CN109474255B - Film bulk acoustic resonator, manufacturing method thereof and filter - Google Patents
Film bulk acoustic resonator, manufacturing method thereof and filter Download PDFInfo
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- CN109474255B CN109474255B CN201811356081.3A CN201811356081A CN109474255B CN 109474255 B CN109474255 B CN 109474255B CN 201811356081 A CN201811356081 A CN 201811356081A CN 109474255 B CN109474255 B CN 109474255B
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Images
Classifications
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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
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator
- H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
- H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
- H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
- H03H2003/023—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks the resonators or networks being of the membrane type
Abstract
The disclosure provides a film bulk acoustic resonator, a manufacturing method thereof and a filter; the film bulk acoustic resonator includes: a substrate; a piezoelectric stack structure formed on the substrate, the piezoelectric stack structure including a bottom electrode, a piezoelectric film, and a top electrode; and a first pad and a second pad formed on the piezoelectric stack structure; the film bulk acoustic resonator further comprises a dielectric layer, wherein the dielectric layer is formed on the etched end face of the piezoelectric film, and/or on the etched end faces of the piezoelectric film and the bottom electrode, and/or on the etched end faces of the piezoelectric film and the top electrode, and/or on the etched end faces of the piezoelectric film, the top electrode and the bottom electrode. The film bulk acoustic resonator, the manufacturing method thereof and the filter improve the device performance, simplify the manufacturing process and reduce the manufacturing cost.
Description
Technical Field
The disclosure belongs to the technical field of wireless communication, and particularly relates to a film bulk acoustic resonator, a manufacturing method thereof and a filter.
Background
With the development of mobile communication technology, the rate requirement for data transmission is higher and higher, the frequency bands for communication are more and more, and the electromagnetic spectrum is more and more crowded. On the one hand, more filter devices are required to ensure that no interference is generated between communication frequency bands, and on the other hand, chips such as filters and the like are required to have lower loss so as to ensure that the power consumption of the terminal product is increased and the battery capacity is increased to match the power consumption under the condition that the number of the chips is continuously increased.
There are currently two main technologies for filters used in mobile communications, particularly in smart phones: surface Acoustic Wave technology (SAW) and bulk Acoustic Wave technology (BAW). The SAW filter has been widely used in 2G and 3G times due to its advantages of simple structure and manufacturing process, low cost, small size, etc., but with the popularization of 4G and the advancement of 5G, the communication frequency is increasing, and the SAW filter has an operating frequency inversely proportional to the width of its Interdigital Transducer (IDT), and when the communication frequency is increasing, the width of the IDT is becoming narrower, which increases the manufacturing difficulty on the one hand, and on the other hand, the power capacity of the device is also decreasing due to the narrowing of the IDT and the increase of the electrode loss. Therefore, SAW technology is not suitable for high frequencies, especially for frequency bands greater than 3.5 GHz. The working frequency of the BAW filter is inversely proportional to the thickness of the film layer, so that the BAW filter can work at higher frequency, and researches show that the BAW filter can meet the requirements of mobile communication within the range of 1.5 GHz-9 GHz.
The film bulk acoustic resonator is an essential element constituting the BAW filter, and its performance directly affects the performance of the BAW filter. The thin film bulk acoustic wave devices currently using BAW technology are mainly of the air gap type and the solid state mount type.
The existing film bulk acoustic resonator mainly has the following defects:
(1) the bottom electrode, the piezoelectric film, the top electrode and the like all need to be deposited step by step, and the surface appearance of the film is deteriorated through the process steps of photoetching, etching and the like, so that the deposition quality of the subsequent film is influenced, and the performance of the film bulk acoustic wave device is influenced.
(2) The etching requirement on the bottom electrode is high, the end face of the bottom electrode needs to be etched into a slope with a small angle, the process difficulty is high, and the manufacturing efficiency is low.
Disclosure of Invention
Technical problem to be solved
The present disclosure provides a film bulk acoustic resonator, a method for manufacturing the same, and a filter, so as to at least partially solve the above technical problems.
