CN111669143B - Piezoelectric resonance micro-channel for liquid detection and preparation method thereof - Google Patents
Piezoelectric resonance micro-channel for liquid detection and preparation method thereof Download PDFInfo
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Abstract
The invention provides a piezoelectric resonance micro-channel for liquid detection and a preparation method thereof. A structural piezoelectric layer is arranged above the active piezoelectric layer, a cavity is formed between the two piezoelectric layers by utilizing a sacrificial layer process, and the active piezoelectric layer, the cavity and the structural piezoelectric layer are combined to form a resonant micro-channel structure. The resonant micro-channel structure can be released to form a suspension structure or not. When the device works, liquid is injected into the micro-channel structure, the resonance frequency of the resonance micro-channel structure changes due to the fact that the micro-channel structure is filled with the liquid, the viscous damping of different liquids is different, the influence degree on the resonance frequency is different, and compared with the intrinsic resonance frequency in an air environment, the detection process is completed.
Description
Technical Field
The invention relates to a micro-electromechanical system (MEMS) resonance micro-channel based on piezoelectric materials and a manufacturing process thereof, in particular to a piezoelectric resonance nano-channel capable of working in a high damping liquid environment and a manufacturing process thereof, which can be applied to biological and chemical detection and other directions and belong to the technical field of piezoelectric sensors.
Background
In analytical testing in the fields of chemistry, biology, etc., reducing the amount of minimum detection reagent required and the detection of very low concentrations of target analytes are all means of detection efforts. In the last few decades, microelectromechanical systems (MEMS) based piezoelectric resonators have made significant progress, making miniaturized devices based on this technology suitable for use in an increasingly large number of fields requiring integrable sensors. In the last ten years, due to the improvement of the quality factor and the reduction of the quality of the resonator, the sensor based on the resonator structure can directly measure the mass of nano particles and single molecules, so that the detection with high resolution is realized. With the design optimization of nanomechanical structures, it is believed that such miniaturized devices ultimately achieve resolution at the level of elemental molecules (see document [1]: lee J, shen W, payer K, et al Toward attogram mass measurements in solution with suspended nanochannel resonators [ J ]. Nano letters,2010,10 (7): 2537-2542 ]) for detection of very low concentrations of target analytes in chemical, biological, and other fields. However, when the resonator is operated directly in a liquid environment, the increase in effective mass and significant increase in resonant cavity energy dissipation due to the presence of viscous drag severely affects device performance, and the frequency resolution of the device decreases, thus achieving effective conduction and enhanced fluid-device interactions in a liquid environment becomes more challenging. The use of micromechanical cantilever resonators (see document [2]: yue M, stachowiak J C, lin H, et al Label-free protein recognition two-dimensional array using nanomechanical sensors [ J ]. Nano letters,2008,8 (2): 520-524.) has been shown to partially overcome these problems, and cantilever resonators can achieve greater displacement to resist the effects of viscous damping on device performance. However, this approach of integrating microfluidic channels into the cantilever sensor requires a large bias voltage (see document [2 ]), limiting the resolution of some applications.
Currently, the development of nanoresonant channels using piezoelectric materials is not mature enough, and the quality factor of the resonator is greatly reduced due to the existence of viscous drag and resonant cavity energy dissipation. While the currently designed suspended resonant nanochannels have a lower operating frequency (100 kHz), the dynamic range of the device is limited when the operating frequency is reduced.
Disclosure of Invention
The invention aims to solve the technical problems that: how to reduce the demand of the tested reagent and how to solve the influence of viscous damping on the performance of the device through structural design, thereby improving the detection resolution of the sensor.
In order to solve the technical problems, the technical conception of the invention is as follows: the micro flow channel and the resonator are combined to form the resonant cavity, the micro flow channel can be used for reducing the required quantity of the detected reagent, detection can be completed by only needing few reagents, the influence of viscous damping on the performance of the device is reduced by designing and optimizing parameters such as the size of the resonant cavity, and higher frequency resolution, namely detection resolution is realized.
