CN110572138A - Filtering device and manufacturing method thereof - Google Patents

Filtering device and manufacturing method thereof Download PDF

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Publication number
CN110572138A
CN110572138A CN201910949986.XA CN201910949986A CN110572138A CN 110572138 A CN110572138 A CN 110572138A CN 201910949986 A CN201910949986 A CN 201910949986A CN 110572138 A CN110572138 A CN 110572138A
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CN
China
Prior art keywords
layer
electrode layer
resonance
upper electrode
resonance device
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CN201910949986.XA
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Chinese (zh)
Inventor
彭波华
李平
胡念楚
贾斌
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Kaiyuan Communication Technology (xiamen) Co Ltd
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Kaiyuan Communication Technology (xiamen) Co Ltd
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Priority to CN201910949986.XA priority Critical patent/CN110572138A/en
Publication of CN110572138A publication Critical patent/CN110572138A/en
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    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/02535Details of surface acoustic wave devices
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/02535Details of surface acoustic wave devices
    • H03H9/02818Means for compensation or elimination of undesirable effects
    • H03H9/02834Means for compensation or elimination of undesirable effects of temperature influence
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/02535Details of surface acoustic wave devices
    • H03H9/0296Surface acoustic wave [SAW] devices having both acoustic and non-acoustic properties
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/125Driving means, e.g. electrodes, coils
    • H03H9/145Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14502Surface acoustic wave [SAW] transducers for a particular purpose
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/125Driving means, e.g. electrodes, coils
    • H03H9/145Driving means, e.g. electrodes, coils for networks using surface acoustic waves
    • H03H9/14544Transducers of particular shape or position
    • HELECTRICITY
    • H03ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46Filters
    • H03H9/64Filters using surface acoustic waves

Abstract

The application discloses a filtering device, which comprises a substrate layer and a resonance layer positioned on the upper surface of the substrate layer, wherein the resonance layer comprises a first resonance device and a second resonance device with different vibration modes; the first resonance device comprises at least a first piezoelectric layer and a first upper electrode layer which are stacked, the second resonance device comprises at least a second piezoelectric layer and a second upper electrode layer which are stacked, at least one of the first resonance device and the second resonance device further comprises a lower electrode layer, and one side, close to the first upper electrode layer, of the interdigital electrodes in the second upper electrode layer is not provided with a bus bar. The filtering device is provided with a resonance device in a mixed vibration mode, so that the situation that a single acoustic wave type filtering device cannot meet the requirements of different frequency band bandwidths is avoided, and the situation that the single DMS type filtering device is not suitable for high frequency is avoided; and one side of the interdigital electrode in the second upper electrode layer is not provided with a bus, and the interdigital electrode is directly connected with the first upper electrode layer, so that the size of the filter device is effectively reduced, and the cost is reduced. The application also provides a manufacturing method with the advantages.

Description

Filtering device and manufacturing method thereof
Technical Field
The present disclosure relates to the field of filter devices, and particularly to a filter device and a method for manufacturing the same.
background
Acoustic Wave resonators are generally classified into Surface Acoustic Wave (SAW) resonators and Bulk Acoustic Wave (BAW) resonators according to vibration modes. The SAW resonator adopts interdigital electrodes to realize mutual conversion of electric energy and acoustic energy, and the BAW resonator generally comprises an upper electrode layer, a piezoelectric layer and a lower electrode layer. Further, there are lamb wave resonators.
the filter device is formed by combining a plurality of acoustic wave resonators, and can form a ladder-type or lattice-type topological structure by connecting the acoustic wave resonators, or form a Double-Mode surface acoustic wave (DMS) structure by one or more interdigital electrodes generating acoustic energy. The BAW type filter device is generally built by a plurality of BAW resonators by utilizing a ladder-type structure, has a large area and high cost, and cannot meet the requirement of miniaturization; the SAW type filter device is divided into a ladder type structure and a DMS structure, and the ladder type structure also has the above-described disadvantages; the DMS structure is not suitable for high frequency due to the reason that the line width of the interdigital electrode is too small and the electrode loss is large; the lamb wave type filter device has larger line width but low equivalent coupling coefficient, and can not meet the requirement of frequency band bandwidth of mobile phone communication.
therefore, how to solve the above technical problems should be a great concern to those skilled in the art.
