Micro-nano wire arrangement method based on laser processing composite liquid self-assembly

Abstract

The invention relates to the technical field of fine wire arrangement, in particular to a micro-nano wire arrangement method based on laser processing composite liquid self-assembly. According to the technical scheme, the method comprises the steps of surface pretreatment, substrate laser machining, micro-nano wire fixing and liquid loading and scraper driving and assembling, specifically, a to-be-machined substrate is cleaned, a lyophobic coating is sprayed, and a lyophobic surface is formed; by combining a laser micromachining technology and a fluid interface regulation and control mechanism, the defects of traditional mechanical clamping and electric field / magnetic field driving technologies are overcome, the method can be suitable for assembling micro-nano wires of various materials and various sizes, a large-scale and damage-free micro-nano wire assembling scheme with material universality is provided, and the method is suitable for large-scale production of the micro-nano wires. The method can be combined with micro-nano photoelectric device manufacturing, and efficient manufacturing and application expansion are achieved in the emerging field of optoelectronic chip and semiconductor manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of fine wire arrangement, and in particular to a micro-nano wire arrangement method based on laser processing composite liquid self-assembly. Background Art

[0002] High-precision assembly of micro- and nanowires has broad applications in optoelectronic chips, optical coupling systems, and semiconductor device manufacturing, and is a crucial technology for functionalizing microdevices. Precise and efficient assembly of micro- and nanowires, such as metal wires and optical fibers, is a crucial method for fabricating structures such as optical solder leads and chip conductors in optoelectronic microdevice production.

[0003] Common methods for assembling micro-nanowires include machining groove structures, embedding micro-nanowires into the grooves using mechanical clamping, or driving them with external electric or magnetic fields. However, these methods have significant drawbacks. The method of embedding micro-nanowires after machining grooves not only requires machining fine structures on the substrate that strictly match the size of the micro-nanowires, but also inevitably damages micro-nanowires assembled from materials such as brittle materials due to mechanical clamping. Laser machining of microfluidics combined with the electrowetting effect to guide metal wires for assembly is not only complex but also unsuitable for non-metallic materials. These methods generally suffer from material damage, low efficiency, and poor material adaptability, making them difficult to meet the needs of large-scale assembly of diverse micro-nanowires.

[0004] With the increasing demand for integrated optoelectronic devices, liquid-guided micro- and nanowire self-assembly technology is gradually demonstrating its unique advantages. Through laser processing or photolithography, the assembly area is constructed on the substrate surface, and then the capillary force field is used to control the precise assembly and distribution of the micro- and nanowires. Compared with traditional micro- and nanowire assembly methods, laser processing combined with liquid-guided micro- and nanowire self-assembly is an efficient and flexible method for arranging fine wire structures. This technology is not only simple to operate and non-destructive, but also has universal material compatibility, achieving good assembly results for micro- and nanowires and substrates made of different materials.

[0005] (1) Existing micro-nanowire assembly technologies, such as the assembly method of preparing a coupling structure (such as a V-groove) with a depth corresponding to the micro-nanowire on a substrate and then embedding the micro-nanowire into it, have significant shortcomings in terms of operational flexibility, damage control, and large-scale production. The processed V-groove must strictly conform to the size of the micro-nanowire to be assembled, and the precision of the processed structure is very high. When embedding the micro-nanowire, mechanical clamping can easily damage it, and the efficiency of assembly one by one is low, which cannot be applied on a large scale.

[0006] (2) The method of using laser-machined microfluidics combined with the electrowetting effect to guide metal wire assembly has obvious drawbacks in terms of material applicability. Optical fibers and polymer fiber insulation materials cannot respond to electric fields and thus be effectively driven, which limits their application in semiconductor devices and optoelectronic chips. In addition, this method has high requirements for the applied electric field, which increases the complexity of the operation.