Based on the technical conception, a specific technical scheme of the invention is to provide a piezoelectric resonance micro-channel for liquid detection, which is characterized by comprising the following components:
the active piezoelectric layer is fixed on the silicon substrate, the active piezoelectric layer is used for fixing electrodes, the electrodes are used for exciting resonance modes, and the electrode roots with the same polarity are mutually communicated; the method comprises the steps of carrying out a first treatment on the surface of the
The active piezoelectric layer and the structural piezoelectric layer are connected directly or by utilizing a cavity formed by a sacrificial layer process according to different driving modes, and the active piezoelectric layer, the cavity and the structural piezoelectric layer are combined to form a resonant micro-channel structure;
the first through hole and the second through hole are respectively used for leading out the upper electrode and the lower electrode;
the first etching hole and the second etching hole are positioned on the structural piezoelectric layer, and the first etching hole and the second etching hole are used for defining the boundary of the device area and providing etching grooves for forming the cavity;
the first filling layer and the second filling layer are used for filling grooves used for etching the sacrificial layer, so that a cavity between the active piezoelectric layer and the structural piezoelectric layer is closed;
the through hole is used for injecting the tested agent into the resonance micro-channel structure.
Preferably, the structural piezoelectric layer is fixed as a resonance body on the silicon substrate, the structural piezoelectric layer has a plurality of resonance periods in a lateral section, and the electrode is used for resonating by means of a piezoelectric effect resonator.
Preferably, the electrodes are arranged in 4 ways according to the resonance mode of the drive: using a surface wave resonance mode, wherein an electrode above the active piezoelectric layer is an interdigital electrode, and an electrode below the active piezoelectric layer is absent; using a contour resonance mode or a vertical electric field lamb wave resonance mode, wherein an electrode above the active piezoelectric layer is an interdigital electrode, and an electrode below the active piezoelectric layer is also an interdigital electrode; using a lamb wave resonance mode of a transverse electric field, wherein an electrode above the active piezoelectric layer is an interdigital electrode, and an electrode below the active piezoelectric layer is a flat plate electrode; and the upper electrode of the active piezoelectric layer is a plate electrode, and the lower electrode is also a plate electrode by using a vertical bulk acoustic wave resonance mode.
Preferably, when the surface wave resonance mode is used, the active piezoelectric layer and the silicon substrate are connected through the cavity or directly connected; when the profile resonance mode, the vertical electric field lamb wave resonance mode, the transverse electric field lamb wave resonance mode or the vertical bulk acoustic wave resonance mode are used, the active piezoelectric layer is connected with the silicon substrate through the cavity, the silicon substrate/sacrificial layer forms a recess below a device area, and the device area is suspended, so that acoustic waves are reflected at an interface between a piezoelectric material and air.
Preferably, the active piezoelectric layer and the structural piezoelectric layer are made of aluminum nitride, lithium niobate, lithium tantalate and lead zirconate titanate; the electrodes are all made of metal materials.
Preferably, the electrode is made of aluminum, gold, platinum, molybdenum, copper or tungsten.
The invention also provides a preparation method of the resonant micro-channel using a contour resonance mode or a vertical electric field lamb wave resonance mode, which is characterized by comprising the following steps:
step 1): depositing a lower electrode of the electrode on the silicon substrate and patterning the lower electrode;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching to form a cavity between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using a contour resonance mode or a vertical electric field lamb wave resonance mode.
The invention also provides a preparation method of the resonant micro-channel using the surface wave resonant mode, which is characterized by comprising the following steps:
step 1): depositing a first layer of piezoelectric material as an active piezoelectric layer over a substrate;
step 2): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 3): depositing and patterning a sacrificial layer over the upper electrode;
step 4): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 5): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 6): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 7): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 8): and (3) depositing a filling material, filling up the groove used for etching the sacrificial layer, and sealing the cavity between the active piezoelectric layer and the structural piezoelectric layer to obtain the resonant micro-channel using the surface wave resonant mode.
The invention also provides a preparation method of the resonance micro-channel using a transverse electric field lamb wave resonance mode, which is characterized by comprising the following steps:
step 1): depositing a flat lower electrode of an electrode on a silicon substrate;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode of the flat plate;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using a lamb wave resonance mode of a transverse electric field.
