CN116111967B - Method for manufacturing resonator and resonator - Google Patents
Method for manufacturing resonator and resonator Download PDFInfo
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- CN116111967B CN116111967B CN202310389487.6A CN202310389487A CN116111967B CN 116111967 B CN116111967 B CN 116111967B CN 202310389487 A CN202310389487 A CN 202310389487A CN 116111967 B CN116111967 B CN 116111967B
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- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 238000000034 method Methods 0.000 title description 11
- 239000000758 substrate Substances 0.000 claims abstract description 32
- 239000000463 material Substances 0.000 claims description 34
- 239000000725 suspension Substances 0.000 claims description 16
- 238000000151 deposition Methods 0.000 claims description 11
- 238000005530 etching Methods 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 5
- 238000002360 preparation method Methods 0.000 abstract description 4
- 239000004065 semiconductor Substances 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- 230000006872 improvement Effects 0.000 description 3
- 230000003071 parasitic effect Effects 0.000 description 3
- 230000008878 coupling Effects 0.000 description 2
- 238000010168 coupling process Methods 0.000 description 2
- 238000005859 coupling reaction Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 230000001902 propagating effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
Classifications
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- 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
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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
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
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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
- H03H9/02—Details
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02047—Treatment of substrates
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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
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/0504—Holders; Supports for bulk acoustic wave devices
- H03H9/0514—Holders; Supports for bulk acoustic wave devices consisting of mounting pads or bumps
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- 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
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Abstract
The application relates to the technical field of semiconductor devices, and particularly discloses a resonator and a preparation method of the resonator. The resonator comprises a substrate and a resonance structure arranged on the substrate, wherein the resonance structure comprises a lower electrode, a piezoelectric layer and an upper electrode which are sequentially arranged on the substrate; a bottom acoustic reflection structure is arranged between the resonance structure and the substrate, and an active area is formed in an overlapping area of the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer and the upper electrode; the piezoelectric layer is provided with a transverse acoustic reflection structure at the edge of the active region, which at least partially overlaps the outer edge of the upper electrode and/or the lower electrode. The resonator provided by the application can strengthen the reflection of the resonator to transverse sound waves through the arrangement of the transverse sound reflection structure, so that the quality factor of the resonator is effectively improved.
Description
Technical Field
The application relates to the technical field of semiconductor devices, in particular to a preparation method of a resonator and the resonator.
Background
Typical structures of conventional thin film bulk acoustic resonators include: upper electrode layer-piezoelectric layer-lower electrode layer. Ideally, the bulk acoustic wave propagating in the thickness direction propagates longitudinally in the piezoelectric layer and the electrode layer using the air reflection boundary of the upper and lower electrodes. In practice, there is a lateral leakage of acoustic waves in the bulk acoustic wave resonator, since the lateral boundaries are continuous, finite. Leakage of transverse acoustic energy can negatively affect the resonator: such as a reduction in quality factor, generation of parasitic modes, reduction in electromechanical coupling coefficient, etc., which affects the performance of the resonator, thereby reducing the performance of the filter: such as increased in-band insertion loss, increased in-band ripple, reduced out-of-band rejection, etc.
Disclosure of Invention
The invention aims to provide a resonator and a preparation method of the resonator, wherein the reflection of the resonator on transverse sound waves can be enhanced through the arrangement of a transverse sound reflection structure, so that the quality factor of the resonator is effectively improved.
Embodiments of the present application are implemented as follows:
in one aspect, the present application provides a resonator, including a substrate and a resonant structure disposed on the substrate, the resonant structure including a lower electrode, a piezoelectric layer, and an upper electrode sequentially disposed on the substrate; a bottom acoustic reflection structure is arranged between the resonance structure and the substrate, and an active area is formed in an overlapping area of the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer and the upper electrode;
the piezoelectric layer is provided with a transverse acoustic reflection structure at the edge of the active region, which at least partially overlaps the outer edge of the upper electrode and/or the lower electrode.
As an embodiment, the transverse acoustic reflection structure is a groove structure provided on the piezoelectric layer.
