High-reliability elastic filter and multiplexer

Abstract

The utility model discloses a high-reliability elastic filter and a multiplexer, and relates to the technical field of elastic wave filters, the high-reliability elastic filter comprises a functional base body, the functional base body comprises a piezoelectric base body and a non-piezoelectric base body matched with the piezoelectric base body; the conductive film comprises a bonding pad electrode group, a resonator group and a plurality of sections of conductive tracks used for realizing electric connection between the bonding pad electrode group and the resonator group, and the resonator group is arranged on the piezoelectric substrate; the bonding pad electrode group comprises a plurality of bonding pad electrodes which are adaptively connected with the resonator group, and at least one bonding pad electrode in the bonding pad electrode group is arranged on the non-piezoelectric substrate. According to the utility model, the reliability of the elastic filter is improved by improving the impact resistance at the bonding pad electrode.

Description

Technical Field

[0001] The utility model relates to the technical field of elastic wave filters, in particular to a high-reliability elastic filter and a multiplexer. Background Art

[0002] Elastic wave devices have the characteristics of low cost, small size and multiple functions, and have been widely used in radar, communication, navigation and other fields. The most commonly used elastic wave devices in mobile phone and base station communications include elastic wave filters and elastic wave duplexers and elastic wave multiplexers composed of multiple elastic wave filters. In any type of elastic wave filter, a conductive material film pattern is set on the piezoelectric functional material to determine multiple interdigital transducer electrodes and multiple conductive tracks and pad electrodes for realizing electrical connection between the interdigital transducer electrodes, and the frequency characteristics of the conversion function of converting the electrical signal of the interdigital transducer electrode into elastic waves are used to obtain the bandpass characteristics.

[0003] With the continuous promotion of 5G technology, the reliability of elastic wave filters has become increasingly important. However, whether in elastic wave filters using flip-chip packaging technology with solder ball connection or in elastic wave filters using ceramic base packaging technology with bonding wire connection, the piezoelectric film at the electrode of the filter pad is very easy to break or fall off due to impact force, which reduces the reliability of the elastic filter. Utility Model Content

[0004] In view of the above problems and technical requirements, the inventors have proposed a high-reliability elastic filter and a multiplexer. The technical solution of the utility model is as follows:

[0005] A high reliability elastic filter, comprising:

[0006] A functional matrix, comprising a piezoelectric matrix and a non-piezoelectric matrix adapted to the piezoelectric matrix;

[0007] The conductive film includes a pad electrode group, a resonator group, and a plurality of conductive tracks for realizing electrical connection between the pad electrode group and the resonator group, wherein:

[0008] The resonator group is arranged on the piezoelectric substrate;

[0009] The pad electrode group includes a plurality of pad electrodes adapted to be connected to the resonator group, and at least one pad electrode in the pad electrode group is disposed on the non-piezoelectric substrate.

[0010] A further technical solution is that the non-piezoelectric substrate is formed based on a non-piezoelectric dielectric material, and the non-piezoelectric substrate is in contact with and connected to the piezoelectric substrate.

[0011] A further technical solution is that it also includes a composite substrate adapted to the functional matrix, wherein:

[0012] When the functional matrix is ​​disposed on a composite substrate, the non-piezoelectric matrix is ​​formed based on the composite substrate or based on a non-piezoelectric dielectric material, wherein:

[0013] When the non-piezoelectric substrate is formed based on a composite substrate, the pad electrode disposed on the non-piezoelectric substrate is located on the composite substrate;

[0014] When the non-piezoelectric matrix is ​​formed based on a non-piezoelectric dielectric material, the non-piezoelectric dielectric material is located on a composite substrate.

[0015] A further technical solution is that when the non-piezoelectric matrix is ​​formed based on a composite substrate, the piezoelectric matrix includes a plurality of etched grooves penetrating the piezoelectric matrix;

[0016] The composite substrate corresponding to the etching groove is exposed through the etching groove, and the non-piezoelectric matrix is ​​formed based on the exposed composite substrate.

[0017] A further technical solution is that when the non-piezoelectric matrix is ​​formed based on a non-piezoelectric dielectric material located on a composite substrate, the piezoelectric matrix includes a plurality of etching grooves, and the etching grooves are filled with non-piezoelectric dielectric material, and the non-piezoelectric matrix is ​​formed based on the filled non-piezoelectric dielectric material.

[0018] A further technical solution is that when the non-piezoelectric substrate is formed based on a non-piezoelectric dielectric material, the non-piezoelectric substrate is flush with the piezoelectric substrate in the height direction, and the pad electrode arranged on the non-piezoelectric substrate is flush with the connected conductive track in the height direction;

[0019] The projection of the pad electrode disposed on the non-piezoelectric substrate in the height direction is located within the projection of the non-piezoelectric substrate in the height direction.

