Preparation method of silicon carbide super-hydrophobic surface with femtosecond laser synchronous construction of physical micro-nano structure and chemical active site

Abstract

The application relates to a preparation method of a silicon carbide super-hydrophobic surface with femtosecond laser synchronous construction of physical micro-nano structures and chemical active sites, and belongs to the field of laser surface interface engineering. The method comprises the following steps: (1) cleaning and drying the surface of the silicon carbide material; (2) directly processing and inducing in-situ gradient oxidation of the surface of the material by using a femtosecond laser to generate micro-nano rough structures and high-density Si-O active sites; (3) performing ultrasonic cleaning to remove weakly combined splashed particles; (4) performing oxygen plasma activation to form a hydroxyl-rich activated interface; and (5) using a fluorosilane solution dissolved in anhydrous ethanol to perform low-surface-energy modification, and performing high-temperature drying and solidification to stably combine the fluorosilane layer on the micro-nano structure surface, so that the super-hydrophobic surface is obtained. The micro-nano morphology and surface active sites induced by the femtosecond laser provide a basis for subsequent silanization modification, and make the silicon carbide surface change from a hydrophilic state to a super-hydrophobic state with a contact angle greater than 150 degrees.

Description

Technical Field

[0001] This invention belongs to the field of laser surface interface engineering, specifically relating to a method for preparing a silicon carbide superhydrophobic surface by simultaneously constructing physical micro-nano structures and chemically active sites using femtosecond lasers. Background Technology

[0002] Silicon carbide (SiC), a typical representative of third-generation wide-bandgap semiconductor materials, possesses high thermal conductivity, high breakdown electric field, excellent chemical stability, and extremely high mechanical hardness, making it valuable for applications in power electronics, aerospace, and extreme environment engineering. However, SiC's high hardness and brittleness, along with its strong chemical inertness, make it prone to cracking, chipping, and subsurface damage during traditional machining processes. Dry and wet etching methods suffer from low efficiency, long process times, and insufficient pattern controllability. Furthermore, SiC surfaces after conventional cleaning or natural oxidation typically have high surface energy, making them susceptible to the formation of continuous water films in humid, condensing, or low-temperature environments. This can negatively impact device insulation, anti-fouling, anti-icing, and long-term service performance. Therefore, constructing a superhydrophobic functional layer on the SiC surface is crucial for improving its environmental adaptability and service reliability under harsh conditions.

[0003] Superhydrophobic surfaces typically require both suitable micro / nano roughness structures and low surface energy chemical compositions. Currently, common methods for constructing superhydrophobic functional layers on silicon carbide surfaces mainly fall into three categories: surface coating with low surface energy coatings, chemical etching combined with fluorosilane modification, and laser processing of micro / nano structures followed by low surface energy modification. Among these, pure coating methods result in a modified layer that is only physically attached to the silicon carbide substrate, exhibiting weak adhesion and easily failing under mechanical scratching or fluid erosion conditions, making it difficult to meet long-term service requirements. Chemical etching methods usually require strong acid or alkali treatment, resulting in poor process controllability, and the extremely high chemical inertness of silicon carbide leads to low etching efficiency, making it difficult to obtain a uniform and consistent roughness morphology. Laser processing combined with low surface energy modification is currently a research hotspot for preparing superhydrophobic functional layers on the surfaces of hard and brittle materials such as silicon carbide. However, in existing laser processing-post-modification strategies, the laser only performs the physical structural processing function, that is, to prepare grooves, holes or protrusion arrays on the material surface to provide a rough substrate for subsequent low surface energy modification. The introduction of surface chemical activity depends entirely on subsequent independent activation treatment steps, which makes it difficult for the activation treatment to fully penetrate into the deep grooves, narrow slits and concave regions of the micro-nano structure. This results in insufficient anchoring of modified molecules deep in the structure and poor surface chemical uniformity, thereby affecting the long-term stability of superhydrophobic properties.

