Flexible electrode and method for preparing same

Abstract

Provided are a flexible electrode and a method for preparing same. The flexible electrode comprises a number of sets of flexible electrode units (1). The flexible electrode unit (1) comprises a support layer (11) and an electrode layer (12). First through holes (111) are arranged in an array on a surface of the support layer (11). The electrode layer (12) is arranged in the first through holes (111) and on the surface of the support layer (11) to form grooves (13) in a grid arrangement. The sets of flexible electrode units (1) are stacked on each other, the first through holes (111) of two sets of flexible electrode units (1) stacked on each other are misaligned with each other, and two electrode layers (12) are in communication with each other. The method comprises: forming a sacrificial layer (3) on a surface of a substrate; forming a support layer (11) on a surface of the sacrificial layer (3); performing photoetching, development, and curing on the support layer (11) to form a plurality of first through holes (111) in the support layer (11); forming an electrode layer (12) on a surface of the resultant product, and forming second through holes (121) in the electrode layer (12); processing the electrode layer (12) to form grooves (13) in a grid arrangement; irradiating a substrate (2) from the bottom with UV light, decomposing the part of the sacrificial layer (3) in contact with the substrate (2), and separating the substrate (2); and cleaning with a BOE solution to remove the remaining sacrificial layer (3). The grooves (13) in the grid arrangement formed by the electrode layer (12) facilitate stress release, enhance flexibility, and make the flexible electrode less prone to damage.

Description

A flexible electrode and its preparation method Technical Field

[0001] This invention relates to electrodes and their manufacturing methods, specifically a flexible electrode and its preparation method. Background Technology

[0002] Early brain-computer interfaces used traditional rigid electrodes, such as silicon-based electrodes. After implantation, these could trigger an immune response, leading to scar tissue buildup, hindering signal transmission, and even causing electrode failure. Due to the softness of brain tissue, rigid electrodes could also cause damage during implantation, such as electrode displacement or brain tissue injury. The emergence of flexible electrodes has significantly improved upon the problems of traditional rigid electrodes, but it has also inevitably introduced some new issues. For example, screen printing inks are typically paste-like solutions made by dissolving conductive materials (such as C, Ag, Cu, etc.) in resin, but these resin solutions are volatile and may have slight toxicity. Inkjet printing technology requires specific conductive polymer inks or other suitable materials; however, the research and production of these materials may face challenges, such as limitations in cost, availability, and performance.

[0003] The existing electrode layers still suffer from high stress, low reliability, and are easily damaged. They can only conduct electricity on one side, making wiring difficult. Furthermore, the material safety of different printing methods in the fabrication process needs further improvement. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a flexible electrode, and another purpose of this invention is to provide a method for preparing a flexible electrode.

[0005] Technical solution: The flexible electrode of the present invention includes several sets of flexible electrode units. Each flexible electrode unit includes a support layer and an electrode layer. The surface of the support layer is provided with an array of through holes. The electrode layer is disposed on the surface of the through holes and the support layer and forms a grid-like groove. The positions of the through holes of the several sets of flexible electrode units are staggered.

[0006] Furthermore, the support layer is made of Su-8 adhesive, polyimide, or polydimethylsiloxane, with a thickness of 1–30 μm.

[0007] Furthermore, the electrode layer thickness is 0.2–2 μm.

[0008] Furthermore, the flexible electrode unit also includes a metal layer, with a metal layer disposed on the surface of the electrode layer. The metal layer is made of gold or platinum, and the total thickness of the electrode layer and the metal layer is 0.5–10 μm.

[0009] The present invention discloses a method for preparing a flexible electrode, comprising the following steps:

[0010] Step 1: Form a sacrificial layer on the substrate surface;

[0011] Step 2: Form a support layer on the surface of the sacrificial layer;

[0012] Step 3: Perform photolithography, development, and curing on the support layer to form several through-holes on the support layer;

[0013] Step four: An electrode layer is formed on the surface of the material obtained in step three, and several through holes are formed on the electrode layer;

[0014] Step 5: Process the electrode layer to form a grid-like groove;

[0015] Step 6: Irradiate the substrate from the bottom with UV light, causing the sacrificial layer to decompose at the contact point with the substrate, thus separating the substrate.