[0007] (3) Regarding substrate processing, traditional surface processing methods, such as acid-base chemical reagent corrosion technology, can produce surface structures through controlled etching reactions, but their drawbacks are insufficient precision and difficulty in achieving fine structure processing. In addition, the corrosion process relies on long-term immersion, which takes a long time to process, and the acid-base waste liquid treatment requires additional costs. The surface structure preparation method using mechanical processing technologies such as turning and milling, although the process is highly mature, uses physical contact cutting, which has poor precision and is very prone to cracking in hard and brittle materials such as ceramics and glass.

[0008] The assembly of traditional micro-nanowires (such as metal wires, optical fibers, protein fibers, etc.) mostly relies on mechanical clamping or external field driving, and these methods have obvious defects. The method of machining groove structures and embedding micro-nanowires requires that the grooves strictly match the size of the micro-nanowires, which requires extremely high processing precision of the substrate. In addition, mechanical clamping during operation will damage brittle or flexible materials, resulting in impaired device processing quality and the inability to achieve large-scale assembly. The assembly of micro-nanowires based on the electrowetting effect requires complex external electric field regulation, has low process tolerance and is difficult to be compatible with insulating materials such as optical fibers and protein fibers. The above technical defects seriously restrict the large-scale and efficient assembly of micro-nanowires.

[0009] In summary, the present application proposes a method for arranging micro-nanowires based on laser processing composite liquid self-assembly. Summary of the Invention

[0010] The purpose of the present invention is to solve the problem in the background technology that micro-nanowires cannot be assembled on a large scale and without damage, and to propose a micro-nanowire arrangement method based on laser processing composite liquid self-assembly.

[0011] The technical solution of the present invention is a method for arranging micro-nanowires based on laser processing composite liquid self-assembly, comprising the following steps:

[0012] Surface pretreatment: Clean the substrate to be processed and perform a low surface energy liquid-repellent surface treatment, which can be achieved by coating with any of silica hydrophobic agents, silanes, and fluoride hydrophobic agents. Liquid-repellent surfaces can also be achieved through high-temperature treatment, oxidation reaction, adhesion of substances, construction of microstructures, and chemical reactions.

[0013] Laser processing substrates: By adjusting the laser wavelength, power, processing times, scanning speed and spacing parameters, a preset pattern of lyophilic areas is processed on the surface of the lyophobic substrate to form a lyophilic / lyophobic interface;

[0014] Fixation of micro-nanowires and liquid loading: Fix one end of the micro-nanowire at the starting end of the lyophilic region and drip liquid at the fixed end;

[0015] Scraper-driven assembly: The scraper is used to drive the droplets to move along the lyophilic area, and the capillary force generated by the dynamic contraction of the liquid-gas interface pulls the micro-nanowires to the lyophilic area for damage-free directional arrangement of the micro-nanowires.

[0016] Optionally, the substrate is selected from any one of silicon wafer, glass, ceramic, and polymer materials, and the substrate is cleaned by soaking in anhydrous ethanol and then naturally air-drying or accelerating drying in an oven.

[0017] Optionally, the laser is any one of a femtosecond laser, a nanosecond laser, a picosecond laser, and a continuous laser, and processing the lyophilic area of ​​a preset pattern on the surface of the lyophobic substrate specifically includes setting it through a computer control system, including path planning by a combination of an XY scanning galvanometer, a reflector and an aperture.

[0018] Optionally, the lyophobic coating is any one of a silica lyophobic agent, a silane lyophobic agent, and a fluoride lyophobic agent.

[0019] Optionally, the liquid is water, an organic solvent, liquid organic matter or liquid metal.

[0020] Optionally, the micro-nanowire is any one of a metal wire, an optical fiber, a protein fiber, and a polymer fiber.

[0021] Optionally, the angle between the scraper and the substrate is 0° to 90°, and the uniform moving speed is 0.1-5 mm / s.

[0022] Optionally, the depth and width of the lyophilic area are controlled by adjusting laser energy, action time and scanning path parameters.

