A method for preparing laser-induced patterned mirror-symmetrical copper electrodes

Abstract

The present invention relates to a method for preparing a laser-induced patterned mirror-symmetrical copper electrode, and belongs to the field of electrode processing technology. First, a copper foil tape is pasted on a glass plate; then two glass slides are placed on the pretreated surfaces of the copper foil tape, and tiny copper particles are sputtered onto the glass slides by laser; then an optically transparent substrate is placed between the two glass slides, and a laser is used to scan the required pattern, and copper particles are simultaneously sputtered to the upper and lower surfaces of the substrate, which serves as a seed layer for chemical plating; finally, it is placed in a copper plating solution for treatment to obtain a mirror-symmetrical copper electrode. The method realizes the patterning of a mirror-symmetrical copper electrode on a transparent substrate. In the obtained symmetrical copper electrode, the copper layers on both sides are dense and firmly bonded to the substrate; the resistance is less affected by bending and temperature, and it has excellent conductivity, and can be used as a sensor electrode.

Description

Technical Field

[0001] The invention relates to a method for preparing a laser-induced patterned mirror-symmetrical copper electrode, belonging to the technical field of electrode processing. Background Art

[0002] The patterning of sensor electrodes is the process of patterning conductive materials on a flexible substrate to form conductors that can be bent, stretched, or folded. This is the basis for manufacturing flexible electronic products. For flexible sensors, electrodes play a role in defining the size and distribution of sensing units, and collecting and outputting electrical signals from the sensing layer. Metals are the preferred materials for electrode preparation due to their excellent conductivity, good stability, and low cost. Among the many conductive materials, copper metal has excellent conductivity (~58.5×10 6 S m -1 ) and ductility, is widely used in the field of electronic technology, and is also one of the preferred materials for electrode manufacturing.

[0003] Conventional metal patterning techniques are based on multi-step photolithography and vacuum sputtering. These processes are expensive and time-consuming. The organic solvents used in the photolithography process are environmentally unfriendly and have poor compatibility with flexible substrates such as plastics or elastomers. A low-cost alternative is to print prefabricated metal nanoparticle inks onto flexible substrates, which are then melted or reduced to form continuous conductive metal structures. However, this approach has significant limitations in the choice of metal precursors, and high-temperature annealing (≥250°C) can damage the substrate. Another strategy is to combine patterning techniques with more gentle electroless plating methods. Guo et al. used printing techniques (dip-pen nanolithography, inkjet printing, and screen printing) to pattern catalytic inks onto flexible substrates such as PET, PDMS, and fabric. They then used electroless plating to metallize designated areas. This approach achieved room-temperature patterning of a variety of metals (copper, silver, nickel, etc.) with a certain degree of universality. However, the use of precious metal-based catalytic inks and the complex pretreatment procedures of the plated substrates have limited its large-scale application.

[0004] Laser direct writing is a maskless, vacuum-free, and ultrafast patterning technology. A common strategy involves directly etching a metal film with a laser, removing unused portions, and indirectly obtaining the desired pattern. Furthermore, its ultrahigh instantaneous power allows for the reduction of some metal precursors, allowing for the direct formation of metal structures on various substrates. Metal salts are combined with organic materials and, after nanosecond pulsed laser treatment, catalytically active metal nanoparticles are formed on flexible substrates, providing reactive sites for electroless plating. However, this approach requires organic materials to act as receptors for absorbing laser energy to generate localized high temperatures for thermal reduction of the metal salts. Furthermore, organic materials are difficult to remove and can contaminate the pre-plated material. Chen et al. used a continuous-wave laser to treat a series of aqueous mixtures of metal salts and semiconductor nanoparticles (reduced graphene oxide and carbon ink). The free electrons of the semiconductor nanoparticles were excited by the laser, triggering a chemical reduction process to form semiconductor-metal composite structures. Metal films were directly patterned onto various substrates without the need for electroless plating, and areas not irradiated by the laser were easily washed away with water. Metal oxides such as CuO, Cu2O, ZnO, and NiO can also be laser-reduced to elemental metals. Typically, their nanoparticles are mixed with a dispersant and a reducing agent to form a homogeneous ink. This ink is then applied to a flexible substrate via spin coating, dipping, or printing. Laser reduction and cleaning processes produce a clean metal pattern. During laser treatment, a photothermal reaction occurs in the irradiated area, generating localized high temperatures that sinter the reduced metal particles into a continuous structure. Simultaneously, other substances in the ink may pyrolyze under the action of the laser to generate reducing gases, which promote the reduction of the metal oxide. The bond strength between the resulting metal structure and the substrate depends on the mechanical interlocking strength. Back et al. fabricated a copper pattern on a glass substrate by laser reduction of CuO and successfully transferred it to a PET substrate. However, this method carries the risk of a weak metal-substrate bond. Furthermore, the difficulty in dispersing metal oxide nanoparticles and the generation of large amounts of harmful gases during laser treatment are drawbacks.

