A laser-induced electroless copper activator and method of use thereof

Abstract

This invention provides a laser-induced chemical copper plating activator and its application method, relating to the field of activator technology. First, one or more of the following ingredients—disodium ethylenediaminetetraacetate, tetrahydroxypropylethylenediamine, triethanolamine, and 2,2'-bipyridine—are added to an aqueous solution and stirred to obtain a first mixed solution. Then, certain amounts of CuSO4, nickel ammonium sulfate (Ni(NH4)2(SO4)2), and stannous chloride (SnCl2) are added to the solution to prepare the aforementioned chemical copper plating activator. This activator can be applied to laser etching-induced chemical copper plating reactions to prepare chemical copper-plated electronic circuit substrates with good bonding strength. This solves the technical problems of high preparation cost and less than ideal application effects of existing laser-induced chemical copper plating activators.

Description

Technical Field

[0001] This invention relates to the field of activator technology, and in particular to a laser-induced chemical copper plating activator and its application method. Background Technology

[0002] Over the past few decades, laser etching technology has been widely used in the fabrication of electronic products due to its advantages such as wide applicability to materials, no pollution, high precision, good controllability, high efficiency, no need for masks, and regional selectivity.

[0003] Electronic circuit boards are a crucial component of electronic products. They are typically fabricated using non-metallic insulating materials as the substrate. However, due to their chemical inertness and low surface energy, most non-metallic materials cannot be directly used to fabricate conductive electronic circuit layers through electroless copper plating. To address this issue, it is usually necessary to first activate the surface of the non-metallic material, thereby acquiring a large number of catalytically active sites. These catalytically active sites then induce the subsequent electroless copper plating reaction.

[0004] Activation treatment is the most critical step in the entire electroless plating process. Its quality directly affects whether the subsequent electroless copper plating reaction will proceed and also influences the quality of the resulting coating. Currently, industrially, Pd-containing activating solutions are commonly used as activators for treating non-metallic substrates. While these solutions offer numerous advantages such as high catalytic activity, good solution stability, and mature technology, the high cost and unpredictable price of Pd metal remain significant challenges in industrial production. Therefore, finding an electroless copper plating activator with high catalytic activity and low cost is particularly necessary.

[0005] Compared to palladium, copper, as a transition metal element, possesses a certain catalytic activity for electroless copper plating, and more importantly, it is less expensive. For example, patent document CN 117385344 A discloses an electroless copper plating activator prepared using copper sulfate (CuSO4), polyvinylpyrrolidone, citric acid, sodium borohydride, and other reagents as raw materials. This electroless copper plating activator is not prone to aggregation and has good chemical stability. Although this invention can successfully obtain metallic copper plating layers on substrates such as acrylonitrile-butadiene-styrene copolymer (ABS) and polyurethane (PU) foam, the bonding strength between the metallic copper plating layer and the substrate only passed the cross-cut adhesion test with a special adhesive tape. The bonding strength corresponding to this test is only about 0.6 MPa, indicating that the bonding strength is not very high. More importantly, whether this method can be applied to laser-induced electroless copper plating has not been explored, which to some extent limits its promotion in industrial production, especially in mass laser manufacturing. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a method for preparing laser-induced chemical copper plating activators, thereby solving at least one of the following problems: high cost of using Pd-containing activators, low bonding strength between the laser-induced chemical copper plating layer and the substrate, difficulty in adapting to mass production, and low industrial application value.

[0007] To achieve the above objectives, the present invention employs the following technical solution: a laser-induced chemical copper plating activator, characterized in that the laser-induced chemical copper plating activator is prepared by the following method: (1) Add one or more of the following reagents to water and stir to obtain a first mixed solution: disodium ethylenediaminetetraacetate, tetrahydroxypropylethylenediamine, triethanolamine and 2,2'-bipyridine.