[0016] Step 7: Wash the product obtained in Step 6 with BOE solution to remove the remaining sacrificial layer and obtain the flexible electrode unit.

[0017] Furthermore, steps two to five are repeated multiple times, preferably 1 to 3 times, so that the positions of the through holes of the resulting sets of flexible electrode units are staggered.

[0018] Furthermore, by coating the electrode layer surface obtained in step four with photoresist, photolithography is performed to remove the photoresist above the second via, a metal layer is electroplated on the exposed electrode layer, excess photoresist is removed, and the electrode layer is processed to form a mesh-like groove.

[0019] Furthermore, in step one, the substrate is made of either sapphire or quartz glass. The sacrificial layer is made of SiNx, polycrystalline silicon, or amorphous silicon, with a thickness of 200–300 nm.

[0020] Furthermore, in step six, the wavelength of the UV light is 193nm to 248nm, and the energy density is 0.1 to 1J / cm2.

[0021] Working principle: Taking a silicon nitride sacrificial layer as an example, when UV light is used to irradiate the substrate from the bottom, the UV light excites electrons in the silicon nitride material, causing them to jump to the conduction band, resulting in a series of chemical reactions such as charge transfer and charge redistribution. These reactions are accompanied by heat generation, causing the part of the silicon nitride sacrificial layer in contact with the substrate to decompose due to high temperature. Silicon nitride has a high UV light absorption coefficient, so the UV light is absorbed at a very shallow area of ​​the interface. At the same time, the thermal conductivity of silicon nitride material is relatively low, so heat is not transferred to the support layer. This decomposition process forms a distinct peeling layer at the interface between the two, thereby achieving the separation of the silicon nitride sacrificial layer from the substrate.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0023] 1. The electrode layer forms a grid-like groove, which helps to effectively release stress, enhances flexibility, and prevents the electrode layer from breaking or damaging the human body when it is bent or twisted, making it less prone to damage;

[0024] 2. After removing the substrate, the double-sided conductive electrode offers greater flexibility and can be applied to more scenarios. At the same time, it can reduce design complexity and save costs when achieving the same function as the single-sided conductive electrode.

[0025] 3. Multiple through holes are provided. On the one hand, the through holes allow current to flow between different parts of the electrode, and at the same time provide a channel for electrolyte or other fluids. On the other hand, the increase of through holes disperses stress, making the flexible electrode more flexible.

[0026] 4. Multiple electrode layers can be stacked, allowing for the design of more complex flexible electrodes to meet the needs of special scenarios. Attached Figure Description

[0027] Figure 1 is a schematic diagram of the structure of the product obtained in step S1 of Embodiment 1 of the present invention;

[0028] Figure 2 is a schematic diagram of the structure of the product obtained in step S2 of Embodiment 1 of the present invention;

[0029] Figure 3 is a schematic diagram of the structure of the product obtained in step S3 of Embodiment 1 of the present invention;

[0030] Figure 4 is a schematic diagram of the structure of the product obtained in step S4 of Embodiment 1 of the present invention;

[0031] Figure 5 is a schematic diagram of the structure of the product obtained in step S5 of Embodiment 1 of the present invention;

[0032] Figure 6 is a schematic diagram of the structure after the second support layer 11 is coated in step S6 of Embodiment 1 of the present invention;

[0033] Figure 7 is a schematic diagram of the structure after photolithography and development in step S6 of Embodiment 1 of the present invention;

[0034] Figure 8 is a schematic diagram of the structure of the product obtained in step S6 of Embodiment 1 of the present invention;

[0035] Figure 9 is a schematic diagram of the structure after photolithography etching in step S6 of Embodiment 1 of the present invention;

[0036] Figure 10 is a schematic diagram of the structure of UV light irradiation in step S7 of Embodiment 1 of the present invention;

[0037] Figure 11 is a schematic diagram of the structure of substrate 2 separation in step S7 of Embodiment 1 of the present invention;

[0038] Figure 12 is a schematic diagram of the structure of the product obtained in step S8 of Embodiment 1 of the present invention;

[0039] Figure 13 is a schematic diagram of the structure after spin coating of photoresist 4 in step S5 of Embodiment 2 of the present invention;

