CN109126918B - A device for generating acoustofluidic tweezers - Google Patents

Abstract

The embodiment of the invention discloses a device for generating acoustic fluid forceps, which comprises: the at least one bulk acoustic wave generating component comprises a bottom electrode, a piezoelectric layer and a top electrode which are sequentially arranged from bottom to top; an acoustic wave reflecting portion provided in contact with one surface of the bulk acoustic wave generating member; the overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflecting part forms a bulk acoustic wave generating area; a backing layer for supporting the bulk acoustic wave generating member; at least one flow channel, wherein a partial area of the flow channel cavity covers an acoustic wave action area of at least one bulk acoustic wave generation area; wherein the acoustic fluid forceps further comprise a passivation layer; the passivation layer covers a portion of the piezoelectric layer where the top electrode is not provided. From the above, the above-mentioned device of this application produces the sound fluid tweezers and can realize carrying out accurate operation to molecules, nano-particles and micrometer scale object.

Description

A device for generating acoustofluidic tweezers

technical field

The invention relates to the field of microelectronic devices, in particular to a device for producing acoustic fluid tweezers.

Background technique

Capturing and precisely manipulating tiny particles or even single molecules has given rise to many methods for the study of biomedical physical processes, and has had a major impact on promoting basic science and applied research in related fields. In the past few decades, various particle capture and manipulation techniques have been developed, such as optical tweezers, acoustic tweezers, magnetic tweezers, and a series of techniques based on electric field control. Among them, optical tweezers are the most widely used. The advantages of high precision and controllability in the manipulation of micro-nano particles make it an important particle manipulation tool in basic research. However, optical tweezers also have some shortcomings such as low operating efficiency, obvious temperature effect, and complicated equipment operation. For this reason, other types of micro-nanoparticle "tweezers" technology have been developed to replace optical tweezers in some applications. For example, acoustic tweezers have the characteristics of low cost and simple operation, and have been verified in applications such as particle sorting and capture. In addition, fluid field control based on low Reynolds number can also achieve precise control of micron-scale and even quantum dots. At the same time, this technology also has technical bottlenecks that hinder further practical application, such as low sample size, relatively complicated operation, and fewer functions. In recent years, using the attenuation of sound waves in liquids to generate fluid driving force to form vortices, and then using special-shaped vortices to capture and manipulate particles has gradually attracted people's attention, and has shown great potential in practical applications. Among them, the surface vibration of microbubbles is used to generate eddy currents, a vortex generation method studied earlier, but this method is limited by the short working life of microbubbles, especially the instability in the fluid. The use of higher frequency surface acoustic wave devices to generate eddy currents in the width direction of micro-nano channels has begun to be used for online capture and screening of micro-nano particles. However, the size of the eddy current is large, and the precision of particle control is very low, which cannot meet the application requirements of more operations similar to optical tweezers. Currently, it is limited to the online screening of particles. Therefore, it is an urgent problem to be solved at present to be able to generate eddy currents of ideal shape and size, and use it to realize various operations on micro-nano particles.

Therefore, there is an urgent need for a device for generating acoustofluidic tweezers, so as to realize precise manipulation of micro-nano-scale fluids, molecules, nanoparticles, and micron-scale objects through the acoustofluidic tweezers.

Contents of the invention

In view of this, the main purpose of the present invention is to provide a device for producing acoustic fluid tweezers, so as to realize precise manipulation of micro-nano-scale fluids, molecules, nanoparticles and micron-scale objects through the acoustic fluid tweezers .

The invention provides a device for producing acoustic fluid tweezers, comprising:

At least one bulk acoustic wave generating component, including a bottom electrode, a piezoelectric layer, and a top electrode arranged sequentially from bottom to top;

an acoustic wave reflector disposed in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflection part constitutes a bulk acoustic wave generation area;

an underlayment for supporting the bulk acoustic wave generating component;

At least one flow channel, a part of the cavity of the flow channel covers the acoustic wave action area of at least one bulk acoustic wave generating area;

Wherein, the acoustofluidic tweezers further include a passivation layer; the passivation layer covers the portion on the piezoelectric layer that is not covered with the top electrode.