As an embodiment, the plurality of groove structures are provided, at least one acoustic impedance structure is provided in the groove structures, and the thickness of the acoustic impedance structure is less than or equal to the depth of the groove structures.
As one implementation, the acoustic impedance structure includes a first acoustic impedance structure and a second acoustic impedance structure, the first acoustic impedance structure being staggered with the second acoustic impedance structure.
As an implementation manner, the transverse acoustic reflection structure is a ring structure arranged at the periphery of the active area, and the bottom acoustic reflection structure is a cavity structure or a solid acoustic mirror.
As an embodiment, the edge of the upper electrode is provided with a top sound reflecting structure.
As one embodiment, the top acoustic reflection structure includes a cantilever structure and a bridge structure disposed at an edge of the active region and extending outside the active region; a first air gap structure is formed between the suspended wing structure and the surface of the transverse sound reflection structure and/or the surface of the piezoelectric layer; a second air gap structure is formed between the bridging structure and the surface of the transverse acoustic reflecting structure and/or the surface of the piezoelectric layer.
As an embodiment, the suspension wing structure includes a first connection end and a suspension end; the first connecting end is connected with the upper electrode; alternatively, the first connection end is connected to the transverse sound reflecting structure.
As an embodiment, the bridging structure includes a second connection end and a third connection end; the second connecting end is connected with the upper electrode at the active area; or the second connecting end is connected with the transverse sound reflection structure; the third connection terminal is connected with the upper electrode or the lower electrode outside the active area.
In another aspect, the present application provides a method for manufacturing a resonator, including the steps of:
providing a substrate;
forming a bottom acoustic reflection structure, a lower electrode, a piezoelectric layer, and an upper electrode on a substrate; wherein, the overlapping area of the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer and the upper electrode forms an active area;
a lateral acoustic reflection structure is formed on the piezoelectric layer at the edge of the active region, the lateral acoustic reflection structure at least partially overlapping the outer edge of the upper electrode.
As an embodiment, forming a transverse acoustic reflection structure on a piezoelectric layer at an edge of an active region includes:
a groove structure is formed on the piezoelectric layer and at least one acoustic impedance material is deposited into the groove structure.
As one embodiment, forming a bottom acoustic reflecting structure, a lower electrode, a piezoelectric layer, and an upper electrode on a substrate, comprises:
depositing a layer of cavity sacrificial material over a substrate;
depositing a lower electrode on the substrate formed with the cavity sacrificial material layer;
forming a piezoelectric layer on the cavity sacrificial material layer and the lower electrode;
depositing an air bridge sacrificial material layer on the piezoelectric layer formed with the transverse acoustic reflection structure;
forming a suspension wing structure, a bridging structure and an upper electrode on the piezoelectric layer with the air bridge sacrificial material layer;
etching a lower electrode lead-out hole on the piezoelectric layer, and forming a guide structure electrically connected with the lower electrode at the lower electrode lead-out hole;
etching a release hole communicated with the cavity sacrificial material layer on the piezoelectric layer, and removing the cavity sacrificial material layer through the release hole to form a cavity structure; at the same time, the air bridge sacrificial material layer is removed such that a first air gap structure is formed under the suspended wing structure and such that a second air gap structure is formed under the bridging structure.
The beneficial effects of the embodiment of the application include:
the application provides a resonator, through bottom sound reflection structure, bottom electrode, piezoelectric layer and the overlap region formation active region of upper electrode, be provided with horizontal sound reflection structure through the piezoelectric layer at the edge of active region, and make horizontal sound reflection structure overlap with the outward flange of upper electrode and/or bottom electrode at least partially. Therefore, the method and the device can form effective sound impedance at the edge of the active area, avoid energy leakage of transverse sound waves and effectively improve quality factors. The performance of the resonator can be effectively improved through the improvement of the quality factor of the resonator.