[0004] Therefore, how to overcome the limitation of existing laser processing technology, which only undertakes the function of physical structure manufacturing, and realize the integrated construction of physical micro-nano structures and chemical active sites on the surface of silicon carbide, so that laser processing itself can simultaneously endow the surface with high-density reactivity, thereby providing an ideal interface for the high-density stable anchoring of low surface energy molecules, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention addresses the shortcomings of existing femtosecond laser processing techniques, which primarily focus on physical structure fabrication and suffer from insufficient surface energy interface bonding due to the separation of physical structures and chemically active sites. It provides a method for fabricating superhydrophobic silicon carbide surfaces by simultaneously constructing micro / nanostructures and chemically active sites using femtosecond lasers. This method utilizes laser-induced non-equilibrium thermo-chemical coupling to integrally generate nanoscale rough morphologies on the trench walls, trench bottoms, and intersection nodes, while simultaneously completing in-situ surface oxidation. This forms a laser-induced active micro / nano interface that combines physical micro / nanostructures with high-density Si-O active sites. After oxygen plasma activation to amplify the hydroxyl density, a stable fluorine-containing low surface energy layer is formed on the micro / nanostructure surface through covalent anchoring with fluorosilanes and high-temperature crosslinking, transforming the silicon carbide surface from a hydrophilic to a superhydrophobic state.

[0006] To achieve the objectives of this invention, the technical solution provided by this invention is as follows:

[0007] A method for preparing a silicon carbide superhydrophobic surface by simultaneously constructing physical micro / nano structures and chemically active sites using femtosecond lasers includes the following steps:

[0008] (1) Pre-treat the silicon carbide sample to remove surface oil and impurities, and dry the sample surface;

[0009] (2) A femtosecond laser is used to perform direct writing on the pretreated sample surface to construct a micron-level cross-groove structure on the silicon carbide surface. Utilizing the non-equilibrium thermo-chemical coupling effect of the femtosecond laser, a nano-rough structure is integrally generated at the groove walls, groove bottom, and cross nodes while constructing the micron-level cross-groove structure. Simultaneously, in-situ oxidation of the surface is completed to form a laser-induced active micro-nano interface that combines physical micro-nano structure with high-density Si-O active sites. After laser processing, ultrasonic-assisted cleaning is performed to selectively remove weakly bound sputtering particles and unstable deposits, while completely preserving the laser-induced active micro-nano interface.

[0010] (3) The laser-induced active micro / nano interface obtained in step (2) is subjected to oxygen plasma activation treatment to increase the surface hydroxyl density and form a hydroxyl-rich activated interface.

[0011] (4) Immerse the activated sample in a fluorosilane solution so that the fluorosilane molecules are covalently anchored to the high-density hydroxyl sites of the active micro-nano interface through hydrolysis and condensation reaction, forming a low surface energy molecular layer.

[0012] (5) After soaking, the sample is cleaned to remove any residual solution from the surface;

[0013] (6) The cleaned sample is dried and solidified at high temperature to allow the fluorosilane molecules to crosslink laterally to form a stable fluorine-containing low surface energy layer, thus obtaining a silicon carbide sample with superhydrophobic surface properties.

[0014] In one embodiment, in step (1), the silicon carbide sample is ultrasonically cleaned sequentially with anhydrous ethanol and deionized water for 10 min each. However, it is understood that adjusting the time within the range of 10 to 15 min can achieve the purpose of this invention.

[0015] In one embodiment, in step (2), the femtosecond laser is linearly polarized light with a center wavelength of 1030 nm, a pulse width of 190 fs, and a repetition frequency of 1 kHz.

[0016] In one embodiment, in step (2), the femtosecond laser processing power is 0.75 W, the scanning speed is 1 mm / s, and the scanning spacing is 100 μm. However, it is understood that the purpose of the present invention can be achieved by adjusting the power within the range of 0.75 to 1.0 W.

[0017] In one embodiment, in step (2), the femtosecond laser etching process path is a cross-grid type with an etching depth of 5~6 μm. However, it is understood that the purpose of the present invention can be achieved by adjusting within the range of 5~10 μm.

[0018] In one embodiment, step (2) involves cleaning the surface after laser etching by sequentially ultrasonically cleaning the sample with anhydrous ethanol and deionized water for 10 min each.

[0019] In one embodiment, the oxygen plasma activation treatment time in step (3) is 3 min.

[0020] In one embodiment, in step (4), the fluorosilane is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and the volume percentage of fluorosilane in the mixed solution of fluorosilane and anhydrous ethanol is 2 vol%, and the soaking time is 90 min.

[0021] In one embodiment, in step (6), the high-temperature drying and bonding temperature is 120°C and the time is 3 hours.