Another technical scheme of the invention provides a preparation method of the resonant micro-channel using a vertical bulk acoustic wave resonant mode, which is characterized by comprising the following steps of
Step 1): depositing a lower electrode of an electrode on a silicon substrate and patterning a flat lower electrode;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal above the active piezoelectric layer and patterning the metal into a flat upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode of the flat plate;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode of the flat plate;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using the vertical bulk acoustic wave resonance mode.
In order to solve the problems in the prior art, the sensor disclosed by the invention is composed of the piezoelectric nano micro-channel vibrating transversely or longitudinally, and the piezoelectric nano-channel can work in a liquid environment with certain damping by designing and optimizing the size and process of the micro-channel, and meanwhile, higher precision is realized, high voltage is not required to serve as electrostatic drive and complex optical reading, and the sensor can be applied to biological and chemical detection and other directions.
Drawings
FIG. 1a is a cross-sectional view of a resonant microchannel of a profile resonant mode or a vertical electric field lamb wave resonant mode provided in example 1;
FIG. 1b is a top view of a cross section of an upper electrode of a piezoelectric microchannel of a surface wave resonant mode provided in example 3;
FIG. 1c is a schematic diagram of the resonant frequencies of the resonant micro-channels of the profile resonant mode or the vertical electric field lamb wave resonant mode provided in example 2, respectively operating in air and liquid;
FIG. 1d is a top view of a micro flow channel and a piezoelectric micro flow channel of a surface wave resonance mode provided in example 3;
FIGS. 2a-2k are schematic diagrams showing states at different steps in the preparation method of the resonance micro-fluidic channel of the profile resonance mode or the vertical electric field lamb wave resonance mode provided in embodiment 2;
FIGS. 3a-3i are schematic diagrams showing states at different steps in the method for preparing a piezoelectric micro flow channel of a surface wave resonance mode according to example 3;
fig. 4a-4k are schematic diagrams of states at different steps in the preparation method of the piezoelectric micro-channel of the transverse electric field lamb wave resonance mode provided in embodiment 4;
FIG. 5a is a schematic diagram of a piezoelectric microchannel of a vertical bulk acoustic wave resonance mode provided in example 5;
fig. 6a is a schematic diagram of a resonant micro-channel with a profile resonant mode or a vertical electric field lamb wave resonant mode according to embodiment 6, in which a protective layer is deposited in the step of depositing a patterned upper electrode.
Detailed Description
The invention will be further illustrated with reference to specific examples. It is to be understood that these examples are illustrative of the present invention and are not intended to limit the scope of the present invention. Further, it is understood that various changes and modifications may be made by those skilled in the art after reading the teachings of the present invention, and such equivalents are intended to fall within the scope of the claims appended hereto.
Example 1
As shown in fig. 1a, a micro-electromechanical system (MEMS) resonant micro-channel based on piezoelectric material using a profile resonant mode or a vertical electric field lamb wave resonant mode provided in this embodiment includes an active piezoelectric layer 7 for fixing upper electrodes 1b, 2b, 3b, 4b and lower electrodes 1a, 2a, 3a, 4a, the active piezoelectric layer 7 being fixed on a silicon substrate 12, the upper and lower electrodes being used for exciting the profile resonant mode or the vertical electric field lamb wave resonant mode. The upper electrode and the lower electrode are patterned into interdigital electrodes, and the electrode roots of the same polarity are mutually communicated. A structural piezoelectric layer 14 is arranged above the active piezoelectric layer 7, a cavity 18 formed by a sacrificial layer process is arranged between the active piezoelectric layer 7 and the structural piezoelectric layer 14, and the active piezoelectric layer 7, the cavity 18 and the structural piezoelectric layer 14 are combined to form a resonant micro-channel structure. The through holes 5 and 9 are used to lead out the upper electrodes 1b, 2b, 3b, 4b and the lower electrodes 1a, 2a, 3a, 4a, respectively. Two etched holes 17a, 17b are located in the piezoelectric layer 14, the etched holes 17a, 17b being used to define the device region boundaries, providing etched trenches for the formation of the cavity 13. The filling layers 8a, 8b fill the grooves used for etching the sacrificial layer, closing the cavity 18 between the active piezoelectric layer 7 and the structural piezoelectric layer 14. As shown in fig. 1b, fig. 1b is a cross-sectional view of the device electrode, and through holes 19a, 19b are the test agent injection holes. Wherein the materials of the active piezoelectric layer 7 and the structural piezoelectric layer 14 are aluminum nitride, lithium niobate, lithium tantalate and lead zirconate titanate; the upper electrodes 1b, 2b, 3b, 4b and the lower electrodes 1a, 2a, 3a, 4a are all made of metal materials, and are made of aluminum, gold, platinum, molybdenum, copper or tungsten.