Disclosure of Invention
The purpose of the application is to provide a filter device and a manufacturing method thereof, so that the filter device has the advantages of miniaturization, suitability for high frequency and low cost.
in order to solve the technical problem, the application provides a filter device, which comprises a substrate layer and a resonance layer located on the upper surface of the substrate layer, wherein the resonance layer comprises a first resonance device and a second resonance device with different vibration modes;
The first resonance device at least comprises a first piezoelectric layer and a first upper electrode layer which are laminated, the second resonance device at least comprises a second piezoelectric layer and a second upper electrode layer which are laminated, at least one of the first resonance device and the second resonance device further comprises a lower electrode layer, and one side, close to the first upper electrode layer, of interdigital electrodes in the second upper electrode layer is not provided with a bus bar.
Optionally, the second upper electrode layer is an interdigital electrode or a combined electrode, and the combined electrode includes a reflective gate electrode and a plurality of interdigital electrodes.
Optionally, the method further includes:
And the energy reflecting layer is positioned on the upper surface of the resonance layer and corresponds to the area where the second resonance device is positioned.
Optionally, the method further includes:
and the metal frequency adjusting layer is positioned on the upper surface of the resonance layer and corresponds to the area where the first resonance device is positioned. .
Optionally, the metal frequency adjusting layer is a frequency adjusting layer formed by any one of the following metals or any combination of the following metals:
aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, titanium, tantalum.
Optionally, the method further includes:
And the dielectric layer is positioned on the upper surfaces of the metal frequency adjusting layer and the energy reflecting layer.
Optionally, when the substrate layer does not have a cavity, the method further includes:
An acoustically reflective layer between the substrate layer and the resonant layer, the acoustically reflective layer comprising a low acoustic impedance layer and a high acoustic impedance layer.
optionally, the substrate layer has a cavity extending through a thickness of the substrate, and the cavity completely corresponds to the first resonance device and the second resonance device.
Optionally, the resonant layer further includes a third resonant device having the same vibration mode as the first resonant device, and the second resonant device is located between the first resonant device and the third resonant device, and a side of the interdigital electrode in the second upper electrode layer close to the third upper electrode layer in the third resonant device does not have a bus bar.
The application also provides a manufacturing method of the filtering device, which comprises the following steps:
Forming a lower electrode layer to be processed on the upper surface of the substrate layer;
Etching the lower electrode layer to be processed to obtain a lower electrode layer corresponding to the first resonance device and/or the second resonance device;
forming a first piezoelectric layer and a second piezoelectric layer corresponding to the first resonating means and the second resonating means, respectively, wherein the first piezoelectric layer and the second piezoelectric layer are located on an upper surface of the lower electrode layer when the first resonating means and the second resonating means have the lower electrode layer;
forming electrode layers on upper surfaces of the first and second piezoelectric layers;
and etching the electrode layer to obtain a first upper electrode layer and a second upper electrode layer which respectively correspond to the first resonance device and the second resonance device, wherein one side, close to the first upper electrode layer, of the interdigital electrode in the second upper electrode layer is not provided with a bus bar.
The filtering device comprises a substrate layer and a resonance layer positioned on the upper surface of the substrate layer, wherein the resonance layer comprises a first resonance device and a second resonance device which have different vibration modes; the first resonance device at least comprises a first piezoelectric layer and a first upper electrode layer which are laminated, the second resonance device at least comprises a second piezoelectric layer and a second upper electrode layer which are laminated, at least one of the first resonance device and the second resonance device further comprises a lower electrode layer, and one side, close to the first upper electrode layer, of interdigital electrodes in the second upper electrode layer is not provided with a bus bar.