[0008] (2) Heat the mixed solution in step (1) to a predetermined temperature, and then add a certain amount of CuSO4, nickel sulfate (Ni(NH4)2(SO4)2) and stannous chloride (SnCl2) to it respectively, and stir to obtain the chemical copper plating activator.

[0009] Preferably, the first mixed solution in step (1) is prepared by adding one or more of the following reagents: disodium ethylenediaminetetraacetate, tetrahydroxypropylethylenediamine, triethanolamine, and 2,2'-bipyridine.

[0010] Preferably, the total concentration of the first mixed solution in step (1), whether it is composed of one reagent or multiple reagents, is preferably 15-30 g / L.

[0011] Preferably, the predetermined temperature to which the mixed solution is heated in step (2) is 40-80°C.

[0012] Preferably, in step (2), the concentration of CuSO4 is 7.5-14.5 g / L, the concentration of Ni(NH4)2(SO4)2 is 0.8-2.0 g / L, and the concentration of SnCl2 is 1.8-4.4 g / L.

[0013] The present invention also proposes a method for using the above-mentioned activator in a laser-induced chemical copper plating process. Specifically, the activator solution of the chemical copper plating solution in step (2) is pre-placed on the surface of a non-metallic substrate. After it dries, the surface is treated by laser etching according to the designed electronic circuit. Then, the non-metallic substrate after laser treatment is placed in a chemical copper plating solution for chemical copper plating treatment, thereby obtaining a non-metallic substrate with electronic circuits on its surface.

[0014] Preferably, in the method of using the activator, the chemical copper plating activator is pre-applied to the non-metallic substrate material by spin coating, brush coating or spray coating.

[0015] Preferably, the pulse width of the laser used for etching the non-metallic substrate material in the activator application method is in the nanosecond or picosecond range.

[0016] Preferably, the laser wavelength used in the activator application method for etching the non-metallic substrate material is a pulsed laser in the infrared or visible light band.

[0017] Overall, compared with the prior art, this technical solution can achieve the following beneficial effects: (1) Effectively reduces the cost of laser-induced electroless plating for electronic circuits. This invention eliminates the need to use high-cost Pd metal as a raw material for preparing electroless copper plating activators, which is of great significance for expanding its application in industrial production, especially in the field of laser processing.

[0018] (2) Compared with traditional commercial Pd activators, the activator in this invention is applied to the preparation of electronic circuits, and its bonding strength with non-metallic substrate is higher, showing higher industrial application value. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation of a laser-induced electroless copper plating activator and its application in the preparation of copper-based electronic circuits using laser-induced electroless plating.

[0020] Figure 2 This shows the microstructure of the carbon fiber composite surface after laser etching.

[0021] Figure 3 XPS spectrum of carbon fiber composite substrate with metal salt film (composed of CuSO4+Ni(NH4)2(SO4)2+SnCl2) after laser etching.

[0022] Figure 4 High-resolution XPS spectrum of Cu element on a carbon fiber composite substrate with a metal salt film (composed of CuSO4+Ni(NH4)2(SO4)2+SnCl2) coated on the surface after laser etching.

[0023] Figure 5 High-resolution XPS spectrum of Ni element after laser etching of a carbon fiber composite substrate with a metal salt film (composed of CuSO4+Ni(NH4)2(SO4)2+SnCl2) on its surface.

[0024] Figure 6High-resolution XPS spectrum of Sn element on carbon fiber composite substrate with metal salt film (composed of CuSO4+Ni(NH4)2(SO4)2+SnCl2) after laser etching.

[0025] Figure 7 Raman spectrum of carbon fiber composite substrate with metal salt film (composed of CuSO4+Ni(NH4)2(SO4)2+SnCl2) after laser etching.

[0026] Figure 8 Photograph of a sample of metallic copper pattern prepared on the surface of carbon fiber composite material.

