A flexible needle tip array dry electrode and its preparation method and application

Abstract

The present invention discloses a flexible needle tip array dry electrode, its preparation method, and application. The flexible needle tip array dry electrode comprises: a flexible substrate, a silicon needle tip array structure, a graphene layer, an antenna base, and copper foil; the flexible substrate is provided with the silicon needle tip array structure; the graphene layer is provided on one side of the flexible substrate provided with the silicon needle tip array structure, and the antenna base is provided on the other side; copper foil is provided around the edges of the flexible substrate, and the graphene layer is electrically connected to the antenna base via the copper foil; a metal conductive layer is sputtered on the silicon needle tips of the silicon needle tip array structure; and the metal conductive layer is electrically connected to the graphene layer. The flexible needle tip array dry electrode provided by the present invention has good biocompatibility and excellent electrical stimulation and recording effects.

Description

Technical Field

[0001] The present invention belongs to the field of micromachining technology and relates to the field of flexible needle tip array electrodes, in particular to a flexible needle tip array dry electrode and a preparation method and application thereof. Background Art

[0002] Brain-computer interface (BCI) is currently at the forefront of human brain engineering and an important direction for interaction between humans and machines. It is a technology born on the basis of a high degree of integration and intersection of disciplines such as mechanics, mechanics, biological sciences, and electronic information. It is a new communication and control technology established between the human or animal brain or brain cell culture and computers or other electronic devices that does not rely on conventional brain information output pathways (peripheral nerves and muscle tissues). Simply put, it is an interactive system established by analyzing human (or animal) EEG signals. It breaks through the limitations of traditional neural reflex arc structures and achieves direct control and communication with external electronic application devices by enabling brain nerve signals to directly communicate with computers through wired or wireless communications.

[0003] In recent years, as the research on brain-computer interfaces has become more and more in-depth, people's demand for high-quality EEG signals has become more and more urgent. How to obtain high-quality EEG signals has become the key to research. According to the location of the electrodes and the method of implantation, brain-computer interfaces can be divided into three types: non-invasive, semi-invasive, and invasive. Among them, non-invasive BCI mainly collects surface electroencephalogram (EEG) (including evoked EEG and spontaneous EEG), magnetoencephalogram (MEG), functional magnetic resonance imaging (fMRI), and functional near-external spectroscopy; semi-invasive BCI includes methods such as cortical electroencephalography (ECoG); invasive brain-computer interfaces use intracortical EEG.

[0004] The three existing brain-computer interfaces mentioned above differ primarily in their penetration depth into the brain. Deeper brain-computer interfaces tend to obtain more accurate EEG signals, but they may also cause more or less damage to the brain. While surface EEG signals may not be as accurate as invasive ones, they are more convenient to collect and are therefore more convenient for clinical diagnosis of diseases such as epilepsy. Furthermore, research on dry electrodes, wet electrodes, and semi-dry and semi-wet electrodes is becoming increasingly in-depth. Flexible dry electrodes are widely used in implantable devices due to their good biocompatibility, excellent conformability, and minimal tissue damage.

[0005] Based on the above statements, the preparation of detection dry electrodes with good biocompatibility and excellent electrical stimulation and recording effects is a key issue in the current research of brain-computer interfaces. Summary of the Invention

[0006] The present invention aims to provide a flexible needle tip array dry electrode and its preparation method and application to solve one or more of the above-mentioned technical problems. The flexible needle tip array dry electrode provided by the present invention has good biocompatibility and excellent electrical stimulation and recording effects.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] The present invention provides a flexible needle tip array dry electrode, comprising: a flexible substrate, a silicon needle tip array structure, a graphene layer, an antenna base and a copper foil;

[0009] The flexible substrate is provided with the silicon needle tip array structure; a graphene layer is provided on one side of the flexible substrate provided with the silicon needle tip array structure, and an antenna base is provided on the other side; copper foil is provided on all four edges of the flexible substrate, and the graphene layer is electrically connected to the antenna base through the copper foil;

[0010] A metal conductive layer is sputtered on the silicon tips of the silicon tip array structure; and the metal conductive layer is electrically connected to the graphene layer.

[0011] A further improvement of the present invention is that the material of the flexible substrate is polydimethylsiloxane, parylene or polyimide.

[0012] A further improvement of the present invention is that the silicon needle tips in the silicon needle tip array structure are solid structures.