[0040] Figure 14 is a schematic diagram of the structure after step S5 of Embodiment 2 of the present invention, where part of the photoresist 4 is photolithographically removed;

[0041] Figure 15 is a schematic diagram of the structure of the product obtained in step S6 of Embodiment 2 of the present invention;

[0042] Figure 16 is a schematic diagram of the structure of the product obtained in step S7 of Embodiment 2 of the present invention;

[0043] Figure 17 is a schematic diagram of the structure of the product obtained in step S8 of Embodiment 2 of the present invention;

[0044] Figure 18 is a schematic diagram of the structure of the product obtained in step S10 of Embodiment 2 of the present invention;

[0045] Figure 19 is a schematic diagram of the structure of UV light irradiation in step S11 of Embodiment 2 of the present invention;

[0046] Figure 20 is a schematic diagram of the structure of substrate 2 separation in step S11 of Embodiment 2 of the present invention;

[0047] Figure 21 is a schematic diagram of the structure of the product obtained in step S12 of Embodiment 2 of the present invention;

[0048] Figure 22 is a top view of Embodiment 2 of the present invention. Detailed Implementation

[0049] Example 1

[0050] A method for preparing a flexible electrode includes the following steps:

[0051] S1. As shown in Figure 1, a transparent substrate 2 is provided. The substrate 2 is cleaned using acetone / isopropanol / deionized water, and then the surface is dried. The substrate 2 can be any material such as sapphire or quartz glass. Plasma-enhanced chemical vapor deposition (PECVD) is used to form a sacrificial layer 3 on the surface of the substrate 2. The sacrificial layer 3 is made of silicon nitride (SiNx). During the deposition process, it is necessary to precisely control the deposition parameters, such as temperature, pressure, and gas flow rate, to obtain the desired silicon nitride film thickness and properties. During plasma-enhanced chemical vapor deposition (PECVD), the deposition temperature is 150℃~350℃, preferably 300℃; the deposition pressure is 100mTorr~1000mTorr, preferably 300mTorr; the gas configuration is: silane (SiH4) with a flow rate of 5sccm~20sccm, preferably 10sccm; ammonia (NH3) with a flow rate of 20sccm~100sccm, preferably 50sccm; the deposition rate is 20 nm / min~100 nm / min, preferably 50 nm / min; and the deposition thickness is 200nm~300nm. PECVD can also be replaced by chemical vapor deposition (CVD) techniques, such as atmospheric pressure chemical vapor deposition (APCVD) and low pressure chemical vapor deposition (LPCVD).

[0052] S2. As shown in Figure 2, thoroughly clean the surface of the sacrificial layer 3 using a suitable cleaning agent (such as deionized water, alcohol, or other specialized cleaning agents) to remove surface contaminants, grease, and impurities. After cleaning, dry the surface with nitrogen or dry air to ensure no moisture residue remains. Apply Su-8 adhesive evenly to the prepared sacrificial layer 3 using a spin coater or other coating equipment to obtain the support layer 11. During the coating process, it is necessary to control the coating speed, adhesive concentration, and coating time to ensure that the support layer 11 can be evenly and without defects covered on the sacrificial layer 3. Due to the high viscosity and slow curing speed of Su-8 adhesive, a slow spin coating speed is required, and multiple coats are needed to achieve the required thickness of the support layer 11. Spin coat speed: 1000 rpm to 4000 rpm, preferably 3000 rpm; Coating time: 30 s to 1 min, preferably 30 s; Support layer 11 thickness: 1 μm to 10 μm, preferably 5 μm.

[0053] S3. As shown in Figure 3, using a UV lithography machine or other lithography equipment, align and expose the mask with the through-hole pattern onto the sample coated with the support layer 11. During exposure, the exposure time and intensity need to be controlled to ensure that the pattern can be clearly transferred onto the support layer 11. Because Su-8 adhesive has high photosensitivity, a shorter exposure time and lower exposure intensity are required. After exposure, use an appropriate developer to remove the unexposed or underexposed parts of the support layer. During development, the development time and developer concentration need to be controlled to ensure that the pattern is completely retained on the support layer 11. Commonly used developers for Su-8 adhesive include organic solvents. The development time needs to be adjusted according to the complexity of the pattern and the thickness of the support layer 11, generally around 5 minutes. During development, the developer needs to be continuously stirred to ensure uniform development and to avoid defects such as blurring or deformation of the pattern. After development, several circular through-holes 111 are formed on the support layer 11. The curing temperature and time need to be adjusted according to the material and thickness of the support layer 11. Su-8 adhesive typically requires a high curing temperature and a long curing time, ranging from 150 to 300°C and 10 to 60 minutes. The curing temperature and time need to be adjusted based on the material and thickness of the support layer. For Su-8 adhesive, a high curing temperature and a long curing time are generally required.

