CN117526896B - A TC-SAW resonant structure with a noise suppression unit - Google Patents
A TC-SAW resonant structure with a noise suppression unit Download PDFInfo
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- CN117526896B CN117526896B CN202311854080.2A CN202311854080A CN117526896B CN 117526896 B CN117526896 B CN 117526896B CN 202311854080 A CN202311854080 A CN 202311854080A CN 117526896 B CN117526896 B CN 117526896B
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- suppression unit
- clutter suppression
- electrode finger
- interdigital transducer
- electrode
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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
- H03H9/25—Constructional features of resonators using surface acoustic waves
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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
- H03H3/08—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 resonators or networks using surface acoustic waves
-
- 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
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02637—Details concerning reflective or coupling arrays
- H03H9/02685—Grating lines having particular arrangements
- H03H9/02724—Comb like grating lines
- H03H9/02732—Bilateral comb like grating lines
-
- 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
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
-
- 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
- H03H9/02535—Details of surface acoustic wave devices
- H03H9/02818—Means for compensation or elimination of undesirable effects
- H03H9/02834—Means for compensation or elimination of undesirable effects of temperature influence
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic elements; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
- H03H9/6489—Compensation of undesirable effects
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- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
Abstract
The invention provides a TC-SAW resonance structure with clutter suppression units, wherein each interdigital transducer comprises a first interdigital transducer and a second interdigital transducer, each first interdigital transducer comprises a first bus bar and each first electrode finger connected to the first bus bar, each second interdigital transducer comprises a second bus bar and each second electrode finger connected to the second bus bar, a temperature compensation layer covers the surfaces of each first electrode finger and each second electrode finger, each clutter suppression unit is a metal structure arranged in the temperature compensation layer, and each clutter suppression unit forms a cosine waveform with continuous periods in a first direction. The invention provides a surface acoustic wave device which has simple structure, lower cost and easier processing, and the clutter suppression units at each end are connected to form a cosine waveform structure with continuous periods by arranging the clutter suppression units above the two ends of the electrode finger of the interdigital transducer to suppress clutter and optimize the performance of the surface acoustic wave device.
Description
Technical Field
The invention relates to the field of filters, in particular to an acoustic filter and a preparation method thereof.
Background
At present, filters using a resonant structure as a basic unit are increasingly widely used in the field of communications, wherein a TC-SAW (Temperature compensated-SAW, temperature compensated surface acoustic wave) filter is one of acoustic filters, and on the basis of a common SAW filter, performance improvement is performed by coating or bonding a temperature compensation layer, so that the frequency Temperature Coefficient (TCF) of a device is reduced. Therefore, the SAW filter has the characteristics of small volume and small insertion loss, has the advantage of good frequency temperature stability, and can solve the anti-interference problem in a severe temperature environment.
However, the conventional TC-SAW resonant structure/filter can generate larger spurious signals, which seriously affect the performance of the resonant structure/filter.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a TC-SAW resonance structure with a clutter suppression unit, and the clutter suppression effect of a filter is improved by arranging the clutter suppression unit.
The technical scheme is that the TC-SAW resonance structure with the clutter suppression unit comprises the following components:
A substrate;
The device comprises a substrate, an interdigital transducer, a first electrode finger, a second electrode finger and a first electrode pad, wherein the interdigital transducer is arranged on the substrate and comprises a first interdigital transducer and a second interdigital transducer;
the temperature compensation layer covers the surfaces of each first electrode finger and each second electrode finger;
And the clutter suppression unit is of a metal structure arranged in the temperature compensation layer, forms a cosine waveform with continuous periods in a first direction, and is parallel to the plane of the substrate.
Further, the clutter suppression unit comprises a distributed metal structure or a continuous metal structure;
The distributed metal structure is configured to be a metal structure correspondingly arranged on the upper sides of each first electrode finger and each second electrode finger;
The continuous metal structure is configured to be a first metal structure correspondingly arranged on the upper sides of each first electrode finger and each second electrode finger and a second metal structure connected with each first metal structure.
Further, the clutter suppression unit is provided with peaks/troughs which are flush with the tail end of one of the first electrode fingers and the second electrode fingers in a second direction perpendicular to the substrate, and the periodic variation range of the cosine waveform corresponds to four first electrode fingers and four second electrode fingers.
Further, the section of the clutter suppression unit in the second direction is rectangular.
Further, contact electrodes are provided on the first bus bar and the second bus bar.