[0013] A further improvement of the present invention is that the material of the metal conductive layer is Pt, Au or Cu.

[0014] A further improvement of the present invention is that the height of the silicon needle tip array structure is 100 to 200 μm; wherein the spacing between adjacent silicon needle tips is 200 to 400 μm.

[0015] A method for preparing a flexible needle tip array dry electrode of the present invention comprises the following steps:

[0016] Using low-pressure chemical vapor deposition, SiO2 and Si3N4 are sequentially deposited on one side of a pre-cleaned silicon wafer to obtain a mask layer; the other side of the silicon wafer is anode-bonded to glass;

[0017] Based on the obtained mask layer, a silicon needle tip array structure is prepared by using photolithography, dry etching and corrosion methods;

[0018] Based on the obtained silicon needle tip array structure, a metal conductive layer is sputtered on the silicon needle tip using a magnetron sputtering method;

[0019] Depositing a preselected material on the side of the glass where the silicon needle tip array structure is prepared to prepare a flexible substrate; wherein the silicon needle tip array structure is embedded in the flexible substrate, and the metal conductive layer on the silicon needle tips is outside the flexible substrate;

[0020] Transferring a graphene layer on the surface of the flexible substrate; wherein the graphene layer is electrically connected to the metal conductive layer;

[0021] The glass is removed by etching to obtain an initial electrode; copper foil is used to wrap the edges of the initial electrode and fixed; an antenna base is attached to the side of the flexible substrate where the silicon needle tip array structure is not prepared, so that the antenna base is electrically connected to the graphene layer through the copper foil to prepare a flexible needle tip array dry electrode.

[0022] A further improvement of the present invention is that the step of preparing the silicon needle tip array structure based on the obtained mask layer by photolithography, dry etching and corrosion methods specifically includes:

[0023] Evenly spin-coating positive photoresist on the mask layer and developing it;

[0024] Using a plasma etching method, the mask layer not covered by the photoresist is etched using SF6 and CHF3 gases respectively;

[0025] The silicon wafer was etched by KOH wet etching method to prepare a silicon needle tip array structure.

[0026] A further improvement of the present invention is that a preselected material is deposited on the side of the glass where the silicon needle tip array structure is prepared to prepare a flexible substrate.

[0027] The thickness of the flexible substrate is 300 to 600 μm.

[0028] A further improvement of the present invention is that, based on the obtained mask layer, photolithography, dry etching and corrosion methods are used to prepare the silicon needle tip array structure.

[0029] The height of the silicon needle tip array structure is 100-200 μm, and the distance between adjacent silicon needle tips is 200-400 μm.

[0030] The flexible needle tip array dry electrode of the present invention is used for measuring electroencephalogram signals.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The flexible needle tip array dry electrode provided by the present invention is a detection dry electrode with good biocompatibility and excellent electrical stimulation and recording effects. Specifically, the present invention uses a silicon needle tip array structure and a flexible substrate as the physical structure. The flexible substrate can make the dry electrode have better conformability and ductility. The silicon needle tip array structure facilitates scalp insertion and is easy to operate. The metal conductive layer, graphene layer, copper foil, and antenna base are used to achieve electrical signal acquisition and output. Conductive gel is not used, and there is no galvanic cell effect. The impedance of the dry electrode of the present invention is relatively stable compared to wet electrodes. Compared with existing traditional dry electrodes, the impedance of the dry electrode of the present invention is also relatively low, and the recording effect is excellent.

[0033] The flexible needle tip array dry electrode provided by the present invention is a solid needle tip array, which can be better used to penetrate the stratum corneum, penetrate deep into the stimulation site, and provide effective recording and stimulation functions.