[0022] In one embodiment, the static contact angle of the silicon carbide sample surface obtained in step (6) is greater than 150°.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0024] (1) This invention breaks through the limitation of existing femtosecond laser processing, which only undertakes the function of physical structure manufacturing. By utilizing the non-equilibrium thermo-chemical coupling effect of femtosecond laser, while constructing micron-level cross-groove structures, a nano-rough structure is integrally generated at the groove walls, groove bottoms, and cross nodes, and the surface in-situ oxidation is completed simultaneously, directly forming a laser-induced active micro-nano interface that integrates "physical micro-nano structure + chemical active site". This interface does not need to rely on subsequent activation to build reactive activity from scratch, thus solving the inherent defect of separation between physical shaping and chemical activation in existing technologies from the source.

[0025] (2) The oxygen plasma activation treatment in this invention is a further amplification based on the high-density Si-O active sites generated by in-situ oxidation with femtosecond laser, rather than building surface hydroxyl groups from scratch. The resulting hydroxyl-rich activation interface has a higher hydroxyl density and a more uniform distribution, providing high-density chemical anchors for subsequent fluorosilane molecules, which is beneficial for achieving high-density covalent anchoring of modified molecules.

[0026] (3) In this invention, fluorosilane molecules are anchored to a hydroxyl-rich activated interface via a hydrolysis-condensation reaction in the form of Si-O-Si covalent bonds, and then dried at high temperature to promote intermolecular lateral condensation crosslinking, forming a dense and stable fluorine-containing low surface energy layer on the surface of the micro / nano structure. This modification method differs from the weak bonding of physical coating and has higher interfacial bonding strength and long-term service stability.

[0027] (4) The superhydrophobic surface obtained by the present invention is achieved by the synergistic effect of micron-level cross grooves, nano-rough structure and fluorine-containing low surface energy layer: micron-level grooves form a droplet support framework, nano-rough structure increases air retention space, and fluorine-containing low surface energy layer reduces solid-liquid interface effect. The three together promote the droplet to maintain a Cassie-Baxter non-wetting state on the silicon carbide surface with a contact angle greater than 150°.

[0028] (5) While maintaining the intrinsic advantages of silicon carbide such as high hardness, high chemical stability, corrosion resistance and high temperature resistance, this invention endows it with superhydrophobic function, which can expand its application range in moisture-proof insulation, anti-icing, self-cleaning, droplet control, corrosion resistance and service in complex and harsh environments. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the process structure of a method for preparing a silicon carbide superhydrophobic surface by simultaneously constructing physical micro-nano structures and chemically active sites using femtosecond lasers according to the present invention.

[0030] Figure 2 This is a schematic diagram of the femtosecond laser processing system in step (2) of the present invention;

[0031] Figure 3 This is a schematic diagram of the laser scanning path for femtosecond laser etching in step (2) of the present invention;

[0032] Figure 4 A physical image showing the static contact angle of an intrinsically hydrophilic surface of silicon carbide.

[0033] Figure 5 The outline of the silicon carbide superhydrophobic surface micro / nano structure prepared in the embodiments of the present invention is shown in the figure.

[0034] Figure 6 Scanning electron microscope image of the silicon carbide superhydrophobic surface micro / nano structure prepared in an embodiment of the present invention;

[0035] Figure 7 XPS energy spectrum of silicon carbide superhydrophobic surface prepared in an embodiment of the present invention.

[0036] Figure 8 The image shows the static contact angle of the silicon carbide superhydrophobic surface prepared according to an embodiment of the present invention.

[0037] Explanation of reference numerals in the attached figures:

[0038] 1. Femtosecond laser; 2. Linear polarizer; 3. Attenuator; 4. Optical switch; 5. CCD camera; 6. First beam splitter; 7. Second beam splitter; 8. Objective lens; 9. Sample; 10. Three-dimensional displacement stage; 11. White light; 12. Computer control system. Detailed Implementation

[0039] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the following embodiments.

[0040] This invention provides a method for preparing a silicon carbide superhydrophobic surface by simultaneously constructing physical micro / nano structures and chemically active sites using femtosecond lasers. The overall process route of this method is as follows: Figure 1 As shown, the process includes the following steps: (1) pretreatment; (2) femtosecond laser direct writing to construct micron-level cross trenches and generate micro-nano composite rough structures on the trench walls, trench bottoms and cross nodes, simultaneously completing in-situ surface oxidation to form laser-induced active micro-nano interfaces and ultrasonic cleaning; (3) oxygen plasma activation treatment to increase the surface hydroxyl density; (4) fluorosilane solution immersion to covalently anchor low surface energy molecules; (5) anhydrous ethanol to wash away residual solution on the surface; (6) high-temperature drying and bonding to form a dense fluorine-containing low surface energy layer.