According to the resonator manufacturing method, the transverse acoustic reflection structure is formed on the piezoelectric layer at the edge of the active area, and the formed transverse acoustic reflection structure at least partially overlaps with the outer edge of the upper electrode and/or the lower electrode. According to the method, at least two acoustic impedance areas can be formed through the overlapped part of the transverse acoustic reflection structure and the upper electrode and/or the lower electrode and the non-overlapped part of the transverse acoustic reflection structure, and the reflection of the resonator on transverse acoustic waves can be effectively enhanced through the formed acoustic impedance areas, so that the quality factor of the resonator is improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered limiting the scope, and that other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of a conventional resonator;
FIG. 2 is a schematic diagram of a resonator according to an embodiment of the present disclosure;
FIG. 3 is a second schematic diagram of a resonator according to an embodiment of the present disclosure;
FIG. 4 is a third schematic diagram of a resonator according to an embodiment of the present disclosure;
FIG. 5 is a schematic diagram of a resonator according to an embodiment of the present disclosure;
FIG. 6 is one of the flowcharts of the method for manufacturing a resonator according to the embodiments of the present application;
FIG. 7 is a second flowchart of a method for manufacturing a resonator according to an embodiment of the present disclosure.
Icon: 100-a substrate; 101-a lower electrode; 102-a piezoelectric layer; 103-upper electrode; 104-a bottom acoustic reflection structure; 105-active area; 106-a transverse acoustic reflection structure; 107-groove structure; 108-acoustic impedance structure; 109-a first acoustic impedance structure; 110-a second acoustic impedance structure; 111-cavity structure; 112-a top acoustic reflection structure; 113-a wing-suspension structure; 114-bridging structure; 115-a first air gap structure; 116-a second air gap structure; 117-first connection; 118-a hanging end; 119-a second connection; 120-a third connection end; 121-lower electrode lead-out hole.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. The components of the embodiments of the present application, which are generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the present application, as provided in the accompanying drawings, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments herein without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present application, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the terms in this application will be understood by those of ordinary skill in the art in a specific context.
Referring to fig. 1, since the lateral boundaries of the resonator are continuous and finite, there are laterally leaking sound waves in the resonator. Leakage of transverse acoustic energy can negatively impact the resonator, including: the reduction of quality factor, the generation of parasitic modes, the reduction of electromechanical coupling coefficient, etc., affect the performance of the resonator, and thus reduce the performance of the filter.
In this regard, referring to fig. 1 and 2, the embodiment of the present application provides a resonator, including a substrate 100 and a resonant structure disposed on the substrate 100, where the resonant structure includes a lower electrode 101, a piezoelectric layer 102, and an upper electrode 103 sequentially disposed on the substrate 100; a bottom acoustic reflection structure 104 is provided between the resonant structure and the substrate 100, and an active region 105 is formed by an overlapping region of the bottom acoustic reflection structure 104, the lower electrode 101, the piezoelectric layer 102, and the upper electrode 103.
The piezoelectric layer 102 is provided with a lateral acoustic reflection structure 106 at the edge of the active region 105, the lateral acoustic reflection structure 106 at least partially overlapping the outer edge of the upper electrode 103.
It should be noted that, in the embodiment of the present application, the transverse acoustic reflection structure 106 is disposed at the edge of the active area 105, that is, the transverse acoustic reflection structure 106 may be continuously disposed around the edge of the active area 105 and be in a closed ring shape. It is also possible to discontinuously arrange a plurality of transverse acoustic reflection structures 106 around the edge of the active region 105, and the cross-sectional shape of the transverse acoustic reflection structures 106 may be an arc shape. It is also possible to arrange a length of the transverse sound reflecting structure 106 continuously around the edge of the active area 105. It is also possible to arrange at least two segments of the transverse acoustic reflection structure 106 intermittently around the edge of the active region 105. In the implementation of the technical solution of the present application, the purpose of improving the quality factor is to enable those skilled in the art to selectively adapt according to the needs. The description of the lateral acoustic reflecting structure 106 at least partially overlapping the outer edge of the upper electrode 103 is: the lateral acoustic reflection structure 106 may entirely overlap with the outer edge of the upper electrode 103, or a portion of the lateral acoustic reflection structure 106 may overlap with the outer edge of the upper electrode 103. The present patent creatively proposes that the lateral acoustic reflecting structure 106 overlaps the edge of the upper electrode 103, but of course, the acoustic reflecting structure may also be arranged to overlap the edge of the lower electrode 101. By providing an overlap region, the upper electrode 103 and/or the lower electrode 101 and the transverse acoustic reflection structure 106 constitute a multiple acoustic impedance region, thereby enhancing reflection of transverse acoustic waves in the piezoelectric layer 102 and avoiding energy leakage of the transverse acoustic waves.