Therefore, the filtering device in the application has the first resonance device and the second resonance device with different vibration modes on the upper surface of the substrate layer, namely the filtering device in the application has the resonance device with the mixed vibration mode, so that the situation that a single acoustic wave mode filtering device cannot meet the requirements of different frequency band bandwidths can be avoided, and meanwhile, the situation that the single DMS type filtering device is not suitable for the requirement of high frequency can be avoided; and the interdigital electrode in the second upper electrode layer does not have a bus on the side close to the first upper electrode layer and is directly connected with the first upper electrode layer, so that the area of the filter device is effectively reduced, the cost is reduced, the size of the filter device is reduced, and the requirement of the industry on miniaturization is met. In addition, the application also provides a manufacturing method of the filtering device with the advantages.
drawings
For a clearer explanation of the embodiments or technical solutions of the prior art of the present application, the drawings needed for the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a schematic structural diagram of a filtering apparatus according to an embodiment of the present disclosure;
Fig. 2 is a schematic top view of a filter device according to an embodiment of the present disclosure;
Fig. 3 is a schematic top view of another filtering apparatus according to an embodiment of the present disclosure;
Fig. 4 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure;
Fig. 5 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure;
Fig. 6 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure;
Fig. 7 is a schematic structural diagram of another filtering apparatus provided in the embodiment of the present application;
fig. 8 is a flowchart of a method for manufacturing a filter device according to an embodiment of the present disclosure.
Detailed Description
In order that those skilled in the art will better understand the disclosure, the following detailed description will be given with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
in the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those specifically described and will be readily apparent to those of ordinary skill in the art without departing from the spirit of the present invention, and therefore the present invention is not limited to the specific embodiments disclosed below.
As described in the background section, existing filter devices are all made of a single type of resonator, resulting in problems of large size, unsuitability for high frequencies, high cost, and the like.
In view of the above, the present application provides a filter device, please refer to fig. 1 and fig. 2, where fig. 1 is a schematic structural diagram of a filter device provided in an embodiment of the present application, fig. 2 is a schematic top view of a filter device provided in an embodiment of the present application, the filter device includes a substrate layer 1 and a resonance layer 2 located on an upper surface of the substrate layer 1, the resonance layer 2 includes a first resonance device X1 and a second resonance device X2 with different vibration modes;
The first resonator device X1 comprises at least a first piezoelectric layer 221 and a first upper electrode layer 231 which are laminated, the second resonator device X2 comprises at least a second piezoelectric layer 222 and a second upper electrode layer 232 which are laminated, at least one of the first resonator device X1 and the second resonator device X2 further comprises a lower electrode layer 21, and the side of the interdigital electrode in the second upper electrode layer 232 close to the first upper electrode layer 231 is not provided with a bus bar.
specifically, the resonant layer 2 includes a lower electrode layer 21, a piezoelectric layer 22, and an upper electrode layer 23, wherein the piezoelectric layer 22 is composed of a first piezoelectric layer 221 and a second piezoelectric layer 222, and the upper electrode layer 23 is composed of a first upper electrode layer 231 and a second upper electrode layer 232.
It should be noted that, in this embodiment, the material of the piezoelectric layer is not particularly limited, and may be set by itself. For example, the piezoelectric layer 22 can be any one or any combination of the following:
aluminum nitride, zinc oxide, lithium niobate, lithium tantalate, and the like.
Preferably, the upper electrode layer 23 and the lower electrode layer 21 may be formed of any one of the following metals or any combination of the metals:
Aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, titanium, tantalum, and the like.
It is to be noted that the substrate layer 1 is not particularly limited in this embodiment, and may be as appropriate. The substrate layer 1 may be, for example, a silicon substrate layer 1, or a quartz substrate layer 1, or an alumina substrate layer 1, etc.