From the above, the above-mentioned device of the present application utilizes the three-dimensional eddy current array that can be generated by ultra-high-frequency sound waves, and uses it to realize ultra-fast mixing in the micro-nano fluid system. The operation of micro-nano particles can be realized by using the regulation of eddy current array. Moreover, the present application is provided with a passivation layer, and the benefits of setting the passivation layer are: (1) the use of the passivation layer makes the shape of the generated eddy current more regular in effect, and is more suitable for the operation of micro-nano particles, so that the micro-nano particles (2) The existence of the passivation layer can make the bonding of the flow channel structure and the substrate very convenient (the bonding of the silicon dioxide surface to PDMS, glass capillary, etc. is more convenient). (3) The piezoelectric layer is protected from the damage of the liquid in the flow channel (especially the corrosion of the alkaline solution), and the application adaptability of the device is improved (making the system work applicable to a wider range of objects).

The present application also provides a device for producing acoustic fluid tweezers, comprising:

at least one bulk acoustic wave generating component comprising: a bottom electrode, a piezoelectric layer and a top electrode;

Wherein, the bottom electrode and the top electrode are respectively arranged on the lower and upper sides of the piezoelectric layer, and there is no overlapping portion between the bottom electrode and the top electrode in the vertical direction; and the piezoelectric A gap is formed between the portion of the layer overlapping the bottom electrode and the top electrode;

an acoustic wave reflector disposed in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflection part constitutes a bulk acoustic wave generation area;

an underlayment for supporting the bulk acoustic wave generating component;

At least one flow channel, a part of the cavity of the flow channel covers the acoustic wave action area of at least one bulk acoustic wave generating area;

A passivation layer, the passivation layer covers the portion on the piezoelectric layer that does not cover the top electrode.

From the above, the gap in the above-mentioned device of the present application can make the sound field be controlled in the gap, so that the eddy current is distributed in the gap. Wherein, the size of the gap can be adjusted as required, providing a new eddy current generating structure. Moreover, the eddy current intensity can be adjusted through the size of the gap, which is more conducive to improving the convenience of regulation. The function of the passivation layer is the same as that described above, and will not be repeated here.

The present application also provides a device for producing acoustic fluid tweezers, comprising:

at least one bulk acoustic wave generating component comprising: a bottom electrode, a piezoelectric layer and a top electrode;

Wherein, the bottom electrode and the top electrode are arranged on the upper side of the piezoelectric layer, and the bottom electrode and the top electrode are in the same horizontal layer; and a gap is formed between the bottom electrode and the top electrode gap;

an acoustic wave reflector disposed in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflection part constitutes a bulk acoustic wave generation area;

an underlayment for supporting the bulk acoustic wave generating component;

At least one flow channel, a part of the cavity of the flow channel covers the acoustic wave action area of at least one bulk acoustic wave generating area.

From the above, the top electrode and the bottom electrode of the above device of the present application are both disposed on the upper side of the piezoelectric layer. Device processing is more convenient, and process steps are reduced. Moreover, a gap is also provided in the above-mentioned device of the present application, so that the sound field can be controlled in the gap, so that the eddy current is distributed in the gap. Wherein, the size of the gap can be adjusted as required, providing a new eddy current generating structure. Moreover, the eddy current intensity can be adjusted through the size of the gap, which is more conducive to improving the convenience of regulation.

Preferably, the device further includes:

The suspended electrode is arranged on the bottom of the piezoelectric layer and overlaps with the gap and the piezoelectric layer in the vertical direction.

From the above, the existence of the suspended electrodes changes the electric field distribution in the gap, so that the electric field mainly existing in the gap moves to the signal electrode. Another form of regulation of the electric field is realized, and then the regulation of the generated acoustofluidic tweezers is realized. Therefore, the suspended electrodes make the sound field realized by the structure of FIG. 5 substantially the same as that of FIG. 2 . But the device shown in Figure 5 has a simpler structure and fewer processing steps.

