Microdroplet driving chip and preparation method thereof

Abstract

The present application relates to a kind of microdroplet driving chip and its preparation method, belong to digital microfluidic technology field, solve the problem of defect in the prior art in the aspect of droplet driving that chip is made by PCB technology.The method of the present application includes: preparing multiple electrodes in close arrangement on PCB substrate to form electrode layer, and each electrode covers corresponding lead hole on PCB substrate respectively;The lead hole is filled by filling material, and the gap between the electrodes is filled by insulating material;The surface of electrode layer is polished to make the surface of electrode layer flat and smooth;In the surface of electrode layer after polishing, medium layer and hydrophobic layer are prepared in turn, and the lower plate of microdroplet driving chip is obtained.The microdroplet driving chip of the present application can greatly reduce the resistance of droplet moving on the chip, and it is easier to drive the droplet when converting control electrode.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of digital microfluidics, and in particular to a micro-droplet driving chip and a preparation method thereof. BACKGROUND

[0002] Lab on a Chip (LOC) refers to connecting multiple units or modules with different functions on a microscale, and cooperatively completing a series of complex biochemical analysis work such as sample preparation, biological and chemical reactions, separation and detection. The core and key of Lab on a Chip is digital microfluidics technology, that is, the generation and control technology of discrete droplets in a micro device. Among them, the electrowetting-on-dielectric (EWOD) effect on the medium is the basis of digital microfluidics technology, which refers to changing the hydrophilic and hydrophobic properties of a liquid on a solid surface by electrostatic force. Specifically, it is the change of the contact angle of the droplet on the solid surface. If the contact angle changes asymmetrically, the surface tension at the contact line of the droplet on both sides will change, and then the droplet will migrate and move.

[0003] The micro-droplet driving chip is the core element of digital microfluidics technology. In the prior art, the substrate of the micro-droplet driving chip is mostly prepared by ITO (indium tin oxide) conductive glass. However, when an experiment with a certain complexity (such as droplet generation, transportation, mixing, splitting, etc.) needs to be completed, a large number of electrode arrays are required to support, and the electrode lead problem is a major bottleneck for preparing large-scale arrayed electrodes on a glass substrate. Another chip substrate prepared based on thin film transistor (TFT) technology can solve the electrode array lead problem, but its price is relatively high and is not suitable for productization.

[0004] In addition to the above method, a printed circuit board (PCB) process can also be used to prepare the chip substrate. The PCB process has the advantages of low price, simple preparation, and large-scale use. The mature via manufacturing process and supporting grid array packaging technology in the PCB process easily solve the lead problem of large-scale arrayed electrodes, but this technology has certain defects in droplet driving. Specifically, since the PCB board is printed, the chip made by the PCB technology has low manufacturing precision, and its surface cannot achieve the smoothness of a glass plane. A rough plane will bring difficulties to droplet driving. On the one hand, the droplet will be subjected to a large friction force from the rough plane during movement, and when the driving force of the droplet under voltage driving cannot exceed the friction force, the droplet will not be able to move. On the other hand, increasing the driving force by increasing the driving voltage will have the risk of breakdown, and since most of the liquids participating in the experiment of the Lab on a Chip chip are high-concentration salt solutions, the risk of breakdown is further increased. At the same time, the through holes 3 of the electrodes 2 and the gaps between the electrodes on the PCB board are not smooth enough to drive the droplet to move. Figure 1) will produce a huge resistance to the movement of the droplets, seriously hindering the movement of the droplets, so it is necessary to solve the resistance problem from the root. Summary of the Invention

[0005] In view of the above analysis, the embodiments of the present invention aim to provide a method for preparing a micro-droplet driving chip and a preparation method thereof, so as to solve the problem that chips made using PCB technology in the prior art have defects in droplet driving.

[0006] In one aspect, an embodiment of the present invention provides a method for preparing a micro-droplet driving chip, the method comprising:

[0007] A plurality of closely arranged electrodes are prepared on a PCB substrate to form an electrode layer, and each electrode covers a corresponding guide hole on the PCB substrate;

[0008] Filling the guide holes with a filling material and filling the gaps between the electrodes with an insulating material;

[0009] Polishing the surface of the electrode layer to make the surface of the electrode layer flat and smooth;

[0010] A dielectric layer and a hydrophobic layer are sequentially prepared on the surface of the polished electrode layer to obtain the lower electrode plate of the micro-droplet driving chip.