Still further, a passivation layer is further included, covering the temperature compensation layer, and an opening is provided on the contact electrode.
Further, the distance between the outer edge of the clutter suppression unit and the tail end of the first electrode finger/the second electrode finger in the third direction is (0-0.1) ×l, where L is the working wavelength of the interdigital transducer, and the third direction is parallel to the plane where the substrate is located and intersects with the first direction.
Further, the width of the clutter suppression unit along the first direction is (0.3-0.6) L, which is the same as the width of the single electrode finger along the first direction, and L is the working wavelength of the interdigital transducer.
Further, the gap length between the first electrode finger tip and the second bus bar is in the range of (0.1-2) L, the gap length between the second electrode finger tip and the first bus bar is in the range of (0.1-2) L, and L is the operating wavelength of the interdigital transducer.
A TC-SAW filter comprising a TC-SAW resonant structure having a clutter suppression unit as described in any one of the preceding claims.
The surface acoustic wave device has the beneficial effects that the chip of the surface acoustic wave device is basically composed of a piezoelectric substrate, a metal electrode structure manufactured on the surface of the piezoelectric substrate, an interdigital transducer, a reflecting grating array, a shielding electrode, a plurality of acoustic wave coupling electrodes, a sensor sensitive structure and the like. Each surface acoustic wave device has at least one interdigital transducer in which periodic electrode fingers perpendicular to the propagation direction of the acoustic wave are arranged side by side in the longitudinal direction, i.e., in the propagation direction of the acoustic wave, and the electrode fingers are alternately connected to the first and second bus bars. The surface acoustic wave excited by the interdigital transducer propagates to two sides, and the acoustic channel transmitted by the surface acoustic wave is related to the characteristics of the propagation substrate, and in practical devices, the acoustic channel is typically gradually diffused. The channel expansion causes spurious wave modes, and the effective acoustic wave energy is lost, the Q value of the device is reduced, and the performance of the device is obviously deteriorated.
The invention provides a surface acoustic wave device which has simple structure, lower cost and easier processing, and the clutter suppression units at each end are connected to form a cosine waveform structure with continuous periods by arranging the clutter suppression units above the two ends of the electrode finger of the interdigital transducer to suppress clutter and optimize the performance of the surface acoustic wave device.
Drawings
FIG. 1 is a cross-sectional view of a TC-SAW resonant structure based on a distributed metal layer (DCM) structure of example 1;
FIG. 2 is a top view of a TC-SAW resonant structure based on a distributed metal layer (DCM) structure of example 1;
FIG. 3 is an enlarged view of a portion of the square frame of FIG. 2;
FIG. 4 is a cross-sectional view of a TC-SAW resonant structure based on a continuous metal layer (CCM) structure of example 2;
FIG. 5 is a top view of a TC-SAW resonant structure based on a continuous metal layer (CCM) structure of example 2;
fig. 6 is a diagram showing the resonator admittance response of example 2 based on the CCM structure and the general structure.
Detailed Description
The technical scheme of the invention is described in detail below through the drawings, but the protection scope of the invention is not limited to the embodiments.
Example 1A TC-SAW resonant structure with clutter suppression unit, as shown in FIG. 1, includes a substrate 1, an interdigital transducer 2, a clutter suppression unit 3, a contact electrode 4, a temperature compensation layer 5, and a passivation layer 6.
As shown in fig. 2, the interdigital transducer 2 is disposed on the substrate 1, the interdigital transducer 2 includes a first interdigital transducer including a first bus bar 211 and respective first electrode fingers 212 connected to the first bus bar 211, and a second interdigital transducer including a second bus bar 221 and respective second electrode fingers 222 connected to the second bus bar 221, the first electrode fingers 212 and the second electrode fingers 222 extending in a third direction, and the first electrode fingers 212 and the second electrode fingers 222 being alternately disposed at intervals in the first direction. The first direction and the third direction are parallel to the plane of the substrate 1, and in this embodiment, the first direction and the third direction are perpendicular to each other.
The material of the electrode fingers of the interdigital transducer 2 can be composed of a single-layer metal film of Ti, ag or Cu, or stacked by multiple layers of metal films, wherein the first layer is Ti, the second layer is Ag, the third layer is Cu, and the fourth layer is Ti.
In the present embodiment, the temperature compensation layer 5 covers the surfaces of each of the first electrode fingers 212 and each of the second electrode fingers 222.