[0005] Although the combination of patterning techniques such as printing and etching with electroless copper plating (ECP) has made outstanding contributions to the patterning of electrodes, the preparation process of the above methods is often very cumbersome, mainly due to the pretreatment of the flexible substrate, such as decontamination, degreasing, micro-etching, pre-impregnation and activation. Laser patterning can replace these technologies by reducing metal precursors as active sites for electroless plating. However, the currently reported methods have special requirements for the selection of metal precursors, substrates to be plated, and lasers, and most of them have the disadvantage of low universality and cannot achieve double-sided simultaneous patterning. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a method for preparing laser-induced patterned mirror-symmetric copper electrodes. A semi-transparent copper film (ST-Cu) is prepared using a laser as a copper seed source. The copper seed is then patterned and sputtered onto the front and back surfaces of optically transparent PET using a laser. Combined with the ECP method, the MS-Cu electrode is prepared to facilitate the co-point integration of pressure and temperature sensing units. This method also has the advantages of high precision, simple process, readily available materials, and wide applicability.

[0007] To achieve the above objectives, the technical solutions of the present invention are as follows.

[0008] A method for preparing a laser-induced patterned mirror-symmetrical copper electrode, the method comprising the following steps:

[0009] (1) Copper foil tape is flatly attached to two glass plates, and the copper foil tape is laser pretreated at a laser pulse frequency of 20 to 30 kHz. Then, two glass slides are placed on the surface of the pretreated copper foil tape, and then laser treatment is performed at a laser pulse frequency of 10 to 20 kHz to sputter copper microparticles onto the glass slides to obtain glass slides with translucent copper films deposited thereon;

[0010] (2) placing an optically transparent substrate flat between two glass slides deposited with a translucent copper film, and then performing laser scanning on the surface of the upper glass slide deposited with the translucent copper film according to the desired electrode pattern at a laser pulse frequency of 50 to 60 kHz. The copper particles on the two glass slides are simultaneously sputtered onto the upper and lower surfaces of the substrate, thereby obtaining a substrate having a mirror-symmetrical patterned copper seed layer;

[0011] (3) The substrate having the mirror-symmetrical patterned copper seed layer is placed in a copper plating solution at 80-90° C. for 3-5 minutes and then taken out to obtain a laser-induced patterned mirror-symmetrical copper electrode.

[0012] Preferably, in step (1), the light transmittance of the glass slide on which the translucent copper film is deposited is 45% to 60%.

[0013] Preferably, in step (2), the optically transparent substrate is polyethylene terephthalate (PET), polyimide (PI) or transparent glass.

[0014] Preferably, in step (2), the laser pulse frequency is 50 to 55 kHz.

[0015] Preferably, in step (2), during laser scanning, the light transmittance of the upper glass slide with the translucent copper film deposited thereon is greater than that of the lower glass slide with the translucent copper film deposited thereon.

[0016] Preferably, in steps (1) and (2), during laser pretreatment, laser treatment, and laser scanning, the processing speed is 700-900 mm / s, the processing distance is 26-27 cm, the pulse width is 10-15 ns, and the scanning line spacing is 10-20 μm.

[0017] Preferably, in step (3), the copper plating solution consists of solution A and solution B; the volume ratio of solution A to solution B is 10 to 20:1;

[0018] Liquid A includes copper sulfate pentahydrate, potassium sodium tartrate tetrahydrate, hydroxide, methanol, sodium lauryl sulfate, anhydrous potassium ferrocyanide and ammonium chloride; Liquid B is formaldehyde aqueous solution.