The specific principle of the embodiment of the application is as follows: thin film bulk acoustic resonators excite not only the thickness direction (TE) mode, but also generate transverse parasitic modes, such as rayleigh-lamb mode acoustic waves. These transverse modes of acoustic waves will be lost at the boundaries of the resonator, resulting in a loss of energy in the longitudinal modes required for the resonator, ultimately leading to a reduction in the quality factor of the resonator. In order to restrain leakage of the transverse mode sound wave of the resonator at the edge, the transverse sound reflection structure 106 is added at the edge of the upper electrode of the resonator, and the transverse mode sound wave is limited in the effective area of the resonator by forming a multiple acoustic impedance area at the transverse sound reflection structure 106, so that the leakage of the transverse mode sound wave is avoided.
Illustratively, the transverse acoustic reflecting structure 106 overlaps the edges of both the upper electrode 103 and the lower electrode 101. Illustratively, the transverse acoustic reflecting structure 106 overlaps the edge of the lower electrode 101.
It is emphasized that: in the resonator provided in the embodiment of the present application, the active region 105 is formed by the overlapping region of the bottom acoustic reflection structure 104, the lower electrode 101, the piezoelectric layer 102, and the upper electrode 103, the lateral acoustic reflection structure 106 is disposed at the edge of the active region 105 by the piezoelectric layer 102, and the lateral acoustic reflection structure 106 is at least partially overlapped with the outer edge of the upper electrode 103 and/or the lower electrode 101. Therefore, the method and the device can form effective sound impedance at the edge of the active region 105, avoid energy leakage of transverse sound waves, and effectively improve the quality factor. The performance of the resonator can be effectively improved through the improvement of the quality factor of the resonator.
Referring to fig. 2, as one embodiment, the transverse acoustic reflection structure 106 is a groove structure 107 disposed on the piezoelectric layer 102. The embodiments of the present application disclose a specific structure of the transverse acoustic reflection structure 106. Illustratively, the non-overlapping region of the upper electrode 103 is formed into a first region by overlapping the groove structure 107 with the edge portion of the upper electrode 103, so that the overlapping region of the groove structure 107 and the upper electrode 103 can be formed into a second region, and the non-overlapping region of the groove structure 107 can be formed into a third region. According to the embodiment of the application, the acoustic impedance mismatch boundary can be formed at the boundary between the first region and the second region and the boundary between the second region and the third region respectively, and the reflection of transverse sound waves is enhanced through the formed acoustic impedance mismatch boundary.
Referring to fig. 3, as an embodiment, at least one acoustic impedance structure 108 is disposed within the groove structure 107. The present embodiment further improves the transverse acoustic reflection structure 106 on the basis of the groove structure 107. Specifically, an acoustic impedance structure 108 is disposed in the groove structure 107, and the thickness of the acoustic impedance structure 108 is smaller than or equal to the depth of the groove structure 107, so that the acoustic impedance mismatch boundary effect can be further enhanced through the arrangement of the acoustic impedance structure 108. The acoustic impedance structure 108 may be one type or a plurality of types. Illustratively, an acoustic impedance structure 108 formed of the material of the upper electrode 103 is disposed within the recess structure 107 such that the acoustic impedance structure 108 overlaps an edge portion of the upper electrode 103. The non-overlapping region of the upper electrode 103 is formed into a first region, the overlapping region of the acoustic impedance structure 108 and the upper electrode 103 is formed into a second region, and the non-overlapping region of the acoustic impedance structure 108 is formed into a third region. According to the embodiment of the application, the acoustic impedance mismatch boundary can be formed at the boundary between the first region and the second region and the boundary between the second region and the third region respectively, and compared with the embodiment, the reflection of transverse sound waves can be further enhanced through the formed acoustic impedance mismatch boundary.
