CN111404509B - Film bulk acoustic resonator - Google Patents
Film bulk acoustic resonator Download PDFInfo
- Publication number
- CN111404509B CN111404509B CN201911380188.6A CN201911380188A CN111404509B CN 111404509 B CN111404509 B CN 111404509B CN 201911380188 A CN201911380188 A CN 201911380188A CN 111404509 B CN111404509 B CN 111404509B
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- China
- Prior art keywords
- electrode
- bulk acoustic
- acoustic resonator
- film bulk
- thin film
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- 239000000758 substrate Substances 0.000 claims abstract description 12
- 239000010409 thin film Substances 0.000 claims description 29
- 239000010408 film Substances 0.000 claims description 14
- 238000002161 passivation Methods 0.000 claims description 3
- 238000005530 etching Methods 0.000 abstract description 9
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000005459 micromachining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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 elements; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02157—Dimensional parameters, e.g. ratio between two dimension parameters, length, width or thickness
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H9/02244—Details of microelectro-mechanical resonators
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H9/125—Driving means, e.g. electrodes, coils
- H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
- H03H9/131—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials consisting of a multilayered structure
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; 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
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/173—Air-gaps
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; 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
- H03H9/172—Means for mounting on a substrate, i.e. means constituting the material interface confining the waves to a volume
- H03H9/174—Membranes
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/02—Details
- H03H2009/02165—Tuning
- H03H2009/02173—Tuning of film bulk acoustic resonators [FBAR]
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H2009/155—Constructional features of resonators consisting of piezoelectric or electrostrictive material using MEMS techniques
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
The invention provides a film bulk acoustic resonator, which comprises a first electrode, a second electrode positioned above the first electrode, a piezoelectric film between the first electrode and the second electrode, a substrate and an acoustic reflection structure arranged below the first electrode, an etching stop layer arranged above the second electrode and a mass load layer arranged above the etching stop layer, wherein the substrate and the acoustic reflection structure are arranged on the upper surface of the substrate; the projection overlap of the acoustic reflecting structure, the first electrode, the piezoelectric film and the second electrode defines an effective area. Compared with the prior art, the invention ensures the high Q value of the device and the consistency of the film thickness of the second electrode and the frame structure of the mass loading layer, thereby improving the consistency of the electrical parameters of the device.
Description
[ Field of technology ]
The invention relates to the field of acoustic wave resonators, in particular to a film bulk acoustic wave resonator.
[ Background Art ]
In the prior art, referring to fig. 1, the thin film bulk acoustic resonator includes: a first electrode 1; a second electrode 2 positioned near and above the first electrode 1; the overlap of the first electrode 1 and the second electrode 2 defines an effective area; a piezoelectric sheet 3 interposed between the first electrode 1 and the second electrode 2; a ring 4 positioned on one surface of one of the first electrode 1 and the second electrode 2; below the first electrode 1a substrate 5 is present, a cavity 6 being formed between the first electrode 1 and the substrate 5.
The structure has certain difficulty in the micro-machining process, and is unfavorable for ensuring the thickness consistency and the film flatness of the second electrode and the ring structure during mass production.
[ Invention ]
Aiming at the problem of high processing difficulty in a film bulk acoustic resonator structure in the prior art, the invention provides a film bulk acoustic resonator, which comprises a first electrode, a second electrode positioned above the first electrode, a piezoelectric film positioned between the first electrode and the second electrode, a substrate arranged below the first electrode, an acoustic reflection structure, an etching stop layer arranged above the second electrode and a mass load layer arranged above the etching stop layer; the projected overlap of the acoustic reflection structure, the first electrode, the piezoelectric film and the second electrode define an effective area in which the thin film bulk acoustic resonator operates; in any section of the film bulk acoustic resonator, the inner edge of the mass loading layer is located inside the outer edge of the active region.