[0020] A further technical solution is that the composite substrate at least includes a supporting substrate;

[0021] The composite substrate further includes an intermediate body disposed on the supporting substrate, wherein:

[0022] The intermediate body includes a low acoustic velocity material film, or a low acoustic velocity material film and a capture material layer disposed below the low acoustic velocity material film.

[0023] A further technical solution is that the sound velocity of the body wave propagating in the low sound velocity material film is lower than the sound velocity of the body wave propagating in the piezoelectric matrix;

[0024] The acoustic velocity of the bulk wave propagating in the supporting substrate is higher than the acoustic velocity of the bulk wave propagating in the piezoelectric base.

[0025] A further technical solution is that the resonator group includes a plurality of resonators, and when the resonator group includes two resonators, the two resonators are connected in parallel or in series;

[0026] When the resonator group includes more than two resonators, the plurality of resonators are connected in series and / or in parallel;

[0027] Each resonator includes an IDT, which includes a plurality of first electrode fingers and a plurality of second electrode fingers arranged in parallel and staggered manner, and a first bus bar and a second bus bar perpendicular to the extending direction of the first electrode fingers and the second electrode fingers and arranged in parallel to each other;

[0028] One end of the first electrode finger is fixed on the first bus bar, and one end of the second electrode finger is fixed on the second bus bar.

[0029] A multiplexer, comprising:

[0030] Antenna terminal, connected to the antenna;

[0031] The filter device group includes a plurality of filter devices connected to the antenna terminal, and at least one filter device in the filter device group is the above-mentioned high-reliability elastic filter.

[0032] The beneficial technical effects of the utility model are:

[0033] The utility model sets at least one pad electrode in the pad electrode group on the non-piezoelectric substrate in the functional substrate, and improves the reliability of the elastic filter by improving the impact resistance at the pad electrode. In addition, when the non-piezoelectric substrate is formed based on a non-piezoelectric dielectric material, the non-piezoelectric substrate and the piezoelectric substrate are flush in the height direction, and the pad electrode set on the non-piezoelectric substrate is flush with the connected conductive track in the height direction, and the reliability of the elastic filter is further improved by eliminating the height difference between the pad electrode and the connected conductive track. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a three-dimensional schematic diagram of an elastic filter in an embodiment provided by the utility model.

[0035] Figure 2 It is a cross-sectional view of an elastic filter at CC' in an embodiment provided by the utility model.

[0036] Figure 3 It is a three-dimensional schematic diagram of an elastic filter in another embodiment provided by the utility model.

[0037] Figure 4 It is a cross-sectional view of an elastic filter at DD' in another embodiment provided by the utility model.

[0038] Figure 5 It is a schematic diagram of a composite substrate in an embodiment provided by the utility model.

[0039] Figure 6 It is a schematic diagram of a composite substrate in another embodiment provided by the utility model.

[0040] Figure 7 It is a schematic diagram of a composite substrate in another embodiment provided by the utility model.

[0041] Figure 8 It is a schematic diagram of a piezoelectric block in another embodiment provided by the utility model.

[0042] Fig. 9 It is a schematic diagram of a resonator in an embodiment provided by the utility model.

[0043] Fig.10 It is a cross-sectional view of a resonator at BB' in an embodiment provided by the utility model.

[0044] Fig.11 It is a cross-sectional view of a resonator at AA' in an embodiment provided by the utility model.

[0045] Figure numerals: 1-first bus bar, 2-second bus bar, 3-first electrode finger, 4-second electrode finger, 5-third bus bar, 6-fourth bus bar, 7-third electrode finger, 8-fourth electrode finger, 9-composite substrate, 10-piezoelectric substrate, 11-low acoustic velocity material film, 13-capture material layer, 14-support substrate, 201-output pad electrode, 202-first ground pad electrode, 203-input pad electrode, 204-second ground pad electrode, 21-first filter first etched groove, 22-first filter second etched groove, 23-first filter third etched groove, 24-first filter fourth etched groove, 21'-the first etched groove of the second filter, 22'-the second etched groove of the second filter, 23'-the third etched groove of the second filter, 24'-the fourth etched groove of the second filter, 211-the first conductive track, 212-the second conductive track, 213-the third conductive track, 214-the fourth conductive track, 215-the fifth conductive track, 216-the sixth conductive track, 217-the seventh conductive track, 218-the eighth conductive track, 219-the ninth conductive track, 231-non-piezoelectric dielectric material body, 61-the middle conductive track, 99-the piezoelectric block, 100-the first elastic filter, 200-the second elastic filter. DETAILED DESCRIPTION

[0046] The specific implementation of the utility model is further described below in conjunction with the accompanying drawings.