[0011] Based on a further improvement of the above method, the polishing treatment of the surface of the electrode layer includes the following steps:

[0012] preparing a buffer layer of a first preset thickness on the surface of the electrode layer;

[0013] The buffer layer is polished until the electrode layer is exposed and polished away by a second preset thickness.

[0014] Based on a further improvement of the above method, a buffer layer of a preset thickness is prepared on the surface of the electrode layer, comprising:

[0015] After the electrode layer is coated with a preset thickness of modified epoxy resin glue, the coated modified epoxy resin glue is subjected to a high-temperature curing treatment to form a buffer layer.

[0016] According to a further improvement of the above method, the buffer layer is polished by a polishing machine under the action of a polishing liquid until the electrode layer is exposed and polished away to a second preset thickness.

[0017] Based on a further improvement of the above method, a plurality of closely arranged electrodes are prepared on a PCB substrate to form an electrode layer, comprising the following steps:

[0018] Depositing a metal layer on the PCB substrate;

[0019] Preparation of a mask, forming a pattern area on the mask, the pattern area comprising a plurality of closely arranged pattern units, the shape of the pattern units being the same as the shape of the electrodes;

[0020] The metal layer is subjected to photolithography using the mask to realize the patterning of the electrode layer, thereby forming a plurality of closely arranged electrodes.

[0021] Based on the further improvement of the above method, the two side edges of the electrode in the microdroplet moving direction are provided with a concave-convex shape.

[0022] Based on the further improvement of the above method, the concave-convex shape comprises a zigzag shape or a corrugated shape.

[0023] Based on the further improvement of the above method, the filling material comprises a resin material, and the insulating material comprises a solder resist.

[0024] Based on the further improvement of the above method, the method further comprises:

[0025] Preparation of a second hydrophobic layer on the ITO conductive glass substrate to obtain an upper plate of the microdroplet driving chip;

[0026] Assembling the upper plate and the lower plate together to obtain the microdroplet driving chip.

[0027] In another aspect, the embodiment of the present application provides a microdroplet driving chip prepared by the method as described above,

[0028] The microdroplet driving chip comprises an upper plate and a lower plate,

[0029] The lower plate comprises:

[0030] The PCB substrate is provided with a guide hole, and the guide hole is provided with a filling material;

[0031] The electrode layer is prepared on the PCB substrate, and the electrode layer comprises a plurality of closely arranged electrodes, each electrode covering a corresponding guide hole on the PCB substrate, and the gap between the electrodes being filled with an insulating material;

[0032] The medium layer is coated on the electrode layer after polishing treatment; and

[0033] The hydrophobic layer is coated on the medium layer.

[0034] Compared with the prior art, the present application can at least achieve one of the following beneficial effects:

[0035] 1. In the present invention, when preparing the electrode layer, the electrodes cover the guide holes on the PCB substrate, and the guide holes and the gaps between the electrodes are filled respectively, thereby achieving rough flattening of the electrode layer surface. Then, fine flattening of the electrode layer surface is further achieved by polishing, and then the dielectric layer and the hydrophobic layer are coated in sequence, thereby finally obtaining a lower electrode plate of the micro-droplet driving chip with a smooth and flat surface, which greatly reduces the resistance of the droplets moving on the chip.

[0036] 2. In the present invention, when polishing the electrode layer, a buffer layer is first prepared on the surface of the electrode layer to increase the thickness, and then the polishing process is started from the surface of the buffer layer, thereby achieving the polishing process of the electrode layer surface with a thickness of micrometer level (less than 1 mm).

[0037] 3. In the present invention, the shape of the electrode is improved, and the edges on both sides of the electrode in the direction of movement of the micro-droplet are set to a concave-convex shape, which can ensure that the droplet is in contact with two adjacent independent electrodes at the same time in its movement path, thereby making it easier to drive the droplet when switching the control electrode.

[0038] In the present invention, the above-mentioned technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of the present invention will be described in the following description, and some advantages will become apparent from the description or be learned through practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like parts throughout the drawings.

[0040] Figure 1 This is a schematic diagram of the structure of a micro-droplet driving chip manufactured using PCB technology in the prior art;

[0041] Figure 2 Flowchart of a method for preparing a micro-droplet driving chip according to an embodiment of the present invention;

[0042] Figure 3 This is a diagram of the decomposition steps of preparing the lower electrode plate according to an embodiment of the present invention;

[0043] Figure 4 Schematic diagram of the relative positions of the electrode layer and the guide hole prepared in step 1 of an embodiment of the present invention;

[0044] Figure 5 This is a top view of the prepared lower electrode plate according to an embodiment of the present invention.