[0023] Optionally, the liquid-repellent effect of the substrate is verified by a droplet sliding method or a contact angle meter.

[0024] Optionally, the assembled micro-nanowire structure is transferred to a target functional substrate through PDMS transfer technology for use in the manufacture of optoelectronic chips or semiconductor devices, and the assembly process is monitored in real time by a microscopic observation system.

[0025] Compared with the prior art, this application has at least one of the following beneficial technical effects:

[0026] The present invention achieves non-destructive and precise positioning of micro-nanowires through the synergistic effect of capillary force and laser-induced lyophilic / lyophobic interface, without the need for mechanical clamping or external field drive, thus avoiding the physical damage to brittle / flexible materials caused by traditional methods.

[0027] It is compatible with a variety of micro-nanowire materials such as metal wires, optical fibers, protein fibers, polymer fibers, and the substrate can be adapted to silicon wafers, glass, ceramics, polymers, etc., breaking through the limitations of traditional technologies on material types.

[0028] A scraper is used to drive the dynamic contraction of the liquid to form a capillary force field, and multiple micro-nanowires can be assembled in parallel in a single operation, significantly improving the efficiency of large-scale production; the laser parameters (energy, speed, path) are adjustable to achieve precise control of the depth and width of the hydrophilic area to meet the needs of micro-nanowires of different sizes.

[0029] There is no need to prepare groove structures or complex microchannels that strictly match the micro-nanowires, and the electric field / magnetic field control link is eliminated. The operation process is simple, the equipment cost is low, and the process fault tolerance is high.

[0030] The assembled micro-nanowire structure can be accurately transferred to functional substrates such as optoelectronic chips and semiconductor devices through transfer technology, providing new solutions for the manufacture of optical welding leads and chip wires, and promoting innovative applications in the fields of optoelectronic integration and flexible electronics.

[0031] The non-contact liquid self-assembly process is used to reduce waste liquid and material loss caused by acid and alkali corrosion or mechanical processing, which is in line with the trend of green manufacturing and reduces the cost of large-scale production.

[0032] The present invention overcomes the shortcomings of traditional mechanical clamping and electric / magnetic field driving technologies by innovatively combining laser micromachining technology with fluid interface control mechanism. It can be applied to the assembly of micro-nanowires of various materials and sizes, and provides a micro-nanowire assembly solution that can be achieved on a large scale, without damage and with universal material applicability. It can be combined with the manufacture of micro-nano optoelectronic devices to achieve efficient manufacturing and application expansion in the emerging fields of optoelectronic chips and semiconductor manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a flow chart of a micro-nanowire arrangement method based on laser processing composite liquid self-assembly;

[0034] Figure 2 Add a regional diagram for the substrate;

[0035] Figure 3 Schematic diagram of placing micro-nanowires at one end of the processing area;

[0036] Figure 4 Schematic diagram of adding liquid to the fixed end of the micro-nanowire;

[0037] Figure 5 Schematic diagram of the scraper guiding the self-assembly of micro-nanowires along the assembly path;

[0038] Figure 6 is the optical path diagram of the system;

[0039] Figure 7 Schematic diagram of the assembly area of ​​multiple micro-nanowires;

[0040] Figure 8 This is a diagram of the simultaneous assembly experiment of three micro-nanowires;

[0041] Figure 9 The experimental pictures of a single micro-nanowire before and after assembly, (a) is the experimental picture before assembly, (b) is the experimental picture after assembly;

[0042] Figure 10 These are experimental pictures of three micro-nanowires before and after assembly, (a) is the experimental picture before assembly, and (b) is the experimental picture after assembly. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below with reference to the accompanying drawings and specific embodiments.

[0044] like Figure 1 As shown, the present invention proposes a micro-nanowire arrangement method based on laser processing composite liquid self-assembly, and the method is described in detail below.