(II) technical scheme
According to one aspect of the present disclosure, there is provided a method for manufacturing a thin film bulk acoustic resonator, including:
depositing a bottom electrode and a piezoelectric film on a substrate continuously and sequentially;
patterning the piezoelectric film to expose part of the bottom electrode;
patterning the bottom electrode;
depositing a dielectric layer and etching the dielectric layer;
depositing a top electrode and patterning the top electrode; and
and manufacturing a bonding pad.
According to another aspect of the present disclosure, there is provided a method for manufacturing a thin film bulk acoustic resonator, including:
depositing a bottom electrode, a piezoelectric film and a top electrode on a substrate in sequence;
patterning the top electrode, the piezoelectric film and the bottom electrode in sequence;
depositing a dielectric layer and etching the dielectric layer; and
and manufacturing a bonding pad.
In some embodiments, the bottom electrode and the piezoelectric film are successively deposited by a magnetron sputtering method under a vacuum condition; or a bottom electrode, a piezoelectric film and a top electrode are continuously and sequentially deposited by adopting a magnetron sputtering method;
depositing a dielectric layer by adopting a spin coating or chemical vapor deposition method;
etching the dielectric layer by adopting a whole-surface dry etching process, and reserving the dielectric layer at the end face of the piezoelectric film; or adopting photoetching and etching processes to make at least one end face of the piezoelectric film retain the dielectric layer.
In some embodiments, the top electrode pattern is defined by one photolithography;
sequentially etching the top electrode and the piezoelectric film by a dry etching method or a wet etching method; and
patterning the bottom electrode by photoetching and etching processes;
in the step of manufacturing the bonding pad, two bonding pads are manufactured, and the width of the overlapping area of one of the two bonding pads and the top electrode is larger than or equal to 1 um.
In some embodiments, the method further comprises, before depositing the bottom electrode: manufacturing an acoustic reflection unit on a substrate; manufacturing a first bonding pad on the top electrode, and manufacturing a second bonding pad on the bottom electrode; the width of the overlapping area of the first pad and the sound reflection unit is greater than or equal to 0.1 um.
According to an aspect of the present disclosure, there is provided a thin film bulk acoustic resonator including:
a substrate;
a piezoelectric stack structure formed on the substrate, the piezoelectric stack structure including a bottom electrode, a piezoelectric film, and a top electrode; and
a first pad and a second pad formed on the piezoelectric stack structure;
the film bulk acoustic resonator further comprises a dielectric layer, wherein the dielectric layer is formed on the etched end face of the piezoelectric film, and/or on the etched end faces of the piezoelectric film and the bottom electrode, and/or on the etched end faces of the piezoelectric film and the top electrode, and/or on the etched end faces of the piezoelectric film, the top electrode and the bottom electrode.
In some embodiments, the dielectric layer is partially formed in a region enclosed by the piezoelectric stack and the substrate, the top electrode includes at least three portions, a first portion is located on the substrate, a second portion is located on the dielectric layer, a third portion is located on the piezoelectric film, and the second portion connects the first portion and the third portion; or
The dielectric layer is partially formed in an area defined by the first bonding pad, the piezoelectric stack structure and the substrate, and the top electrode is located on the piezoelectric film.
In some embodiments, the dielectric layer is partially formed in an area enclosed by the piezoelectric stack structure and the substrate, the thin film bulk acoustic resonator further includes an acoustic reflection unit on the substrate, the first pad is formed on the top electrode, and a width of an overlapping area with the acoustic reflection unit is greater than or equal to 0.1 um.
In some embodiments, the dielectric layer is partially formed in an area surrounded by the first pad, the piezoelectric stack structure and the substrate, and a width of an overlapping area of the first pad and the top electrode is greater than or equal to 1 um.
According to another aspect of the present disclosure, there is provided a filter comprising a plurality of the thin film bulk acoustic resonators in cascade.