[0041] The femtosecond laser processing system used in step (2) is as follows: Figure 2As shown, the system includes a femtosecond laser 1, a linear polarizer 2, an attenuator 3, an optical switch 4, a CCD camera 5, a first beam splitter 6, a second beam splitter 7, an objective lens 8, a three-dimensional displacement stage 10, and a white light source 11, arranged sequentially. The beam emitted by the femtosecond laser 1 passes through the linear polarizer 2, attenuator 3, and optical switch 4, is reflected by the second beam splitter 7, and focused onto the surface of the sample 9 on the three-dimensional displacement stage 10 by the objective lens 8. The white light source 11 illuminates the sample through the first beam splitter 6 and the objective lens 8, and the reflected light returns along the same path to the CCD camera 5 for real-time observation of the processed appearance.

[0042] The scanning path of the femtosecond laser in step (2) is as follows: Figure 3 As shown, a cross-grid pattern is formed on the silicon carbide surface through this path. Simultaneously, laser-induced local melting, vaporization, and resolidification are used in the trench walls and node regions to generate a nano-roughened structure, while in-situ surface oxidation is completed concurrently, imparting a high density of Si-O active sites to the structure surface. By adjusting parameters such as femtosecond laser power, scanning speed, and scanning spacing, the depth and spacing of the micro-grooves, as well as the distribution density of the nano-roughened structure, can be controlled.

[0043] Example 1

[0044] This embodiment provides a method for preparing a silicon carbide superhydrophobic surface by simultaneously constructing physical micro / nano structures and chemically active sites using femtosecond lasers. The specific steps are as follows:

[0045] (1) Place the silicon carbide sample in anhydrous ethanol and deionized water in sequence, and ultrasonically clean for 10 min each to remove surface oil and impurities. Then dry with nitrogen.

[0046] (2) The pretreated sample surface was directly written using a femtosecond laser. The femtosecond laser parameters were: linearly polarized light, center wavelength 1030 nm, pulse width 190 fs, repetition frequency 1 kHz; processing power 0.75 W, scanning speed 1 mm / s, scanning spacing 100 μm. The processing path was a cross-grid type, and the etching depth was 5~6 μm. After laser processing, the sample was ultrasonically cleaned in anhydrous ethanol and deionized water for 10 min respectively to selectively remove weakly bound sputtering particles and unstable deposits, while completely preserving the laser-induced active micro-nano interface.

[0047] (3) The cleaned sample was subjected to oxygen plasma activation treatment for 3 min. Based on femtosecond laser in-situ oxidation, the surface hydroxyl density was further increased to form a hydroxyl-rich activation interface.

[0048] (4) The activated sample was immersed in a mixed solution of 1H,1H,2H,2H-perfluorodecyltrimethoxysilane and anhydrous ethanol, with a fluorosilane volume percentage of 2 vol% and an immersion time of 90 min. After hydrolysis, the fluorosilane molecules undergo a condensation reaction with the surface hydroxyl groups, anchoring themselves to the micro / nano structure surface in the form of Si-O-Si covalent bonds. The fluorine-containing long chain ends are arranged outwards, forming a low surface energy molecular layer.

[0049] (5) After soaking, take out the sample and rinse it with anhydrous ethanol to remove the residual solution on the surface.

[0050] (6) Place the rinsed sample in an oven and dry it at 120°C for 3 h to promote the lateral condensation and cross-linking between fluorosilane molecules, forming a dense and stable fluorine-containing low surface energy layer, and obtain a superhydrophobic silicon carbide sample.

[0051] Effect characterization of Example 1:

[0052] Figure 4 This is a static contact angle measurement diagram of the original silicon carbide surface. As can be seen from the figure, the original silicon carbide surface is relatively flat and lacks micro-nano rough structures that can trap air. At the same time, no low surface energy modification layer has been introduced into the surface, and water droplets spread out on the surface, exhibiting intrinsic hydrophilicity.