As shown in fig. 4 and 5, as an implementation manner, the first acoustic impedance structure 109 and the second acoustic impedance structure 110 are arranged in segments in the width direction in the groove structure 107, where the first acoustic impedance structure 109 and the second acoustic impedance structure 110 with different acoustic impedance values are staggered. It should be further noted that the number of the groove structures 107 in the embodiment of the present application may be plural. Illustratively, the groove structure 107 is a plurality of concentric rings. The embodiments of the present application disclose that a plurality of acoustic impedance structures 108 are disposed within the groove structure 107, and the plurality of acoustic impedance structures 108 may be formed in segments of a first acoustic impedance structure 109 and a second acoustic impedance structure 110. Illustratively, the first acoustic impedance structure 109 is disposed in the groove structure 107 in the width direction, and the first acoustic impedance structure 109 is completely overlapped with the edge of the upper electrode 103, and the second acoustic impedance structure 110 is disposed in the groove structure 107 in the width direction. It should be noted that the second acoustic impedance structure 110 may be completely overlapped with the edge of the upper electrode 103. It is also possible that the second acoustic impedance structure 110 overlaps with a portion of the edge of the upper electrode 103. The first acoustic impedance structure 109 may overlap a portion of the edge of the upper electrode 103. The second acoustic impedance structure 110 may be partially overlapped with the edge of the upper electrode 103 in the case where the first acoustic impedance structure 109 is completely overlapped with the upper electrode 103. It should be understood that the present application also includes the case where the first acoustic impedance structure 109 and the second acoustic impedance structure 110 are completely overlapped with the outer edge of the upper electrode 103, and also includes the case where multiple first acoustic impedance structures 109 or multiple second acoustic impedance structures 110 are provided. By way of example, two first acoustic impedance structures 109, a second acoustic impedance structure 110, specific arrangements and overlapping arrangements may be provided within the groove structure 107, and may be selected as desired by one skilled in the art. The purpose is that by providing the transverse acoustic reflection structure 106, a plurality of acoustic impedance mismatch boundaries can be formed in the piezoelectric layer 102, and reflection of the transverse acoustic wave can be achieved.
Referring to fig. 3, as an embodiment, the lateral acoustic reflection structure 106 is a ring structure disposed at the periphery of the active region 105, and the bottom acoustic reflection structure 104 is a cavity structure 111 or a solid-state acoustic mirror. The transverse acoustic reflection structure 106 may be continuously disposed around the edge of the active region 105, and may be a closed loop. The transverse acoustic reflection structure 106 may be discontinuously arranged around the edge of the active region 105, and may be in a ring shape that is not closed. The bottom acoustic reflection structure 104 may be a cavity structure 111, an acoustic impedance structure 108 disposed in the cavity structure 111, or a solid-state acoustic mirror. Wherein, the solid-state sound mirror can adopt a Bragg reflector. The purpose is to realize the reflection of longitudinal sound wave and avoid the leakage of longitudinal sound wave energy.
Referring to fig. 2, as an embodiment, the edge of the upper electrode 103 is provided with a top acoustic reflection structure 112. Further, the top acoustic reflection structure 112 is arranged at the edge of the upper electrode 103, and acoustic wave energy can be reflected at the edge through the top acoustic reflection structure 112, so that the quality factor of the resonator is further improved.