Preferably, the device further includes:

At least one set of microfluidic sampling system is connected with the flow channel cavity, and is used to control the injection amount of microfluid flowing into the flow channel cavity, and to control the injection speed of microfluid.

From the above, by controlling the injection volume of the microfluid, and for controlling the injection speed of the microfluid. It is more conducive to the generation of acoustofluidic tweezers for precise manipulation of molecules, nanoparticles, and micron-scale objects.

Preferably, the acoustic wave reflection part includes: a low acoustic impedance layer and a high acoustic impedance layer disposed between the bulk acoustic wave generating component and the substrate;

Wherein, the low acoustic impedance layer and the high acoustic impedance layer are superimposed alternately;

The adjacent low acoustic impedance layers and high acoustic impedance layers form a group, and the number of the groups is set to be greater than or equal to three.

From the above, it is conducive to better sound wave reflection.

Preferably, the acoustic wave reflection part includes: a cavity formed on the substrate, the cavity is opened on a side facing away from the bulk acoustic wave generating component or is closed by the substrate.

Based on the above, the sound wave reflection part may also be a cavity formed on the substrate, and the sound wave is reflected by using the cavity.

Preferably, the flow channel is arranged on a side of the bulk acoustic wave generating component opposite to the acoustic wave reflecting part.

From the above, the above arrangement makes the sound wave reflected by the sound wave reflection part act on the liquid in the flow channel to generate acoustofluidic tweezers.

Preferably, the ratio of the horizontal plane projected area of the flow channel cavity to the horizontal plane projected area of the bulk acoustic wave generating region is greater than or equal to 100%;

The height of the channel cavity is 2 to 5 times the diameter of the micro-nano particles, or the height of the channel cavity is in the range of 10nm-10mm or 10μm-10mm.

From the above, the ratio of the projected area of the horizontal plane of the channel cavity to the projected area of the horizontal plane of the bulk acoustic wave generation area is greater than or equal to 100%; it is based on the comprehensive consideration of the processing difficulty of the actual device and the control effect of the acoustofluidic tweezers generated value. From the above, the height of the flow channel cavity is 2 to 5 times the diameter of the micro-nano particles, and within this range, acoustofluidic tweezers with better control effects can be produced. The height range of the channel cavity is 10nm-10mm or 10μm-10mm. Within this range, acoustofluidic tweezers with better control effects can be produced.

Preferably, the material of the passivation layer is silicon dioxide or silicon nitride;

The bulk acoustic wave generating component is a film bulk acoustic wave resonator or a Lamb acoustic wave resonator whose working frequency is set to 0.5-50 GHz.

From the above, the material of the passivation layer is silicon dioxide or silicon nitride; (1) the shape of the generated eddy current is more regular, which is more suitable for the operation of micro-nano particles, so that the operation effect of micro-nano particles is improved; (2) It can make the bonding of the channel structure and the substrate very convenient (the bonding of the silicon dioxide surface to PDMS, glass capillary, etc. is more convenient). (3) The piezoelectric layer is protected from the damage of the liquid in the flow channel (especially the corrosion of the alkaline solution), and the application adaptability of the device is improved (making the system work applicable to a wider range of objects). The bulk acoustic wave generating component is a film bulk acoustic wave resonator or a Lamb acoustic wave resonator whose working frequency is set to 0.5-50 GHz. In this frequency range, acoustofluidic tweezers with better manipulation effect can be produced.