[0047] In order to improve the reliability of the elastic filter, the utility model provides a high-reliability elastic filter, comprising:

[0048] A functional matrix, comprising a piezoelectric matrix and a non-piezoelectric matrix adapted to the piezoelectric matrix;

[0049] The conductive film includes a pad electrode group, a resonator group, and a plurality of conductive tracks for realizing electrical connection between the pad electrode group and the resonator group, wherein:

[0050] The resonator group is arranged on the piezoelectric substrate;

[0051] The pad electrode group includes a plurality of pad electrodes adapted to be connected to the resonator group, and at least one pad electrode in the pad electrode group is disposed on the non-piezoelectric substrate.

[0052] Specifically, the piezoelectric substrate 10 generally includes a front side and a back side corresponding to the front side, and the front side crystal axis of the piezoelectric substrate 10 is usually cut to coincide with the back side crystal axis. The functional substrate includes a piezoelectric substrate 10 and a non-piezoelectric substrate, and the non-piezoelectric substrate adapted to the piezoelectric substrate 10 means that the piezoelectric substrate 10 and the non-piezoelectric substrate form a whole, and the specific adaptation method of the piezoelectric substrate 10 and the non-piezoelectric substrate can refer to the following description.

[0053] The conductive film is arranged on the functional substrate, wherein the resonator group is arranged on the piezoelectric substrate, at least one pad electrode in the pad electrode group is arranged on the non-piezoelectric substrate, the resonator group includes a plurality of resonators, the multiple sections of conductive tracks are connected between the pad electrodes and the resonators, and between the resonators, and the conductive tracks are arranged on the piezoelectric substrate 10. The number and distribution of the conductive tracks are set according to the number and distribution of the pad electrodes and the resonators. The adaptation method of the piezoelectric substrate 10 and the non-piezoelectric substrate, and the specific connection method between the pad electrode group and the resonator group can refer to the following embodiments.

[0054] The impact resistance of the non-piezoelectric substrate is better than that of the piezoelectric substrate 10. Therefore, the pad electrodes in the pad electrode group are arranged on the non-piezoelectric substrate, which can effectively improve the reliability of the elastic filter. Preferably, all the pad electrodes in the pad electrode group are arranged on the non-piezoelectric substrate, thereby maximizing the reliability of the elastic filter. In specific implementation, the number of pad electrodes arranged on the non-piezoelectric substrate in the pad electrode group can be selected according to actual needs, specifically based on the need to meet the reliability improvement of the elastic filter.

[0055] Furthermore, the elastic filter also includes a composite substrate 9 adapted to the functional matrix, wherein:

[0056] When the functional matrix is ​​disposed on the composite substrate 9, the non-piezoelectric matrix is ​​formed based on the composite substrate 9 or based on a non-piezoelectric dielectric material located on the composite substrate 9, wherein:

[0057] When the non-piezoelectric base is formed based on the composite substrate 9 , the pad electrode provided on the non-piezoelectric base is located on the composite substrate 9 .

[0058] Specifically, when the non-piezoelectric matrix is ​​formed based on the composite substrate 9, the piezoelectric matrix includes a plurality of etching grooves penetrating the piezoelectric matrix 10, and the composite substrate 9 corresponding to the etching grooves is exposed through the etching grooves, and the non-piezoelectric matrix is ​​formed based on the exposed composite substrate 9.

[0059] Typically, the pad electrode group includes an input pad electrode 203, an output pad electrode 201 and at least one ground pad electrode. In specific implementation, the number of the ground pad electrodes can be selected according to actual needs.

[0060] In one embodiment of the present invention, the non-piezoelectric matrix of the first elastic filter 100 is formed based on the composite substrate 9. Figure 1 is a three-dimensional schematic diagram of the first elastic filter 100, as shown in Figure 1 As shown, the pad electrode group of the first elastic filter 100 includes an input pad electrode 203, an output pad electrode 201, a first ground pad electrode 202 and a second ground pad electrode 204. All pad electrodes of the first elastic filter 100 are arranged on a non-piezoelectric substrate. Corresponding to the number of pad electrodes arranged on the non-piezoelectric substrate, the first elastic filter 100 is respectively provided with a first filter first etching groove 21, a first filter second etching groove 22, a first filter third etching groove 23 and a first filter fourth etching groove 24 at the four corners of the piezoelectric substrate 10. For any etching groove, the etching groove runs through the piezoelectric substrate 10, and the area of ​​the composite substrate 9 corresponding to the projection of the etching groove in the height direction is exposed, forming the non-piezoelectric substrate. At this time, the pad electrode arranged on the non-piezoelectric substrate is arranged on the composite substrate 9 corresponding to the projection of the etching groove in the height direction. The height direction, that is, parallel to Figure 1 The direction of the z-axis in the three-dimensional coordinate system is the direction from the composite substrate 9 to the piezoelectric matrix 10 .