In the present embodiment, the clutter suppression unit 3 is configured as a distributed metal structure and is disposed only on the upper side of each of the first electrode finger 212 and the second electrode finger 222, and therefore, an intermittent cosine waveform is formed in the first direction, as shown in fig. 2. The distributed metal structure has higher degree of freedom and is easier to adjust the size, thereby achieving the effect of clutter suppression.
As an extension, the cosine waveform structure of the clutter suppression unit 3 may also extend further to the upper side of the reflection grating along the first direction as shown in fig. 2.
Specifically, the distributed metal structure has peaks/valleys flush with the ends of one of the first electrode fingers 212 and the second electrode fingers 222 in a second direction perpendicular to the substrate 1, and with continued reference to fig. 2, the clutter suppression unit 3 forms two sets of intermittent cosine waveforms, one having peaks/valleys flush with the ends of the first electrode fingers 212 in the second direction perpendicular to the substrate 1 and the other having peaks/valleys flush with the ends of the second electrode fingers 222 in the second direction perpendicular to the substrate 1. The periodic variation range of the cosine waveform corresponds to four first electrode fingers 212 and four second electrode fingers 222, and is of course also adjusted according to the acoustic wave transmission condition.
The section of the clutter suppression unit 3 in the second direction is rectangular, and of course, the section in the second direction is rectangular and rhombic conforming to the cosine waveform change, which can also meet the requirement.
Further, the clutter suppression unit 3 may be constituted by a metal structure, constituted by a Ti or Cu single-layer metal film, or constituted by a stack of Ti and Cu metal films, wherein the first layer is Ti and the second layer is Cu.
The temperature compensation layer 5 is typically a SiO 2 layer, which is coated over the interdigital transducer 2 and the substrate 1, and which is filled between the distributed metal structure and the interdigital transducer 2. Specifically, the clutter suppression unit 3 is surrounded by a temperature compensation layer 5, and the temperature compensation layer 5 fills the gaps between the interdigital transducers 2.
The contact electrodes 4 are provided on the first bus bar and the second bus bar. The material of the contact electrode 4 may be Ti or AlCu.
The passivation layer 6 covers the temperature compensation layer 5 and has an opening in the contact electrode 4. The passivation layer 6 may protect the metal structure from oxidation, and the material of the passivation layer 6 may be silicon oxide or SiN x.
The relevant parameters of the clutter suppression unit 3 include, as shown in fig. 3:
the width dimension b of the single distributed metal structure in the first direction is 0.3-0.6 times of the central wavelength of the working frequency of the filter, and the width and the height of the single distributed metal structure are 10-100 nm.
The distance a between the outer edge of the clutter suppression unit 3 and the end of the first electrode finger 212/the second electrode finger 222 in the third direction is 0-0.1 times of the central wavelength of the filter working frequency.
The gap length c between the end of the first electrode finger 212 and the second bus bar 221 is in the range of 0.1-2 times the center wavelength of the filter operating frequency, and the gap length c between the end of the second electrode finger 222 and the first bus bar 211 is in the range of 0.1-2 times the center wavelength of the filter operating frequency.
The embodiment also provides a TC-SAW filter comprising the TC-SAW resonant structure with the clutter suppression unit 3.
Embodiment 2 is substantially the same as embodiment 1 except that the clutter suppression unit 3 is a continuous metal structure, and as shown in fig. 4 and 5, the continuous metal structure is configured to correspond to the first metal structure 301 disposed on the upper side of each first electrode finger 212 and each second electrode finger 222 and the second metal structure 302 connecting each adjacent first metal structure 301, so that a continuous cosine waveform is formed in the second direction. The continuous metal structure is easier to process than the distributed metal structure.
Fig. 6 is a diagram showing the frequency characteristics of a conventional filter and a filter employing a continuous metal structure according to this embodiment, in which the burr is much smoother and the spurious signals are significantly eliminated.
As described above, although the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
Claims (9)
1. A TC-SAW resonant structure having a clutter suppression unit, comprising:
A substrate;
The device comprises a substrate, an interdigital transducer, a first electrode finger, a second electrode finger and a first electrode pad, wherein the interdigital transducer is arranged on the substrate and comprises a first interdigital transducer and a second interdigital transducer;
the temperature compensation layer covers the surfaces of each first electrode finger and each second electrode finger;
the clutter suppression unit is of a metal structure arranged in the temperature compensation layer, forms a cosine waveform with continuous periods in a first direction, the first direction is parallel to a plane where the substrate is located, has peaks/troughs which are flush with the tail end of one of the first electrode fingers and the second electrode fingers in a second direction, is perpendicular to the plane where the substrate is located, and corresponds to four first electrode fingers and four second electrode fingers in a periodic variation range of the cosine waveform.