[0019] Preferably, in the liquid A, the concentration of copper sulfate pentahydrate is 40-50 g / L, the concentration of potassium sodium tartrate tetrahydrate is 60-70 g / L, the concentration of the complexing agent is 60-70 g / L, the concentration of the hydroxide is 15-20 g / L, the concentration of methanol is 50-70 mL / L, the concentration of sodium lauryl sulfate is 0.02-0.05 g / L, the concentration of anhydrous potassium ferrocyanide is 0.08-0.1 g / L, and the concentration of ammonium chloride is 0.5-1 g / L; in the liquid B, the concentration of the formaldehyde aqueous solution is 37 wt%-40 wt%.

[0020] Preferably, the hydroxide is potassium hydroxide or sodium hydroxide.

[0021] A laser-induced patterned mirror-symmetrical copper electrode is prepared by the above method.

[0022] Beneficial effects

[0023] This invention provides a method for fabricating laser-induced patterned, mirror-symmetrical copper electrodes. By combining laser processing under specific conditions with an ECP process, the method successfully achieves mirror-symmetrical patterning of copper electrodes on transparent substrates. The resulting symmetrical copper electrodes have dense copper layers on both sides, firmly bonded to the substrate, exhibit minimal resistance changes with bending and temperature, and possess excellent conductivity, making them suitable for use as sensor electrodes.

[0024] The present invention provides a method for preparing a laser-induced patterned mirror-symmetrical copper electrode. First, a copper foil tape is adhered to a glass plate, and laser pretreatment is performed to remove surface impurities. At the same time, copper is longitudinally etched to create a certain gap between the glass slide and the copper to prevent the two from being welded together by molten copper particles during subsequent laser treatment. Then, two glass slides are respectively placed on the surfaces of the pretreated copper foil tape, and tiny copper microparticles are sputtered onto the glass slides by laser. Thereafter, an optically transparent substrate is placed between the two glass slides, and a desired pattern is scanned by laser. Copper particles are simultaneously sputtered to the upper and lower surfaces of the substrate, which serve as a seed layer (catalytic active sites) for chemical plating. Finally, the substrate is placed in a copper plating solution for treatment to obtain a mirror-symmetrical copper electrode. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a preparation flow chart of the method of the present invention.

[0026] Figure 2 The transmittance and SEM results of different ST-Cu in the examples and comparative examples are shown.

[0027] Figure 3 2 are actual images of substrates with mirror-symmetrical patterned copper seed layers at different laser frequencies in the examples and comparative examples.

[0028] Figure 4 The SEM images of the PET substrate with the mirror-symmetrical patterned copper seed layer obtained in Examples 1-3 are shown.

[0029] Figure 5 1 is the XPS graph of ST-Cu and the substrate PET with a mirror-symmetrical patterned copper seed layer in Example 1.

[0030] Figure 6 The SEM and AFM images of the MS-Cu pattern, upper and lower copper layers in Example 1 are shown.

[0031] Figure 7 The mechanical strength test results of copper in MS-Cu in Example 1 are shown. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below with reference to specific embodiments.

[0033] In the following examples and comparative examples, the reagents, materials and instruments used are as follows:

[0034] Copper tape (0.15 mm), glass slide (1 mm), glass plate, PET (12.5 μm), and conductive double-sided tape (10 μm, vertical resistance ≤ 0.03 Ω) are all commercial products. The chemical copper plating solution consists of solution A and solution B. The specific parameters are shown in Table 1. When used, the ratio of A:B = 16:1 (v / v) is mixed. Under the action of the catalyst, the copper plating reaction occurs: Cu 2+ Complex + 2HCHO + 4OH - →Cu+2HCOO - +H2+2H2O+complex.

[0035] Table 1

[0036]

[0037] The laser processing system consists of a UV pulsed laser (Advanced Opto-wave AMT-355-5W), a high-precision galvanometer, a computer system for pattern control, and a Z-axis motor for processing distance. The focal length is 26.2 mm. The processing parameters are shown in Table 2.

[0038] Table 2

[0039]

[0040] Scanning electron microscopy (SEM), atomic force microscopy (AFM), and optical microscopy were used to characterize the surface morphology of the materials. X-ray photoelectron spectroscopy (XPS) was used to characterize the elemental composition of the copper seed layer. A force-controlled folding platform actuator (RM-RPLA-11-5-2-HP50-001) was used to test the mechanical strength of the copper film. A four-probe tester was used to measure the square resistance of the coating. A Keithley 2400A was used to provide power and collect resistance signals.