[0061] Specifically, the output pad electrode 201 is arranged on the composite substrate 9 corresponding to the projection of the first etching groove 21 of the first filter in the height direction, the first grounding pad electrode 202 is arranged on the composite substrate 9 corresponding to the projection of the second etching groove 22 of the first filter in the height direction, the grounding pad electrode 203 is arranged on the composite substrate 9 corresponding to the projection of the third etching groove 23 of the first filter in the height direction, and the input pad electrode 204 is arranged on the composite substrate 9 corresponding to the projection of the fourth etching groove 24 of the first filter in the height direction.

[0062] Figure 3 A cross-sectional view of the first elastic filter 100 at C-C' is shown in the figure. In the figure, the dotted line portion represents the composite substrate 9 exposed by the first etching groove 21 of the first filter. The output pad electrode 201 is arranged on the composite substrate 9 corresponding to the projection of the first etching groove 21 of the first filter in the height direction. The output pad electrode 201 is connected to the first conductive track 211 through the intermediate conductive track 61 located at the boundary of the first etching groove 21 of the first filter. Normally, the thickness of the pad electrode group, the resonator group and the multiple conductive tracks in the conductive film are consistent, and the thickness of the piezoelectric substrate 10 is constant. Therefore, the output pad electrode 201 located in the first etching groove 21 of the first filter and the first conductive track 211 located on the piezoelectric substrate 10 have a height difference, so that the intermediate conductive track 61 located between the output pad electrode 201 and the first conductive track 211 is not flat. During subsequent packaging, since the middle conductive track 61 has an uneven surface, whether it is a flip-chip packaging process using solder balls or a ceramic base packaging process using bonding wires, the middle conductive track 61 located under the package body is prone to peeling, breaking or falling off under long-term stress, thereby affecting the reliability of the first elastic filter 100. Figure 1 The connection between the first ground pad electrode 202, the ground pad electrode 203 and the input pad electrode 204 and the corresponding conductive tracks is the same as the connection between the output pad electrode 201 and the intermediate conductive track 61 and the first conductive track 211, and will not be elaborated here one by one.

[0063] In order to avoid a height difference between the pad electrode and the connected conductive track, in another embodiment of the utility model, the non-piezoelectric matrix of the second elastic filter 200 is formed based on a non-piezoelectric dielectric material. When the non-piezoelectric matrix is ​​formed based on a non-piezoelectric dielectric material, the non-piezoelectric dielectric material is located on the composite substrate 9.

[0064] Figure 2 A three-dimensional schematic diagram of the second elastic filter 200 is shown, as shown in FIG. Figure 2As shown, the pad electrodes included in the pad electrode group of the second elastic filter 200 are the same as those of the first elastic filter 100, and all the pad electrodes in the pad electrode group of the elastic filter 200 are arranged on the non-piezoelectric substrate, corresponding to the number of pad electrodes arranged on the non-piezoelectric substrate. The second elastic filter 200 is respectively provided with a second filter first etching groove 21', a second filter second etching groove 22', a second filter third etching groove 23' and a second filter fourth etching groove 24' at the four corners of the piezoelectric substrate 10. For any etching groove, the etching groove is filled with non-piezoelectric dielectric material, and the filled non-piezoelectric dielectric material forms a non-piezoelectric dielectric material body 231, and the non-piezoelectric substrate is formed based on the non-piezoelectric dielectric material body 231.

[0065] Specifically, the output pad electrode 201 is arranged on the non-piezoelectric dielectric material filled in the first etching groove 21' of the second filter, the first grounding pad electrode 202 is arranged on the non-piezoelectric dielectric material filled in the second etching groove 22' of the second filter, the grounding pad electrode 203 is arranged on the non-piezoelectric dielectric material filled in the third etching groove 23' of the second filter, and the input pad electrode 204 is arranged on the non-piezoelectric dielectric material filled in the fourth etching groove 24' of the second filter.