[0054] S4. As shown in Figure 4, high-energy particles (such as ions or electrons) bombard the metal target, causing metal atoms to be sputtered from the target surface and deposited on the support layer 11. Sputtering has a high deposition rate and can deposit high-purity metal thin films. In a vacuum chamber, a gold, platinum, or noble metal alloy target is used as the sputtering source. An inert gas (such as argon) is introduced and an electric field is applied to ionize it to form plasma. Ions in the plasma are accelerated by the electric field and then collide with the target surface, sputtering metal atoms from the target. These sputtered atoms are then deposited on the substrate surface. After a period of accumulation, a uniform, dense, and chemically stable gold, platinum, or noble metal alloy electrode layer 12 is finally formed on the product obtained in step S3. Several through holes 121 are formed on the electrode layer 12. The thickness of the electrode layer 12 is 0.2 μm to 2 μm, preferably 0.5 μm.

[0055] S5. As shown in Figure 5, the electrode layer 12 is photolithographically etched to form a grid-like groove 13.

[0056] S6. Repeat steps S2 to S5, that is, coat the second support layer 11 on the surface of the material obtained in step S5 using the same process as in step S2, as shown in Figure 6. Using the same photolithography and development method as in step S3, form several circular through-holes 111 on the second support layer 11, as shown in Figure 7. Deposit the second electrode layer 12 using the same sputtering method as in step S4, as shown in Figure 8. Remove the second electrode layer 12 using the same method as in step S5 and perform photolithography etching to form a grid-like groove 13, as shown in Figure 9. This results in two sets of stacked flexible electrode units 1, with the through-holes 121 of different sets of flexible electrode units 1 staggered, and the two electrode layers 12 connected.

[0057] S7. As shown in Figures 10-11, UV light is used to irradiate the bottom of substrate 2. The heat causes partial decomposition of the material in contact with substrate 2, forming a release layer at the interface, thus separating substrate 2. The thickness of the release layer is approximately 30-50 nm. The UV light wavelength is 193 nm-248 nm, preferably 193 nm; the energy density is 0.1 J / cm²-1 J / cm², preferably 0.2 J / cm². 2 .

[0058] S8. As shown in Figure 12, the material obtained in S7 is cleaned with buffered oxide etching solution (BOE solution) to remove the remaining sacrificial layer 3. The material is then laser-cut to obtain a flexible electrode with double-sided conductivity.

[0059] The flexible electrode obtained in this embodiment includes several sets of flexible electrode units 1, including flexible electrode units 1 stacked vertically. The through holes 121 of the upper flexible electrode unit 1 and the through holes 121 of the lower flexible electrode unit 1 are staggered to facilitate processing. The flexible electrode unit 1 includes a support layer 11 and an electrode layer 12. The surface of the support layer 11 is provided with an array of through holes 111. The electrode layer 12 forms a grid-like groove 13 on the surface of the through holes 111 and the support layer 11.

[0060] Example 2

[0061] To further improve connectivity and structural strength, making it less prone to breakage, this embodiment, based on embodiment 1, adds a metal layer 14 to the surface of each electrode layer 12 for thickening.