[0027] Figure 9 This is a schematic diagram of the vertical tensile test for the bonding strength of metal coatings in solder welding. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings to further illustrate the technical solutions of the present invention. However, the present invention is not limited to these embodiments.

[0029] The preparation process and usage of the activator are detailed below: (1) Add one or more of ethylenediaminetetraacetic acid disodium salt, tetrahydroxypropyl ethylenediamine, triethanolamine and 2,2'-bipyridine to an aqueous solution and stir to obtain a first mixed solution.

[0030] The purpose of adding one or more of ethylenediaminetetraacetic acid disodium salt, tetrahydroxypropylethylenediamine, triethanolamine and 2,2'-bipyridine in step (1) is to enable them to act as organic ligands to react with metal ions in CuSO4, Ni(NH4)2(SO4)2 and SnCl2 to form coordination compounds, thereby improving the stability of the chemical copper plating activator solution.

[0031] (2) Heat the mixed solution in step (1) to a predetermined temperature, and then add a certain amount of CuSO4, nickel sulfate (Ni(NH4)2(SO4)2) and stannous chloride (SnCl2) to it respectively, and stir to obtain the chemical copper plating activator.

[0032] The reason why CuSO4, Ni(NH4)2(SO4)2 and SnCl2 were chosen as raw materials for preparing chemical copper plating activators instead of traditional PdCl2 in step (2) is that CuSO4, Ni(NH4)2(SO4)2 and SnCl2 are the most common chemical reagents on the market and have low prices.

[0033] In step (2), in addition to CuSO4 as the active species for subsequent electroless copper plating, Ni(NH4)2(SO4)2 and SnCl2 were also added to the electroless copper plating activator. This is because Cu's catalytic activity is not as good as that of the traditional PdCl2 activator. If only CuSO4 is added to the electroless copper plating activator, the quality and effect of the subsequent electroless copper plating will be poor. Therefore, to improve the quality and effect of the subsequent electroless copper plating, Ni(NH4)2(SO4)2 and SnCl2 were also added.

[0034] In step (2), the purpose of adding Ni(NH4)2(SO4)2 is to allow the metal salt film to simultaneously reduce the generated Cu and Ni metals under subsequent laser etching. Together, they form Cu-Ni active sites, reducing the activation energy of subsequent electroless plating and thus forming a copper-nickel synergistic catalytic center with higher catalytic activity. This improves the bonding strength of the subsequent electroless copper plating layer. At the same time, the addition of a small amount of Ni(NH4)2(SO4)2 allows Cu and Ni to co-deposit under subsequent laser etching, thereby improving the crystal structure of copper, increasing the deposition rate of subsequent electroless copper plating, and making the coating more dense. This is also beneficial to improving the bonding strength of the subsequent electroless copper plating layer.

[0035] In step (2), the purpose of adding SnCl2 is to Sn 2+ It exhibits strong adhesion to non-metallic substrates, and simultaneously, Sn 2+ With a moderate reduction potential, its presence will also cause more Cu to be released. 2+ and Ni 2+ The process involves reducing metal particles to obtain more and more uniformly distributed catalytic active centers for electroless copper plating on the surface of non-metallic materials. Ultimately, this ensures that a more uniform, continuous, and better-bonded copper plating layer can be obtained on the surface of a non-metallic substrate through subsequent electroless copper plating reactions.

[0036] (3) The activator solution of the chemical copper plating solution in step (2) is pre-placed on the surface of the non-metallic substrate. After it dries, the surface is treated by laser etching according to the designed electronic circuit. Then, the non-metallic substrate after laser treatment is placed in the chemical copper plating solution for chemical copper plating treatment, thus obtaining a non-metallic substrate with electronic circuits on the surface.

