CN111342814B - Bulk acoustic wave filter, multiplexer and electronic equipment - Google Patents
Bulk acoustic wave filter, multiplexer and electronic equipment Download PDFInfo
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- CN111342814B CN111342814B CN202010083787.8A CN202010083787A CN111342814B CN 111342814 B CN111342814 B CN 111342814B CN 202010083787 A CN202010083787 A CN 202010083787A CN 111342814 B CN111342814 B CN 111342814B
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- 238000010897 surface acoustic wave method Methods 0.000 description 4
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/70—Multiple-port networks for connecting several sources or loads, working on different frequencies or frequency bands, to a common load or source
- H03H9/703—Networks using bulk acoustic wave devices
- H03H9/706—Duplexers
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
Abstract
The invention provides a piezoelectric acoustic wave filter, which comprises a carrier plate, an upper wafer and a lower wafer, wherein the upper wafer and the lower wafer are positioned on the carrier plate and are sequentially arranged from top to bottom, and a metal shielding layer is arranged on the upper surface and/or the lower surface of the upper wafer and is grounded. The piezoelectric acoustic wave filter has a better grounding effect and good grounding shielding characteristics.
Description
Technical Field
The invention relates to the technical field of filtering devices for communication, in particular to a bulk acoustic wave filter which is manufactured by utilizing the piezoelectric effect principle and can be assembled by gold wire bonding.
Background
At present, a small-sized filtering device capable of meeting the use requirement of a communication terminal is mainly a piezoelectric acoustic wave filter, and resonators constituting the acoustic wave filter mainly include: FBAR (Film Bulk Acoustic Resonator), SMR (solid Mounted Resonator), SAW (Surface Acoustic Wave), and Bulk Acoustic Resonator BAW manufactured based on the Bulk Acoustic Wave principles FBAR and SMR.
Since SAW is a piezoelectric device fabricated on a specific piezoelectric crystal and is not compatible with a general semiconductor silicon process, SAW is mostly fabricated into a plastic package product by flip chip CSP (chip scale package).
The manufacturing process of the BAW is a general silicon wafer semiconductor process, and can realize the sealing protection of the internal resonator through wafer-level bonding, so that the micro-assembly can be realized through a gold wire bonding mode. However, the bonding micro-assembly of BAW has a technical problem that it is not easy to solve, firstly, all bonding wires can be equivalent to an inductor of about 0.3 nH-1 nH, especially, the grounded inductance value determines the position of transmission zero, thereby affecting the far-band rejection of the filter, and the rejection tends to be-20 dB or even worse at the position of frequency doubling or frequency tripling. Moreover, too many bonding wires are also susceptible to external radio frequency interference, thereby deteriorating out-of-band rejection or isolation characteristics.
In most communication systems, interference signals with a frequency equal to two or three times the signal frequency are generated, and the filter is used as an important frequency selection device, and the suppression of the filter at the frequency doubling or frequency tripling part is particularly important. Therefore, how to realize the high far band rejection and high isolation of the BAW filter under the micro-assembly condition still remains a problem to be solved urgently.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a bulk acoustic wave filter, a multiplexer and electronic equipment, which realize better grounding effect and good grounding shielding characteristic.
To achieve the above object, according to one aspect of the present invention, there is provided a bulk acoustic wave filter.
The bulk acoustic wave filter comprises a carrier plate, an upper wafer and a lower wafer, wherein the upper wafer and the lower wafer are positioned on the carrier plate and are sequentially arranged from top to bottom, and a metal shielding layer is arranged on the upper surface and/or the lower surface of the upper wafer and is grounded. By adding the metal shielding layer, the grounding effect and the shielding characteristic of the filter are improved.