[0062] A method for preparing a flexible electrode includes the following steps:

[0063] S1. Provide a transparent substrate 2. Clean the substrate 2 using acetone / isopropanol / deionized water, and then dry the surface. The substrate 2 can be any material such as sapphire or quartz glass. Use plasma-enhanced chemical vapor deposition (PECVD) to form a sacrificial layer 3 on the surface of the substrate 2. The sacrificial layer 3 is made of silicon nitride (SiNx). During the deposition process, it is necessary to precisely control the deposition parameters, such as temperature, pressure, and gas flow rate, to obtain the desired silicon nitride film thickness and properties. During plasma-enhanced chemical vapor deposition (PECVD), the deposition temperature is 150℃~350℃, preferably 300℃; the deposition pressure is 100mTorr~1000mTorr, preferably 300mTorr; the gas configuration is: silane (SiH4) with a flow rate of 5sccm~20sccm, preferably 10sccm; ammonia (NH3) with a flow rate of 20sccm~100sccm, preferably 50sccm; the deposition rate is 20 nm / min~100 nm / min, preferably 50 nm / min; and the deposition thickness is 200nm~300nm. PECVD can also be replaced by chemical vapor deposition (CVD) techniques, such as atmospheric pressure chemical vapor deposition (APCVD) and low pressure chemical vapor deposition (LPCVD).

[0064] S2. Thoroughly clean the surface of the sacrificial layer 3 using a suitable cleaning agent (such as deionized water, alcohol, or other specialized cleaning agents) to remove surface contaminants, grease, and impurities. After cleaning, dry the surface with nitrogen or dry air to ensure no moisture residue remains. Apply the PI adhesive evenly to the prepared sacrificial layer 3 using a spin coater or other coating equipment to obtain the support layer 11. During the coating process, it is necessary to control the coating speed, adhesive concentration, and coating time to ensure that the support layer 11 can be uniformly and without defects covered on the sacrificial layer 3. Spindle speed: 1000 rpm to 4000 rpm, preferably 3000 rpm; Coating time: 30 s to 1 min, preferably 30 s; Support layer 11 thickness: 1 μm to 10 μm, preferably 5 μm.

[0065] S3. Using a UV lithography machine or other lithography equipment, align and expose the mask with the through-hole pattern onto the sample coated with the support layer 11. During exposure, the exposure time and intensity need to be controlled to ensure that the pattern can be clearly transferred onto the support layer 11. PI adhesives may have different photosensitivity, which needs to be adjusted according to their specific material properties. After exposure, use an appropriate developer to remove the unexposed or underexposed portions of the support layer 11. During development, the development time and developer concentration need to be controlled to ensure that the pattern is completely retained on the support layer 11. The developer for PI adhesive is tetramethylammonium hydroxide (TMAH), and the development time is approximately 1 minute. During development, the developer needs to be continuously stirred to ensure uniform development and to avoid defects such as blurring or deformation of the pattern. After development, several circular through-holes 111 are formed on the support layer 11. The curing temperature and time need to be adjusted according to the material and thickness of the support layer 11. The curing temperature and time need to be adjusted according to the material and thickness of the support layer. The curing temperature is between 200 and 250°C, and the curing time is between 10 and 50 minutes.

[0066] S4. High-energy particles (such as ions or electrons) bombard the metal target, causing metal atoms to be sputtered from the target surface and deposited on the support layer 11. Sputtering has a high deposition rate and can deposit high-purity metal films. In a vacuum chamber, a gold, platinum, or noble metal alloy target is used as the sputtering source. An inert gas (such as argon) is introduced and an electric field is applied to ionize it to form a plasma. Ions in the plasma are accelerated by the electric field and then collide with the target surface, sputtering metal atoms from the target. These sputtered atoms are then deposited on the substrate surface. After a period of accumulation, a uniform, dense, and chemically stable gold, platinum, or noble metal alloy electrode layer 12 is finally formed on the product obtained in step S3. Several through holes 121 are formed on the electrode layer 12. The thickness of the electrode layer 12 is 0.2 μm to 2 μm, preferably 0.5 μm.

[0067] S5. As shown in Figure 13, a layer of photoresist 4 is spin-coated on top of the electrode layer 12, with the upper surface of the photoresist 4 flush. During the coating process, the thickness and uniformity of the photoresist 4 must be controlled to ensure the effectiveness of subsequent exposure and development. Mask fabrication, as shown in Figure 14, involves photolithography to remove the photoresist 4 above the via 121 of the electrode layer 12, exposing the portion of the electrode layer 12 with the via 121.