(III) advantageous effects
According to the technical scheme, the film bulk acoustic resonator, the manufacturing method thereof and the filter have at least one of the following beneficial effects:
(1) by continuously depositing the piezoelectric film and the bottom electrode, the adverse effect of roughening the surface of the bottom electrode in photoetching and etching on the deposition quality of a subsequent piezoelectric film is avoided.
(2) The top electrode, the piezoelectric film and the bottom electrode are continuously deposited, so that the influence of photoetching and etching processes on the surface of the intermediate film layer is reduced, the deposition quality of the film is improved, and the product performance is improved. Meanwhile, the top electrode and the piezoelectric film can be patterned by one-step photoetching, so that the manufacturing steps are reduced, and the manufacturing cost is reduced.
(3) The film bulk acoustic resonator comprises the arc-shaped dielectric layer, so that the step coverage effect is improved, and effective isolation is realized; a first part of the dielectric layer is formed in an area enclosed by the piezoelectric stack structure and the substrate or formed in an area enclosed by the first bonding pad, the piezoelectric stack structure and the substrate; the second part of the dielectric layer is formed between the piezoelectric stack structure and the second bonding pad, so that acoustic impedance discontinuity is formed at the boundary of the resonator, energy leaked transversely can be reflected, and the performance of the bulk acoustic wave resonator is improved.
Drawings
Fig. 1 is a schematic structural diagram of a film bulk acoustic resonator according to an embodiment of the disclosure.
Fig. 2-9 are schematic diagrams illustrating a process for fabricating a film bulk acoustic resonator according to an embodiment of the present disclosure.
Fig. 10 is a schematic structural diagram of a second film bulk acoustic resonator according to an embodiment of the disclosure.
Fig. 11-17 are schematic diagrams illustrating a manufacturing process of a second film bulk acoustic resonator according to an embodiment of the disclosure.
Detailed Description
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
The present disclosure provides a thin film bulk acoustic resonator, including:
a substrate;
a piezoelectric stack structure formed on the substrate, the piezoelectric stack structure including a bottom electrode, a piezoelectric film, and a top electrode; and
a first pad and a second pad formed on the piezoelectric stack structure;
the film bulk acoustic resonator further comprises a dielectric layer, wherein the dielectric layer is formed on the etched end face of the piezoelectric film, and/or formed on the etched end faces of the piezoelectric film and the bottom electrode, and/or formed on the etched end faces of the piezoelectric film and the top electrode, and/or formed on the etched end faces of the piezoelectric film, the top electrode and the bottom electrode.
Therefore, acoustic impedance discontinuity is formed at the boundary of the resonator, and energy leaked transversely can be reflected, so that the performance of the bulk acoustic wave resonator is improved.
Specifically, the dielectric layer may include two portions: the first part can be formed in an area enclosed by the piezoelectric stack structure and the substrate, and can also be formed in an area enclosed by the first bonding pad, the piezoelectric stack structure and the substrate; a second portion may be formed between the piezoelectric stack structure and the second pad.
More specifically, for the film bulk acoustic resonator of the present disclosure, a first portion of the dielectric layer is formed in a region enclosed by the piezoelectric stack structure and the substrate; the top electrode may include at least three portions, a first portion on the substrate, a second portion on the dielectric layer, and a third portion on the piezoelectric film, the second portion connecting the first portion and the third portion. Of course, the film bulk acoustic resonator may further include an acoustic reflection unit on the substrate, the first pad is formed on the top electrode, and a width of an overlapping area with the acoustic reflection unit is greater than or equal to 0.1um, so that acoustic impedance discontinuity is formed at an edge of the resonator, and a Q value of the resonator is improved.
Or, the first part of the dielectric layer is formed in a region surrounded by the first bonding pad, the piezoelectric stack structure and the substrate, and the top electrode is located on the piezoelectric film. The width of the overlapping area of the first pad and the top electrode is larger than or equal to 1um, so that the connection resistance is reduced, the acoustic impedance discontinuity at the boundary is formed, and the Q value of the resonator is improved.