Optionally, in an embodiment of the present embodiment, the substrate layer 1 is a substrate layer 1 having a cavity structure, but the present application is not limited to this specifically, and in other embodiments of the present application, the substrate layer 1 is a substrate layer 1 without a cavity structure.
Further, when the substrate layer 1 is the substrate layer 1 having a cavity structure, the cavity may be a sacrificial layer that is built in during the process of manufacturing the substrate layer 1, the thickness of the sacrificial layer is smaller than that of the substrate layer 1, and then the sacrificial layer is subjected to release etching so that the substrate layer 1 has the cavity. The material of the sacrificial layer includes but is not limited to silicon dioxide, phosphosilicate glass, porous silicon, photoresist.
In this embodiment, the interdigital electrode in the second upper electrode layer 232 does not have a bus bar on the side close to the first upper electrode layer 231, so that the interdigital electrode is directly connected to the first upper electrode layer 231, the area of the filter device is reduced, the size of the filter device is reduced, and the requirement for miniaturization is met.
specifically, in the present embodiment, the first upper electrode layer 231 is a plate-shaped electrode layer, that is, the vibration mode of the first resonance device X1 is bulk acoustic wave vibration.
Optionally, the second upper electrode layer 232 is an interdigital electrode or a combined electrode, the combined electrode includes a reflection gate electrode and a plurality of interdigital electrodes, and correspondingly, the vibration mode of the second resonance device X2 is surface acoustic wave vibration or lamb wave vibration. The filter device in this embodiment will be specifically described below by taking the vibration mode of the second resonator device X2 as an example of DMS.
When the lower electrode layer 21 exists in both the first resonance device X1 and the second resonance device X2, the lower electrode layer 21 of the first resonance device X1 is used as an input, and the lower electrode layer 21 of the second resonance device X2 is used as an output, so that a topological structure that one resonator is connected with the dual-mode surface acoustic wave in series is formed, and a filter device is formed; alternatively, the first upper electrode layer 231 of the first resonator device X1 may be used as an input, and the first resonator device X1 may be used as a parallel connection, in which case the lower electrode layer 21 of the first resonator device X1 is grounded.
When the lower electrode layer 21 is not present in the first resonator device X1, the first resonator device X1 cannot constitute a resonator, and is connected to the second resonator device X2 only through the first upper electrode layer 231 as a metal connection. Similarly, the interdigital electrode of the second resonant device X2 can be used as the output of the filter device to change the connection mode.
therefore, the filter device in this embodiment can form various topological structures according to the input connection mode and whether the lower electrode layer 21 is etched or not. The first resonance device X1, for example, as a series resonator, can form a transmission zero point on the right side of the passband of the DMS transmission curve, thereby improving the roll-off characteristic on the right side of the passband; if the parallel resonator is used, a transmission zero point can be formed on the left side of the passband of the transmission curve of the dual-mode surface acoustic wave, and the roll-off characteristic and the out-of-band rejection capability on the left side of the passband are improved.
it should be noted that, in the present embodiment, the filtering device is not specifically limited, and may be determined as the case may be. For example, the filtering device may be a filter, or a duplexer, or a multiplexer, etc.
The filtering device in this embodiment has the first resonance device X1 and the second resonance device X2 with different vibration modes on the upper surface of the substrate layer 1, that is, the filtering device in this embodiment has a resonance device with a mixed vibration mode, which can prevent a single acoustic wave mode filtering device from failing to meet the requirements of different frequency band bandwidths, and can also prevent a single DMS type filtering device from being unsuitable for the requirements of high frequencies; and the interdigital electrode in the second upper electrode layer 232 does not have a bus bar on the side close to the first upper electrode layer, and is directly connected with the first upper electrode layer 231, so that the area of the filter device is effectively reduced, the cost is reduced, the size of the filter device is reduced, and the requirement of the industry on miniaturization is met.
referring to fig. 3, fig. 3 is a schematic top view of another filtering apparatus according to an embodiment of the present disclosure.