Optionally, the metal shielding layer on the upper surface of the upper wafer is connected to the metal ground plane on the lower surface of the lower wafer through the wafer-level bonding region and the via holes of the upper wafer and the lower wafer; and/or the metal shielding layer on the lower surface of the upper wafer is connected with the metal ground plane on the lower surface of the lower wafer through the wafer-level bonding region and the plurality of through holes of the lower wafer. Therefore, all resonators of the filter are located in the metal shielding space formed by the metal shielding layer of the upper wafer, the upper wafer grounding via hole, the lower wafer grounding via hole and the metal ground plane on the lower surface of the lower wafer, and the filter is enabled to obtain better electromagnetic isolation. In the case of using a plurality of vias, the ground inductance of the metal shield layer constituting the shield space described above will be smaller.
Optionally, all resonators of the filter are located on the upper surface of the lower wafer.
Optionally, part or all of the resonators to be grounded in the filter are connected to the metal shielding layer on the upper surface of the upper wafer through the wafer-level bonding region and the plurality of vias of the upper wafer.
Optionally, part or all of the resonators to be grounded in the filter are connected to the metal shielding layer on the lower surface of the upper wafer through the wafer-level bonding region.
Optionally, part or all of the resonators to be grounded in the filter are connected to the metal ground plane on the lower surface of the lower wafer through vias of the lower wafer.
Optionally, at least one of the resonators to be grounded is connected with a plurality of vias.
The resonator is connected to the metal shielding layer, so that the grounding inductance of the resonator is reduced, the transmission zero point with out-of-band rejection is formed to move towards high frequency, and when the transmission zero point moves to double frequency, even triple frequency, the out-of-band rejection and isolation characteristics of the corresponding position can be improved; when a certain resonator is connected through a plurality of via holes, the ground inductance of the resonator can be further reduced.
Optionally, the metal ground plane of the lower surface of the lower wafer is bonded to the ground plane of the carrier board through a conductive adhesive so as to be grounded.
According to another aspect of the present invention, there is provided a multiplexer including the bulk acoustic wave filter of the present invention.
According to yet another aspect of the present invention, there is provided an electronic device comprising the bulk acoustic wave filter of the present invention.
Drawings
The drawings are included to provide a better understanding of the invention and are not to be construed as unduly limiting the invention. Wherein:
fig. 1 is a structural diagram of a conventional filter;
fig. 2 is a circuit diagram of a conventional filter;
FIG. 3a is a simulation of the amplitude-frequency response of a conventional filter as a function of the mutual inductance M1 between IN and G1;
FIG. 3b is a simulation of the amplitude-frequency response curve of a conventional filter as a function of the mutual inductance M2 between G1 and G2;
fig. 4 is a schematic diagram of components of a prior art filter in a top view;
fig. 5 and 6 are structural views of a piezoelectric acoustic wave filter according to an embodiment of the present invention;
fig. 7 is a structural view of a piezoelectric acoustic wave filter according to a second embodiment of the present invention;
fig. 8 is a structural view of a three-piezoelectric acoustic wave filter according to an embodiment of the present invention;
FIG. 9a is a graph of the amplitude-frequency response of the filter adjacent to the stop band;
FIG. 9b is a graph of the amplitude-frequency response of the far stop band of the filter;
fig. 10a and 10b are schematic diagrams of the effect of the ground inductance connecting the parallel resonators on the resonator transmission zero.
Detailed Description
The invention is further described with reference to the following figures and examples.
Fig. 1 is a structural diagram of a conventional filter; fig. 2 is a circuit diagram of a conventional filter. IN fig. 1, IN is an input signal bonding wire, OUT is an output signal bonding wire, G1 is a ground bonding wire of the first-stage parallel branch, and G2 is a ground bonding wire of the second-stage parallel branch. Because the bonding wires have certain lengths, the lengths of the four bonding wires IN, OUT, G1 and G2 are generally between 0.5mm and 2mm, and the inductance introduced by the four bonding wires is generally between 0.4nH and 1.5 nH. Because the chip size is small, the distance between the bonding wires is very close, mutual inductance is inevitably introduced, the mutual inductance is related to the inductance of the bonding wires and the distance between the bonding wires, generally ranging from 3pH to 20pH, the closer the distance, the larger the mutual inductance, the farther the distance, and the smaller the mutual inductance. Because the input and the output are generally farthest, and are positioned at two sides of the chip and are IN the same direction, the mutual inductance between the IN and the OUT is minimum and can be ignored. Here only the effect of the mutual inductance M1 between IN and G1, the mutual inductance M2 between G1 and G2, and the mutual inductance M3 between G2 and OUT on the filter performance was analyzed. Since the filter can be generally considered as a network with two reciprocal ends from the circuit point of view, the functions of M1 and M3 in the circuit are similar, and are represented by M1.