[0066] Further, in the second elastic filter 200, the first etching groove 21' of the second filter, the second etching groove 22' of the second filter, the third etching groove 23' of the second filter, and the fourth etching groove 24' of the second filter may penetrate or not penetrate the piezoelectric matrix 10. The non-piezoelectric dielectric material located on the composite substrate 9 specifically refers to the non-piezoelectric dielectric material directly or indirectly disposed on the composite substrate 9. Taking any etching groove as an example, when the etching groove penetrates the piezoelectric matrix 10, the piezoelectric dielectric material filled in the etching groove is directly disposed on the composite substrate 9. When the etching groove does not penetrate the piezoelectric matrix 10, the piezoelectric dielectric material filled in the etching groove is indirectly disposed on the composite substrate 9. In specific implementation, the etching depths of the first etching groove 21' of the second filter, the second etching groove 22' of the second filter, the third etching groove 23' of the second filter, and the fourth etching groove 24' of the second filter can be selected according to actual needs to meet the formation of the non-piezoelectric matrix.

[0067] Furthermore, when the non-piezoelectric matrix is ​​formed based on the non-piezoelectric dielectric material located on the composite substrate 9, the non-piezoelectric matrix is ​​flush with the piezoelectric matrix 10 in the height direction, and the pad electrode arranged on the non-piezoelectric matrix is ​​flush with the connected conductive track in the height direction.

[0068] Figure 4, a cross-sectional view of the second elastic filter 200 at D-D' is shown in the figure, in which the first etching groove 21' of the second filter passes through the piezoelectric matrix 10, and the etching groove is filled with non-piezoelectric dielectric material to form a non-piezoelectric dielectric material body 231, and the surface of the filled non-piezoelectric dielectric material away from the composite substrate 9 is flush with the piezoelectric matrix 10, that is, the formed non-piezoelectric matrix is ​​flush with the piezoelectric matrix 10 in the height direction. At this time, there is no height difference between the output pad electrode 201 located on the non-piezoelectric matrix and the first conductive track 211 located on the piezoelectric matrix 10, and the intermediate conductive track 61 located between the output pad electrode 201 and the first conductive track 211 can be kept flat. The hidden danger of the intermediate conductive track 61 peeling, breaking or falling off in subsequent bonding packaging and other processes is eliminated, and the reliability of the elastic filter is further improved. Figure 2 The connection between the first ground pad electrode 202, the ground pad electrode 203 and the input pad electrode 204 and the corresponding conductive tracks is the same as the connection between the output pad electrode 201 and the intermediate conductive track 61 and the first conductive track 211 described herein, and will not be elaborated here one by one.

[0069] Furthermore, the projection of the pad electrode disposed on the non-piezoelectric substrate in the height direction is located within the projection of the non-piezoelectric substrate in the height direction.

[0070] Specifically, the projection of the pad electrode arranged on the non-piezoelectric substrate in the height direction is located within the projection of the non-piezoelectric substrate in the height direction, that is, the pad electrodes arranged on the non-piezoelectric substrate need to be all located on the non-piezoelectric substrate, thereby maximizing the area of ​​the pad electrodes located on the non-piezoelectric substrate to improve the reliability of the elastic filter. The definition of the height direction is consistent with the definition of the height direction in the above-mentioned embodiment, and will not be repeated here. For the above-mentioned first elastic filter 100, the pad electrodes arranged on the non-piezoelectric substrate are all located on the non-piezoelectric substrate, that is, the pad electrodes arranged on the non-piezoelectric substrate are completely located on the composite substrate 9. For the above-mentioned second elastic filter 200, the pad electrodes arranged on the non-piezoelectric substrate are all located on the non-piezoelectric substrate, that is, the pad electrodes arranged on the non-piezoelectric substrate are completely located on the filled non-piezoelectric dielectric material.

[0071] Further, the piezoelectric substrate 10 is formed of a piezoelectric material, and the piezoelectric material includes lithium tantalate, lithium niobate, quartz, aluminum nitride, and zinc oxide. The non-piezoelectric dielectric material is formed of one or more combinations of non-piezoelectric dielectric materials, and the non-piezoelectric dielectric material includes silicon dioxide, silicon nitride, etc. In specific implementation, the piezoelectric material used in the piezoelectric substrate 10 and the material used in the non-piezoelectric dielectric material can be selected according to actual needs.

[0072] Further, the composite substrate 9 at least includes a supporting substrate 14;

[0073] The composite substrate 9 also includes an intermediate body disposed on the support substrate 14, wherein:

[0074] The intermediate body includes a low acoustic velocity material film 11 , or a low acoustic velocity material film 11 and a capture material layer 13 disposed below the low acoustic velocity material film.