Referring to fig. 2 and 3, as one implementation, the top acoustic reflection structure 112 includes a cantilever structure 113 and a bridge structure 114 disposed at an edge of the active region 105 and extending outside the active region 105; a first air gap structure 115 is formed between the suspended wing structure 113 and the surface of the lateral acoustic reflection structure 106 and/or the surface of the piezoelectric layer 102; the bridging structure 114 forms a second air gap structure 116 with the surface of the transverse acoustic reflection structure 106 and/or the surface of the piezoelectric layer 102. The embodiment of the application discloses a specific arrangement mode of the top acoustic reflection structure 112, wherein the arrangement of the suspension wing structure 113 can form a first air gap structure 115, and the arrangement of the bridge structure 114 can form a second air gap structure 116; by arranging the first air gap structure 115 and the second air gap structure 116, an acoustic wave reflection boundary can be formed at the periphery of the active region 105, acoustic wave leakage can be further avoided, and the quality factor of the resonator is improved. The patent proposes that horizontal sound reflection structure 106 and upper electrode 103 and/or bottom electrode 101 part overlap, and horizontal sound reflection structure 106 is connected with suspension wing structure 113, bridging structure 114, avoids upper electrode 103, bottom electrode 101 and suspension wing structure 113, bridging structure 114 lug connection, solves prior art electrode edge and sets up the air gap structure, needs overlap joint air gap structure on the electrode, increases electric capacity, leads to product production technology complicacy, the low problem of yields. In addition, when the first acoustic impedance structure 109 is made of metal acoustic impedance material, the upper electrode 103 and the lower electrode 101 are connected with the cantilever structure 113 and the bridge structure 114 through the first acoustic impedance structure 109, so that electrode wiring is more convenient. When the first acoustic impedance structure 109 is made of a nonmetallic acoustic impedance material, the acoustic impedance values of the upper electrode 103, the lower electrode 101 and the cantilever structure 113 are different from those of the first acoustic impedance structure 109, so that a multiple acoustic impedance area is formed, and acoustic leakage can be further avoided, and the quality factor of the resonator is improved.
Referring to fig. 4, as one embodiment, the wing structure 113 includes a first connection end 117 and a suspension end 118; the first connection terminal 117 is connected to the upper electrode 103; alternatively, the first connection end 117 is connected to the transverse acoustic reflecting structure 106. Embodiments of the present application disclose specific implementations of a wing structure 113. Illustratively, the first connection end 117 is connected to the upper electrode 103 and extends to the outside of the active region 105, so that the first air gap structure 115 is formed between the suspended wing structure 113 and the lateral acoustic reflection structure 106, or the suspended end 118 of the suspended wing structure 113 extends above the piezoelectric layer 102, which can expand the layout range of the first air gap structure 115. Illustratively, the first connection end 117 is connected to the transverse acoustic reflection structure 106 such that a first air gap structure 115 is formed between the cantilever structure 113 and the piezoelectric layer 102.
Referring to fig. 3, as an embodiment, the bridging structure 114 includes a second connection end 119 and a third connection end 120; the second connection terminal 119 is connected to the upper electrode 103 at the active region 105; alternatively, the second connection end 119 is connected to the transverse sound reflecting structure 106; the third connection terminal 120 is connected to the upper electrode 103 or the lower electrode 101 outside the active region 105. Illustratively, the second connection 119 is connected to the upper electrode 103 at the active region 105, and the third connection 120 is connected to the upper electrode 103 outside the active region 105. Such that the second air gap structure 116 is formed below the bridge structure 114, above the lateral acoustic reflecting structure 106 and the piezoelectric layer 102. Illustratively, the second connecting end 119 is connected to the transverse acoustic reflecting structure 106 and the third connecting end 120 is connected to the lower electrode 101 outside the active region 105. Such that a second air gap structure 116 is formed between the bridge structure 114 and the piezoelectric layer 102.
Fig. 6 is one of flowcharts of a preparation method of a resonator according to an embodiment of the present application, as shown in fig. 6, including the following steps:
s10, providing a substrate 100;
s20, forming a bottom acoustic reflection structure 104, a lower electrode 101, a piezoelectric layer 102, and an upper electrode 103 on a substrate 100;
wherein an overlapping region of the bottom acoustic reflection structure 104, the lower electrode 101, the piezoelectric layer 102, and the upper electrode 103 forms an active region 105;
s30, a transverse acoustic reflection structure 106 is formed on the piezoelectric layer 102 at the edge of the active region 105, and the transverse acoustic reflection structure 106 at least partially overlaps with the outer edge of the upper electrode 103.
It is emphasized that: according to the resonator manufacturing method provided by the embodiment of the application, the transverse acoustic reflection structure 106 is formed on the piezoelectric layer 102 at the edge of the active region 105, and the formed transverse acoustic reflection structure 106 at least partially overlaps with the outer edge of the upper electrode 103 and/or the lower electrode 101. According to the method, at least two acoustic impedance areas can be formed through the overlapped part of the transverse acoustic reflection structure 106 and the upper electrode 103 and the non-overlapped part of the transverse acoustic reflection structure 106, and the reflection of the resonator on transverse acoustic waves can be effectively enhanced, so that the quality factor of the resonator is improved.