Preferably, the dielectric layer is arc-shaped, so that the step coverage effect is improved, and effective isolation is realized. In addition, the film bulk acoustic resonator of the present disclosure may further optionally include an isolation layer to further improve the performance of the film bulk acoustic resonator.
The present disclosure provides a method for manufacturing a film bulk acoustic resonator, including:
depositing a bottom electrode and a piezoelectric film on a substrate continuously and sequentially;
patterning the piezoelectric film to expose part of the bottom electrode;
patterning the bottom electrode;
depositing a dielectric layer and etching the dielectric layer;
depositing a top electrode and patterning the top electrode; and
and manufacturing a bonding pad.
The present disclosure also provides another method for manufacturing a film bulk acoustic resonator, including:
depositing a bottom electrode, a piezoelectric film and a top electrode on a substrate in sequence;
patterning the top electrode, the piezoelectric film and the bottom electrode in sequence;
depositing a dielectric layer and etching the dielectric layer; and
and manufacturing a bonding pad.
The film bulk acoustic resonator and the manufacturing method thereof according to the present disclosure are described in detail below with reference to the first embodiment and the second embodiment.
Example one
As shown in fig. 1, the film bulk acoustic resonator of the present embodiment includes: the acoustic reflection unit comprises a substrate 1, an acoustic reflection unit 2, an isolation layer 3, a bottom electrode 4, a piezoelectric film 5, dielectric layers 6a and 6b, a top electrode 7 and bonding pads 8a and 8 b.
The acoustic reflection unit 2 is formed on the substrate 1, and the surface of the acoustic reflection unit is flush with the surface of the substrate. The isolation layer 3 is formed on the substrate and the acoustic reflection unit. The bottom electrode 4 is formed on the isolation layer. The dielectric layer 6a is formed on the etched end faces of the piezoelectric film and the bottom electrode, and the dielectric layer 6b is formed on the etched end face of the piezoelectric film. A first portion of the top electrode 7 is located on the spacer layer, a second portion is located on the dielectric layer 6a, and a third portion is located on the piezoelectric film, the second portion connecting the first and third portions. The bonding pads 8a are formed on the first and second portions of the top electrode, and the bonding pads 8b are formed on the bottom electrode and located outside the dielectric layer 6 b.
Wherein the substrate may be silicon (Si), glass, Sapphire (Sapphire), gallium nitride (GaN), gallium arsenide (GaGs), lithium niobate (LiNbO)3) Lithium tantalate (LiTaO)3) And the like.
The acoustic reflection unit can be an air cavity or a Bragg reflection layer formed by alternately stacking materials with different high and low acoustic impedances.
The isolation layer may be silicon oxide (SiO)2) Silicon nitride (Si)3N4) And an insulating material such as aluminum nitride (AlN).
The bottom electrode may be one or more of molybdenum (Mo), tungsten (W), chromium (Cr), aluminum (Al), copper (Cu), iridium (Ir), ruthenium (Ru), silicon (Si), Graphene (Graphene), and Carbon Nanotube (Carbon Nanotube).
The piezoelectric thin film may be aluminum nitride (AlN), zinc oxide (ZnO), lead zirconate titanate (PZT), or the above material doped with a rare earth element.
The dielectric layer can be silicon oxide (SiO2), silicon glass (USG), phosphosilicate glass (PSG), borosilicate glass (BSG), borophosphosilicate glass (BPSG), Tetraethoxysilane (TEOS) and other dielectric materials
The top electrode may be one or more of molybdenum (Mo), tungsten (W), chromium (Cr), aluminum (Al), copper (Cu), iridium (Ir), ruthenium (Ru), silicon (Si), Graphene (Graphene), and Carbon Nanotube (Carbon Nanotube).
The bonding pad may be one or more of chromium (Cr), nickel (Ni), tungsten (W), titanium Tungsten (TiW), aluminum (Al), copper (Cu), gold (Au).