It can be seen from the above that the acoustic fluid tweezers provided by the present invention for micro-nano-scale fluid and particle manipulation can realize precise manipulation of molecules, nanoparticles, and micron-scale objects.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

FIG. 1 is a perspective structural schematic diagram of a device for generating acoustic fluid tweezers according to an embodiment of the present invention;

Fig. 2 is a schematic structural view of the first embodiment of the device for generating acoustic fluid tweezers according to the embodiment of the present invention;

3 is a schematic structural view of a second embodiment of the device for generating acoustic fluid tweezers according to the embodiment of the present invention;

FIG. 4 is a schematic structural view of a third embodiment of the device for generating acoustic fluid tweezers according to an embodiment of the present invention;

FIG. 5 is a schematic structural view of a fourth embodiment of the device for generating acoustic fluid tweezers according to the embodiment of the present invention;

Fig. 6 is a schematic structural view of a fifth embodiment of the device for generating acoustic fluid tweezers according to the embodiment of the present invention;

Fig. 7 is a top view of the acoustic fluid tweezers produced by the device of the embodiment of the present invention and some functions for realizing the operation of micro-nano particles;

Fig. 8 is a top view of the flow channel and the bulk acoustic wave generating area of the embodiment of the present invention;

Fig. 9a is a schematic diagram of finite element simulation of the flow field of the eddy current generated by the device of the embodiment of the present invention;

Fig. 9b is the velocity field distribution diagram obtained after the simulation of Fig. 9a;

Fig. 10a is a schematic diagram of analyzing the size and shape of the vortex hole in Fig. 9b.

Fig. 10b is a schematic diagram of the relationship between the size of the vortex hole and the height of the liquid level.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments It is a part of embodiments of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

In order to overcome the defects in the prior art, the present invention provides a device for producing acoustic fluid tweezers, which can realize precise manipulation of molecules, nanoparticles and micron-scale objects.

Embodiment one

In the specific implementation process of this embodiment, the characteristic scale of the flow channel is mainly at the micron level, so the flow channel is also called a micro-channel. Microchannel is the basic unit of microfluidic system and the carrier of fluid operation. As shown in FIG. 1 , it is a three-dimensional schematic diagram of the device for producing acoustofluidic tweezers proposed by the present invention. Different fluid samples enter the microchannel from port I and flow out from port H. The fluid flows over the bulk acoustic wave generating region (ie, the boxed region shown in the microfluidic channel in Figure 1). FIG. 2 is a schematic cross-sectional view of the central position of the bulk acoustic wave generation region in FIG. 1 along the direction perpendicular to the flow direction of the microfluid in the microfluidic channel. As shown in Figure 2, the device for producing acoustic fluid tweezers includes:

The substrate layer 210 may be composed of materials such as silicon, silicon dioxide, glass, gallium arsenide, PDMS, parylene, and similar materials.

The acoustic reflection layer 220 disposed on the base layer 210; wherein, the acoustic reflection layer in this embodiment is an acoustic impedance layer. The acoustic impedance layer includes: a high acoustic impedance layer 221 and a low acoustic impedance layer 222 . Wherein, the low acoustic impedance layer and the high acoustic impedance layer are alternately stacked. One layer of the low acoustic impedance layer and one layer of the high acoustic impedance layer form a group, and the number of the groups is set to be greater than or equal to three. The high acoustic impedance layer 221 and the low acoustic impedance layer 222 can be composed of silicon, silicon dioxide, aluminum nitride, molybdenum and other metals, parylene and other materials with different acoustic impedances. If a multilayer combination of high and low acoustic impedance is used as the acoustic wave reflection structure, the thickness of each layer should be adjusted accordingly with the change of the design operating frequency, so that the acoustic wavelength in each acoustic impedance layer is a quarter wavelength.

The bottom electrode layer 230 and the bottom electrode layer 203 disposed on the acoustic wave reflection layer 220 may be composed of gold, aluminum, molybdenum, iron, titanium, copper and other metals and alloys. The thickness of the bottom electrode layer is 1000A, and the Chinese name of the thickness unit A here is Angstrom, which means that 1A is equal to one tenth of a nanometer.