2. The TC-SAW resonant structure with clutter suppression unit of claim 1, wherein said clutter suppression unit comprises a distributed metal structure or a continuous metal structure;
The distributed metal structure is configured to be a metal structure correspondingly arranged on the upper sides of each first electrode finger and each second electrode finger;
The continuous metal structure is configured to be a first metal structure correspondingly arranged on the upper sides of each first electrode finger and each second electrode finger and a second metal structure connected with each first metal structure.
3. The TC-SAW resonator structure having a clutter suppression unit of claim 1 wherein said clutter suppression unit has a rectangular cross section in the second direction.
4. The TC-SAW resonant structure with clutter suppression unit of claim 1, further comprising contact electrodes disposed on the first bus bar and the second bus bar.
5. The TC-SAW resonator structure with clutter suppression unit of claim 4 further comprising a passivation layer covering the temperature compensation layer and having an opening on the contact electrode.
6. The TC-SAW resonant structure having a clutter suppression unit of claim 1 wherein a distance between an outer edge of said clutter suppression unit and a tip of said first electrode finger/said second electrode finger in a third direction is in a range of (0-0.1) x L, L being an operating wavelength of an interdigital transducer, said third direction being parallel to a plane of said substrate and intersecting said first direction.
7. The TC-SAW resonator structure having clutter suppression unit of claim 1 wherein a width of an individual clutter suppression unit along a first direction ranges from (0.3-0.6) x L, which is the same as a width of an individual electrode finger of the first direction, L being an operating wavelength of an interdigital transducer.
8. The TC-SAW resonator structure with clutter suppression unit of claim 1 wherein the gap length between the first electrode finger tip and the second bus bar is in the range of (0.1-2) x L, the gap length between the second electrode finger tip and the first bus bar is in the range of (0.1-2) x L, L is the operating wavelength of the interdigital transducer.
9. A TC-SAW filter comprising a TC-SAW resonant structure having a clutter suppression unit according to any one of claims 1 to 8.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311854080.2A CN117526896B (en) | 2023-12-29 | 2023-12-29 | A TC-SAW resonant structure with a noise suppression unit |
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| CN202311854080.2A CN117526896B (en) | 2023-12-29 | 2023-12-29 | A TC-SAW resonant structure with a noise suppression unit |
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| CN117526896B true CN117526896B (en) | 2024-12-20 |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115149922A (en) * | 2022-09-01 | 2022-10-04 | 阿尔伯达(苏州)科技有限公司 | Structure for inhibiting transverse parasitic mode of acoustic coupling filter |
| CN116961619A (en) * | 2023-09-21 | 2023-10-27 | 苏州声芯电子科技有限公司 | Surface acoustic wave resonator structure with double transverse mode inhibition |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115989635A (en) * | 2020-11-03 | 2023-04-18 | 华为技术有限公司 | Resonator, filter and electronic device |
| US20230070350A1 (en) * | 2021-09-08 | 2023-03-09 | Skyworks Solutions, Inc. | Acoustic wave device with floating interdigital transducer |
| CN113824423B (en) * | 2021-09-13 | 2023-08-04 | 江苏卓胜微电子股份有限公司 | Transducer structure for improving Q value and inhibiting transverse mode and surface acoustic wave resonator |
| US20230223917A1 (en) * | 2022-01-13 | 2023-07-13 | Skyworks Solutions, Inc. | Acoustic wave device with vertically mass loaded multi-layer interdigital transducer electrode for transverse mode suppression |
| CN116667808B (en) * | 2023-08-02 | 2024-10-22 | 深圳新声半导体有限公司 | Temperature compensation type surface acoustic wave resonator and preparation method thereof |
| CN117254789A (en) * | 2023-11-15 | 2023-12-19 | 深圳新声半导体有限公司 | Surface acoustic wave resonator for inhibiting in-band harmonic wave |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115149922A (en) * | 2022-09-01 | 2022-10-04 | 阿尔伯达(苏州)科技有限公司 | Structure for inhibiting transverse parasitic mode of acoustic coupling filter |
| CN116961619A (en) * | 2023-09-21 | 2023-10-27 | 苏州声芯电子科技有限公司 | Surface acoustic wave resonator structure with double transverse mode inhibition |
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