As shown in fig. 2 to 9, the manufacturing process of the film bulk acoustic resonator of this embodiment is as follows:
s1, forming an acoustic reflection unit on the substrate, as shown in fig. 2. Optionally, the acoustic reflection unit is fabricated on the substrate by etching the substrate to form a trench, filling the sacrificial material, and then polishing.
S2, sequentially depositing the isolation layer, the bottom electrode, and the piezoelectric film, for example, by magnetron sputtering, wherein the deposition process is not vacuumized, and after one layer of thin film is deposited, the substrate is transferred into the next layer of thin film deposition chamber under high vacuum environment to continue deposition until the isolation layer, the bottom electrode, and the piezoelectric film are deposited, as shown in fig. 3.
S3, the piezoelectric film is patterned to expose a portion of the bottom electrode, as shown in fig. 4. Optionally, the piezoelectric film is etched by using a photolithography, dry etching or wet etching method.
S4, the bottom electrode is patterned, as shown in fig. 5. Optionally, a photolithography, dry etching or wet etching method is used.
S5, depositing a dielectric layer, as shown in fig. 6. Optionally, the dielectric layer is deposited by spin coating or chemical vapor deposition, and since the step at the end face of the piezoelectric film is higher, a dielectric material thicker than other regions is deposited at the end face.
And S6, etching the dielectric layer, and removing the dielectric layer at other positions except the dielectric layer at the end face of the piezoelectric film by controlling the etching condition. Typically, this step uses a full-surface dry etching process, rather than a photolithography process, and since the thickness of the dielectric layer at the end face of the piezoelectric film is the thickest, the dielectric layer is retained only at the end face of the piezoelectric film by precisely controlling the etching time, as shown in fig. 7.
S7, depositing and patterning the top electrode, as shown in fig. 8. Optionally, photolithography and etching processes are adopted.
And S8, manufacturing a pad, wherein, referring to FIG. 9, the pad connected with the top electrode extends to the interior of the acoustic reflection unit and is overlapped with the acoustic emission unit, and the width of the overlapped area is greater than or equal to 0.1um, so that acoustic impedance discontinuity is formed at the edge of the resonator, and the Q value of the resonator is improved.
Example two
As shown in fig. 10, the film bulk acoustic resonator of the present embodiment includes: the acoustic reflection unit comprises a substrate 1, an acoustic reflection unit 2, an isolation layer 3, a bottom electrode 4, a piezoelectric film 5, dielectric layers 6a and 6b, a top electrode 7 and bonding pads 8a and 8 b.
The acoustic reflection unit 2 is formed on the substrate 1, and the surface of the acoustic reflection unit is flush with the surface of the substrate. The isolation layer 3 is formed on the substrate and the acoustic reflection unit. The bottom electrode 4 is formed on the isolation layer. The dielectric layer 6a is formed on the etched end faces of the top electrode, the piezoelectric film and the bottom electrode, and the dielectric layer 6b is formed on the etched end faces of the top electrode and the piezoelectric film. The top electrode 7 is located on the piezoelectric film. A first portion of the pad 8a is formed on the isolation layer, a second portion is formed on the dielectric layer 6a, and a third portion is formed on the top electrode, the second portion connecting the first and third portions. The bonding pad 8b is formed on the bottom electrode and located on the outer side of the dielectric layer 6 b.
In the manufacturing process of the second embodiment, the isolation layer, the bottom electrode, the piezoelectric film, and the top electrode are deposited continuously without breaking vacuum, and then the top electrode and the piezoelectric film are etched away simultaneously by using the same photolithography mask.
As shown in fig. 11 to 17, the manufacturing process of the film bulk acoustic resonator of this embodiment is as follows:
s1, an acoustic reflection unit is fabricated, as shown in fig. 11. Optionally, the acoustic reflection unit is manufactured by etching the substrate to form a trench, filling the sacrificial material, and then polishing.
S2, depositing the isolation layer, the bottom electrode, the piezoelectric film, and the top electrode in sequence, for example, by magnetron sputtering, wherein the deposition process is not vacuumized, and after one layer of thin film is deposited, the substrate is transferred into the next thin film deposition chamber in a high vacuum environment to continue deposition until the isolation layer, the bottom electrode, the piezoelectric film, and the top electrode are deposited, as shown in fig. 12.