FIG. 3a is a simulation of the amplitude-frequency response of a conventional filter as a function of the mutual inductance M1 between IN and G1; FIG. 3b is a simulation of the amplitude-frequency response curve of a conventional filter as a function of the mutual inductance M2 between G1 and G2; the variation of mutual inductance is 3-18 pH, and the step is 3 pH. As can be seen from the simulation results of fig. 3a, the variation of M1 has little effect on the filter performance, and all curves almost overlap. As shown in the simulation result of fig. 3b, the change of M2 has a large effect on the out-of-band transmission zero point of the filter, and for example, at 2.27GHz, the out-of-band rejection is about-58 dB when M2 is 3pH, about-44 dB when M2 is 18pH, and even if M2 is 6pH, the out-of-band rejection is sharply deteriorated to-53 dB, and deteriorated by 5 dB.
In the assembly method of gold wire bonding, because the length, included angle, height and direction of the bonding wire have great inconsistency, taking the second drop point of the bonding wire on the carrier as an example, the position deviation of the bonding point which can be realized by the existing automatic bonding machine with high precision is +/-25um, and the change of M2 by 5pH or even 20pH is very likely to occur due to the combination of various factors, but the bonding factors are unavoidable.
Fig. 4 is a schematic diagram of components in a top view of a conventional filter. As shown IN FIG. 4, there are four pads distributed on the top surface, with IN at the top left, OUT at the top right, G1 at the bottom left, and G2 at the bottom right. The bonding pad is provided with a wafer level bonding area, and a wafer through hole is formed in the bonding area. The filter has 3 series resonators, S1, S2, S3, and 2 parallel resonators, P1 and P2.
Based on the mutual inductance mode of the bonding wire inside the existing filter, when the micro-assembly is generally adopted, the filter can be exposed in a severe electromagnetic environment, and when an interference signal exists outside, the performance of the filter can be also deteriorated.
Meanwhile, the position of the out-of-band rejection zero of the filter is closely related to the inductance of the grounding bonding wire, generally, the larger the inductance of the grounding is, the closer the transmission zero at two sides of the filter is to the low frequency direction, at the moment, the far band rejection at the high frequency side of the filter is changed along with the movement of the transmission zero position to the low frequency direction, and particularly, the position from center frequency doubling to triple frequency is. Conversely, the smaller the inductance of the ground, the closer the transmission zero on both sides of the filter is to the high frequency direction, and at this time, the better the far band suppression on the high frequency side of the filter is as the transmission zero position moves to the high frequency.
Fig. 10a and 10b are schematic diagrams showing the effect of the ground inductance connecting the parallel resonators on the transmission zero point of the resonators, the dotted line is the impedance response of the resonator and inductor combination circuit when the ground inductance is 0.4nH, and the solid line is the impedance response of the resonator and inductor combination circuit when the ground inductance is 0.2 nH. It can be seen that the inductance is reduced by half, and the transmission zero point on the left side and the transmission zero point on the right side both move from low frequency to high frequency in the direction indicated by the arrows.
In most communication systems, interference signals with a frequency equal to two or three times the signal frequency are generated, and the filter is used as an important frequency selection device, and the suppression of the filter at the frequency doubling or frequency tripling part is particularly important. Therefore, how to realize the performance of the filter out-of-band, especially the performance of the rejection and isolation of the high-frequency far stop band under the condition of the bonding wire assembly is a problem to be solved.