The piezoelectric layer 240 disposed on the bottom electrode layer 230 ; the piezoelectric layer 240 may be composed of piezoelectric materials such as aluminum nitride, zinc oxide, lead zirconate titanate, and lithium niobate. The thickness of the piezoelectric layer is 100A-100000A, and the Chinese name of the thickness unit A here is Angstrom, which means that 1A is equal to one tenth of a nanometer.

The top electrode layer 250 is disposed on the piezoelectric layer. The top electrode layer 250 may be composed of gold, aluminum, molybdenum, iron, titanium, copper and other metals and alloys. The thickness of the top electrode is 2000A, and the Chinese name of the thickness unit A here is Angstrom, which means that 1A is equal to one tenth of a nanometer.

At least one flow channel structure 260; the flow channel cavity 261 of the flow channel structure covers and contacts the bulk acoustic wave generation formed by overlapping the acoustic wave reflection layer 220, the bottom electrode layer 230, the piezoelectric layer 240, and the top electrode layer 250. above area 270.

Wherein, the number of the bulk acoustic wave generating regions is greater than or equal to one.

Wherein, the acoustofluidic tweezers further include a passivation layer 280; the passivation layer covers the portion on the piezoelectric layer that is not covered with the top electrode.

The benefits of setting the passivation layer are: (1) the use of the passivation layer makes the eddy current shape more regular in effect, which is more suitable for the operation of micro-nano particles, so that the operation effect of micro-nano particles is improved; (2) passivation The existence of the layer can make the bonding of the flow channel structure and the substrate very convenient (the bonding of the silicon dioxide surface to PDMS, glass capillary, etc. is more convenient). (3) The piezoelectric layer is protected from the damage of the liquid in the flow channel (especially the corrosion of the alkaline solution), and the application adaptability of the device is improved (making the system work applicable to a wider range of objects).

As shown in FIG. 8 , the top view of the thin film bulk acoustic wave microfluidic mixing device. Figure 8 shows the proportional relationship between the projected area of the bulk acoustic wave generation area 82 in the horizontal direction and the projected area of the micro-channel 81, and the relative position setting of the bulk acoustic wave generation area, specifically:

When the number of the bulk acoustic wave generating regions is 2, the relative position of the bulk acoustic wave generating regions is set as follows:

Arranged side by side at a specified distance along the fluid flow direction of the runner; or,

arranged side by side at a specified distance perpendicular to the fluid flow direction of the runner; or,

They are arranged side by side according to a specified distance in a 45-degree angle direction between the fluid flow direction of the flow channel and the direction perpendicular to the fluid flow direction of the flow channel.

When the number of the bulk acoustic wave generating regions is greater than 2, the relative positions of the bulk acoustic wave generating regions include at least but not limited to one of the following:

Arranged side by side according to the specified distance along the fluid flow direction of the runner;

Arranged side by side according to the specified distance in the direction perpendicular to the fluid flow of the flow channel;

and / or,

They are arranged side by side according to a specified distance in a 45-degree angle direction between the fluid flow direction of the flow channel and the direction perpendicular to the fluid flow direction of the flow channel.

Wherein, the ratio of the projected area in the horizontal direction of the channel cavity to the projected area in the horizontal direction of the bulk acoustic wave generating region is greater than or equal to 100%.

Wherein, the height of the channel cavity is 10nm-10mm. Within this range, the mixing effect is significant. Preferably, the cavity height of the flow channel is 10um-1mm. In the interval between 10um-1mm, the significance of the manipulation effect of the acoustofluidic tweezers increases with the increase of the height.

Wherein, the operating frequency of the device in this embodiment for generating bulk acoustic waves in the bulk acoustic wave generating region is 0.5-50 GHz. Significant acoustofluidic tweezers manipulation effects can be achieved in this frequency range.

There are two main methods of microfluidic processing. The first is to use a microchannel structure made of glass, metal, and organic polymers such as PDMS, PMMA, and hydrogel, and bond or press it on the surface of the thin-film bulk acoustic wave generating device. The second is to fill the sacrificial layer in the microchannel cavity in advance, and then deposit silicon dioxide, aluminum nitride, parylene, SU-8, and metals and metal oxides on the sacrificial layer to form a microchannel structure 260. Finally, the microchannel cavity 261 is formed by releasing the sacrificial layer.