Preferably, in any section of the thin film bulk acoustic resonator, an outer edge of the mass loading layer is flush with an outer edge of the second electrode.
Preferably, in any section of the thin film bulk acoustic resonator, the outer edge of the mass loading layer is located inside the outer edge of the second electrode.
Preferably, in any section of the thin film bulk acoustic resonator, an outer edge of the mass loading layer is located outside an outer edge of the second electrode.
Preferably, the thin film bulk acoustic resonator further comprises a passivation layer overlying the mass loading layer and the etch stop layer.
Preferably, a groove is formed in the middle portion of the substrate inwards, a cavity is formed between the groove and the first electrode, and the cavity forms the sound reflection structure.
Compared with the prior art, the thin film bulk acoustic resonator provided by the invention has the advantages that the etching stop layer is newly inserted between the mass load layer and the second electrode, and the mass load ring is added to the etching stop layer, so that the high Quality factor (Q) value of the device is ensured, the consistency of the film thicknesses of the second electrode and the frame-shaped structure of the mass load layer is ensured, and the consistency of the electric parameters of the device is improved.
[ Description of the drawings ]
For a clearer description of the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the description below are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art, wherein:
FIG. 1 is a schematic diagram of a thin film bulk acoustic resonator in the prior art;
FIG. 2 is a schematic cross-sectional view of a thin film bulk acoustic resonator according to an embodiment of the present invention;
FIG. 3 is a schematic cross-sectional view of a thin film bulk acoustic resonator according to a second embodiment of the present invention;
fig. 4 is a schematic cross-sectional structure of a thin film bulk acoustic resonator according to a third embodiment of the present invention.
[ Detailed description ] of the invention
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 2, the thin film bulk acoustic resonator provided by the present invention includes a first electrode 10, a second electrode 20 located above the first electrode 10, and a piezoelectric thin film 30 located between the first electrode 10 and the second electrode 20, and further includes a substrate 40 located below the first electrode 10, an etching stop layer 50 located above the second electrode 20, a mass loading layer 60 and a passivation layer 80 located above the etching stop layer 50, wherein a groove 70 is disposed in a middle portion of the substrate 40, a cavity is formed between the groove 70 and the first electrode 10, and the cavity forms an acoustic reflection structure.
The projected overlap of the acoustically reflective structure, the first electrode 10, the piezoelectric film 30 and the second electrode 20 defines the active area in which the thin film bulk acoustic resonator operates. The mass loading layer 60 has a frame structure, and an inner edge 601 of the frame structure is smaller than an outer edge of the effective area.
In a first embodiment, referring to fig. 2, the outer edge 602 of the mass-loaded layer 60 is flush with the outer edge 202 of the second electrode 20.
In a second embodiment, referring to fig. 3, the outer edge 602 of the mass-loading layer 60 is located inside the outer edge 202 of the second electrode 20.
In a third example, referring to fig. 4, the outer edge 602 of the mass-loaded layer 60 is located outside the outer edge 202 of the second electrode 20.
In particular, in the above embodiment, the effective area of the thin film bulk acoustic resonator may be, for example, a cylinder, a tetragonal body, a pentagonal cylinder, a hexagonal cylinder, or any other shape, and the first electrode, the second electrode, the piezoelectric film, the substrate, the etching stop layer, and the mass loading layer are similarly disposed according to the regular shape of the thin film bulk acoustic resonator. Compared with the prior art, the thin film bulk acoustic resonator provided by the invention has the advantages that the etch stop layer is newly inserted between the mass load layer and the second electrode, and the mass load ring is added to the etch stop layer, so that the high Q value of the device is ensured, the consistency of the film thickness of the frame-shaped structure of the second electrode and the mass load layer is ensured, and the consistency of the electric parameters of the device is improved.
While the invention has been described with respect to the above embodiments, it should be noted that modifications can be made by those skilled in the art without departing from the inventive concept, and these are all within the scope of the invention.