[0045] Reference numerals:

[0046] 1, PCB substrate; 2, electrode; 3, through hole; 4, filling material; 5, insulating material;

[0047] 6, dielectric layer; 7, hydrophobic layer. DETAILED DESCRIPTION

[0048] The preferred embodiments of the present application will be described in detail below with reference to the drawings, which constitute a part of this application, and are used to explain the principles of the present application, and are not used to limit the scope of the present application.

[0049] One specific embodiment of the present application provides a preparation method of a micro-droplet driving chip, as shown in Figure 2 The method comprises:

[0050] Step 1, a plurality of electrodes 2 are prepared on the PCB substrate 1 to form an electrode layer, and each electrode 2 covers a corresponding through hole 3 on the PCB substrate 1;

[0051] Step 2, the through holes 3 are filled with the filling material 4, and the gaps between the electrodes 2 are filled with the insulating material 5;

[0052] Step 3, the surface of the electrode layer is polished to make the surface of the electrode layer flat and smooth;

[0053] Step 4, a dielectric layer 6 and a hydrophobic layer 7 are prepared on the surface of the electrode layer after polishing to obtain the lower plate of the micro-droplet driving chip.

[0054] In implementation, the PCB substrate 1 is used as the chip substrate, the electrode layer is first made on the PCB substrate 1, then the through holes 3 of the PCB substrate 1 are filled with the filling material 4 to make the surface of the PCB substrate 1 flat, and the gaps between the electrodes 2 are filled with the insulating material 5 to achieve the rough planarization of the surface of the electrode layer. The filling of the through holes 3 of the PCB substrate 1 with the filling material 4 achieves the planarization of the surface of the PCB substrate 1, which makes the electrode layer better adhere to the surface of the PCB substrate 1, and is conducive to the planarization of the surface of the electrode layer. After the rough planarization of the electrode layer is achieved, fine planarization is achieved by polishing, and then the dielectric layer 6 and the hydrophobic layer 7 are coated in sequence, so as to achieve the purpose of replacing the glass substrate with the PCB substrate.

[0055] Compared with the prior art, in the present application, the electrode 2 covers the through hole 3 on the PCB substrate 1 when the electrode layer is prepared, and the gap between the through hole 3 and the electrode 2 is filled to realize rough leveling of the surface of the electrode layer, then further polishing is used to realize fine leveling of the surface of the electrode layer, and then the medium layer 6 and the hydrophobic layer 7 are coated in sequence, so that the lower plate of the micro-liquid droplet driving chip with a smooth and flat surface is finally obtained, and the resistance of the liquid droplet moving on the chip is greatly reduced.

[0056] In step 1, the two side edges of the electrode 2 in the micro-liquid droplet moving direction are both provided in a concave-convex shape.

[0057] In the present application, the shape of the electrode 2 is improved, and the two side edges of the electrode 2 in the micro-liquid droplet moving direction are both provided in a concave-convex shape, which can ensure that the liquid droplet is in contact with both adjacent two independent electrodes 2 on its moving path, so that the liquid droplet is more easily driven when the electrodes 2 are switched.

[0058] Specifically, the concave-convex shape includes a zigzag shape or a corrugated shape. Figure 4 And Figure 5 The electrode 2 with the two side edges in the micro-liquid droplet moving direction being in a corrugated shape is shown in Figs. 1 and 2.

[0059] In the operation process of the micro-liquid droplet driving chip, the contact angle of the liquid droplet is controlled by adjusting the voltage of the electrode 2, so as to control the movement or splitting of the liquid droplet, as shown in Figs. 3 and 4. Figure 4 And 5 The electrode 2 with the edges in a concave-convex shape can make the liquid droplet in contact with both two independent electrodes 2, so that the liquid droplet is more easily driven when the electrodes 2 are switched (if only in contact with a single electrode 2, the liquid droplet cannot be driven). Compared with the triangular or other regular-shaped electrodes 2, the electrode 2 with the edges in a concave-convex shape such as a zigzag shape or a corrugated shape has an interaction site between the two adjacent electrodes 2 in the moving direction of the micro-liquid droplet, has a high space utilization rate, and each convex part can act on the liquid droplet. The multi-point force has a higher use efficiency than the single-point force, and the driving effect is more obvious.