In the embodiments of the present invention, the bonding wires required to be interconnected with the carrier are classified into two types, one is a signal bonding wire connected to a signal wire bonding finger on the carrier, and the other is a ground bonding wire connected to a ground of the carrier. And conducting the signal wire to a gasket positioned on the front surface of the chip. The ground is connected to the metallization plane on the back side of the chip through the via hole by making the via hole in the wafer. During micro-assembly, the metalized plane on the back of the chip is adhered to the ground plane of the packaging carrier plate through the conductive adhesive, and the signal bonding gasket on the front of the chip is connected to the signal bonding finger on the carrier plate through the bonding wire.
Example one
Fig. 5 and 6 are structural diagrams of a piezoelectric acoustic wave filter according to an embodiment of the present invention. In which figure 6 shows the components in a top view. It should be noted that fig. 5 and 6 are only schematic diagrams of components and connection relationships, and both show components and basic positions and connection relationships of the same piezoelectric acoustic wave filter, but the proportions and dimensions of the components in the two do not correspond to each other to form a cross-sectional view and a top view of the device.
As shown in fig. 5, the piezoelectric acoustic wave filter mainly includes a carrier board 1, and a top wafer 4, a bottom wafer 5, a first metal shielding layer 13 and a seal ring 7 located on the carrier board 1. An input signal bonding pad 3 and an output signal bonding pad 11 are arranged on the upper surface of the upper wafer 4, and an input signal bonding finger 2 and an output signal bonding finger 12 are arranged on the carrier plate 1; the input signal bonding pad 3 on the upper surface of the upper wafer 4 is connected to the input signal bonding finger 2 of the carrier board through an input signal bonding wire IN, and the output signal bonding pad 11 on the upper surface of the upper wafer 4 is connected to the output signal bonding finger 12 of the carrier board through an output signal bonding wire OUT, so that the electrical interconnection between the chip and the carrier board is realized.
As shown in fig. 6, the first metallic shield layer 13 spreads over almost the entire upper surface of the upper wafer 4, leaving only bonding pads. Also shown in fig. 6 are vias in upper wafer 4 and lower wafer 5, which are not actually visible in plan view, and in fig. 6 to show their location, multiple vias can be seen and are staggered.
Referring to fig. 5 again, the first metal shielding layer 13 is disposed on the upper surface of the upper wafer 4, and a sealing ring 7 is disposed between the lower surface of the upper wafer 4 and the upper surface of the lower wafer 5 for sealing the sensitive circuit between the two wafers. Seal ring 7 is one type of wafer level bonding region that, in addition to functioning as a connecting wafer for conventional wafer level bonding regions (e.g., wafer level bonding regions 71, 72 in the figure), also functions to seal and shield the inter-wafer gap. The upper surface of the lower wafer 5 is provided with a metal pattern connected with the seal ring, the metal pattern is an irregular metal layer (not shown in the figure) and plays a role of electrical connection, and a resonator needing grounding in the filter is connected to the seal ring 7 through the metal pattern to form an equipotential body with the same potential; the lower surface of the lower wafer 5 is provided with a metal ground plane 8, and the metal ground plane 8 on the lower surface of the lower wafer is adhered to the ground plane 6 of the carrier board through a conductive adhesive 16.
Two through holes 9 are formed in the lower wafer 5 and can be symmetrically arranged; the equipotential body is connected to a metal ground plane 8 on the lower surface of the lower wafer 5 through two via holes 9, and the metal ground plane 8 on the lower surface of the lower wafer is adhered to the ground plane 6 of the carrier plate through a conductive adhesive 16. Through the two through holes 9 arranged in parallel, the equipotential body is connected with the metal ground plane 8 in parallel, so that the geometric length of the conductor is reduced, the common-ground inductance is reduced, and the potential difference between the equipotential body and the metal ground plane is also reduced.