On the basis of any one of the above embodiments, in an embodiment of the present application, the filtering apparatus further includes:
and the energy reflecting layer 3 is positioned on the upper surface of the resonance layer 2 and corresponds to the area where the second resonance device X2 is positioned.
Optionally, the energy reflection layer 3 is formed by any one or any combination of the following metals:
Aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, titanium, tantalum, and the like.
The energy reflecting layer 3 is provided for the purpose of reducing the energy leakage of the acoustic wave in the lateral direction.
Preferably, the filtering apparatus further includes: and the metal frequency adjusting layer 4 is positioned on the upper surface of the resonance layer 2 and corresponds to the area where the first resonance device X1 is positioned.
note that, in the present embodiment, the metal frequency adjustment layer 4 is not particularly limited as long as it is formed of a metal material having good conductivity, as the case may be. For example, the metal frequency adjustment layer 4 is a frequency adjustment layer formed of any one of the following metals or any combination of the metals:
Aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, titanium, tantalum, and the like.
it should be noted that, in this embodiment, the relationship between the thickness of the energy reflection layer 3 and the thickness of the metal frequency adjustment layer 4 is not specifically limited, and the thicknesses of the two layers may be equal or different. Preferably, the metal frequency adjusting layer 4 and the energy reflecting layer 3 share the same material and the same thickness, which can effectively save cost.
Further, referring to fig. 4, in an embodiment of the present application, the filtering apparatus further includes:
And the dielectric layer 5 is positioned on the upper surfaces of the metal frequency adjusting layer 4 and the energy reflecting layer 3. The dielectric layer 5 can further adjust the frequency of the first resonator device X1, protect the electrode layer of the first resonator device X1 and the interdigital electrode layer of the second resonator device X2 from external contamination, and adjust the frequency of the second resonator device X2.
It should be noted that, in this embodiment, the material of the dielectric layer 5 is not particularly limited, and may be determined as the case may be. For example, the material of the dielectric layer 5 may be silicon dioxide, or silicon nitride, or aluminum nitride, etc.
Taking silicon dioxide as an example, the second resonator device X2 and the silicon dioxide dielectric layer 5 thereon can constitute a temperature compensated surface acoustic wave device (TC-SAW) having a higher Q value and a better temperature coefficient of frequency than conventional surface acoustic wave devices.
Referring to fig. 5, fig. 5 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure.
When the substrate layer 1 does not have a cavity, the filter device further comprises:
An acoustically reflective layer 6 located between said substrate layer 1 and said resonant layer 2, said acoustically reflective layer 6 comprising a low acoustic impedance layer 62 and a high acoustic impedance layer 61. To inhibit the propagation of acoustic energy towards the substrate.
Note that the high acoustic impedance layer 61 is close to the backing layer 1, and the low acoustic impedance layer 62 is far from the backing layer 1.
preferably, the number of the acoustic reflection layer 6 is two or more to achieve better energy reflection effect and increase the Q value, but the number of the acoustic reflection layer is not too large, which may increase the production cost. The thicknesses of the low acoustic impedance layer 62 and the high acoustic impedance layer 61 are about 1/4 of the equivalent wavelength of the materials of the respective layers at the resonance frequency.
Optionally, the material of the high acoustic impedance layer 61 includes, but is not limited to, any of the following materials: tungsten, molybdenum, aluminum nitride, and the like.
optionally, the material of the low acoustic impedance layer 62 includes, but is not limited to, any of the following materials: silicon dioxide, porous silicon, and the like. When the low acoustic impedance layer 62 is a silicon dioxide impedance layer, since the low acoustic impedance layer 62 is close to the resonance region, the silicon dioxide is a positive frequency temperature coefficient material, and can perform a temperature compensation function.
Referring to fig. 6, fig. 6 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure.