[0034] The preparation method of the present invention is specifically a method for producing a flexible needle tip array electrode based on a silicon wafer corrosion method, graphene transfer technology and flexible substrate deposition technology. The method can produce a solid needle tip array for piercing the stimulation site, obtain effective signals and reverse stimulation, and is low-cost and can be mass-produced. Specifically, it uses a single corrosion to obtain a silicon array, which is low-cost and simple in method. Ultimately, the needle tip height can be adjusted according to the thickness of the silicon wafer and the corrosion time, which can meet actual needs and is very flexible. The graphene layer is transferred in a simple method and graphene can be used to optimize the conductive effect and comfort level at the same time. The IPX4 antenna seat on the back is very convenient for actual use and connection, and copper foil is used for connection and protection of the side walls, which is both stable and convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art; obviously, the drawings described below are some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0036] Figure 1 This is a schematic diagram of the overall structure of a flexible needle tip array dry electrode according to an embodiment of the present invention;

[0037] Figure 2 1 is a schematic diagram of the back structure of the flexible needle tip array dry electrode in an embodiment of the present invention;

[0038] In the figure, 1. Metal conductive layer; 2. Silicon tip array structure; 3. Graphene layer; 4. Flexible substrate; 5. Antenna base; 6. Copper foil. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the solutions of the present invention, 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 embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0041] The present invention is described in further detail below with reference to the accompanying drawings:

[0042] See also Figure 1 and Figure 2 A flexible needle tip array dry electrode for measuring EEG signals according to an embodiment of the present invention comprises: a metal conductive layer 1, a silicon needle tip array structure 2, a graphene layer 3, a flexible substrate 4, an antenna base 5 and a copper foil 6; wherein, the flexible substrate 4 is embedded with the silicon needle tip array structure 2; each silicon needle tip of the silicon needle tip array structure 2 is sputtered with a metal conductive layer 1; the graphene layer 3 is provided on one side of the flexible substrate 4 embedded with the silicon needle tip array structure 2, and the antenna base 5 is provided on the other side; copper foil 6 is provided on the four sides of the flexible substrate 4, which is used as a wrapping protection support layer and a conductive layer; the metal conductive layer 1 is in contact and electrically connected with the graphene layer 3, and the graphene layer 3 is electrically connected to the antenna base 5 through the copper foil 6.

[0043] Specifically, a metal conductive layer 1 is sputtered on the silicon needle tip of the silicon needle tip array structure 2, and a flexible substrate 4 is deposited, the needle tip portion is exposed, a graphene layer 3 is transferred on the flexible substrate 4, a copper foil 6 is wrapped around the side of the electrode structure and welded, and finally an antenna base 5 is attached to the four corners of the back.

[0044] In the embodiment of the present invention, the material of the flexible substrate 4 is PDMS (polydimethylsiloxane), parylene or polyimide (PI).

[0045] In the embodiment of the present invention, the silicon needle tip is a solid structure.

[0046] In the embodiment of the present invention, the material of the metal conductive layer 1 is Pt / Au, Au is on the upper layer of Pt, and the thickness is 10nm / 150nm, or the material is Pt, Au or Cu.

[0047] In the embodiment of the present invention, the antenna base 5 may be an IPX4 antenna base.

[0048] The flexible needle tip array dry electrode disclosed in the embodiment of the present invention is provided with a flexible substrate 4, a graphene layer 3 and a silicon needle tip array structure 2, and has good biocompatibility and electrical stimulation; in addition, the metal conductive layer 1 is electrically connected to the graphene layer 3, and the graphene layer 3 is electrically connected to the antenna base 5 through the copper foil 6 to realize electrical signal transmission. No conductive gel is used, there will be no galvanic cell effect, the impedance is relatively stable relative to the wet electrode, and the impedance is relatively low compared to the existing traditional dry electrode, and the recording effect is excellent.

[0049] In summary, Figure 1 The structure of a semiconductor-based flexible needle tip array electrode is shown in a three-dimensional schematic diagram, including a metal conductive layer, a silicon needle tip, a graphene layer, and a flexible substrate; Figure 2 The back structure of the flexible needle tip array electrode is shown, including the IPX4 antenna base and copper foil. The silicon needle tips are densely and independently distributed, and the needle tip heads are covered by a sputtered conductive layer. The flexible substrate completely wraps the upper silicon needle tips to form a complete flexible needle tip array. Finally, a layer of graphene is transferred to the PDMS surface to wrap the surface of the flexible array electrode. The silicon needle tips are a solid structure, and the conductive layer is composed of metal Pt and Au, which ensures the conductivity of the needle tip part and causes less damage to the tissue after implantation. The entire flexible substrate can be made of polydimethylsiloxane (PDMS), which has excellent ductility and can fit well on the human body surface. The IPX4 antenna base on the back is used to connect the electrode to external circuit equipment, while the copper foil serves to connect the conductive parts on both sides and fix the overall structure. All of the above materials have good biocompatibility. Among them, the graphene, PDMS, and Au that actually come into contact with the tissue have excellent stability and biocompatibility. The silicon material of the needle tip serves only as a mechanical part and does not come into contact with the human body, nor does it serve as a conductive component. It has excellent stability and anti-interference capabilities.