S3, sequentially patterning the top electrode and the piezoelectric film, typically, defining a top electrode pattern by one-time photolithography, etching the top electrode pattern by a dry etching method or a wet etching method to form a top electrode shape, and then etching the piezoelectric film by a dry etching method or a wet etching method using a top electrode mask, as shown in fig. 13.
S4, the bottom electrode is patterned, as shown in fig. 14. Optionally, the bottom electrode is patterned by using photolithography and etching processes.
S5, a dielectric layer is deposited, for example, by spin coating or chemical vapor deposition, and since the step at the end surface of the piezoelectric film is higher, a thicker dielectric material is deposited at the end surface than other areas, as shown in fig. 15.
And S6, etching the dielectric layer, and removing the dielectric layer at other positions except the dielectric layer at the end face of the piezoelectric film by controlling the etching condition. Typically, this step uses a full-surface dry etching process, rather than a photolithography process, and since the thickness of the dielectric layer at the end face of the piezoelectric film is the thickest, the dielectric layer is retained only at the end face of the piezoelectric film by precisely controlling the etching time, as shown in fig. 16.
S7, fabricating a pad, wherein, referring to fig. 17, the overlapping width of the pad connected to the top electrode and the top electrode is greater than or equal to 1um, so as to reduce the connection resistance, form the acoustic impedance discontinuity at the boundary, and improve the Q value of the resonator.
In addition, the disclosure also provides a filter which comprises a plurality of thin film bulk acoustic resonators which are cascaded.
The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.
So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. From the above description, those skilled in the art should clearly recognize the present disclosure.
It is to be noted that, in the attached drawings or in the description, the implementation modes not shown or described are all the modes known by the ordinary skilled person in the field of technology, and are not described in detail. Further, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or arrangements of parts mentioned in the examples, which may be easily modified or substituted by those of ordinary skill in the art.
(1) The present disclosure may further include a passivation layer covering all areas of the top electrode not contacted by the pad, and all areas of the bottom electrode not covered by the pad and the piezoelectric film.
(2) The present disclosure may also eliminate the use of a barrier layer.
(3) The dielectric layer can be removed in subsequent etching, and an air interface is formed around the piezoelectric film.
Of course, the method of the present disclosure may also include other steps according to actual needs, which are not described herein again since they are not related to the innovations of the present disclosure.
The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.
Claims (8)
1. A method for manufacturing a film bulk acoustic resonator comprises the following steps:
depositing a bottom electrode and a piezoelectric film on a substrate continuously and sequentially;
patterning the piezoelectric film to expose part of the bottom electrode;
patterning the bottom electrode;
depositing a dielectric layer and etching the dielectric layer;
depositing a top electrode and patterning the top electrode; and
manufacturing a bonding pad;
wherein, before depositing the bottom electrode, further comprising: manufacturing an acoustic reflection unit on a substrate; manufacturing a first bonding pad on the top electrode, and manufacturing a second bonding pad on the bottom electrode; the width of an overlapping area of the first pad and the sound reflection unit is greater than or equal to 0.1 μm so as to form acoustic impedance discontinuity at the edge of the resonator;
the dielectric layer is provided with an arc-shaped surface, and all end faces of the piezoelectric film are surrounded by the dielectric layer.
2. A method for manufacturing a film bulk acoustic resonator comprises the following steps:
depositing a bottom electrode, a piezoelectric film and a top electrode on a substrate in sequence;
patterning the top electrode, the piezoelectric film and the bottom electrode in sequence;
depositing a dielectric layer and etching the dielectric layer; and
manufacturing a bonding pad, wherein the manufacturing method comprises the following steps: manufacturing two bonding pads, wherein the width of the overlapping area of one of the two bonding pads and the top electrode is larger than or equal to 1 mu m so as to form acoustic impedance discontinuity at the edge of the resonator;
the dielectric layer is provided with an arc-shaped surface, and all end faces of the piezoelectric film are surrounded by the dielectric layer.