Two through holes 9 are formed in the upper wafer 4, and the equipotential body is connected to the first metal shielding layer 13 on the upper surface of the upper wafer 4 through the two through holes 9 in the upper wafer 4. The first metal shielding layer 13 is fully or almost fully paved on the upper surface of the upper wafer 4 except the input signal bonding pad 3 and the output signal bonding pad 11, and is connected with the equipotential body through two via holes, so that the connection with the metal ground plane on the lower surface of the lower wafer 5 is realized, and good grounding shielding characteristics are realized.
Two symmetrically arranged through holes 9 are formed in the upper wafer 4, and two symmetrically arranged second through holes 9 are also formed in the lower wafer 5; the input signal line is connected to the input signal bonding pad 3 on the upper surface of the upper wafer through a via hole 9 in the upper wafer 4; the output signal wire is connected to an output signal bonding pad 11 on the upper surface of the upper wafer through another via hole 9 in the upper wafer 4; the grounding wires G1 and G2 are respectively connected to the metal ground plane 8 on the lower surface of the lower wafer through the via holes 9 in the lower wafer 5; the metal ground plane 8 of the lower surface of the lower wafer 5 is glued to the ground plane 6 of the carrier plate by means of an electrically conductive glue. The vias in the upper wafer 4 and the lower wafer 5 provide the effect of the bonding region to enhance wafer-level bonding, enabling electrical interconnection between the two wafers.
The piezoelectric acoustic wave filter provided by the embodiment realizes the minimization of the grounding inductors G1 and G2, the inductance value of the piezoelectric acoustic wave filter can reach 0.05nH and even approach to 0nH, the reduction of the grounding inductors enables the transmission zero point forming out-of-band rejection to move to high frequency, and when the transmission zero point moves to double frequency, even triple frequency, the out-of-band rejection and isolation characteristics of corresponding positions can be improved.
Meanwhile, according to the structure, all resonators of the filter are located in a metal shielding space formed by the upper surface shielding ground plane of the upper wafer, the upper wafer grounding via hole, the lower wafer grounding via hole and the metal ground plane of the lower surface of the lower wafer, only the input and output signal bonding gasket is connected with the internal device of the chip and is connected to an external carrier plate through a bonding wire, and therefore the internal circuit of the filter is wrapped by the metal shielding space to obtain better electromagnetic isolation.
Example two
Fig. 7 is a structural diagram of a second piezoelectric acoustic wave filter of the present embodiment. As shown in fig. 7, the piezoelectric acoustic wave filter mainly includes a carrier board 1, and a top wafer 4, a bottom wafer 5, a first metal shielding layer 13, a seal ring 7, and the like, which are located on the carrier board 1. The main difference between the present embodiment and embodiment 1 is that the metal shielding layer 13 is located on the lower surface of the upper wafer 4. The upper surface of the lower wafer 5 is provided with a metal pattern (not shown in the figure) connected with the seal ring 7, and resonators in the filter, which need to be grounded, are connected on the seal ring 7 through the metal pattern to form equipotential bodies with the same potential, and the equipotential bodies are connected to the first metal shielding layer 13 on the lower surface of the upper wafer 4 through bonding regions.
Through the two through holes 9 arranged in parallel, the equipotential body is connected with the metal ground plane 8 in parallel, so that the geometric length of the grounded conductor is shortened, the common-ground inductance is reduced, and the potential difference between the equipotential body and the metal ground plane is reduced.
As shown in fig. 7, similar to the first embodiment, the plurality of vias 9 in the upper wafer 4 and the lower wafer 5 provide the effect of the bonding region to enhance wafer-level bonding, and thus, electrical interconnection between the two wafers is achieved. And the inductance is greatly reduced compared with the prior art by connecting a plurality of through holes in parallel.