Optionally, forming the transverse acoustic reflection structure 106 on the piezoelectric layer 102 at the edge of the active region 105 includes:
a groove structure 107 is formed on the piezoelectric layer 102 and at least one acoustic impedance material is deposited into the groove structure 107.
Therein, the recess structure 107 may be formed on the piezoelectric layer 102 by etching.
Fig. 7 is a third flowchart of a method for manufacturing a resonator according to an embodiment of the present application, as shown in fig. 7, in which a bottom acoustic reflection structure 104, a lower electrode 101, a piezoelectric layer 102, and an upper electrode 103 are formed on a substrate 100, and the method includes the following steps:
s21: depositing a layer of cavity sacrificial material over the substrate 100;
s22: depositing a lower electrode 101 on the substrate 100 formed with the cavity sacrificial material layer;
s23: forming a piezoelectric layer 102 on the cavity sacrificial material layer and the lower electrode 101;
s24: depositing a layer of air bridge sacrificial material over the piezoelectric layer 102 formed with the transverse acoustic reflection structure 106;
s25: forming a suspended wing structure 113, a bridge structure 114, and an upper electrode 103 by deposition on the piezoelectric layer 102 on which the air bridge sacrificial material layer is formed;
s26: etching a lower electrode lead-out hole 121 on the piezoelectric layer 102, and depositing a guide structure electrically connected with the lower electrode 101 at the lower electrode lead-out hole 121;
s27: etching a release hole communicated with the cavity sacrificial material layer on the piezoelectric layer 102, and removing the cavity sacrificial material layer through the release hole to form a cavity structure 111; at the same time, the air bridge sacrificial material layer is removed such that a first air gap structure 115 is formed under the overhanging wing structure 113 and such that a second air gap structure 116 is formed under the bridging structure 114.
It should be noted that the size and shape of the structure in the embodiments of the present application are not particularly limited. Wherein the acoustic wave wavelength is lambda. Taking the thickness of the piezoelectric layer 102 as an example, the thickness of the piezoelectric layer 102 may be 0.5λ, the depth of the groove structure 107 may be 0.1-0.5λ, and the width of the groove structure 107 may be 10-100deg.λ, and the specific data may be selected by those skilled in the art as desired.
The foregoing description is only of the preferred embodiments of the present application and is not intended to limit the same, but rather, various modifications and variations may be made by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims (9)
1. The resonator is characterized by comprising a substrate and a resonance structure arranged on the substrate, wherein the resonance structure comprises a lower electrode, a piezoelectric layer and an upper electrode which are sequentially arranged on the substrate; a bottom acoustic reflection structure is arranged between the resonance structure and the substrate, and an active area is formed by the overlapping area of the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer and the upper electrode; the piezoelectric layer is provided with a transverse sound reflection structure at the edge of the active area, and the transverse sound reflection structure at least partially overlaps with the edge of the upper electrode, wherein the transverse sound reflection structure is a groove structure arranged on the piezoelectric layer, an acoustic impedance structure is arranged in the groove structure, and the acoustic impedance structure partially overlaps with the edge of the upper electrode; the acoustic impedance structure is made of metal acoustic impedance materials; the edge of the upper electrode is provided with a top sound reflection structure, and the top sound reflection structure comprises a suspension wing structure and a bridging structure, wherein the suspension wing structure and the bridging structure are arranged at the edge of the active region and extend to the outer side of the active region; the suspension wing structure comprises a first connecting end and a suspension end; the first connecting end of the suspension structure is connected with the metal acoustic impedance material; the bridging structure comprises a second connecting end and a third connecting end; the second connection end is connected with the metal acoustic impedance material. .
2. The resonator of claim 1, wherein the groove structure is provided in plurality, and at least one acoustic impedance structure is provided in the groove structure, and the thickness of the acoustic impedance structure is less than or equal to the depth of the groove structure.