When different fluid samples flow over the bulk acoustic wave generation region, by applying an electrical excitation signal to the device for generating acoustic fluid tweezers, the multi-layer structure of the device for generating acoustic fluid tweezers (i.e., towards the bottom electrode layer) is excited. 23 and the top electrode layer 23 are energized and act on the piezoelectric layer 24), and the acoustic wave will act on the fluid above the bulk acoustic wave generation area to generate a closed vortex, realizing the rapid and efficient mixing of microfluids. The mixed fluid flows over the area where the bulk acoustic waves are generated.

Experimental effect

As shown in FIG. 7 , it shows the top view of the acoustofluidic tweezers for micro-nano-scale fluid and particle manipulation and some functions to realize the manipulation of micro-nano particles. Micro-nanoscale eddy currents (arrays) 3 are generated at the edge of the acoustic wave device 2 . Arrow 5 represents the flow direction of fluid and micro-nano particles 4 in the micro-nano channel 1 . Combinations of other shapes and their topological structures are based on the principles of this patent to realize the operation function of micro-nano particles, which are all examples of the scope of protection of this patent.

In addition, in an unshown embodiment, due to actual needs, a flow channel cavity without a top cover can be packaged above the bulk acoustic wave generation area, and the functions realized by the present invention can also be realized. Therefore, a device for producing acoustofluidic tweezers formed by microchannels without a cap is also within the protection scope of the present invention.

Embodiment two

As shown in Figure 3, the embodiment of the present application also provides a device for producing acoustic fluid tweezers, including:

Bulk acoustic wave generating components, including: a bottom electrode 330, a piezoelectric layer 340 and a top electrode 350;

Wherein, the bottom electrode 330 and the top electrode 350 are arranged on the lower and upper sides of the piezoelectric layer 340 respectively, and the bottom electrode 330 and the top electrode 350 have no overlap in the vertical direction; And a gap 370 of a specified size is formed between the portion where the piezoelectric layer 340 overlaps with the bottom electrode 330 and the top electrode 350 ;

An acoustic wave reflection part 320 arranged in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode 330, the piezoelectric layer 340, the top electrode 350 and the acoustic wave reflection part 320 constitutes a bulk acoustic wave generation area;

a backing layer 310 for supporting the bulk acoustic wave generating component;

Part of the channel cavity 361 of the channel 360 covers the acoustic wave action area of at least one bulk acoustic wave generating area.

A passivation layer 380 , the passivation layer covers the portion on the piezoelectric layer 340 that does not cover the top electrode 350 .

From the above, the gap 370 in the above-mentioned device of the present application can make the sound field be controlled in the gap, so that the eddy current is distributed in the gap. Wherein, the size of the gap can be adjusted as required, providing a new eddy current generating structure. Moreover, the eddy current intensity can be adjusted through the size of the gap, which is more conducive to improving the convenience of regulation.

Since the configuration and materials of the other parts are the same as those in the first embodiment, they will not be repeated here. Wherein, FIG. 9a is a schematic diagram of the finite element simulation of the flow field of the eddy current generated by the device of the embodiment of the present invention; FIG. 9b is a distribution diagram of the velocity field obtained after the simulation of FIG. 9a. Among them, the N direction represents the high speed, and the M direction represents the speed decreasing direction. It is obvious that there is a hole-shaped region with low velocity in the center of the vortex. Wherein, Fig. 10a is a schematic diagram of analyzing the size and shape of the vortex hole in Fig. 9b. Fig. 10b is a schematic diagram of the relationship between the size of the vortex hole and the height of the liquid level.