[0053] Figure 5 This is a three-dimensional contour image of the silicon carbide surface after femtosecond laser processing in this embodiment. Figure 6 The image shown is the corresponding scanning electron microscope (SEM) image. Figure 5 and Figure 6 Visually, femtosecond laser processing creates a micro / nano matrix structure on the silicon carbide surface, characterized by papillary, grooved, and locally nano-rough features. This structure is regularly shaped and uniformly distributed, with individual rectangles approximately 100 μm on each side and pits 5–6 μm deep. In this structure, the micrometer-scale grooves provide droplet support boundaries, while the nano-rough structure provides air retention space and molecular bonding interfaces, laying the structural foundation for subsequent low surface energy modification and the formation of a superhydrophobic state.

[0054] Figure 7 XPS spectrum of the silicon carbide superhydrophobic surface prepared in this embodiment. Characteristic peaks of Si 2p and C 1s from the silicon carbide substrate, as well as distinct O 1s and F 1s peaks, were detected on the sample surface. The O 1s signal confirms the presence of an oxide layer, hydroxyl groups, and other oxygen-rich active structures on the surface after femtosecond laser in-situ oxidation and oxygen plasma activation. The high density of oxygen-containing groups provides a chemical anchor for the silanization reaction. The appearance of the F 1s peak confirms that fluorinated silane molecules have been successfully anchored to the silicon carbide surface via covalent bonds. The coexistence of Si, O, and F characteristic peaks strongly demonstrates the successful preparation of the integrated superhydrophobic interface of "physical micro / nano structure - chemically active interface - low surface energy molecular layer" constructed in this invention.

[0055] Figure 8 This is a static contact angle measurement image of the final silicon carbide superhydrophobic surface obtained in this embodiment. The water droplet exhibits an approximately standard spherical shape on the surface, with a contact angle greater than 150°, indicating that the silicon carbide surface has successfully transitioned from a hydrophilic state to a superhydrophobic state. This result demonstrates the synergistic regulatory effect among the droplet support framework provided by the micron-cross grooves, the air retention space provided by the nano-roughened active interface, and the solid-liquid interface effect reduced by the fluorine-containing low surface energy layer.

[0056] Comparative Example 1 (laser processing only, no activation, no fluorosilane modification)

[0057] Femtosecond laser processing was performed according to steps (1) and (2) of Example 1. After processing, oxygen plasma activation treatment was not performed (step (3)), nor was fluorosilane solution immersion and subsequent drying treatment performed (steps (4) to (6)). The surface contact angle was directly tested. The results showed that the silicon carbide surface with only micro-nano structures still exhibited a hydrophilic state, and water droplets spread rapidly on the surface. This indicates that the simple physical micro-nano structure cannot achieve superhydrophobic properties and must be combined with subsequent chemical activation and low surface energy modification.

[0058] Comparative Example 2 (fluorosilane modification only, no laser processing)

[0059] The silicon carbide sample pretreated in step (1) was taken and, without femtosecond laser processing (skipping step (2)), directly subjected to oxygen plasma activation treatment in step (3) and fluorosilane modification in steps (4) to (6). The surface contact angle was tested, and the results showed that even after low surface energy modification, the contact angle of the flat silicon carbide surface without micro / nano structure support was still far below 150°, and superhydrophobicity could not be achieved. This indicates that micro / nano rough structure is a necessary condition for achieving superhydrophobicity, and the air retention space and molecular bonding interface it provides are indispensable.

[0060] Comparative Example 3 (laser processing + fluorosilane modification, oxygen-free plasma activation)

[0061] After femtosecond laser processing according to steps (1) and (2) of Example 1, step (3) (oxygen plasma activation treatment) was skipped, and fluorosilane modification in steps (4) to (6) was performed directly. The surface contact angle was tested and compared with that of Example 1. The results showed that although in-situ oxidation during femtosecond laser processing can provide certain basic active sites, without further amplification of hydroxyl density by oxygen plasma activation, the number of surface active sites was relatively insufficient, the anchoring density and uniformity of fluorosilane molecules decreased, the resulting surface contact angle was significantly lower than that of Example 1, and the surface hydrophobic uniformity was poor. This comparison result shows that oxygen plasma activation treatment, based on femtosecond laser in-situ oxidation, further amplifies the hydroxyl density, which plays an important role in improving the quality of fluorosilane modification and achieving uniform and stable superhydrophobic properties.