[0037] The pulse width of the laser used in step (3) is preferably in the nanosecond and picosecond range, and the wavelength is preferably in the infrared and visible light bands. The main reason is that the photon energy of infrared and visible light lasers is about 1.0~2.5 eV, which is much smaller than the bond energy of chemical bonds such as CC, CH, CO, and CF in non-metallic substrates (3~5 eV). Therefore, the photon energy of an infrared or visible light is not enough to directly break these chemical bonds. In addition, the pulse width of nanosecond and picosecond lasers is relatively wide, so the laser with a wider pulse and longer wavelength mainly interacts with the material through photothermal action. This can induce more metal salts to decompose, thereby generating more catalytically active metal nanoparticles, which are embedded in the etched holes or recast layers of the substrate, becoming activation sites for the subsequent electroless copper plating deposition layer.

[0038] The instantaneous high temperature generated by laser etching in step (3) causes the organic polymer material on the surface of the non-metallic substrate to undergo pyrolysis, generating amorphous carbon. Simultaneously, this generated amorphous carbon, acting as a reducing agent, will also react with Cu metal salt ions covering its surface through a redox reaction. 2+ and Ni 2+ The metals are reduced to elemental metals, which then provide a large number of catalytic active sites for the subsequent electroless copper plating reaction.

[0039] In step (3), the non-metallic substrate will form a large number of etching trenches and holes in the laser etching area under the laser etching action. Then, the copper plating layer generated during the chemical plating process will fill these trenches and holes, thereby forming a mechanical anchoring structure, which can effectively improve the bonding strength between the copper plating layer and the non-metallic substrate. Example

[0040] Figure 1 This is a flowchart illustrating the preparation of a laser-induced electroless copper plating activator and its application in the laser-induced electroless plating process for copper-based electronic circuits. The steps are as follows: preparing a first mixed solution → preparing an electroless copper plating activator solution → pre-applying the copper plating activator to the substrate surface → laser etching and surface cleaning → performing electroless plating → obtaining the electronic circuit substrate.

[0041] (1) First, dissolve 0.36g of disodium ethylenediaminetetraacetate in 20ml of deionized water and stir until completely dissolved to obtain the first mixed solution.

[0042] (2) Heat the mixed solution to 50°C, and then add 0.16g CuSO4, 0.02g Ni(NH4)2(SO4)2 and 0.05g SnCl2 to the above solution. Stir thoroughly and wait for the reaction to proceed for about 10 minutes to obtain the laser-induced chemical copper plating activator.

[0043] (3) The above-mentioned chemical copper plating activator was applied to the surface of the carbon fiber composite material by brushing. Then, it was dried in an oven at 80°C for 30 minutes to obtain a carbon fiber composite material with a metal salt film on the surface. Next, a picosecond pulsed laser with a wavelength of 532nm was used. The laser output power was set to 6 W, the scanning speed to 500 mm / s, the pulse frequency to 200 kHz, and the laser scanning spacing to 18 μm. The surface of the carbon fiber composite material with a metal salt film was processed by unidirectional parallel line scanning. Then, it was ultrasonically cleaned in water for 10 seconds.

[0044] Figure 2 The image shows the microstructure of the carbon fiber composite material surface after laser etching. It can be seen that laser etching creates a deep groove structure on the surface of the carbon fiber composite material. At the same time, the groove is filled with a large number of nano-sized protrusions and pores.

[0045] Figure 3 The image shows the XPS spectrum of the carbon fiber composite surface after laser etching. It can be seen that different elements such as Cu, Ni, O, C and Sn can be detected on the surface of the carbon fiber composite after laser etching.

[0046] Figure 4 The image shows a high-resolution XPS spectrum of Cu on a carbon fiber composite substrate with a metal salt film coated on its surface after laser etching. It can be seen that Cu appears at 953.6 eV after laser etching. 2p1 / 2 Characteristic peaks and Cu appearing at 933.6 eV 2p3 / 2 The characteristic peaks are mainly attributed to Cu in the metal salt film that was not reduced by laser etching. 2+ Cu appears at 952.3 eV 2p1 / 2 Characteristic peaks and Cu appearing at 932.5 eV 2p3 / 2 The characteristic peaks are mainly attributed to Cu metal reduced by laser etching in the metal salt film. Furthermore, through fitting and calculation analysis of the curve, it was found that after laser etching, 69.7% of the Cu in the metal salt film... 2+ It is reduced to elemental Cu metal.