[0068] S6. As shown in Figure 15, a metal layer 14 is deposited on the electrode layer 12 using an electrochemical method. The height of the metal layer 14 does not exceed the height of the remaining photoresist 4. The surface of the metal layer 14 has cylindrical through-holes 141. Specifically, the material obtained in step S5 is placed in an electroplating solution, and appropriate voltage and current are applied. Under the action of the electric field, metal ions move towards the cathode support layer 11 and are reduced to metal atoms thereon. By controlling the electroplating time and current density, the thickness of the deposited layer can be precisely controlled. After thickening the electrode layer 12 and the metal layer 14, the total thickness is 0.5 μm to 10 μm.

[0069] S7. As shown in Figure 16, reverse photolithography is performed to remove excess photoresist 4.

[0070] S8. As shown in Figure 17, the excess metal layer 14 on the support layer 11 is removed by chemical etching, and the electrode layer 12 is treated to form a grid-like groove 13.

[0071] S9. Then, the sample is dried with nitrogen or dry air. After the electrode layer 12 is thickened with the metal layer 14, it is less prone to breakage and the connectivity of the through holes is enhanced.

[0072] S10. Repeat steps S2 to S9. The support layer 11 and the metal layer 14 each have two layers, as shown in Figure 18, to obtain two sets of flexible electrode units 1 stacked on each other. The positions of the through holes 141 of the flexible electrode units 1 in different sets are staggered. The metal layer 14 of the next set is connected to the electrode layer 12 of the previous set.

[0073] S11. As shown in Figures 19-20, UV light is used to irradiate the bottom of substrate 2. The heat causes partial decomposition of the material in contact with substrate 2, forming a release layer at the interface, thus separating substrate 2. The thickness of the release layer is approximately 30-50 nm. The UV light wavelength is 193 nm-248 nm, preferably 193 nm; the energy density is 0.1 J / cm²-1 J / cm². 2 The preferred concentration is 0.2 J / cm².

[0074] S12, as shown in Figure 21, the material obtained in S11 is cleaned with buffer oxide etching solution (BOE solution) to remove the remaining sacrificial layer 3, and then laser-cut to obtain a flexible electrode with double-sided conductivity.

[0075] While sputtering can form high-quality thin films, its relatively low deposition rate makes it difficult to directly form electrode layers of sufficient thickness to meet certain application requirements, thus preventing the formation of target thickness electrode layers in a single sputtering operation. Electroplating, on the other hand, boasts a higher deposition rate, allowing for rapid thickening of electrode layers. Electroplating also provides a uniform coating, contributing to improved electrode surface quality and performance. The electrode layer offers excellent adhesion; as a pre-plating layer, it enhances the adhesion between the metal layer and the support layer. This helps prevent the metal layer from detaching or peeling during subsequent use. The electrode layer provides a uniform substrate, ensuring the metal layer maintains a uniform thickness and morphology during deposition. This contributes to improved electrode performance and reliability. The method of forming an electrode layer through sputtering followed by electroplating allows for flexible adjustment of the electrode composition and structure. For example, different sputtering materials can be selected as the electrode layer to improve metal layer performance or meet specific application requirements. Although both sputtering and electroplating are mature processes, their costs differ. The method of forming a thinner electrode layer through sputtering followed by electroplating can reduce material costs while maintaining electrode performance.

[0076] As shown in Figure 22, the flexible electrode obtained in this embodiment includes several sets of flexible electrode units 1, including flexible electrode units 1 stacked vertically. The through holes 141 of the upper flexible electrode unit 1 and the through holes 141 of the lower flexible electrode unit 1 are staggered to facilitate processing. The flexible electrode unit 1 includes a support layer 11, an electrode layer 12, and a metal layer 14. The surface of the support layer 11 is provided with an array of cylindrical through holes 111. The electrode layer 12 forms a grid-like square groove 13 and cylindrical through holes 121 on the surface of the support layer 11. The surface of the metal layer 14 has cylindrical through holes 141.

[0077] Example 3

[0078] The remaining steps in this embodiment are the same as in embodiment 2, except that the support layer 11 is made of polydimethylsiloxane (PDMS).