Claims (6)
1. A thin film bulk acoustic resonator comprising a first electrode, a second electrode above the first electrode, and a piezoelectric thin film between the first electrode and the second electrode, characterized in that the thin film bulk acoustic resonator further comprises a substrate and an acoustic reflection structure below the first electrode, an etch stop layer above the second electrode, and a mass loading layer above the etch stop layer; the projected overlap of the acoustic reflection structure, the first electrode, the piezoelectric film and the second electrode define an effective area in which the thin film bulk acoustic resonator operates; the mass load layer is in a frame-shaped structure, and the inner edge of the mass load layer is positioned on the inner side of the outer edge of the effective area in any section of the film bulk acoustic resonator.
2. The thin film bulk acoustic resonator of claim 1 wherein an outer edge of the mass loading layer is flush with an outer edge of the second electrode in any cross section of the thin film bulk acoustic resonator.
3. The thin film bulk acoustic resonator of claim 1 wherein in any cross section of the thin film bulk acoustic resonator, the outer edge of the mass loading layer is located inboard of the outer edge of the second electrode.
4. The thin film bulk acoustic resonator of claim 1 wherein the outer edge of the mass loading layer is located outside the outer edge of the second electrode in any cross section of the thin film bulk acoustic resonator.
5. The thin film bulk acoustic resonator of claim 1 further comprising a passivation layer overlying the mass loading layer and the etch stop layer.
6. The thin film bulk acoustic resonator of claim 1, wherein a recess is provided inwardly of the intermediate portion of the substrate, a cavity being formed between the recess and the first electrode, the cavity constituting the acoustic reflection structure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911380188.6A CN111404509B (en) | 2019-12-27 | 2019-12-27 | Film bulk acoustic resonator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911380188.6A CN111404509B (en) | 2019-12-27 | 2019-12-27 | Film bulk acoustic resonator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111404509A CN111404509A (en) | 2020-07-10 |
| CN111404509B true CN111404509B (en) | 2024-07-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911380188.6A Active CN111404509B (en) | 2019-12-27 | 2019-12-27 | Film bulk acoustic resonator |
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| Country | Link |
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| CN (1) | CN111404509B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112242826B (en) * | 2020-10-14 | 2024-11-05 | 瑞声声学科技(深圳)有限公司 | A thin film bulk acoustic resonator |
| CN113824420A (en) * | 2021-08-23 | 2021-12-21 | 杭州电子科技大学 | Preparation method of single crystal thin film bulk acoustic wave resonator with double ring structure electrodes |
| CN113839637A (en) * | 2021-08-26 | 2021-12-24 | 杭州电子科技大学 | Preparation method of single crystal thin film bulk acoustic wave resonator with electrode with ring groove and strip protrusion |
| CN116094485A (en) * | 2023-02-02 | 2023-05-09 | 瑞声科技（南京）有限公司 | Thin film acoustic resonator |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103296992A (en) * | 2013-06-28 | 2013-09-11 | 中国电子科技集团公司第二十六研究所 | Film bulk acoustic resonator structure and manufacturing method thereof |
| CN110504938A (en) * | 2019-07-26 | 2019-11-26 | 杭州左蓝微电子技术有限公司 | Thin film bulk acoustic wave resonator, filter and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011036979A1 (en) * | 2009-09-28 | 2011-03-31 | 太陽誘電株式会社 | Acoustic wave device |
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2019
- 2019-12-27 CN CN201911380188.6A patent/CN111404509B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103296992A (en) * | 2013-06-28 | 2013-09-11 | 中国电子科技集团公司第二十六研究所 | Film bulk acoustic resonator structure and manufacturing method thereof |
| CN110504938A (en) * | 2019-07-26 | 2019-11-26 | 杭州左蓝微电子技术有限公司 | Thin film bulk acoustic wave resonator, filter and preparation method thereof |
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| CN111404509A (en) | 2020-07-10 |
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