In operation, liquid is injected into the micro flow channel cavity 18 through the injection hole 19a or the injection hole 19b, the resonance frequency of the resonance micro flow channel structure changes due to the fact that the liquid is filled, the viscous damping of different liquids is different, the influence degree on the resonance frequency is different, and compared with the intrinsic resonance frequency in an air environment, the detection process is completed.
As shown in fig. 1c, curve one (air) is an admittance curve when the resonance micro-channel resonates in air, and f2 is a resonance frequency of the resonance micro-channel; curve two (liquid) is the admittance curve of the resonant micro-channel when resonating in the liquid, f1 is the true resonance frequency of the resonant micro-channel; Δf is the difference between the resonant frequencies of the resonant micro-channels when operating in air and liquid, respectively, and the detection process is accomplished by detecting the resonant frequency in the liquid as compared to the intrinsic resonant frequency in the air environment.
As shown in fig. 1d, fig. 1d is a top view of a micro-channel and a piezoelectric micro-channel in a surface wave resonance mode, liquid is injected into the micro-channel through a liquid inlet, flows in the micro-channel from the liquid flow direction, detects the resonance frequency when passing through the resonance micro-channel, flows in the micro-channel from the liquid flow direction until reaching a liquid outlet, and the detection process is completed by comparing the detected resonance frequency in the liquid with the intrinsic resonance frequency in an air environment.
Example 2
The preparation method of the resonance micro-channel of the contour resonance mode or the vertical electric field lamb wave resonance mode comprises the following steps:
step 1): depositing a lower electrode of the electrode on the silicon substrate and patterning the lower electrode, as shown in fig. 2 a;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode, as shown in fig. 2 b;
step 3): depositing metal over the active piezoelectric layer and patterning into the upper electrode, as shown in fig. 2 c;
step 4): depositing and patterning a sacrificial layer over the upper electrode, as shown in fig. 2 d;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer, as shown in fig. 2 e;
step 6): etching the structural piezoelectric layer to form a through hole connecting the upper electrode, as shown in fig. 2 f;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer, as shown in fig. 2 g;
step 8): etching the sacrificial layer by isotropic etching to form a cavity between the active piezoelectric layer and the structural piezoelectric layer, as shown in fig. 2 h;
step 9): depositing a filling material to fill the grooves used for etching the sacrificial layer, so that the cavity between the active piezoelectric layer and the structural piezoelectric layer is closed, as shown in fig. 2 i;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connecting the lower electrode, as shown in fig. 2 j;
step 11): and etching the structural piezoelectric layer and the active piezoelectric layer, defining a device region boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, namely the resonance micro-channel using a contour resonance mode or a vertical electric field lamb wave resonance mode, as shown in fig. 2 k.
Example 3
The preparation method of the piezoelectric micro-channel of the surface wave resonance mode comprises the following steps:
step 1): depositing a first layer of piezoelectric material as an active piezoelectric layer over a substrate, as shown in fig. 3 a;
step 2): depositing metal over the active piezoelectric layer and patterning into the upper electrode, as shown in fig. 3 b;
step 3): depositing and patterning a sacrificial layer over the upper electrode, as shown in fig. 3 c;
step 4): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer, as shown in fig. 3 d;
step 5): etching the structural piezoelectric layer to form a through hole connecting the upper electrode, as shown in FIG. 3 e;
step 6): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer, as shown in FIG. 3 f;
step 7): etching the sacrificial layer by isotropic etching, wherein the cavity between the active piezoelectric layer and the structural piezoelectric layer is shown in fig. 3 g;
step 8): depositing a filling material to fill the grooves used for etching the sacrificial layer, so that the cavity between the active piezoelectric layer and the structural piezoelectric layer is closed, as shown in fig. 3 h;
step 9): and etching the structural piezoelectric layer and the active piezoelectric layer, and defining the boundary of the device region to obtain the resonant micro-channel using the surface wave resonant mode, as shown in figure 3 i.