[0041] like Figure 1 As shown, a method for preparing a laser-induced patterned mirror-symmetrical copper electrode comprises the following steps:

[0042] (1) Using laser to sputter a layer of translucent copper film on a glass slide: copper foil tape is flatly pasted on two glass plates, and the copper foil tape is laser pretreated at a laser pulse frequency of 20 to 30 kHz. Then, two glass slides are placed on the surface of the pretreated copper foil tape, and then laser treatment is performed at a laser pulse frequency of 10 to 20 kHz to sputter copper microparticles onto the glass slide to obtain a glass slide with a translucent copper film deposited thereon. In this process, the metallic copper on the surface is melted into tiny copper particles after absorbing the energy of the laser, and an explosion occurs to sputter the molten particles onto the glass slide to form ST-Cu.

[0043] (2) placing an optically transparent substrate flat between two glass slides deposited with a translucent copper film, and then performing laser scanning on the surface of the upper glass slide deposited with the translucent copper film according to the desired electrode pattern at a laser pulse frequency of 50 to 60 kHz. The copper particles on the two glass slides are simultaneously sputtered onto the upper and lower surfaces of the substrate, thereby obtaining a substrate having a mirror-symmetrical patterned copper seed layer;

[0044] (3) The substrate having the mirror-symmetrical patterned copper seed layer is placed in a copper plating solution at 80-90° C. for 3-5 minutes and then taken out to obtain a laser-induced patterned mirror-symmetrical copper electrode.

[0045] Example 1

[0046] (1) Copper foil tape was flatly pasted on two glass plates, and the copper foil tape was laser pretreated at a laser pulse frequency of 20 kHz. Then, two glass slides were placed on the surface of the pretreated copper foil tape. Then, one glass slide was laser treated at a laser pulse frequency of 10 kHz to obtain a first glass slide (denoted as ST-Cu-10) with a semi-transparent copper film deposited thereon; and one glass slide was laser treated at a laser pulse frequency of 20 kHz to obtain a second glass slide (denoted as ST-Cu-20) with a semi-transparent copper film deposited thereon.

[0047] (2) An optically transparent substrate is placed flatly between a first glass slide and a second glass slide, and then the surface of the first glass slide is laser scanned according to the desired electrode pattern at a laser pulse frequency of 50 kHz. The copper particles on the two glass slides are simultaneously sputtered to the upper and lower surfaces of the substrate, obtaining a substrate with a mirror-symmetrical patterned copper seed layer.

[0048] (3) The substrate having the mirror-symmetrical patterned copper seed layer is placed in a copper plating solution at 80° C. for 3 minutes and then taken out. The burrs of the overplating at the edge of the copper film are ultrasonically removed to make the pattern outline clear. The substrate is rinsed with deionized water to remove the water on the surface, thereby obtaining a laser-induced patterned mirror-symmetrical copper electrode (denoted as MS-Cu).

[0049] Example 2

[0050] The laser pulse frequency in step (2) of this embodiment is 55 kHz, and the rest is the same as in embodiment 1.

[0051] Example 3

[0052] In step (1) of this embodiment, when two glass slides are laser-treated, the laser pulse frequency is 10 kHz, and in step (2), the laser pulse frequency is 60 kHz. The rest is the same as in embodiment 1.

[0053] Comparative Example 1

[0054] In step (1) of this comparative example, when two glass slides were laser treated, the laser pulse frequencies were 30 kHz (denoted as ST-Cu-30) and 40 kHz (denoted as ST-Cu-40), respectively, and the rest were the same as in Example 1.

[0055] Comparative Example 3

[0056] In this comparative example, the laser pulse frequency in step (2) is 65 kHz, and the rest is the same as in Example 1.

[0057] In the examples and comparative examples, the transmittance and SEM results of different ST-Cu are as follows: Figure 2 As shown in the figure, the transmittance of ST-Cu increases from 45.2% to 80% with increasing laser frequency (the incident light wavelength is consistent with the laser wavelength, 355nm). SEM test results of ST-Cu processed at different laser frequencies and glass slides without copper particles show that a large number of irregularly shaped copper particles are present on the surface of ST-Cu, and their content decreases with increasing frequency.