3. The production method according to claim 1 or 2,
under the vacuum condition, a bottom electrode and a piezoelectric film are continuously and sequentially deposited by adopting a magnetron sputtering method; or a bottom electrode, a piezoelectric film and a top electrode are continuously and sequentially deposited by adopting a magnetron sputtering method;
depositing a dielectric layer by adopting a spin coating or chemical vapor deposition method;
etching the dielectric layer by adopting a whole-surface dry etching process, and reserving the dielectric layers at all end surfaces of the piezoelectric film; or photoetching and etching processes are adopted to ensure that the dielectric layers are reserved on all end faces of the piezoelectric film.
4. The manufacturing method according to claim 2,
defining a top electrode pattern by one-time photoetching;
sequentially etching the top electrode and the piezoelectric film by a dry etching method or a wet etching method; and
and patterning the bottom electrode by photoetching and etching processes.
5. A film bulk acoustic resonator prepared by the method for manufacturing the film bulk acoustic resonator according to any one of claims 1 to 4, comprising:
a substrate;
a piezoelectric stack structure formed on the substrate, the piezoelectric stack structure including an acoustic reflection unit, an isolation layer, a bottom electrode, a piezoelectric film, and a top electrode; and
a first pad and a second pad formed on the piezoelectric stack structure, wherein the width of an overlapping region of the first pad and the acoustic reflection unit is greater than or equal to 0.1 μm, and the width of an overlapping region of the first pad and the top electrode is greater than or equal to 1 μm;
the film bulk acoustic resonator further comprises a dielectric layer, wherein the dielectric layer is provided with an arc-shaped surface, and the dielectric layer is formed on all etched end faces of the piezoelectric film, and/or formed on all etched end faces of the piezoelectric film and the bottom electrode, and/or formed on all etched end faces of the piezoelectric film and the top electrode, and/or formed on all etched end faces of the piezoelectric film, the top electrode and the bottom electrode; the first part of the dielectric layer can be formed in an area enclosed by the piezoelectric stack structure and the substrate, and can also be formed in an area enclosed by the first bonding pad, the piezoelectric stack structure and the substrate; a second portion of the dielectric layer may be formed between the piezoelectric stack structure and the second pad.
6. The thin film bulk acoustic resonator of claim 5,
the top electrode comprises at least three parts, wherein a first part is positioned on the substrate, a second part is positioned on the dielectric layer, a third part is positioned on the piezoelectric film, and the second part is connected with the first part and the third part; or
The top electrode is located on the piezoelectric film.
7. The thin film bulk acoustic resonator of claim 6,
the first pad is formed on the top electrode.
8. A filter comprising a plurality of thin film bulk acoustic resonators as claimed in any one of claims 5 to 7 in cascade.
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| CN111082775B (en) * | 2019-12-30 | 2021-09-07 | 中国电子科技集团公司第五十五研究所 | Film bulk acoustic resonator with high quality factor |
| CN111554800B (en) * | 2020-04-23 | 2022-07-26 | 瑞声声学科技(深圳)有限公司 | Planarization method |
| CN112151511A (en) * | 2020-08-17 | 2020-12-29 | 中国科学院微电子研究所 | Semiconductor structure and preparation method thereof |
| CN112165310A (en) * | 2020-09-25 | 2021-01-01 | 中国科学技术大学 | Film bulk acoustic wave resonant filter |
| CN112242826A (en) * | 2020-10-14 | 2021-01-19 | 瑞声声学科技(深圳)有限公司 | Film bulk acoustic resonator |
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| US7466213B2 (en) * | 2003-10-06 | 2008-12-16 | Nxp B.V. | Resonator structure and method of producing it |
| KR101973423B1 (en) * | 2014-12-08 | 2019-04-29 | 삼성전기주식회사 | Acoustic resonator and manufacturing method thereof |
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