[0045] Step 1: Surface Pretreatment

[0046] First, to facilitate subsequent lyophobic treatment, clean the substrate surface with anhydrous ethanol to ensure it remains clean and will not affect subsequent work before proceeding with the lyophobic treatment. Use a spray gun to evenly apply the lyophobic coating to the substrate surface and allow it to dry completely in a natural environment. Test the substrate for lyophobicity by applying a drop of liquid. If the effect is poor, repeat the spraying process until the surface is effectively lyophobic.

[0047] Step 2: Adjust laser parameters to process substrate

[0048] Next, place the substrate that has been treated with liquid repellency on a three-dimensional moving platform. Select the appropriate laser and processing parameters, including laser wavelength, laser power, number of processing times, processing speed, and scanning spacing, such as Figure 2 Process the hydrophilic area required for subsequent processing. The depth and width of the laser processing area will directly affect the success rate of subsequent assembly.

[0049] To meet the varying capillary force requirements of micro- and nanowires of varying materials and sizes during the liquid assembly process, the laser's active area and energy can be flexibly adjusted, enabling precise control of the depth and width of the assembly area. This adjustment method allows the laser parameters to be adapted to various assembly requirements, ensuring that the micro- and nanowires can be stably and precisely assembled into the desired area in the liquid environment.

[0050] Step 3: Pretreatment of Micro-Nanowire Assembly

[0051] After the liquid-repellent substrate is laser processed, the liquid-repellent coating on the processed area is removed, revealing the liquid-repellent properties of the substrate itself. Figure 3 As shown in FIG, the micro-nanowire to be assembled is placed on a substrate, and one end of the micro-nanowire is fixed on one side of the processing area. Then, a liquid is dropped on the fixed end of the micro-nanowire, as shown in FIG. Figure 4 As shown, in order to meet the different requirements of micro-nanowires of different materials and sizes on the size of capillary force during the liquid assembly process, the liquid used to guide the assembly can be flexibly selected.

[0052] Step 4: The scraper drives the liquid to assemble micro-nanowires

[0053] Then, a glass slide is used as a scraper, which is moved at a constant speed along the processing path to drive the droplets to move the micro-nanowires. As the scraper moves, a dynamic contraction line is formed at the liquid-gas interface, and its movement trajectory is regulated by the wettability of the substrate. Due to the low surface energy in the lyophobic area, the liquid slides off quickly without residue; while in the lyophilic area, due to the high surface energy, the droplets shrink and remain in the lyophilic area to form a stable liquid bridge. In this process, the droplets retained in the lyophilic area pull the micro-nanowires (such as optical fibers, metal wires, protein fibers, polymer fibers) into the lyophilic area through capillary force. Specifically, under the action of the surface tension of the liquid bridge, the micro-nanowires automatically align along the lyophilic area and are eventually fixed at the preset position in the lyophilic area. As Figure 5 As shown, this assembly process requires no complex external drive or precise positioning. Simply by using a scraper to move the liquid along the laser-processed area, the liquid in the lyophilic region converts capillary forces into directional driving forces for the micro-nanowires. Ultimately, the micro-nanowires are precisely aligned along the lyophilic region, forming an assembly area that matches the laser-processed pattern.

[0054] Through the above steps, the capillary force of the liquid can be effectively utilized to achieve self-assembly of micro-nanowires, which has significant advantages such as no mechanical damage, high efficiency, low cost, cross-scale assembly, and a wide range of applicable materials.

[0055] It is worth noting that this embodiment also includes:

[0056] (1) A femtosecond laser, which serves as a processing light source and emits laser light for processing the substrate in the assembly area.

[0057] (2) Pre-optical path, which adjusts the energy and phase of the laser and other related parameters, including optical components such as XY scanning galvanometer, reflector, aperture, half-wave plate and Glan Taylor prism.

[0058] (3) The three-dimensional moving stage has a travel range of 110 mm × 75 mm × 100 mm. The position of the sample to be processed is adjusted by adjusting the X, Y, and Z knobs of the moving stage.

