied to electronic devices, which may include but are not limited to tablet computers, laptop computers, desktop computers, navigators, mobile phones, electronic watches and other electronic devices or components with wireless communication functions, which are not limited in this application.

[0155] In some embodiments, the RF front-end module may include multiple filters, and the multiple filters may be two, three, etc.

[0156] In some implementations, the RF front-end module may further include a low noise amplifier, a RF switch, a power amplifier, etc. The specific connection method thereof may refer to the prior art and will not be described in detail here.

[0157] In addition, since the RF front-end module includes the above-mentioned filter, and the filter includes the above-mentioned resonator 100, the RF front-end module has all the beneficial effects of the filter and the resonator 100, which will not be repeated here.

[0158] Those skilled in the art may combine and associate different embodiments or examples and features of different embodiments or examples described in this specification without mutual contradiction.

[0159] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed in the present application, and these modifications or replacements should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A resonator, characterized in that: include: A piezoelectric substrate having a first surface; an interdigital transducer, wherein the interdigital transducer is disposed on the first surface of the piezoelectric substrate; as well as A first dielectric layer, wherein the first dielectric layer covers a partial area of ​​the interdigital transducer; The interdigital transducer comprises: Two bus bars disposed opposite to each other on the piezoelectric substrate; a plurality of electrode finger pairs located between the two bus bars, the two bus bars being a first bus bar and a second bus bar, each of the electrode finger pairs comprising first electrode fingers and second electrode fingers alternately arranged at intervals from each other, the first electrode fingers being connected to the first bus bar and spaced from the second bus bar, and the second electrode fingers being connected to the second bus bar and spaced from the first bus bar; and a thickening layer disposed on at least one of the bus bars; Wherein, in a first direction, a side surface of the thickened layer away from the piezoelectric substrate is higher than a side surface of the first dielectric layer away from the piezoelectric substrate, and the first direction is a thickness direction of the piezoelectric substrate.

2. The resonator according to claim 1, characterized in that A side of the thickened layer away from the piezoelectric substrate is a first side, and a side of the thickened layer abutting against the bus bar is a second side; The length of the first side surface in the second direction is greater than the length of the second side surface in the second direction, the second direction is the arrangement direction of the two bus bars, and the second direction is perpendicular to the first direction.

3. The resonator according to claim 2, characterized in that In the second direction, the side where the two bus bars are opposite to each other is a first side, and the side where the two bus bars are opposite to each other is a second side; In the second direction, the first side surface has a first edge facing the first side, and the second side surface has a second edge facing the first side; A distance between the first edge and an edge of the bus bar located on the first side is D1, and a distance between the second edge and an edge of the bus bar located on the first side is D2, wherein D2>D1>0.

4. The resonator according to claim 3, characterized in that The first side surface also has a third edge opposite to the first edge, and the second side surface also has a fourth edge opposite to the second edge, the distance between the third edge and the edge of the bus bar located on the second side is D3, and the distance between the fourth edge and the edge of the bus bar located on the second side is D4, wherein D4≥D3≥0.

5. The resonator according to claim 1, characterized in that The first dielectric layer is provided with a slot penetrating along the first direction to the surface of the bus bar, and the thickened layer is filled in the slot and protrudes above the slot.

6. The resonator according to claim 5, characterized in that The portion of the thickened layer protruding above the groove extends along the second direction to a side of the first dielectric layer away from the piezoelectric substrate; and / or, In the second direction, the side opposite to the two bus bars is the first side, the side opposite to the two bus bars is the second side, and the distance between the edge of the slot facing the first side and the first side is D5, D5>3μm; The second direction is an arrangement direction of the two bus bars, and the second direction is perpendicular to the first direction.

7. The resonator according to claim 6, characterized in that The portion of the thickened layer protruding above the slot extends along the second direction until it meets the edge of the first dielectric layer; or, The portion of the thickened layer protruding above the groove extends along the second direction to overlap with a partial area of ​​the first dielectric layer.

8. The resonator according to claim 7, characterized in that The first dielectric layer covers a partial area of ​​the bus bar, and in the second direction, a gap is provided between an edge of the thickened layer and an edge of the bus bar.

9. The resonator according to any one of claims 1 to 8, characterized in that: The thickness of the thickened layer is 1 μm-5 μm; and / or, The material of the thickened layer includes titanium, aluminum or aluminum-copper alloy.

10. The resonator according to any one of claims 1 to 8, characterized in that: The first dielectric layer is a temperature compensation layer, which is used to adjust the frequency temperature coefficient of the resonator; and / or, The material of the first dielectric layer includes silicon dioxide or silicon nitride.

11. The resonator according to any one of claims 1 to 8, characterized in that: The resonator further includes a second dielectric layer, and the second dielectric layer covers the thickened layer and the first dielectric layer.

12. The resonator according to claim 11, characterized in that The material of the second dielectric layer includes silicon nitride or silicon oxynitride; and / or, The thickness of the second dielectric layer is 10nm-200nm.

13. The resonator according to any one of claims 1 to 8, characterized in that: A thickening layer is provided on each of the two bus bars, and one of the thickening layers is used for arranging a solder ball; The thickness of the thickened layer used for setting the solder balls is greater than or equal to the thickness of another thickened layer.

14. A resonator, characterized in that: include: A piezoelectric substrate having a first surface; an interdigital transducer, wherein the interdigital transducer is disposed on the first surface of the piezoelectric substrate; as well as A temperature compensation layer, the temperature compensation layer covers a part of the IDT and is used to adjust the frequency temperature coefficient of the resonator; The interdigital transducer comprises: two bus bars disposed opposite to each other on the piezoelectric substrate; a plurality of electrode finger pairs located between the two bus bars, the two bus bars being a first bus bar and a second bus bar, the electrode finger pairs comprising first electrode fingers and second electrode fingers alternately arranged at intervals from each other, the first electrode fingers being connected to the first bus bar and spaced from the second bus bar, and the second electrode fingers being connected to the second bus bar and spaced from the first bus bar; and a thickening layer disposed on at least one of the bus bars; The thickened layer includes a first layer abutting against the bus bar and a second layer arranged on a side of the first layer away from the piezoelectric substrate, and a projection area of ​​the second layer on the first surface is larger than a projection area of ​​the first layer on the first surface.

15. A filter, characterized in that: Comprising a resonator as claimed in any one of claims 1 to 14.

16. A radio frequency front-end module, characterized in that: Comprising the filter as claimed in claim 15.

Images