[0060] Further specifically, in step 1, the plurality of electrodes 2 are prepared on the PCB substrate 1 to form an electrode layer, including the following steps:

[0061] Step 11, depositing a metal layer on the PCB substrate 1; specifically, a metal target can be sputtered and deposited on the PCB board by using a magnetron sputtering (PVD) technology;

[0062] Step 12, preparing a mask plate, forming a pattern area on the mask plate, the pattern area including a plurality of pattern units arranged closely, and the shape of the pattern unit is the same as that of the electrode 2;

[0063] Step 13, using the mask to perform photoetching on the metal layer to realize patterning of the electrode layer, and form a plurality of closely arranged electrodes 2.

[0064] The shape of the pattern unit is that both side edges in the microdroplet moving direction are concave-convex shapes.

[0065] In step 2, the filling material 4 includes a resin material, such as epoxy resin.

[0066] In the embodiment of the present application, the resin material is used to fill the through hole 3 on the PCB substrate 1. In the implementation, the resin plug hole process is used to plug the through hole 3 (blind hole) with resin and then press, which can not only avoid the problems of low fullness caused by material shrinkage and hole blowing caused by green oil (solder resist) plug hole, but also balance the contradiction between the thickness control of the medium layer 6 of the press and the design of the inner layer blind hole filling glue.

[0067] In step 2, the insulating material 5 includes solder resist.

[0068] The solder resist can play the role of insulation and prevent solder from adhering to some copper wires that do not need to be welded. Specifically, the solder resist can use liquid light imaging solder resist.

[0069] In addition, if the solder resist is selected to fill the gap between the electrodes 2, the gap between the electrodes 2 is set to 0.23-0.25 mm when the closely arranged plurality of electrodes 2 is prepared on the PCB substrate 1 to form the electrode layer in step 1.

[0070] Considering the limitation of the printing process, the solder resist can enter when the gap between the electrodes 2 is greater than or equal to 0.23 mm, so the gap between the electrodes 2 is set to 0.23-0.25 mm.

[0071] In the specific implementation, compared with the existing design, the gap between the electrodes 2 is increased, and the gap between the electrodes 2 can be increased by reducing the size of the electrodes 2.

[0072] In addition, it should be noted that the solder resist layer manufacturing process in the PCB process is very rough, and the existing microdroplet driving chip prepared by using the PCB process usually has a solder resist layer on the surface of the electrode 2. However, the roughness of the surface of the solder resist layer is large, and the resistance to the movement of the droplet is very large, which requires a higher voltage for driving. However, too high voltage is easy to cause breakdown and other adverse phenomena, which affects the use effect of the device. Therefore, in the embodiment of the present application, the solder resist layer on the surface of the electrode layer is cancelled, and only the solder resist is filled in the gap between the electrodes 2.

[0073] After the electrode layer is roughened by step 2, the surface of the electrode layer is still rough, and cannot reach the smoothness of the glass plane. The rough surface will bring difficulties to the liquid droplet driving. Therefore, in the embodiment of the present application, the smoothness of the surface of the electrode layer is improved by polishing process.

[0074] Preferably, in step 3, the polishing treatment of the surface of the electrode layer comprises the following steps:

[0075] Step 31, a buffer layer with a first preset thickness is prepared on the surface of the electrode layer; and

[0076] Step 32, the buffer layer is polished until the electrode layer is exposed and polished by a second preset thickness.

[0077] In the PCB process, the thickness of the electrode layer and other metal conductive layers is very small, generally 2-4 ounces (1 ounce = 45 um). Therefore, due to the thickness limitation of the metal layer, the automatic polishing treatment of the metal layer cannot be directly realized by the polishing machine in the prior art.

[0078] In the embodiment of the present application, when the electrode layer is polished, a buffer layer is first prepared on the surface of the electrode layer to increase the thickness, and then the polishing treatment is performed from the surface of the buffer layer, so that the polishing treatment of the surface of the electrode layer with a thickness of microns (less than 1 mm) is realized.

[0079] Specifically, the buffer layer with a preset thickness is prepared on the surface of the electrode layer, comprising: after the electrode layer is coated with a modified epoxy resin adhesive with a preset thickness, the coated modified epoxy resin adhesive is subjected to high-temperature curing treatment to form the buffer layer.