[0079] Accordingly, step S2 is replaced with: S2.1, Cleaning the surface of sacrificial layer 3: Thoroughly clean the surface of sacrificial layer 3 using a suitable cleaning agent (such as deionized water, alcohol, or other specialized cleaning agents) to remove surface contaminants, grease, and impurities. After cleaning, dry the surface with nitrogen or dry air to ensure no moisture residue remains. S2.2, Preparation of PDMS support layer 11: Mix PDMS prepolymer and curing agent evenly in a certain proportion to form a PDMS solution. Avoid introducing air bubbles during mixing; remove air bubbles using methods such as vacuum degassing. Use a spin coater or other coating equipment to evenly coat the PDMS solution onto sacrificial layer 3. During coating, control the coating speed, solution concentration, and coating time to ensure that the PDMS layer can uniformly and without defects cover the sacrificial layer 3. First support layer thickness: 10μm~100μm, preferably 20μm. Place the sample coated with the PDMS layer on a hot plate for curing. The curing temperature and time need to be adjusted according to the specific material and thickness of the PDMS to ensure that the PDMS layer is completely cured and has good mechanical properties. Since PDMS is not photosensitive, electrode area patterns cannot be directly formed on it using conventional methods such as photolithography.

[0080] Step S3 is replaced by: using a laser cutting device to precisely cut the PDMS layer according to the preset electrode via pattern. Laser cutting has the advantages of high precision and high efficiency, which can ensure the accuracy and integrity of the electrode area and via pattern. The sidewalls of the vias have a certain inclination to ensure the continuity of the vias.

Claims

1. A flexible electrode, characterized by: The device includes several sets of flexible electrode units (1), each flexible electrode unit (1) including a support layer (11) and an electrode layer (12). The surface of the support layer (11) is provided with an array of through holes (111). The electrode layer (12) is disposed on the surface of the through holes (111) and the support layer (11) and forms a grid-like groove (13). The positions of the through holes (13) of the several sets of flexible electrode units (1) are staggered.

2. The flexible electrode of claim 1, wherein: The support layer (11) is made of Su-8 glue, polyimide or polydimethylsiloxane, and has a thickness of 1 to 30 μm.

3. The flexible electrode of claim 1, wherein: The electrode layer (12) has a thickness of 0.2 to 2 μm.

4. The flexible electrode of claim 1, wherein: The flexible electrode unit (1) further includes a metal layer (14), which is disposed on the surface of the electrode layer (12). The metal layer (14) is made of gold or platinum, and the total thickness of the electrode layer (12) and the metal layer (14) is 0.5 to 10 μm.

5. The method of claim 1, wherein the flexible electrode is prepared by the steps of: Includes the following steps: Step 1: A sacrificial layer (3) is formed on the surface of the substrate (2); Step 2: Form a support layer (11) on the surface of the sacrificial layer (3); Step 3: Photolithography, development and curing are performed on the support layer (11) to form a number of through holes (111) on the support layer (11); Step four, an electrode layer (12) is formed on the surface of the material obtained in step three, and a plurality of through holes (121) are formed on the electrode layer (12); Step 5: Process the electrode layer (12) to form a grid-like groove (13); Step 6: UV light is used to irradiate the substrate (2) from the bottom, and the sacrificial layer (3) decomposes at the contact point with the substrate (2), and the substrate (2) separates; Step 7: Wash the product obtained in Step 6 with BOE solution to remove the remaining sacrificial layer (3) and obtain the flexible electrode unit (1).

6. The method of claim 5, wherein: Steps two to five are repeated multiple times, and the positions of the through holes (111) of the resulting sets of flexible electrode units (1) are staggered.

7. The method of claim 5, wherein: In step four, photoresist (4) is coated on the surface of the electrode layer (12), the photoresist (4) above the second through hole (121) is photolithographically removed, a metal layer (14) is electroplated on the exposed electrode layer (12), excess photoresist (4) is removed, and the electrode layer (12) is processed to form a mesh-like groove (13).

8. The method of claim 5, wherein: In step one, the substrate (2) is made of either sapphire or quartz glass.

9. The method of claim 5, wherein: In step one, the sacrificial layer (3) is made of SiNx, polycrystalline silicon or amorphous silicon, with a thickness of 200-300 nm.

10. The method of claim 5, wherein: In the sixth step, the wavelength of the UV light is 193 nm to 248 nm, and the energy density is 0.1 to 1 J / cm 2 .

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