Meanwhile, according to the structure, all resonators of the filter are connected with the chip internal device only through the input and output signal bonding gasket in the metal shielding space formed by the upper wafer lower surface shielding ground plane, the upper wafer grounding via hole, the lower wafer grounding via hole and the metal ground plane on the lower wafer lower surface, and are connected to the external carrier plate through the bonding wire, so that the internal circuit of the filter is wrapped by the metal shielding space to obtain electromagnetic isolation, the filter is not interfered by external signals, and the best filter performance is achieved.
EXAMPLE III
Fig. 8 is a structural diagram of the three piezoelectric acoustic wave filters of the present embodiment. As shown in fig. 8, the piezoelectric acoustic wave filter mainly includes a carrier board 1, and a first metal shielding layer 13, a second metal shielding layer 14 and a sealing ring 7 located on the carrier board 1 and formed by an upper wafer 4, a lower wafer 5. The main difference from the foregoing embodiment is that, in the present embodiment, the upper and lower surfaces of the upper wafer 4 are both provided with metal shielding layers. The other structure is similar to the foregoing embodiment. As can be seen from the structure of fig. 8, in the metal shielding space formed by the first metal shielding layer 13, the second metal shielding layer 14, the upper wafer ground via hole, the lower wafer ground via hole, and the metal ground plane on the lower surface of the lower wafer, only the input/output signal bonding pad is connected to the internal device of the chip and is connected to the external carrier board through the bonding wire, so that the internal circuit of the filter is wrapped by the metal shielding space to obtain better electromagnetic isolation.
Fig. 9a and 9b are graphs showing the loss of the piezoelectric acoustic wave filter proposed in the first embodiment (solid line) compared with the loss of the conventional piezoelectric acoustic wave filter (dotted line), in which the center frequency of the filter is 6GHz, fig. 9a is a graph showing the amplitude-frequency response of the filter adjacent to the stop band, and the arrow on the left side of the filter shows the effect of moving the transmission zero on the left side of the pass band to a high-frequency position after the structure of the filter proposed in the first embodiment is changed from the bond wire grounding. Fig. 9b is a graph of the amplitude-frequency response of the far stop band of the filter. The arrow on the right side of the filter shows the effect of moving the transmission zero on the right side of the passband to a high frequency position after the bond wire grounding is changed into the filter structure proposed in this embodiment.
It can be seen that the far band out-of-band rejection of the filter on the high frequency side is improved due to the shift of the transmission zero to the high frequency. In particular, the out-of-band rejection is improved from the original-14 dB to-46 dB at the double frequency of 12 GHz. Due to the isolation structure shown in the filter provided by the embodiment, a main circuit of the filter is located in the grounding shielding structure, so that the influence of external interference on the filter is avoided, and the performance of each aspect is greatly improved.
Embodiments of the present invention have been illustrated above with reference to several examples. The details of implementation of the invention are not limited to the above-described modes. For example, there may be parts of the resonators in the filter that need to be grounded, which are directly connected to some metal ground plane, and not necessarily connected to the seal ring. In the embodiment of the present invention, the resonator in the filter, for example, the film bulk acoustic resonator FBAR, is formed on the upper surface of the lower wafer, so that the distance between the metal shielding layer 13 and the resonator FBAR is the distance between the upper wafer and the lower wafer, and is about 2um to 20 um. This is because the distance setting is made in consideration of the fact that when the distance between the metal shield layer 13 and the resonator FBAR is too close, the return loss characteristic of the filter is slightly changed due to the presence of the parasitic capacitance, but the characteristic of far band suppression is hardly changed.
Although the embodiments of the present invention have been described with reference to the accompanying drawings, it is not intended to limit the scope of the present invention, and it should be understood by those skilled in the art that various modifications and variations can be made without inventive efforts by those skilled in the art based on the technical solution of the present invention.