[0058] In the examples and comparative examples, the substrates with mirror-symmetrical patterned copper seed layers at different laser frequencies are as follows: Figure 3 As shown in Figure 3, the results show that the lower the frequency, the more conducive it is to the formation of the coating. This is because the greater the laser power, the more copper seed microparticles are sputtered and transferred.

[0059] The SEM test results of the substrate PET with mirror-symmetrical patterned copper seed layer obtained in Examples 1-3 are as follows: Figure 4As shown, a and b are schematic diagrams of the structure of the substrate with a mirror-symmetrical patterned copper seed layer, and c is the SEM result of the upper and lower surfaces of the substrate PET obtained in step (2). The results show that during the laser scanning process, the laser passes through ST-Cu and PET, sputtering the copper seeds to the upper and lower surfaces of PET, and the copper microparticles that are melted again will thermally corrode PET, which is conducive to the growth and adhesion of copper during the ECP process. This step of treatment achieves micro-etching, sensitization, and patterning on both sides of the substrate, greatly simplifying the process flow and shortening the time. The SEM results of the upper and lower surfaces of PET after laser treatment with frequencies of 50, 55, and 60 kHz show that micro-etching increases with decreasing laser frequency, with more micron-sized copper particles on the upper surface of PET, and more significant than the micro-etching on its lower surface. This is because larger particles are difficult to sputter from bottom to top, and the laser energy is attenuated after passing through PET and ST-Cu-20. d and e are the SEM results of the upper and lower surfaces of the substrate PET obtained in step (2) of Example 1. The copper particles on the ST-Cu are irregular, while the copper particles on the PET are spherical and smaller in size. This indicates that the secondary laser treatment causes the copper particles on the ST-Cu to melt, explode, and sputter again. This process further reduces the size of the copper particles and increases their specific surface area, which may also increase their chemical reactivity and accelerate the occurrence of the copper plating reaction.

[0060] The XPS results of ST-Cu and the substrate PET with mirror-symmetrical patterned copper seed layer obtained in Example 1 are as follows: Figure 5 As shown in the figure, ST-Cu and PET both have obvious satellite peaks near 943eV, and ST-Cu has a stronger peak, which indicates that the copper microparticles on the surface of both contain a certain amount of divalent copper, and the content of ST-Cu is higher. The two peaks other than the satellite peak were fitted, and the peaks near 935eV and 954eV correspond to the 2P of divalent copper, respectively. 3 / 2 and 2P 1 / 2 peaks, while 933eV and 952eV correspond to the 2P 3 / 2 and 2P 1 / 2 Peak area results show that the zero-valent copper contents of ST-Cu and PET are 46% and 76%, respectively. This indicates that during the preparation of ST-Cu, the laser will oxidize copper under the action of O2 in the air, and the oxidized copper will be reduced to a certain extent during the secondary laser sputtering process on PET.

[0061] The SEM and AFM results of the MS-Cu pattern and the upper and lower copper layers in Example 1 are as follows: Figure 6As shown, SEM results show that the copper coating is dense, and the upper surface is rougher than the lower surface, which is caused by more significant micro-etching. AFM results show that the surface morphology is consistent with the SEM results, and the thickness of the copper layer on the upper and lower surfaces is 600-800 and 400-500 nm, respectively. The rough surface can be used to fabricate temperature sensors because it provides more anchor points to enhance the bonding strength between GO and the electrode. In addition, the four-probe tester shows that both the upper and lower surfaces have very low square resistance, respectively. 0.138 ± 0.008 and 0.278 ± 0.026Ω / sq.