[0047] Figure 5 The high-resolution XPS spectrum of Ni elemental composition is shown in the image of a carbon fiber composite substrate with a metal salt film coated on its surface after laser etching. It can be seen that Ni appears at 872.5 eV after laser etching. 2p1 / 2 Characteristic peaks and Ni appearing at 855.8 eV 2p3 / 2 The characteristic peaks are mainly attributed to the Ni in the metal salt film that was not reduced by laser etching. 2+Ni appears at 852.6 eV 2p1 / 2 Characteristic peaks and Ni appearing at 869.8 eV 2p3 / 2 The characteristic peaks are mainly attributed to the Ni metal reduced by laser etching in the metal salt film. Furthermore, through fitting and calculation analysis of the curve, it was found that after laser etching, 72.4% of the Ni in the metal salt film... 2+ It is reduced to elemental Ni metal.

[0048] Figure 6 The image shows a high-resolution XPS spectrum of Sn elemental composition on a carbon fiber composite substrate with a metal salt film coated on its surface after laser etching. It can be seen that Sn appears at 494.3 eV after laser etching. 3d3 / 2 Characteristic peaks and Sn appearing at 485.8 eV 3d5 / 2 The characteristic peaks are mainly attributed to Sn in the metal salt. 2+ Sn appears at 495.6 eV 3d3 / 2 Characteristic peaks and Sn appearing at 487.1 eV 3d5 / 2 The characteristic peaks are mainly attributed to the Sn oxidized by laser etching in the metal salt. 4+ Meanwhile, XPS measurements also revealed that no elemental metal Sn was present during the laser etching process. 0 It was restored and generated.

[0049] Figure 7 The image shows the surface Raman spectrum of the carbon fiber composite material after laser etching. It is clear that, compared to the original carbon fiber composite material, the surface Raman spectrum of the laser-etched carbon fiber composite material exhibits a significant improvement in the 1000-2000 cm⁻¹ range. -1 A relatively wide characteristic absorption band appears at the location, which is mainly related to the amorphous carbon generated on the surface of the carbon fiber composite material after laser etching.

[0050] (4) The processed carbon fiber composite board is placed in a commercial chemical copper plating solution for chemical copper plating treatment, thereby obtaining an electronic circuit board with a copper base on its surface.

[0051] Figure 8 The photograph shows a sample with a copper pattern on the surface of a carbon fiber composite material. It can be seen that each 10mm × 10mm laser-etched area is completely covered by a copper layer.

[0052] Figure 9This diagram illustrates the test of the bonding strength of metal plating using the solder welding vertical tensile method. The specific method is as follows: First, a 1mm × 1mm square copper layer is prepared on the surface of a carbon fiber composite material using laser etching. Then, a metal wire is soldered to this square copper layer. Next, a force gauge is used to gradually increase the tensile force along a direction perpendicular to the substrate. When the copper layer is pulled off, the tensile force displayed on the force gauge is the bonding strength between the substrate and the surface copper layer. Each sample is measured 5 times, and the average value is taken as the final result.

[0053] The bonding strength of the copper layer on the surface of the prepared carbon fiber composite board was determined by the vertical tensile welding method with solder. Meanwhile, to compare the application effect of the chemical copper plating activator in this invention, CuSO4 solution, PdCl2 solution, and CuSO4+Ni(NH4)2(SO4)2 solution (prepared at a mass ratio of 7:1) were selected as activators. Under the premise of ensuring that the molar concentration of metal ions in each activator solution was equal to that in the CuSO4+Ni(NH4)2(SO4)2+SnCl2 solution, the solutions were pre-placed on the surface of the carbon fiber composite board. After drying and laser treatment, the board was placed in a chemical copper plating solution for chemical copper plating treatment, and the bonding strength of the obtained copper plating layer was tested. The results are shown in Table 1.