[0075] The acoustic velocity of the body wave propagating in the low acoustic velocity material film 11 is lower than the acoustic velocity of the body wave propagating in the piezoelectric substrate 10;

[0076] The acoustic velocity of the bulk wave propagating in the supporting substrate 14 is higher than the acoustic velocity of the bulk wave propagating in the piezoelectric base 10 .

[0077] like Figure 7 As shown, when the composite substrate 9 only includes the supporting substrate 14, the piezoelectric matrix 10 is directly disposed on the supporting substrate 14. Figure 6 As shown, the composite substrate 9 includes a supporting substrate 14 and an intermediate, and when the intermediate only includes a low acoustic velocity material film 11, the piezoelectric matrix 10 is directly disposed on the low acoustic velocity material film 11, and the low acoustic velocity material film 11 is directly disposed on the supporting substrate 14. Figure 5 As shown, the composite substrate 9 includes a supporting substrate 14 and an intermediate, and the intermediate includes a low-acoustic-velocity material film 11 and a capture material layer 13, the piezoelectric matrix 10 is directly disposed on the low-acoustic-velocity material film 11, the low-acoustic-velocity material film 11 is directly disposed on the capture material layer 13, and the capture material layer 13 is directly disposed on the supporting substrate 14. In the above two embodiments, the form of the composite substrate 9 used in the first elastic filter 100 and the second elastic filter 200 is the same as Figure 5 The forms shown are the same. During specific implementation, the combination form of the composite substrate 9 can be selected according to actual needs.

[0078] Furthermore, the low acoustic velocity material film 11 is composed of one or more combinations of silicon dioxide, glass, silicon oxynitride, tantalum oxide, or silicon dioxide with a compound containing fluorine, carbon, or boron as the main component. The capture material layer 13 is formed by one or more combinations of amorphous silicon, polycrystalline silicon, amorphous germanium, and polycrystalline germanium. In specific implementation, the materials used in the low acoustic velocity material film 11 and the capture material layer 13 can be selected according to actual needs.

[0079] Furthermore, the piezoelectric substrate 10 may be a piezoelectric film. When the elastic filter includes a composite substrate 9, such as the first elastic filter 100 and the second elastic filter 200, the piezoelectric substrate 10 is a piezoelectric film.

[0080] Furthermore, the elastic filter may not have the composite substrate 9. When the elastic filter does not have the composite substrate 9, the non-piezoelectric matrix is ​​formed based on a non-piezoelectric dielectric material, and the non-piezoelectric matrix is ​​in contact with and connected to the piezoelectric matrix 10.

[0081] Specifically, when the elastic filter does not have the composite substrate 9, the piezoelectric matrix 10 is as follows: Figure 8 As shown in the piezoelectric block 99, at this time, the conductive film is directly arranged on the piezoelectric block 99, the thickness of the piezoelectric block 99 is greater than the piezoelectric film, and the piezoelectric block 99 replaces the composite substrate 9 to support the conductive film.

[0082] The specific formation method of the non-piezoelectric matrix can be the same as the formation method of the non-piezoelectric matrix of the elastic filter 200 in the above embodiment. That is, a plurality of etching grooves with a preset etching depth are etched on the front surface of the piezoelectric block 99 corresponding to the conductive film, and a non-piezoelectric dielectric material is filled in the etching groove. The non-piezoelectric matrix is ​​formed based on the filled non-piezoelectric dielectric material. Preferably, the formed non-piezoelectric matrix is ​​flush with the piezoelectric matrix 10 in the height direction, so that the pad electrode arranged on the non-piezoelectric matrix is ​​flush with the connected conductive track in the height direction. This eliminates the hidden danger of the conductive track located at the edge of the etching groove being peeled off, broken or falling off in subsequent bonding packaging and other processes, and further improves the reliability of the elastic filter.

[0083] Further, the resonator group includes a plurality of resonators, and when the resonator group includes two resonators, the two resonators are connected in parallel or in series;

[0084] When the resonator group includes more than two resonators, the plurality of resonators are connected in series and / or in parallel.

[0085] Specifically, in the above two embodiments, the number and connection method of the resonators in the resonator group of the elastic filter 100 and the elastic filter 200 are the same, and the connection method of each resonator in the resonator group of the first elastic filter 100 is used as an example for description. Figure 1 As shown, in the first elastic filter 100, the resonator group includes a resonator S1, a resonator S2, a resonator S3, a resonator S4, a resonator S5 and a resonator S6, wherein the resonator S1, the resonator S2 and the resonator S3 are connected in series with each other, and the resonator S4, the resonator S5 and the resonator S6 are connected in parallel with each other.