[0062] To measure the mechanical strength of the copper coating in Example 1, a 60×2 mm long electrode strip was prepared, folded in a "Z" shape, and fixed between two glass slides. A force of 50 N was repeatedly applied using a force-controlled folding platform push rod. The resistance response was as follows: Figure 7 As shown in Figure a (using conductive double-sided tape and copper foil to connect to the test instrument): the resistance increases slightly under load conditions and decreases when the load is removed. After 63 cycles, the resistance increases sharply to several thousand ohms due to the breakage of the copper layer, and then returns to a few ohms after unfolding. This shows that the copper coating is firmly bonded to the PET substrate. In addition, the coating can withstand several tape sticking and separation tests, such as Figure 7 As shown in Figure b, no obvious coating peeling phenomenon was observed after three tests, which also proves that the coating is firmly attached to the PET. Figure 7 The method shown in the small illustration in middle c is conformally bent and fixed on cylinders with different radii, and the relationship between its resistance and bending curvature is measured (the number of samples is 3), as shown in Figure 7 As shown in Figure c, the results show that even with a bending curvature of 0.5 mm, the resistance change of the copper electrodes on both sides is very low (ΔR < 0.4Ω). Figure 7 Figure d) shows that within the 20°C to 100°C range, temperature has little effect on the total resistance between the copper electrode and the conductive double-sided tape, less than 1Ω. This indicates that bending and temperature have minimal effects on the resistance of the copper electrode and its connection, far less than the resistance change caused by pressure or temperature sensors under the same stimulus, and therefore can be ignored.

[0063] In summary, the invention includes but is not limited to the above embodiments. Any equivalent replacement or partial improvement made under the spirit and principle of the present invention shall be deemed to be within the scope of protection of the present invention.

Claims

1. A method for preparing a laser-induced patterned mirror-symmetrical copper electrode, characterized in that: The method steps include: (1) Copper foil tape was flatly pasted on two glass plates, and the copper foil tape was laser pretreated at a laser pulse frequency of 20-30 kHz. Then, two glass slides were placed on the surface of the pretreated copper foil tape, and then laser treatment was performed at a laser pulse frequency of 10-20 kHz to sputter copper microparticles onto the glass slides to obtain glass slides with translucent copper films deposited on them. (2) An optically transparent substrate is placed flat between two glass slides deposited with a translucent copper film. The surface of the upper glass slide deposited with the translucent copper film is then laser scanned at a laser pulse frequency of 50 to 60 kHz according to the desired electrode pattern. The copper particles on the two glass slides are simultaneously sputtered to the upper and lower surfaces of the substrate, obtaining a substrate with a mirror-symmetrical patterned copper seed layer. (3) placing the substrate having the mirror-symmetrical patterned copper seed layer in a copper plating solution at 80-90° C. for 3-5 minutes and then taking it out to obtain a laser-induced patterned mirror-symmetrical copper electrode; Wherein, in step (2), during laser scanning, the light transmittance of the glass slide on the upper layer with the translucent copper film deposited thereon is greater than that of the glass slide on the lower layer with the translucent copper film deposited thereon.

2. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 1, wherein: In step (1), the light transmittance of the glass slide on which the translucent copper film is deposited is 45% to 60%.

3. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 1, wherein: In step (2), the optically transparent substrate is polyethylene terephthalate, polyimide or transparent glass.

4. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 1, wherein: In step (2), the laser pulse frequency is 50~55 kHz.

5. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 1, wherein: In steps (1) and (2), during laser pretreatment, laser treatment, and laser scanning, the processing speed is 700-900 mm / s, the processing distance is 26-27 cm, the pulse width is 10-15 ns, and the scanning line spacing is 10-20 μm.

6. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 1, wherein: In step (3), the copper plating solution consists of solution A and solution B; the volume ratio of solution A to solution B is 10-20:1; Liquid A includes copper sulfate pentahydrate, potassium sodium tartrate tetrahydrate, hydroxide, methanol, sodium lauryl sulfate, anhydrous potassium ferrocyanide and ammonium chloride; Liquid B is formaldehyde aqueous solution.

7. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 6, wherein: In the liquid A, the concentration of copper sulfate pentahydrate is 40-50 g / L, the concentration of potassium sodium tartrate tetrahydrate is 60-70 g / L, the concentration of the complexing agent is 60-70 g / L, the concentration of the hydroxide is 15-20 g / L, the concentration of methanol is 50-70 mL / L, the concentration of sodium lauryl sulfate is 0.02-0.05 g / L, the concentration of anhydrous potassium ferrocyanide is 0.08-0.1 g / L, and the concentration of ammonium chloride is 0.5-1 g / L; in the liquid B, the concentration of the formaldehyde aqueous solution is 37 wt%-40 wt%.

8. The method for preparing a laser-induced patterned mirror-symmetrical copper electrode according to claim 7, wherein: The hydroxide is potassium hydroxide or sodium hydroxide.

9. A laser-induced patterned mirror-symmetrical copper electrode, characterized in that: It is prepared by the method according to any one of claims 1 to 8.

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