Embodiment three

As shown in FIG. 4 , the embodiment of the present application also provides a device for generating acoustofluidic tweezers. include:

Bulk acoustic wave generating components, including: a bottom electrode 440, a piezoelectric layer 430 and a top electrode 450;

Wherein, the bottom electrode 440 and the top electrode 450 are arranged on the upper side of the piezoelectric layer 430, and the bottom electrode 440 and the top electrode 450 are in the same horizontal layer; and the bottom electrode 440 and the A gap 470 is formed between the top electrodes 450;

An acoustic wave reflector 420 arranged in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode 440, the piezoelectric layer 430, the top electrode 450 and the acoustic wave reflection part 420 constitutes a bulk acoustic wave generation area;

a backing layer 410 for supporting the bulk acoustic wave generating component;

Part of the channel cavity 461 of the channel 460 covers the acoustic wave action area of at least one bulk acoustic wave generating area.

From the above, the top electrode and the bottom electrode of the above device of the present application are both disposed on the upper side of the piezoelectric layer. Device processing is more convenient, and process steps are reduced. Moreover, a gap is also provided in the above-mentioned device of the present application, so that the sound field can be controlled in the gap, so that the eddy current is distributed in the gap. Wherein, the size of the gap can be adjusted as required, providing a new eddy current generating structure. Moreover, the eddy current intensity can be adjusted through the size of the gap, which is more conducive to improving the convenience of regulation.

Embodiment four

As shown in FIG. 5 , the embodiment of the present application also provides a device for generating acoustofluidic tweezers. include:

Bulk acoustic wave generating components, including: a bottom electrode 540, a piezoelectric layer 530 and a top electrode 550;

Wherein, the bottom electrode 540 and the top electrode 550 are arranged on the upper side of the piezoelectric layer 530, and the bottom electrode 540 and the top electrode 550 are in the same horizontal layer; and the bottom electrode 540 and the A gap 570 is formed between the top electrodes 550;

An acoustic wave reflection part 520 arranged in contact with one side of the bulk acoustic wave generating component;

The overlapping area of the bottom electrode 540, the piezoelectric layer 530, the top electrode 550 and the acoustic wave reflection part 520 constitutes a bulk acoustic wave generation area;

a backing layer 510 for supporting the bulk acoustic wave generating component;

Part of the channel cavity 561 of the channel 560 covers the acoustic wave action area of at least one bulk acoustic wave generating area.

On this basis, it further includes: a suspension electrode 580 disposed at the bottom of the piezoelectric layer and vertically overlapped with the gap and the piezoelectric layer.

The existence of the suspended electrodes changes the distribution of the electric field in the gap, so that the electric field mainly existing in the gap moves to the signal electrode. Another form of regulation of the electric field is realized, and then the regulation of the generated acoustofluidic tweezers is realized. Therefore, the suspended electrodes make the sound field realized by the structure of FIG. 5 substantially the same as that of FIG. 2 . But the device shown in Figure 5 has a simpler structure and fewer processing steps.

Since the settings and materials of other parts are the same as those in Embodiment 3, they will not be repeated here.

Embodiment five

As shown in FIG. 6 , the embodiment of the present application also provides a device for generating acoustofluidic tweezers. include:

The bottom layer 610, the acoustic wave reflection layer 620 arranged in the bottom layer; the bottom electrode layer 630 arranged on the sound wave reflection layer 620; the piezoelectric layer 640 arranged on the bottom electrode layer; a top electrode layer 650 on the piezoelectric layer;

At least one flow channel structure 660; the flow channel cavity 661 of the flow channel structure covers and contacts the bulk acoustic wave generation formed by overlapping the acoustic wave reflection layer 620, the bottom electrode layer 630, the piezoelectric layer 640, and the top electrode layer 650. above area 670.

A passivation layer 690 , the passivation layer covers the portion on the piezoelectric layer 640 that does not cover the top electrode layer 650 .