[0086] One end of the resonator S1 is connected to the output pad electrode 201 through the first conductive track 211, the other end of the resonator S1 is connected to one end of the resonator S2 through the second conductive track 211, the other end of the resonator S2 is connected to the resonator S3 through the conductive track 214, and the other end of the resonator S3 is connected to the input pad electrode 203 through the conductive track 216.

[0087] One end of the resonator S4 is connected to the first ground pad electrode 202, and the other end of the resonator S4 is connected to the input pad electrode 203 through the fifth conductive track 215. One end of the resonator S5 is connected to one end of the resonator S3 through the ninth conductive track 219, and the other end of the resonator S5 is connected to one end of the resonator S6 and the second ground pad electrode 204 through the seventh conductive track 217. One end of the resonator S6 is connected to the second ground pad electrode 204 through the eighth conductive track 218, and the other end of the resonator S6 is connected to one end of the resonator S1 and the resonator S2 through the third conductive track 213. In specific implementation, the number of resonators in the resonator group and the connection method can be selected according to actual needs.

[0088] Further, each resonator includes an IDT, which includes a plurality of first electrode fingers 3 and a plurality of second electrode fingers 4 arranged in parallel and staggered manner, and a first bus bar 1 and a second bus bar 2 arranged in parallel and perpendicular to the extending direction of the first electrode fingers 3 and the second electrode fingers 4;

[0089] Specifically, the structure of the resonator is described by taking any one resonator in the resonator group as an example. Fig. 9 As shown, the resonator is fixed on the piezoelectric substrate 10 and parallel to Figure 1 The direction of the x-axis in the coordinate system is taken as the direction of elastic wave propagation, which is parallel to Figure 1 The direction of the y-axis in the coordinate system is used as the extension direction of the electrode finger. The first bus bar 1 and the second bus bar 2 are parallel to the elastic wave propagation direction, and the end of the first electrode finger 3 away from the second bus bar 2 is fixed to the first bus bar 1, and the end of the second electrode finger 4 away from the first bus bar 1 is fixed to the second bus bar 2. Fig.10 is the cross-sectional view of the resonator at B-B', as Fig.10 As shown, when the elastic filter has a composite substrate 9, the resonator is located on a piezoelectric substrate 10, and the piezoelectric substrate 10 is located on the composite substrate 9. In the figure, AP represents the overlapping distance between the first electrode finger 3 and the second electrode finger 4 of the resonator. This distance is usually called the aperture of the interdigital transducer. In specific implementation, the aperture of the interdigital transducer can be set according to actual needs.

[0090] Fig.11It is a cross-sectional view of the resonator at AA'. In the figure, the spacing distance λ between adjacent first electrode fingers 3 or adjacent second electrode fingers 4 is usually called the wavelength of the IDT. In specific implementation, the wavelength of the IDT and the number of fingers of the first electrode fingers 3 and the second electrode fingers 4 can be selected according to actual needs.

[0091] Furthermore, the resonator further comprises a reflector, the IDT and the reflector are arranged along the propagation direction of the elastic wave, and a reflector is disposed on both sides of each IDT;

[0092] The reflector includes a plurality of third electrode fingers 7 and a plurality of fourth electrode fingers 8 which are arranged in parallel and staggered manner, and a third bus bar 5 and a fourth bus bar 6 which are perpendicular to the extending direction of the third electrode fingers 7 and the fourth electrode fingers 8 and are arranged in parallel with each other.

[0093] like Fig. 9 As shown, the third bus bar 5 and the fourth bus bar 6 are parallel to the propagation direction of the elastic wave, and the end of the third electrode finger 7 away from the third bus bar 5 is fixed to the third bus bar 5, and the end of the fourth electrode finger 8 away from the third bus bar 5 is fixed to the fourth bus bar 6. The spacing distance between the first electrode finger 3 and the fourth electrode finger 8 and the number of fingers can be selected according to actual needs.

[0094] The utility model also provides a multiplexer, comprising:

[0095] Antenna terminal, connected to the antenna;

[0096] The filter device group includes a plurality of filter devices connected to the antenna terminal, and at least one filter device in the filter device group is the high-reliability elastic filter.

[0097] The multiplexer generally refers to a type of device that includes multiple filter devices and can transmit and receive multiple frequency bands simultaneously. The filter devices in the multiplexer are usually connected in parallel to a common node, that is, connected to the antenna through the same antenna terminal. In specific implementation, the number of high-reliability elastic filters included in the filter device group can be set according to actual needs.