[0050] A method for preparing a flexible needle tip array dry electrode according to an embodiment of the present invention comprises the following steps:

[0051] SiO2 and Si3N4 are sequentially deposited on one side of a pre-cleaned silicon wafer; one side of the silicon wafer is anode-bonded to glass;

[0052] Based on deposited SiO2 and Si3N4, a silicon needle tip array structure was prepared by photolithography, dry etching and corrosion methods.

[0053] Using a magnetron sputtering method, sputtering a metal conductive layer on the silicon tips of the silicon tip array structure;

[0054] Depositing preselected materials to prepare a flexible substrate while embedding the silicon needle tip array structure into the flexible substrate; the metal conductive layer of the silicon needle tip is outside the flexible substrate;

[0055] transferring a graphene layer on the surface of the flexible substrate, wherein the graphene layer is electrically connected to the metal conductive layer;

[0056] The glass is removed by etching to release the flexible needle-tip array electrode; the side structure of the electrode is wrapped with copper foil and soldered on both sides; the antenna base is attached to the four corners of the back to finally obtain the flexible needle-tip array electrode.

[0057] A method for preparing a flexible needle tip array electrode according to an embodiment of the present invention includes the following steps:

[0058] 1) Clean the silicon wafer and grow a Si3N4 / SiO2 mask layer on both sides using low pressure chemical vapor deposition (LPCVD);

[0059] 2) evenly spin-coating a positive photoresist and developing the same;

[0060] 3) Using plasma etching technology, the SiO2 / Si3N4 layer not masked by the photoresist is etched using SF6 and CHF3 gases respectively;

[0061] 4) Using KOH wet etching technology to etch the silicon wafer into a silicon needle tip array structure; for example, accurately measuring the etching rate of silicon under the KOH conditions, using a square mask and compensation strips to etch the silicon needle tips in one step;

[0062] 5) Aligning the mask and performing a second photolithography and development; using magnetron sputtering to sputter a metal layer on the surface as a conductive layer;

[0063] 6) Deposit PDMS so that the height is less than half of the needle tip height;

[0064] 7) Transferring a layer of graphene to the surface of the electrode by transferring graphene on the surface;

[0065] 8) Flip the edge lead to the back of the electrode, and then plate a layer of copper foil at the folded part for conductivity and protection of the electrode structure; wrap the side with copper foil so that the front and back can be conductive. In actual use, silver glue or other methods can be used to conduct the front and back, while also protecting the side structure;

[0066] 9) Stick the IPX4 type antenna base on the four edges of the back.

[0067] In step 3), the etching time for silicon nitride is 40 seconds, and the etching time for silicon oxide is 20 seconds. In step 4), the etching solution concentration is 20 wt% to 40 wt%, and the etching temperature is 60° C. to 90° C. In step 6), the thickness of the flexible substrate is 300 to 600 μm.

[0068] A method for preparing a flexible needle tip array dry electrode for EEG signal measurement according to an embodiment of the present invention comprises the following steps:

[0069] Step 1: Ultrasonic cleaning of the silicon wafer using acetone, anhydrous ethanol, and deionized water in sequence, followed by sequential deposition of SiO2 and Si3N4 using low-pressure chemical vapor deposition (LPCVD) to obtain a Si3N4 / SiO2 mask layer;

[0070] Step 2: On the back of the silicon wafer, use paraffin wax as a bonding agent to anodize the silicon wafer and the wafer glass;

[0071] Step 3: Photolithography is performed on the front side of the silicon wafer. First, positive photoresist is spin-coated and pre-baked. Then, UV exposure is performed for photolithography and development. Finally, post-baking is performed to complete the photolithography.

[0072] Step 4: Dry-etch the SiO2 / Si3N4 protective layer using a plasma etcher to dry-etch away the unblocked SiO2 / Si3N4 to form a KOH etching mask.