Example 4
The preparation method of the piezoelectric micro-channel of the transverse electric field lamb wave resonance mode comprises the following steps:
step 1): depositing a planar lower electrode of an electrode on a silicon substrate as shown in fig. 4 a;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode, as shown in fig. 4 b;
step 3): depositing metal over the active piezoelectric layer and patterning into the upper electrode, as shown in fig. 4 c;
step 4): depositing and patterning a sacrificial layer over the upper electrode, as shown in fig. 4 d;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer, as shown in fig. 4 e;
step 6): etching the structural piezoelectric layer to form a through hole connecting the upper electrode, as shown in fig. 4 f;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer, as shown in fig. 4 g;
step 8): etching the sacrificial layer by isotropic etching, wherein the cavity between the active piezoelectric layer and the structural piezoelectric layer is shown in fig. 4 h;
step 9): depositing a filling material to fill the grooves used for etching the sacrificial layer, so that the cavities between the active piezoelectric layer and the structural piezoelectric layer are closed, as shown in fig. 4 i;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole (optional) connecting with the lower electrode of the flat plate, as shown in fig. 4 j;
step 11): and etching the structural piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel. And a resonance micro-channel using a lamb wave resonance mode of a transverse electric field is obtained, as shown in fig. 4 k.
Example 5
The preparation method given in example 2 optionally patterns the plate upper electrode and the plate lower electrode in the deposition lower electrode and the upper electrode to form a piezoelectric microchannel of the vertical bulk acoustic wave resonance mode, as shown in fig. 5 a.
Example 6
The preparation methods in embodiments 2-5 can be used to deposit a protective layer in the step of depositing the patterned upper electrode, as shown in fig. 6a, where the protective layer is made of dielectric material such as silicon dioxide.
Claims (10)
1. A piezoelectric resonator microchannel for liquid detection, comprising:
the active piezoelectric layer (7) is fixed on the silicon substrate (12), the active piezoelectric layer (7) is used for fixing electrodes, the electrodes are used for exciting resonance modes, and the electrode roots with the same polarity are mutually communicated;
the structure piezoelectric layer (14) is positioned above the active piezoelectric layer (7), a cavity (18) formed by a sacrificial layer process or direct connection is formed between the active piezoelectric layer (7) and the structure piezoelectric layer (14), and the active piezoelectric layer (7), the cavity (18) and the structure piezoelectric layer (14) are combined to form a resonance micro-channel structure;
the first through hole (5) and the second through hole (9) are respectively used for leading out the upper electrode and the lower electrode;
the first etching hole (17 a) and the second etching hole (17 b) are positioned on the structural piezoelectric layer (14), and the first etching hole (17 a) and the second etching hole (17 b) are used for defining a boundary of a device area and providing an etching groove for forming the cavity (13);
the first filling layer (8 a) and the second filling layer (8 b) are used for filling grooves used for etching the sacrificial layer, so that a cavity (18) between the active piezoelectric layer (7) and the structural piezoelectric layer (14) is closed;
through holes (19 a, 19 b), and a test agent is injected into the resonance micro flow channel structure through the through holes (19 a, 19 b).
2. A piezoelectric resonator microchannel for liquid detection according to claim 1, characterized in that the structural piezoelectric layer (14) is fixed as a resonating body on the silicon substrate (12), the active piezoelectric layer (7) having a plurality of resonance periods in transverse cross section, the electrodes being arranged to resonate by means of a piezoelectric effect resonator.
3. A piezoelectric resonator microchannel for liquid detection according to claim 1, wherein the electrodes are arranged in 4 ways according to the resonance modes of driving: using a surface wave resonance mode, wherein an electrode above the active piezoelectric layer (7) is an interdigital electrode, and an electrode below the active piezoelectric layer (7) is absent; the contour resonance mode or the vertical electric field lamb wave resonance mode is used, the upper electrode of the active piezoelectric layer (7) is an interdigital electrode, and the lower electrode is also an interdigital electrode; using a transverse electric field lamb wave resonance mode, wherein an electrode above the active piezoelectric layer (7) is an interdigital electrode, and an electrode below the active piezoelectric layer is a flat plate electrode; and a vertical bulk acoustic wave resonance mode is used, wherein the upper electrode of the active piezoelectric layer (7) is a flat plate electrode, and the lower electrode is also a flat plate electrode.