[0054] Table 1. Determination of the bonding strength of different activators for electroless copper plating on laser-induced carbon fiber surfaces. As shown in Table 1, CuSO4 solution, PdCl2 solution, and CuSO4+Ni(NH4)2(SO4)2 solution were used as activators in laser-induced electroless copper plating, and the bonding strength of the copper plating layers was tested. The results were 8.48 MPa, 13.51 MPa, and 10.91 MPa, respectively. In contrast, the copper plating layer obtained by using CuSO4+Ni(NH4)2(SO4)2+SnCl2 as the activator in this invention was 15.55 MPa, which represents an improvement of approximately 83%, 15%, and 42%, respectively. Example

[0055] (1) First, dissolve 0.50g of tetrahydroxypropylethylenediamine in 20ml of deionized water and stir until completely dissolved to obtain the first mixed solution.

[0056] (2) Heat the mixed solution to 60°C, and then add 0.20g CuSO4, 0.03g Ni(NH4)2(SO4)2 and 0.07g SnCl2 to the above solution respectively. Stir thoroughly and wait for the reaction to proceed for about 15 minutes to obtain the laser-induced chemical copper plating activator.

[0057] (3) The above-mentioned chemical copper plating activator was applied to the surface of polytetrafluoroethylene (PTFE) by brushing, and then dried in an oven at 90 °C for 30 min to obtain PTFE with a metal salt film on the surface. Next, a picosecond pulsed laser with a wavelength of 1064 nm was used, with the laser output power set to 12 W, the scanning speed to 800 mm / s, the pulse frequency to 400 KHz, and the laser scanning spacing to 22 μm. The PTFE sheet with the metal salt film on the surface was processed by a unidirectional parallel line scanning method, and then ultrasonically cleaned in water for 10 s.

[0058] (4) The processed PTFE sheet was placed in a commercial chemical copper plating solution for chemical copper plating, thus obtaining a copper-based electronic circuit board with a surface coating. The bonding strength of the copper layer on the surface of the prepared PTFE sheet was found to be 7.21 MPa after being tested by the vertical tensile test of solder welding. Meanwhile, to compare the application effect of the electroless copper plating activator in this invention, under the condition that other parameters remain unchanged, CuSO4 solution, PdCl2 solution, and CuSO4+Ni(NH4)2(SO4)2 solution (prepared at a mass ratio of 6:1) were selected as activators. Ensuring that the molar concentration of metal ions in each activator solution was equal to that in the CuSO4+Ni(NH4)2(SO4)2+SnCl2 solution, the solution was pre-placed on the surface of a PTFE sheet. After drying and laser treatment, it was placed in an electroless copper plating solution for electroless copper plating. The bonding strength of the obtained copper plating layers was tested, and the results were 4.49 MPa, 6.42 MPa, and 5.86 MPa, respectively. Clearly, compared to using CuSO4 solution, traditional PdCl2 solution, and CuSO4+Ni(NH4)2(SO4)2 solution as activators, using CuSO4+... Ni(NH4)2(SO4)2+SnCl2, as an activator for electroless copper plating, increased the bonding strength of the copper plating layer by approximately 60%, 12%, and 23%, respectively. Example

[0059] (1) First, dissolve 0.42 g of 2,2'-bipyridine in 20 ml of deionized water and stir until completely dissolved to obtain the first mixed solution.

[0060] (2) Heat the mixed solution to 60°C, and then add 0.24g CuSO4, 0.03g Ni(NH4)2(SO4)2 and 0.08g SnCl2 to the above solution respectively. Stir thoroughly and wait for the reaction to proceed for about 15 minutes to obtain the laser-induced chemical copper plating activator.