[0073] Step 5: Use KOH solution to etch to form a silicon tip array, and then clean;

[0074] Step 6: Perform photolithography for the second time, using the designed overlay mask and alignment marks, and repeat the photolithography steps of step 3 to form a mask pattern for the sputtered metal electrode;

[0075] Step 7: Use magnetron sputtering to sputter a metal conductive layer on the front surface of the needle tip array electrode. Specifically, for example, Pt is sputtered first, then Au is sputtered, and acetone is used to remove the glue and ultrasonic peeling is used to make a metal connection pattern;

[0076] Step 8: Deposit PDMS. The height of the deposition should cover part of the needle tip, but the top of the needle tip should still be exposed.

[0077] Step 9: Transfer a layer of graphene onto the PDMS surface, taking care not to damage the tip array structure;

[0078] Step 10: Use HF to etch away the backside wafer glass to release the flexible needle tip array electrode;

[0079] Step 11: Wrap the electrode side structure with copper foil and solder it on both sides;

[0080] Step 12: Attach the IPX4 antenna base to the four corners of the back to obtain a flexible needle tip array electrode.

[0081] The graphene transfer step in step 9 of the embodiment of the present invention includes:

[0082] (1) Spin-coat a layer of molten paraffin on the bottom of the growth substrate / graphene and cool it down;

[0083] (2) Spin-coating a protective layer material on the bottom of the paraffin wax and removing the growth substrate using an etching solution;

[0084] (3) Keep in deionized water at 40°C for one hour to eliminate wrinkles;

[0085] (4) transferring the structure to a target substrate and drying;

[0086] (5) Use an organic solvent to remove the protective layer and paraffin, clean and dry to complete the transfer.

[0087] The area of ​​the dry electrode of the embodiment of the present invention is 1 to 4 cm 2 The thickness of the flexible substrate is 300 to 600 μm. The height of the silicon needle tip array structure is 100 to 200 μm, and the spacing between adjacent needle tips is 200 to 400 μm. The thickness of the metal conductive layer (3) is 10 to 20 nm of Pt and 100 to 200 nm of Au. The thickness of the silicon wafer used is 300 to 600 μm, and the type is N-type.

[0088] The preparation method of the embodiment of the present invention uses a single etching to obtain a silicon array, which is low-cost and simple. Ultimately, the needle tip height can be adjusted according to the thickness of the silicon wafer and the etching time, and it can be very flexible according to actual needs. The graphene layer is transferred in a simple method, and graphene can be used to optimize the conductive effect and comfort level. The IPX4 antenna seat on the back is very convenient for actual use and connection. Copper foil is used for connection and protection of the side wall, which is both stable and convenient.

[0089] A method for manufacturing a flexible needle tip array electrode according to an embodiment of the present invention includes the following steps:

[0090] 100 nm of SiO2 / Si3N4 were grown on a 400 μm thick N-type (100) silicon wafer using LPCVD, and the back side of the wafer was anodically bonded to the wafer glass using paraffin wax as a bonding agent.

[0091] Design the mask, use overlay on the mask, perform photolithography with positive photoresist, and make alignment marks;

[0092] A mask pattern is left on the SiO2 / Si3N4 support layer, and then the SiO2 / Si3N4 are removed in sequence using a plasma etcher;

[0093] Using SiO2 / Si3N4 as a mask, use KOH solution to etch the silicon pillars. KOH is used to etch the silicon anisotropically. The longitudinal direction is mainly <110> The corrosion rate is faster on the horizontal side, while <111> The corrosion rate is slow. By taking advantage of the fact that the longitudinal corrosion rate is greater than the lateral corrosion rate, a pyramid shape can be made through a mask to etch away 320um of silicon.

[0094] Clean the residual KOH solution on the surface of the silicon wafer and perform a second photolithography, using the previously made marks and the designed overlay mask for masking;

[0095] Magnetron sputtering is used to grow a metal conductive layer on the front side, with Pt / Au 10nm / 150nm respectively, so that the silicon needle tip is wrapped by the metal layer to achieve the growth of the conductive layer;

[0096] Deposit PDMS so that it partially covers the needle tip, leaving about 40 μm of the needle tip covered by the metal.

[0097] Transfer graphene, transferring the prepared graphene to the deposition surface;

[0098] Use HF to etch the glass on the back to release the prepared flexible needle tip electrode. After release, a certain thickness of PDMS is deposited on the back to stabilize the structure.