4. A piezoelectric resonator microchannel for liquid detection according to claim 3, characterized in that the active piezoelectric layer (7) is connected to the silicon substrate (12) via the cavity (13) or directly when using the surface wave resonance mode; when the profile resonance mode, the vertical electric field lamb wave resonance mode, the transverse electric field lamb wave resonance mode or the vertical bulk acoustic wave resonance mode are used, the active piezoelectric layer (7) is connected with the silicon substrate (12) through the cavity (13), and the device area is suspended, so that acoustic waves are reflected at the interface between the piezoelectric material and air.
5. A piezoelectric resonator microchannel for liquid detection according to claim 1, characterized in that the active piezoelectric layer (7) and the structural piezoelectric layer (14) are made of aluminum nitride, lithium niobate, lithium tantalate, lead zirconate titanate; the electrodes are all made of metal materials.
6. The piezoelectric resonator microchannel for liquid detection according to claim 1, wherein the electrode is made of aluminum, gold, platinum, molybdenum, copper or tungsten.
7. A method of manufacturing a resonant micro-channel according to any one of claims 1 to 6 using a contour resonance mode or a vertical electric field lamb wave resonance mode, comprising the steps of:
step 1): depositing a lower electrode of the electrode on the silicon substrate and patterning the lower electrode;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching to form a cavity between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using a contour resonance mode or a vertical electric field lamb wave resonance mode.
8. A method for producing a resonant micro flow channel according to any one of claims 1 to 6 using a surface wave resonance mode, comprising the steps of:
step 1): depositing a first layer of piezoelectric material as an active piezoelectric layer over a substrate;
step 2): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 3): depositing and patterning a sacrificial layer over the upper electrode;
step 4): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 5): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 6): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 7): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 8): and (3) depositing a filling material, filling up the groove used for etching the sacrificial layer, and sealing the cavity between the active piezoelectric layer and the structural piezoelectric layer to obtain the resonant micro-channel using the surface wave resonant mode.
9. A method for manufacturing a resonance micro flow channel according to any one of claims 1 to 6 using a lamb wave resonance mode of a transverse electric field, comprising the steps of:
step 1): depositing a flat lower electrode of an electrode on a silicon substrate;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal over the active piezoelectric layer and patterning into an upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode of the flat plate;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using a lamb wave resonance mode of a transverse electric field.
10. The method for producing a resonant micro flow channel according to any one of claims 1 to 6, using a vertical bulk acoustic wave resonance mode, comprising the steps of
Step 1): depositing a lower electrode of an electrode on a silicon substrate and patterning a flat lower electrode;
step 2): depositing a first layer of piezoelectric material as an active piezoelectric layer over the lower electrode;
step 3): depositing metal above the active piezoelectric layer and patterning the metal into a flat upper electrode;
step 4): depositing and patterning a sacrificial layer over the upper electrode;
step 5): depositing a second layer of piezoelectric material as a structural piezoelectric layer over the sacrificial layer;
step 6): etching the structural piezoelectric layer to form a through hole connected with the upper electrode of the flat plate;
step 7): etching the structural piezoelectric layer to form a groove for etching the sacrificial layer;
step 8): etching the sacrificial layer by using isotropic etching, wherein the cavity is formed between the active piezoelectric layer and the structural piezoelectric layer;
step 9): depositing a filling material, filling up the grooves used for etching the sacrificial layer, and sealing the cavities between the active piezoelectric layer and the structural piezoelectric layer;
step 10): etching the structural piezoelectric layer and the active piezoelectric layer to form a through hole connected with the lower electrode of the flat plate;
step 11): and etching the structure piezoelectric layer and the active piezoelectric layer, defining a device area boundary, and etching the silicon substrate by using isotropic etching to form a cavity below the piezoelectric resonance micro-channel, thus obtaining the resonance micro-channel using the vertical bulk acoustic wave resonance mode.
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