3. The resonator of claim 2, wherein the acoustic impedance structures comprise first acoustic impedance structures and second acoustic impedance structures, the first acoustic impedance structures being interleaved with the second acoustic impedance structures.
4. The resonator according to claim 1, characterized in that the lateral acoustic reflection structure is a ring structure arranged at the periphery of the active area, and the bottom acoustic reflection structure is a cavity structure or a solid-state acoustic mirror.
5. Resonator according to claim 1, characterized in that the suspension wing structure forms a first air gap structure with the surface of the transverse acoustic reflection structure and/or the surface of the piezoelectric layer; a second air gap structure is formed between the bridging structure and the surface of the transverse acoustic reflection structure and/or the surface of the piezoelectric layer.
6. The resonator according to claim 1, characterized in that the third connection terminal is connected to an upper electrode or a lower electrode outside the active area.
7. A method of manufacturing a resonator, comprising the steps of:
providing a substrate;
forming a bottom acoustic reflection structure, a lower electrode, a piezoelectric layer, and an upper electrode on the substrate; wherein the overlapping areas of the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer and the upper electrode form an active area;
forming a lateral acoustic reflection structure on the piezoelectric layer at the edge of the active region, wherein the lateral acoustic reflection structure at least partially overlaps with the outer edge of the upper electrode, and depositing an air bridge sacrificial material layer on the piezoelectric layer with the lateral acoustic reflection structure formed thereon;
forming a suspension wing structure, a bridging structure and an upper electrode on the piezoelectric layer on which the air bridge sacrificial material layer is formed; the transverse acoustic reflection structure comprises a first acoustic impedance structure, the first acoustic impedance structure is partially overlapped with the active area, wherein when the first acoustic impedance structure is made of metal acoustic impedance materials, the upper electrode and the lower electrode are connected with the suspension wing structure and the bridge structure through the first acoustic impedance structure.
8. The method of manufacturing according to claim 7, wherein forming the lateral acoustic reflection structure on the piezoelectric layer at the edge of the active region comprises:
a groove structure is formed on the piezoelectric layer and at least one acoustic impedance material is deposited into the groove structure.
9. The method of manufacturing according to claim 7 or 8, wherein forming the bottom acoustic reflection structure, the lower electrode, the piezoelectric layer, and the upper electrode on the substrate comprises:
depositing a layer of cavity sacrificial material on the substrate;
depositing a lower electrode on the substrate formed with the cavity sacrificial material layer;
forming a piezoelectric layer on the cavity sacrificial material layer and the lower electrode; etching a lower electrode lead-out hole on the piezoelectric layer, and forming a guide structure electrically connected with the lower electrode at the lower electrode lead-out hole;
etching a release hole communicated with the cavity sacrificial material layer on the piezoelectric layer, and removing the cavity sacrificial material layer through the release hole to form a cavity structure; at the same time, the air bridge sacrificial material layer is removed such that an air gap structure is formed under the suspended wing structure and such that a second air gap structure is formed under the bridging structure.
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| CN202310389487.6A CN116111967B (en) | 2023-04-13 | 2023-04-13 | Method for manufacturing resonator and resonator |
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| CN202310389487.6A CN116111967B (en) | 2023-04-13 | 2023-04-13 | Method for manufacturing resonator and resonator |
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| JP5161698B2 (en) * | 2008-08-08 | 2013-03-13 | 太陽誘電株式会社 | Piezoelectric thin film resonator and filter or duplexer using the same |
| US9490418B2 (en) * | 2011-03-29 | 2016-11-08 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Acoustic resonator comprising collar and acoustic reflector with temperature compensating layer |
| JPWO2013108608A1 (en) * | 2012-01-20 | 2015-05-11 | パナソニックＩｐマネジメント株式会社 | Elastic wave sensor |
| US11595016B2 (en) * | 2018-10-05 | 2023-02-28 | Samsung Electro-Mechanics Co., Ltd. | Bulk-acoustic wave resonator |
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| CN114070233A (en) * | 2020-08-04 | 2022-02-18 | 诺思(天津)微系统有限责任公司 | Bulk acoustic wave resonator, filter and electronic device with reduced parasitic mode |
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