[0099] Wrap the sides of the electrode with copper foil and solder it on to electrically connect the front and back sides and protect the overall structure;

[0100] IPX4 connection pads are welded on the four corners of the back for connection with subsequent circuits, ultimately obtaining a complete flexible needle tip array electrode.

[0101] This invention provides a method for preparing and testing a flexible needle-tip array electrode for measuring electroencephalographic (EEG) signals. The method includes preparing a needle-tip structure on a high-conductivity silicon substrate and encapsulating the electrodes. A metal layer is sputtered onto the needle-tip array structure as a conductive layer. Polydimethylsiloxane (PDMS) is then deposited as a flexible substrate material. A layer of graphene is then transferred onto the surface. Finally, external devices, such as soldering equipment, are encapsulated on the back of the electrodes. The materials used in this invention, such as platinum and gold metals, graphene, and PDMS, all have good biocompatibility, reducing skin irritation and discomfort during use. The needle-tip structure and graphene layer effectively reduce contact impedance with the skin, thereby obtaining higher-quality EEG signals.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A flexible needle tip array dry electrode, characterized in that: include: Flexible substrate (4), silicon needle tip array structure (2), graphene layer (3), antenna base (5) and copper foil (6); The flexible substrate (4) is provided with the silicon needle tip array structure (2); a graphene layer (3) is provided on one side of the flexible substrate (4) provided with the silicon needle tip array structure (2), and an antenna base (5) is provided on the other side; copper foil (6) is provided on the four edges of the flexible substrate (4), and the graphene layer (3) is electrically connected to the antenna base (5) through the copper foil (6); a metal conductive layer (1) is sputtered on the silicon needle tips of the silicon needle tip array structure (2); the metal conductive layer (1) is electrically connected to the graphene layer (3); in, The material of the flexible substrate (4) is polydimethylsiloxane or polyimide; The silicon needle tips in the silicon needle tip array structure (2) are solid structures; The material of the metal conductive layer (1) is Pt, Au or Cu; The height of the silicon needle tip array structure (2) is 100 to 200 μm; wherein the spacing between adjacent silicon needle tips is 200 to 400 μm; The flexible needle tip array dry electrode is used for measuring EEG signals; The method for preparing the flexible needle tip array dry electrode comprises the following steps: Using low-pressure chemical vapor deposition, SiO2 and Si3N4 are sequentially deposited on one side of a pre-cleaned silicon wafer to obtain a mask layer; the other side of the silicon wafer is anode-bonded to glass; Based on the obtained mask layer, a silicon needle tip array structure (2) is prepared by using photolithography, dry etching and corrosion methods; Based on the obtained silicon needle tip array structure (2), a metal conductive layer (1) is sputtered on the silicon needle tip by using a magnetron sputtering method; A preselected material is deposited on the side of the glass on which the silicon needle tip array structure (2) is prepared, to prepare a flexible substrate (4); wherein the silicon needle tip array structure (2) is embedded in the flexible substrate (4), and the metal conductive layer (1) on the silicon needle tip is located outside the flexible substrate (4); Transferring a graphene layer (3) on the surface of the flexible substrate (4); wherein the graphene layer (3) is electrically connected to the metal conductive layer (1); The glass is removed by etching to obtain an initial electrode; copper foil (6) is used to wrap the four edges of the initial electrode and fixed; an antenna base (5) is attached to the side of the flexible substrate (4) where the silicon needle tip array structure (2) is not prepared, so that the antenna base (5) is electrically connected to the graphene layer (3) through the copper foil (6), thereby preparing a flexible needle tip array dry electrode.

2. The flexible needle tip array dry electrode according to claim 1, characterized in that: The steps of preparing the silicon needle tip array structure (2) based on the obtained mask layer by photolithography, dry etching and corrosion methods specifically include: Evenly spin-coating positive photoresist on the mask layer and developing it; Using a plasma etching method, the mask layer not covered by the photoresist is etched using SF6 and CHF3 gases respectively; A silicon wafer is etched by a KOH wet etching method to prepare a silicon needle tip array structure (2).

3. The flexible needle tip array dry electrode according to claim 1, characterized in that: A preselected material is deposited on one side of the glass where the silicon needle tip array structure (2) is prepared to prepare a flexible substrate (4), wherein the thickness of the flexible substrate (4) is 300-600 μm.

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