[0059] (4) Computer control system, using SAMLight marking program to set the laser processing path, drawing the laser scanning path pattern in the program, which can achieve flexible and high-precision structural design and processing.

[0060] (5) CCD microscopic observation system, used to observe the assembly process in real time.

[0061] 2. Implementation process:

[0062] (1) Open the optical path and adjust the laser processing parameters such as power. Import the processing file to be assembled into the control software.

[0063] (2) Clean the substrate surface by soaking and cleaning it with anhydrous ethanol (purity ≥ 99.8%) to remove surface dust and other particulate contaminants. Allow to air dry to ensure the substrate surface is clean and free of impurities to avoid affecting the adhesion of the subsequent lyophobic coating.

[0064] (3) Spraying the liquid-repellent coating: Use a spray gun to evenly spray the liquid-repellent coating on the surface of the substrate and place it in a natural environment for 10 minutes until the coating is completely dry.

[0065] (4) Tilt the substrate and drop a drop of liquid onto the dried lyophobic coating. If the liquid rolls down quickly in a ball shape after contacting the substrate, the lyophobic effect is achieved. If the lyophobic effect is not achieved, repeat the spraying 1-2 times until a uniform and continuous lyophobic surface is formed.

[0066] (5) Fix the substrate after liquid-repellent treatment on a three-dimensional mobile platform to ensure that the laser focus is on the substrate surface. Use a femtosecond laser to process the pattern to be assembled on the surface of the liquid-repellent coating on the substrate, such as Figure 6 Laser machining removes the surface material in the area to be assembled on the substrate, exposing the liquid-wet material surface. After machining, a CCD camera is used to check the integrity of the machined area.

[0067] (6) Cut the micro-nanowire to be assembled, such as a thin wire with a diameter of 60 μm, into a suitable length, fix one end of the wire to the starting end of the lyophilic region, ensure that the fixing point is within the lyophilic region, and drip liquid near the starting point.

[0068] (7) A glass slide (size 25 mm × 75 mm × 1 mm) was used as a scraper, and the scraper was kept at an angle of 0 to 90 degrees to the substrate, such as Figure 8 As shown, the droplet contacts and drives the droplet to move along the processing area on the substrate surface.

[0069] 3. The actual effects of the laser processing combined with liquid-guided micro-nanowire self-assembly proposed in the present invention are as follows:

[0070] Product 1: Single wire assembly

[0071] According to the assembly process, the capillary force of liquid is used to guide the self-assembly of micro-nanowires, thus avoiding damage to the micro-nanowires. The capillary force of the droplets in the hydrophilic area can pull the micro-nanowires to the hydrophilic area, e.g. Figure 9 As shown, the assembly can be completed after natural drying.

[0072] Product 2: Multiple thin wires assembled in parallel

[0073] After processing to obtain multiple parallel hydrophilic regions, micro-nanowires are fixed at one end, and the capillary force of the droplet can pull multiple micro-nanowires to the area to be assembled, such as Figure 10 As shown, large-scale, high-throughput assembly can be completed after natural drying.

[0074] The present invention is an efficient and flexible method for arranging fine wires. Compared with traditional processing methods, this method does not require the preparation of a coupling structure (such as a V-shaped groove) with a depth corresponding to the size of the micro-nanowire on the substrate and then embedding the micro-nanowire therein, nor does it require the use of laser processing microfluidics combined with the electrowetting effect to guide the metal wires for assembly. This technology is not only simple to operate and does not require fine structures and external electric field control that strictly match the size of the micro-nanowires, but it can also improve the assembly efficiency of the micro-nanowires and achieve effective assembly. The method proposed in the present invention has material universality in terms of both micro-nanowire and substrate selection. In terms of the selection of assembled micro-nanowire materials, materials such as protein fibers, optical fibers, polymer fibers, and metal wires can all achieve efficient assembly; in terms of substrate adaptability, this method is not limited by materials and is applicable to a variety of substrates such as silicon wafers, glass, ceramics, and polymers.