[0080] The modified epoxy resin adhesive refers to the epoxy resin adhesive with modified hardness. The shear strength of the modified epoxy resin adhesive is 25-35 kg / mm 2 , the tensile strength is 42 kg / mm 2 , and the compressive strength is 90 kg / mm 2 .

[0081] Further specifically, the modified epoxy resin adhesive can be coated on the surface of the electrode layer in a scraping manner. When the coated modified epoxy resin adhesive is subjected to high-temperature curing treatment, the treatment temperature is set to 110-120℃, and the treatment time is set to 60-90 min.

[0082] Specifically, the first preset thickness is 10-12 mm. That is, the thickness of the buffer layer is 10-12 mm.

[0083] In addition, in step 3, the buffer layer is polished completely, and only a small thickness of the electrode layer needs to be polished to achieve the required smoothness. In practice, the electrode layer is usually polished to a thickness of 50-100 um. That is, the second preset thickness is 50-100 um.

[0084] Preferably, the buffer layer is polished by a polishing machine under the action of the polishing liquid until the electrode layer is exposed and polished to the second preset thickness.

[0085] In view of the high requirements of droplet driving on surface flatness and smoothness, and the poor surface uniformity of mechanical polishing, the buffer layer is polished by a polishing machine under the action of the polishing liquid, so that the mechanical polishing method is combined with the chemical method to improve the polishing uniformity.

[0086] Specifically, the polishing liquid is a metallographic polishing liquid. The polishing machine is polished with 5000-5500 mesh fine sandpaper.

[0087] In addition, in the embodiment of the application, the polishing thickness is controlled by the polishing time. Specifically, the electrode layer surface is polished for 10-20 s with 5000-5500 mesh fine sandpaper under the action of the metallographic polishing liquid.

[0088] In a specific embodiment, the roughness Ra of the electrode layer surface before polishing is 3.287, and the roughness Ra of the electrode layer surface after polishing by the method described above is 2.036.

[0089] Specifically, in step 4, the material of the medium layer 6 is SU-8 (silicon oxide, silicon nitride), and the material of the hydrophobic layer 7 is Teflon.

[0090] The medium layer 6 prevents the droplet from contacting the electrode 2 and leaking electricity. The hydrophobic layer 7 adjusts the contact angle of the droplet and the interface, so that the droplet can be more easily driven.

[0091] It should be noted that the medium layer 6 and the hydrophobic layer 7 are both thin films that can be closely attached to the surface of the electrode layer. Therefore, the flatness and smoothness of the surface of the lower plate of the micro-droplet driving chip prepared by the method of the embodiment of the application are determined by the surface of the electrode layer.

[0092] The surface roughness of the lower plate prepared by the method of the embodiment of the application and the height difference between the filled gap and the surface of the electrode 2 are tested, and it is found that the micro-droplet driving chip using the lower plate meets the requirements of a lab-on-a-chip chip in terms of droplet driving.

[0093] In one embodiment, the method further comprises:

[0094] Step 5, preparing a second hydrophobic layer 7 on the ITO conductive glass substrate to obtain the upper electrode plate of the micro-droplet driving chip;

[0095] Step 6: Assemble the upper electrode plate and the lower electrode plate together to obtain a micro-droplet driving chip.

[0096] In this embodiment, since the upper electrode plate of the micro-droplet driving chip does not require the preparation of a large number of electrodes 2, it can be directly obtained by coating a hydrophobic layer 7 on an ITO conductive glass substrate, and the prepared upper electrode plate and the lower electrode plate are placed opposite each other and assembled together to obtain the micro-droplet driving chip.

[0097] On the other hand, a specific embodiment of the present invention provides a micro-droplet driving chip. The micro-droplet driving chip includes an upper electrode plate and a lower electrode plate. The lower electrode plate includes: a PCB substrate 1, provided with a guide hole 3, and a filling material 4 is provided in the guide hole 3; an electrode layer, prepared on the PCB substrate 1, the electrode layer including a plurality of closely arranged electrodes 2, each electrode 2 covering a corresponding guide hole 3 on the PCB substrate 1, and the gaps between the electrodes 2 are filled with an insulating material, preferably a solder resist; a dielectric layer 6, coated on the polished electrode layer; and a hydrophobic layer 7, coated on the dielectric layer 6.