[0098] It should be noted that the words "front", "rear", "left", "right", "up" and "down" used in the following description refer to the directions in the drawings of the present application specification, and the words "bottom surface" and "top surface", "inside" and "outside" refer to the direction toward or away from a specific component, respectively. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application specification, the meaning of "multiple" is two or more.

[0099] The above is only a preferred embodiment of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A high reliability elastic filter, characterized in that: include: A functional matrix, comprising a piezoelectric matrix and a non-piezoelectric matrix adapted to the piezoelectric matrix; The conductive film includes a pad electrode group, a resonator group, and a plurality of conductive tracks for realizing electrical connection between the pad electrode group and the resonator group, wherein: The resonator group is arranged on the piezoelectric substrate; The pad electrode group includes a plurality of pad electrodes adapted to be connected to the resonator group, and at least one pad electrode in the pad electrode group is disposed on the non-piezoelectric substrate.

2. The high reliability elastic filter according to claim 1, characterized in that: The non-piezoelectric substrate is formed based on a non-piezoelectric dielectric material, and the non-piezoelectric substrate is in contact with and connected to the piezoelectric substrate.

3. The high reliability elastic filter according to claim 1, characterized in that: Also included is a composite substrate adapted to the functional matrix, wherein: When the functional matrix is ​​disposed on a composite substrate, the non-piezoelectric matrix is ​​formed based on the composite substrate or based on a non-piezoelectric dielectric material, wherein: When the non-piezoelectric substrate is formed based on a composite substrate, the pad electrode disposed on the non-piezoelectric substrate is located on the composite substrate; When the non-piezoelectric matrix is ​​formed based on a non-piezoelectric dielectric material, the non-piezoelectric dielectric material is located on a composite substrate.

4. The high reliability elastic filter according to claim 3, characterized in that: When the non-piezoelectric matrix is ​​formed based on a composite substrate, the piezoelectric matrix includes a plurality of etched grooves penetrating the piezoelectric matrix; The composite substrate corresponding to the etching groove is exposed through the etching groove, and the non-piezoelectric matrix is ​​formed based on the exposed composite substrate.

5. The high reliability elastic filter according to claim 3, characterized in that: When the non-piezoelectric matrix is ​​formed based on the non-piezoelectric dielectric material located on the composite substrate, the piezoelectric matrix includes a plurality of etching grooves, and the etching grooves are filled with the non-piezoelectric dielectric material, and the non-piezoelectric matrix is ​​formed based on the filled non-piezoelectric dielectric material.

6. The high reliability elastic filter according to any one of claims 1 to 5, characterized in that: When the non-piezoelectric substrate is formed based on a non-piezoelectric dielectric material, the non-piezoelectric substrate is flush with the piezoelectric substrate in the height direction, and the pad electrode arranged on the non-piezoelectric substrate is flush with the connected conductive track in the height direction; The projection of the pad electrode disposed on the non-piezoelectric substrate in the height direction is located within the projection of the non-piezoelectric substrate in the height direction.

7. The high reliability elastic filter according to claim 3, characterized in that: The composite substrate at least comprises a supporting substrate; The composite substrate further comprises an intermediate body disposed on the supporting substrate, wherein: The intermediate body includes a low acoustic velocity material film, or a low acoustic velocity material film and a capture material layer disposed below the low acoustic velocity material film.

8. The high reliability elastic filter according to claim 7, characterized in that: The acoustic velocity of the body wave propagating in the low acoustic velocity material film is lower than the acoustic velocity of the body wave propagating in the piezoelectric matrix; The acoustic velocity of the bulk wave propagating in the supporting substrate is higher than the acoustic velocity of the bulk wave propagating in the piezoelectric base.

9. The high reliability elastic filter according to claim 1, characterized in that: The resonator group includes a plurality of resonators. When the resonator group includes two resonators, the two resonators are connected in parallel or in series. When the resonator group includes more than two resonators, the plurality of resonators are connected in series and / or in parallel; Each resonator includes an IDT, which includes a plurality of first electrode fingers and a plurality of second electrode fingers arranged in parallel and staggered manner, and a first bus bar and a second bus bar perpendicular to the extending direction of the first electrode fingers and the second electrode fingers and arranged in parallel to each other; One end of the first electrode finger is fixed on the first bus bar, and one end of the second electrode finger is fixed on the second bus bar.

10. A multiplexer, characterized in that: include: Antenna terminal, connected to the antenna; The filter device group comprises a plurality of filter devices connected to the antenna terminal, wherein at least one filter device in the filter device group is a high reliability elastic filter as claimed in any one of claims 1 to 9.

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