[0062] Comprehensive analysis of various embodiments and comparative examples:

[0063] The comparison between Example 1 and Comparative Examples 1-3 shows that the present invention achieves a superhydrophobic silicon carbide surface by synergistically combining femtosecond laser synchronous construction of physical micro / nano structures and chemically active sites, oxygen plasma activation to amplify hydroxyl density, and fluorosilane covalent anchoring modification, thereby transforming the intrinsically hydrophilic state of silicon carbide into a superhydrophobic state with a contact angle greater than 150°. Specifically, femtosecond laser processing not only provides a micro / nano rough structure but also generates a high density of Si-O active sites through in-situ oxidation; oxygen plasma activation further amplifies the hydroxyl density; and fluorosilane molecules are covalently anchored at a high density to the hydroxyl-rich activated interface, forming a stable and dense fluorine-containing low surface energy layer. These three steps are indispensable and together constitute the complete technical path for achieving a superhydrophobic silicon carbide surface according to the present invention.

[0064] The above description is merely a preferred embodiment of the present invention and does not limit the scope of the patent. Any equivalent structural transformations, parameter adjustments, or process optimizations made within the concept and technical solution of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for fabricating a superhydrophobic silicon carbide surface with femtosecond laser synchronized construction of physical micro-nano structures and chemical active sites, characterized in that, The method utilizes a femtosecond laser to form a micron-scale cross-groove structure on the surface of silicon carbide, and forms an active micro / nano interface containing nano-rough morphology and Si-O active sites at the groove walls, groove bottoms, and cross nodes of the cross-groove structure. This allows low surface energy fluorosilane molecules to be activated and bound to the surface of the active micro / nano interface. The method includes the following steps: (1) Pre-treat the silicon carbide sample to remove surface oil and impurities, and dry the sample surface; (2) A femtosecond laser is used to perform direct writing on the pretreated sample surface to construct a micron-level cross-groove structure on the silicon carbide surface. Utilizing the non-equilibrium thermo-chemical coupling effect of the femtosecond laser, a nano-rough structure is integrally generated at the groove walls, groove bottom, and cross nodes while constructing the micron-level cross-groove structure. Simultaneously, in-situ oxidation of the surface is completed to form a laser-induced active micro-nano interface that combines physical micro-nano structure with high-density Si-O active sites. After laser processing, ultrasonic-assisted cleaning is performed to selectively remove weakly bound sputtering particles and unstable deposits, while completely preserving the laser-induced active micro-nano interface. (3) The laser-induced active micro / nano interface obtained in step (2) is subjected to oxygen plasma activation treatment to increase the surface hydroxyl density and form a hydroxyl-rich activated interface. (4) Immerse the activated sample in a fluorosilane solution so that the fluorosilane molecules are covalently anchored to the high-density hydroxyl sites of the active micro-nano interface through hydrolysis and condensation reaction, forming a low surface energy molecular layer. (5) After soaking, the sample is cleaned to remove any residual solution from the surface; (6) The cleaned sample is dried and solidified at high temperature to allow the fluorosilane molecules to crosslink laterally to form a stable fluorine-containing low surface energy layer, thus obtaining a silicon carbide sample with superhydrophobic surface properties.

2. The method according to claim 1, characterized in that, In step (1), the silicon carbide sample is ultrasonically cleaned sequentially with anhydrous ethanol and deionized water.

3. The method according to claim 1, characterized in that, The ultrasonic cleaning time is 10-15 minutes.

4. The method according to claim 1, characterized in that, In step (2), the femtosecond laser is linearly polarized light with a center wavelength of 1030±10 nm, a pulse width of 190 fs, and a repetition frequency of 1 kHz.

5. The method according to claim 1, characterized in that, In step (2), the femtosecond laser processing power is 0.75~1.0 W, the scanning speed is 1 mm / s, and the scanning spacing is 100 μm.

6. The method according to claim 1, characterized in that, In step (2), the femtosecond laser etching process path is a cross-grid type, and the etching depth is 5~10 μm.

7. The method according to claim 1, characterized in that, In step (2), the selective cleaning includes ultrasonic cleaning of the sample in sequence with anhydrous ethanol and deionized water.

8. The method according to claim 1, characterized in that, In step (3), the oxygen plasma activation treatment takes 3 minutes.

9. The method according to claim 1, characterized in that, In step (4), the fluorosilane is 1H,1H,2H,2H-perfluorodecyltrimethoxysilane, and the volume percentage of fluorosilane in the mixed solution of fluorosilane and anhydrous ethanol is 2 vol%, and the soaking time is 90 min.

10. The method according to claim 1, characterized in that, In step (6), the high-temperature drying and solidification temperature is 120°C and the time is 3 hours.

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