[0061] (3) The above-mentioned chemical copper plating activator is applied to the surface of polyimide (PI) by brushing, and then placed in an oven at 90°C for 30 min to dry, thus obtaining PI with a metal salt film on the surface.

[0062] Next, a nanosecond laser with a wavelength of 1064 nm was used. The laser output power was set to 20 W, the scanning speed to 1000 mm / s, the pulse frequency to 100 kHz, and the laser scanning spacing to 25 μm. The PI board with a metal salt film on its surface was processed by a unidirectional parallel line scanning method. Then, it was placed in water for ultrasonic cleaning for 20 seconds.

[0063] (4) The processed PI board was placed in a commercial electroless copper plating solution for electroless copper plating, thus obtaining a copper-based electronic circuit board with a surface covered by copper. The bonding strength of the copper plating layer on the surface of the prepared PI board was found to be 1.48 MPa after being measured by the vertical tensile test of solder welding. At the same time, in order to compare the application effect of the electroless copper plating activator in this invention, CuSO4 solution was used as the activator in the electroless copper plating reaction while keeping other conditions unchanged. The bonding strength of the copper plating layer obtained was 0.78 MPa. Obviously, compared with using CuSO4 solution as the activator, using CuSO4 + Ni(NH4)2(SO4)2 + SnCl2 as the electroless copper plating activator improved the bonding strength of the copper plating layer by about 90%.

[0064] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A laser-induced electroless copper activator, characterized in that, The process for obtaining the activator includes the following steps: (1) Add one or more of the following reagents to water and stir to obtain a first mixed solution; (2) Heat the mixed solution in step (1) to a predetermined temperature, and then add a certain amount of CuSO4, nickel sulfate (Ni(NH4)2(SO4)2) and stannous chloride (SnCl2) to it respectively, and stir to obtain the chemical copper plating activator.

2. The laser-induced electroless copper activator of claim 1, wherein, The first mixed solution in step (1) is prepared by adding one or more of the following reagents: disodium ethylenediaminetetraacetate, tetrahydroxypropylethylenediamine, triethanolamine and 2,2'-bipyridine.

3. The laser-induced electroless copper activator of claim 2, wherein the activator is characterized by: Step (1) Regardless of whether the first mixed solution is composed of one reagent or multiple reagents, its total concentration is 15-30 g / L.

4. The laser-induced chemical copper plating activator according to claim 1, characterized in that, In step (2), the mixed solution is heated to a predetermined temperature of 40-80℃.

5. The laser-induced electroless copper activator of claim 1, wherein, In step (2), the concentration of CuSO4 is 7.5-14.5 g / L, the concentration of Ni(NH4)2(SO4)2 is 0.8-2.0 g / L, and the concentration of SnCl2 is 1.8-4.4 g / L.

6. A method of using a laser-induced electroless copper activator, characterized by, The activator solution of the electroless copper plating solution described in any one of claims 1 to 5 is pre-placed on the surface of a non-metallic substrate. After drying, the surface is treated by laser etching according to the designed electronic circuit. Then, the laser-treated non-metallic substrate is placed in an electroless copper plating solution for electroless copper plating treatment, thereby obtaining a non-metallic substrate with electronic circuits on its surface.

7. The method of claim 6, wherein the laser-induced electroless copper activator is used in a process for forming a copper circuit on a substrate. The chemical copper plating activator is pre-applied to the non-metallic substrate material by spin coating, brush coating or spray coating.

8. The method of claim 6, wherein the laser-induced electroless copper activator is used in the form of a solution. The pulse widths of lasers used for etching non-metallic substrate materials are in the nanosecond and picosecond ranges.

9. The method of claim 6, wherein the laser-induced electroless copper activator is used in a process for forming a copper circuit on a substrate. Pulsed lasers in the infrared and visible light bands are used to etch non-metallic substrate materials.

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