Claims (7)
1. A bulk acoustic wave filter includes a carrier and an upper wafer and a lower wafer sequentially arranged from top to bottom on the carrier,
all resonators of the filter are located on the upper surface of the lower wafer; the upper surface of the upper wafer is provided with an input signal bonding pad and an output signal bonding pad, the input signal bonding pad is connected to an input signal bonding finger of the carrier plate through input signal bonding money, and the output signal bonding pad is connected to an output signal bonding finger of the carrier plate through output signal bonding money;
the upper surface and the lower surface of the upper wafer are respectively provided with a metal shielding layer, a distance exists between the metal shielding layer on the upper surface of the upper wafer and an input signal bonding gasket and between the metal shielding layer on the upper surface of the upper wafer and an output signal bonding gasket, the upper wafer is provided with a plurality of first through holes, a plurality of second through holes and a plurality of third through holes, and the input signal bonding gasket and the output signal bonding gasket are respectively connected with the resonator through the first through holes; the metal shielding layer on the upper surface of the upper wafer is connected with the metal shielding layer on the lower surface of the upper wafer through a plurality of second via holes and a plurality of third via holes; a sealing ring is arranged between the lower surface of the upper wafer and the upper surface of the lower wafer;
the upper surface of the lower wafer is provided with a metal pattern connected with the sealing ring, the metal pattern is an irregular metal layer, and a resonator needing grounding in the filter is connected to the sealing ring through the metal pattern to form an equipotential body with the same potential;
a plurality of fourth through holes are formed in the lower wafer and located on the lower side of the sealing ring, and the sealing ring is connected to the metal ground plane on the lower surface of the lower wafer through the fourth through holes;
the lower wafer is also provided with a plurality of fifth via holes and a plurality of sixth via holes, the resonators needing to be grounded in the filter are connected to the metal ground plane on the lower surface of the lower wafer through the fifth via holes and are connected to the second via holes, and the resonators needing to be grounded in the rest part of the filter are connected to the metal ground plane on the lower surface of the lower wafer through the sixth via holes and are connected to the third via holes.
2. The bulk acoustic wave filter according to claim 1,
the metal shielding layer on the upper surface of the upper wafer is connected with the metal ground plane on the lower surface of the lower wafer through a plurality of second through holes and a plurality of third through holes in the upper wafer, a wafer-level bonding region and a plurality of fifth through holes and sixth through holes in the lower wafer; and the number of the first and second electrodes,
the metal shielding layer on the lower surface of the upper wafer is connected with the metal ground plane on the lower surface of the lower wafer through the wafer-level bonding region and the fifth through holes and the sixth through holes of the lower wafer.
3. The bulk acoustic wave filter according to claim 1, wherein some or all of the resonators to be grounded in the filter are connected to the metal shielding layer on the upper surface of the upper wafer through the wafer level bonding region and the second and/or third plurality of vias of the upper wafer.
4. The bulk acoustic wave filter according to claim 1, wherein some or all of the resonators to be grounded are connected to the metal shielding layer on the lower surface of the upper wafer through wafer level bonding regions.
5. The bulk acoustic wave filter of claim 1, wherein the metal ground plane of the lower surface of the lower wafer is bonded to the ground plane of the carrier plate by a conductive adhesive to ground.
6. A multiplexer comprising the bulk acoustic wave filter according to any one of claims 1 to 5.
7. An electronic device comprising the bulk acoustic wave filter according to any one of claims 1 to 5.
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| CN202010083787.8A CN111342814B (en) | 2020-02-10 | 2020-02-10 | Bulk acoustic wave filter, multiplexer and electronic equipment |
| PCT/CN2020/141266 WO2021159880A1 (en) | 2020-02-10 | 2020-12-30 | Bulk acoustic wave filter, multiplexer, and electronic device |
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| CN111342814B (en) * | 2020-02-10 | 2021-09-21 | 诺思(天津)微系统有限责任公司 | Bulk acoustic wave filter, multiplexer and electronic equipment |
| CN112187212B (en) * | 2020-09-18 | 2021-12-07 | 杭州星阖科技有限公司 | Acoustic resonator assembly and filter |
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