[0098] like Figure 3 As shown in the figure, the lower electrode plate of the micro-droplet driving chip is prepared by the following method: a plurality of closely arranged electrodes 2 are prepared on a PCB substrate 1 to form an electrode layer, and each electrode 2 covers a corresponding guide hole 3 on the PCB substrate 1; the guide holes 3 are filled with a filling material 4, and the gaps between the electrodes 2 are filled with an insulating material, preferably a solder resist; the surface of the electrode layer is polished to make the surface of the electrode layer flat and smooth; a dielectric layer 6 and a hydrophobic layer 7 are sequentially prepared on the surface of the polished electrode layer to obtain the lower electrode plate of the micro-droplet driving chip.

[0099] Preferably, the gap between the electrodes 2 is set to 0.23 mm to 0.25 mm.

[0100] Preferably, both side edges of the electrode 2 in the moving direction of the droplet are configured to be concave-convex.

[0101] The upper electrode plate of the micro-droplet driving chip is prepared by the following method: a second hydrophobic layer 7 is prepared on an ITO conductive glass substrate to obtain the upper electrode plate of the micro-droplet driving chip.

[0102] The micro-droplet driving chip of the embodiment of the application is prepared based on the PCB process, adopts the PCB substrate 1 as the chip substrate, can obtain the lower plate of the micro-droplet driving chip which is smooth and flat in surface, greatly reduces the resistance of the droplet moving on the chip, is low in cost, and simple in processing process, is beneficial to mass production, and provides convenience for large-flux micro-fluid control.

[0103] The above merely describes the preferred embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A method for preparing a micro-droplet driving chip, characterized in that: The method comprises: A plurality of closely arranged electrodes are prepared on the PCB substrate to form an electrode layer, and each electrode covers a corresponding guide hole on the PCB substrate; Filling the guide holes with a filling material and filling the gaps between the electrodes with an insulating material; Polishing the surface of the electrode layer to make it flat and smooth includes the following steps: preparing a buffer layer of a first preset thickness on the surface of the electrode layer; polishing the buffer layer until the electrode layer is exposed and polished away by a second preset thickness; A dielectric layer and a hydrophobic layer are sequentially prepared on the surface of the polished electrode layer to obtain the lower electrode plate of the micro-droplet driving chip.

2. The method according to claim 1, characterized in that A buffer layer of a preset thickness is prepared on the surface of the electrode layer, comprising: After the electrode layer is coated with a preset thickness of modified epoxy resin glue, the coated modified epoxy resin glue is subjected to a high-temperature curing treatment to form a buffer layer.

3. The method according to claim 1 or 2, characterized in that Under the action of the polishing liquid, the buffer layer is polished by a polishing machine until the electrode layer is exposed and polished away by a second preset thickness.

4. The method according to any one of claims 1 and 2, characterized in that Preparing a plurality of closely arranged electrodes on a PCB substrate to form an electrode layer includes the following steps: Depositing a metal layer on the PCB substrate; preparing a mask, and forming a pattern area on the mask, wherein the pattern area includes a plurality of closely arranged pattern units, and the shape of the pattern units is the same as the shape of the electrode; The metal layer is photoetched using the mask to achieve patterning of the electrode layer, thereby forming a plurality of closely arranged electrodes.

5. The method according to any one of claims 1 and 2, characterized in that The edges of both sides of the electrode in the moving direction of the micro-droplet are both arranged in a concave-convex shape.

6. The method according to claim 5, characterized in that The concave-convex shape includes a sawtooth shape or a corrugated shape.

7. The method according to any one of claims 1 and 2, characterized in that The filling material includes a resin material, and the insulating material includes a solder resist.

8. The method according to any one of claims 1 and 2, characterized in that The method further comprises: A second hydrophobic layer is prepared on an ITO conductive glass substrate to obtain the upper electrode plate of the micro-droplet driving chip; The upper electrode plate and the lower electrode plate are assembled together to obtain a micro-droplet driving chip.

9. A micro-droplet driving chip, characterized in that: The micro-droplet driving chip is prepared by the method according to any one of claims 1 to 8. The micro-droplet driving chip includes an upper electrode plate and a lower electrode plate. The lower plate comprises: The PCB substrate is provided with a guide hole, and a filling material is provided in the guide hole; An electrode layer is prepared on the PCB substrate. The electrode layer includes a plurality of closely arranged electrodes, each electrode covering a corresponding guide hole on the PCB substrate, and the gaps between the electrodes are filled with insulating material; a dielectric layer coated on the polished electrode layer; and The hydrophobic layer is coated on the dielectric layer.

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