[0075] Among them, a method based on liquid capillary force-guided micro- and nanowire self-assembly overcomes the limitations of individual assembly methods, such as manual embedding and mechanical positioning, and achieves large-scale, high-throughput assembly. Capillary force guidance avoids mechanical contact such as clamping and does not require electric field control. Therefore, this method, which utilizes capillary force assembly, is not only applicable to a variety of brittle and flexible materials, but also enables damage-free, large-scale assembly of micro- and nanowires.

[0076] In addition, the substrate is processed by laser processing to obtain a lyophilic area on the lyophobic substrate. Compared with the traditional method of using acid-base chemical reagents to corrode the surface and mechanical turning processing, the laser processing method of the substrate has good flexibility and high precision. The lyophilic area can be flexibly controlled by changing laser parameters such as laser energy, action time, and processing speed. Thanks to the technical advantages of the present invention, the micro-nanowire self-assembly method can be further expanded to the field of optoelectronic chips and semiconductor devices. The micro-nanowire self-assembly method of the present invention can be combined with transfer technology to accurately transfer the assembled structure to the target functional substrate (such as optoelectronic chips, circuits, etc.). This provides a new solution for the production of optical welding leads and chip wire structures, and expands the application of the efficient arrangement method of micro-nanowires self-assembled by laser processing composite liquid in the field of semiconductor devices and optoelectronic chip production.

[0077] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant inspirations of the above embodiments, those skilled in the art may make various alternative improvements and combinations to the above specific embodiments.

Claims

1. A method for arranging micro-nanowires based on laser processing composite liquid self-assembly, characterized in that: The following steps are involved: Surface pretreatment: Clean the substrate to be processed and spray a liquid-repellent coating to form a liquid-repellent surface; Laser processing substrates: By adjusting the laser wavelength, power, processing times, scanning speed and spacing parameters, a preset pattern of lyophilic areas is processed on the surface of the lyophobic substrate to form a lyophilic / lyophobic interface; Fixation of micro-nanowires and liquid loading: Fix one end of the micro-nanowire at the starting end of the lyophilic region and drip liquid at the fixed end; Scraper-driven assembly: The scraper is used to drive the droplets to move along the lyophilic area, and the capillary force generated by the dynamic contraction of the liquid-gas interface pulls the micro-nanowires to the lyophilic area for damage-free directional arrangement of the micro-nanowires.

2. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The substrate is selected from any one of silicon wafer, glass, ceramic, and polymer materials. The substrate is cleaned by soaking in anhydrous ethanol and then naturally air-drying or drying in an oven.

3. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The laser is any one of a femtosecond laser, a nanosecond laser, a picosecond laser, and a continuous laser. Processing a lyophilic area of ​​a preset pattern on the surface of a lyophobic substrate specifically includes setting it through a computer control system, including path planning by a combination of an XY scanning galvanometer, a reflector, and an aperture.

4. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The low surface energy liquid-repellent surface can be obtained by coating the surface with any one of silica hydrophobic agents, silanes, and fluoride liquid-repellent agents, and can also be obtained by high temperature treatment, oxidation reaction, adhesion of substances, construction of microstructures, and chemical reactions.

5. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The liquid is water, an organic solvent, liquid organic matter or liquid metal.

6. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The micro-nano wire is any one of metal wire, optical fiber, protein fiber and polymer fiber.

7. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: When the scraper is driven and assembled, the angle between the scraper and the substrate is 0° to 90°, and the moving speed is 0.1-5 mm / s.

8. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The depth and width of the lyophilic area are controlled by adjusting laser energy, action time and scanning path parameters.

9. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The liquid-repellent effect of the substrate is verified by a drop-down method or a contact angle meter.

10. The method for arranging micro-nanowires based on laser processing composite liquid self-assembly according to claim 1, characterized in that: The assembled micro-nanowire structure is used for the manufacture of optoelectronic chips or semiconductor devices, and the assembly process is monitored and detected by a microscopic observation system.

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