In one embodiment of the application, the substrate layer 1 has a cavity through the thickness of the substrate and the cavity completely corresponds to the first resonating means X1 and the second resonating means X2. So as to prevent the transmission of the sound waves to the substrate layer 1, and the Q value of the filter device is improved.
referring to fig. 7, fig. 7 is a schematic structural diagram of another filtering apparatus according to an embodiment of the present disclosure.
On the basis of any of the above embodiments, in an embodiment of the present application, the resonant layer 2 further includes a third resonant device X3 having the same vibration mode as the first resonant device X1, and the second resonant device X2 is located between the first resonant device X1 and the third resonant device X3, and a side of the interdigital electrode in the second upper electrode layer 232 close to the third upper electrode layer in the third resonant device X3 does not have a bus bar.
It should be noted that the specific structure of the third resonator device X3 is the same as that of the first resonator device X1, and detailed description thereof is omitted here.
the filter device provided by the embodiment comprises three resonance parts, namely a first resonance device X1, a second resonance device X2 and a third resonance device X3, and the adjustment of each parameter in the filter device is more diversified, and the degree of freedom of parameter change is higher.
Referring to fig. 8, fig. 8 is a flowchart illustrating a method for manufacturing a filter device according to an embodiment of the present disclosure, where the method includes:
Step S101: and forming a lower electrode layer to be processed on the upper surface of the substrate layer.
specifically, a lower electrode layer to be processed is grown on the upper surface of the substrate layer by using an evaporation method or a magnetron sputtering method.
step S102: and etching the lower electrode layer to be processed to obtain a lower electrode layer corresponding to the first resonance device and/or the second resonance device.
It should be noted that, when the first resonance device and the second resonance device each have a lower electrode layer, the lower electrode layers of the first resonance device and the second resonance device also need to be etched.
Step S103: forming a first piezoelectric layer and a second piezoelectric layer corresponding to the first resonating means and the second resonating means, respectively, wherein when the first resonating means and the second resonating means have the lower electrode layer, the first piezoelectric layer and the second piezoelectric layer are located on an upper surface of the lower electrode layer.
Specifically, the first piezoelectric layer and the second piezoelectric layer may be formed by an evaporation method, a magnetron sputtering method, or a chemical vapor deposition method.
it will be appreciated that the first piezoelectric layer is located on the upper surface of the substrate layer when the first resonator device does not have the lower electrode layer, and similarly, the second piezoelectric layer is located on the upper surface of the substrate layer when the second resonator device does not have the lower electrode layer.
Step S104: forming electrode layers on upper surfaces of the first piezoelectric layer and the second piezoelectric layer.
Specifically, the electrode layer is grown by an evaporation method or a magnetron sputtering method.
step S105: and etching the electrode layer to obtain a first upper electrode layer and a second upper electrode layer which respectively correspond to the first resonance device and the second resonance device, wherein one side, close to the first upper electrode layer, of the interdigital electrode in the second upper electrode layer is not provided with a bus bar.
Optionally, in an embodiment of the present application, when the substrate layer is a substrate layer having a cavity structure, before forming the lower electrode layer to be processed on the upper surface of the substrate layer, the method further includes:
carrying out graphical processing on the substrate layer to be processed to form a groove, wherein the depth of the groove is smaller than the thickness of the substrate layer to be processed;
Forming a sacrificial layer in the groove to obtain a processed substrate layer;
grinding the upper surface of the processed substrate layer by adopting a chemical mechanical polishing technology to obtain the substrate layer;
correspondingly, after the electrode layer is etched, the method further comprises the following steps:
And etching the sacrificial layer.
Optionally, in an embodiment of the application, when the substrate layer is a cavity penetrating through a thickness of the substrate, and the cavity completely corresponds to the first resonance device and the second resonance device, after etching the electrode layer, the method further includes:
And etching the position of the substrate layer corresponding to the area of the first resonance device and the second resonance device.