As shown in FIG. 6 , the difference between the mixing device in this embodiment and the device in Embodiment 1 lies in the position and shape of the acoustic wave reflection layer 620 . This is mainly due to the different processing methods of the two. The processing process of the acoustic wave reflection layer 620 (air cavity reflection layer) is as follows: first, the air cavity is processed on the underlayer 610 by wet or dry etching; then the air cavity is filled with a sacrificial layer; layers of structure. Finally, the material in the sacrificial layer is released to form a closed air cavity at the bottom, that is, the acoustic wave reflection layer 620 .

Since the configuration and materials of the other parts are the same as those in the first embodiment, they will not be repeated here.

To sum up, the device for generating acoustic fluid tweezers provided by the present invention uses sound waves to generate vortices of ideal shape and size in liquids in microchannels, and uses them to perform tweezers on molecules, nanoparticles, and micron-scale objects. Precise handling.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (8)

1. A device for producing acoustic fluid tweezers, comprising: At least one bulk acoustic wave generating component, including a bottom electrode, a piezoelectric layer, and a top electrode arranged sequentially from bottom to top; an acoustic wave reflector disposed in contact with one side of the bulk acoustic wave generating component; The overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflection part constitutes a bulk acoustic wave generation area; an underlayment for supporting the bulk acoustic wave generating component; At least one flow channel, a part of the cavity of the flow channel covers the acoustic wave action area of at least one bulk acoustic wave generating area; A passivation layer, the passivation layer covers the portion on the piezoelectric layer that does not cover the top electrode. 2. A device for producing acoustic fluid tweezers, comprising: at least one bulk acoustic wave generating component comprising: a bottom electrode, a piezoelectric layer and a top electrode; Wherein, the bottom electrode and the top electrode are respectively arranged on the lower and upper sides of the piezoelectric layer, and there is no overlapping portion between the bottom electrode and the top electrode in the vertical direction; and the piezoelectric A gap of a specified size is formed between the portion of the layer overlapping the bottom electrode and the top electrode; an acoustic wave reflector disposed in contact with one side of the bulk acoustic wave generating component; The overlapping area of the bottom electrode, the piezoelectric layer, the top electrode and the acoustic wave reflection part constitutes a bulk acoustic wave generation area; an underlayment for supporting the bulk acoustic wave generating component; At least one flow channel, a part of the cavity of the flow channel covers the acoustic wave action area of at least one bulk acoustic wave generating area; A passivation layer, the passivation layer covers the portion on the piezoelectric layer that does not cover the top electrode. 3. The device according to any one of claims 1-2, further comprising: At least one set of microfluidic sampling system is connected with the flow channel cavity, and is used to control the injection amount of microfluid flowing into the flow channel cavity, and to control the injection speed of microfluid. 4. The device according to any one of claims 1-2, wherein the acoustic wave reflection part comprises: a low acoustic impedance layer and a high acoustic impedance layer arranged between the bulk acoustic wave generating component and the substrate; Wherein, the low acoustic impedance layer and the high acoustic impedance layer are superimposed alternately; The adjacent low acoustic impedance layers and high acoustic impedance layers form a group, and the number of the groups is set to be greater than or equal to three. 5. The device according to any one of claims 1-2, characterized in that, the acoustic wave reflection part comprises: a cavity formed on the substrate, the cavity is open on a side facing away from the bulk acoustic wave generating component Or be set closed by the backing. 6. The device according to any one of claims 1-2, characterized in that, the flow channel is arranged on a side of the bulk acoustic wave generating component opposite to the acoustic wave reflecting part. 7. The device according to any one of claims 1-2, characterized in that, the ratio of the horizontal plane projected area of the flow channel cavity to the horizontal plane projected area of the bulk acoustic wave generating region is greater than or equal to 100%; The height of the channel cavity is 2 to 5 times the diameter of the micro-nano particles, or the height of the channel cavity is in the range of 10nm-10mm or 10μm-10mm. 8. The device according to any one of claims 1-2, wherein the material of the passivation layer is silicon dioxide or silicon nitride; The bulk acoustic wave generating component is a film bulk acoustic wave resonator or a Lamb acoustic wave resonator whose working frequency is set to 0.5-50 GHz.

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