In the filter device obtained by the filter device manufacturing method provided by the embodiment, the first resonance device and the second resonance device with different vibration modes are arranged on the upper surface of the substrate layer, that is, the filter device in the present application has a resonance device with a mixed vibration mode, so that the problem that a single acoustic wave type filter device cannot meet the requirements of different frequency band bandwidths can be avoided, and meanwhile, the problem that a single DMS type filter device is not suitable for the requirement of high frequency can be avoided; and the interdigital electrode in the second upper electrode layer does not have a bus on the side close to the first upper electrode layer and is directly connected with the first upper electrode layer, so that the area of the filter device is effectively reduced, the cost is reduced, the size of the filter device is reduced, and the requirement of the industry on miniaturization is met.
the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The filter device and the manufacturing method thereof provided by the present application are described in detail above. The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. It should be noted that, for those skilled in the art, it is possible to make several improvements and modifications to the present application without departing from the principle of the present application, and such improvements and modifications also fall within the scope of the claims of the present application.

Claims (10)

1. a filter device comprising a substrate layer and a resonant layer on an upper surface of the substrate layer, the resonant layer comprising first and second resonant means having different modes of vibration;
The first resonance device at least comprises a first piezoelectric layer and a first upper electrode layer which are laminated, the second resonance device at least comprises a second piezoelectric layer and a second upper electrode layer which are laminated, at least one of the first resonance device and the second resonance device further comprises a lower electrode layer, and one side, close to the first upper electrode layer, of interdigital electrodes in the second upper electrode layer is not provided with a bus bar.
2. the filtering apparatus according to claim 1, wherein the second upper electrode layer is an interdigitated electrode or a combined electrode including a reflective gate electrode and a plurality of interdigitated electrodes.
3. The filtering apparatus of claim 1, further comprising:
And the energy reflecting layer is positioned on the upper surface of the resonance layer and corresponds to the area where the second resonance device is positioned.
4. The filtering apparatus of claim 3, further comprising:
And the metal frequency adjusting layer is positioned on the upper surface of the resonance layer and corresponds to the area where the first resonance device is positioned.
5. The filtering device according to claim 4, wherein the metal frequency adjustment layer is formed by any one or any combination of the following metals:
aluminum, molybdenum, copper, gold, platinum, silver, nickel, chromium, tungsten, titanium, tantalum.
6. The filtering apparatus of claim 4, further comprising:
And the dielectric layer is positioned on the upper surfaces of the metal frequency adjusting layer and the energy reflecting layer.
7. the filtering arrangement of claim 1, wherein when the substrate layer does not have a cavity, further comprising:
an acoustically reflective layer between the substrate layer and the resonant layer, the acoustically reflective layer comprising a low acoustic impedance layer and a high acoustic impedance layer.
8. a filtering arrangement according to claim 1, wherein the substrate layer has a cavity extending through the thickness of the substrate, the cavity corresponding entirely to the first resonator means and the second resonator means.
9. A filter device according to any one of claims 1 to 8, wherein the resonant layer further comprises a third resonant device having the same vibration mode as the first resonant device, and the second resonant device is located between the first resonant device and the third resonant device, and the interdigital electrode in the second upper electrode layer does not have a bus bar on the side thereof adjacent to the third upper electrode layer in the third resonant device.
10. A method for manufacturing a filter device, comprising:
forming a lower electrode layer to be processed on the upper surface of the substrate layer;
Etching the lower electrode layer to be processed to obtain a lower electrode layer corresponding to the first resonance device and/or the second resonance device;
forming a first piezoelectric layer and a second piezoelectric layer corresponding to the first resonating means and the second resonating means, respectively, wherein the first piezoelectric layer and the second piezoelectric layer are located on an upper surface of the lower electrode layer when the first resonating means and the second resonating means have the lower electrode layer;
Forming electrode layers on upper surfaces of the first and second piezoelectric layers;
And etching the electrode layer to obtain a first upper electrode layer and a second upper electrode layer which respectively correspond to the first resonance device and the second resonance device, wherein one side, close to the first upper electrode layer, of the interdigital electrode in the second upper electrode layer is not provided with a bus bar.
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