A method for preparing a conductive circuit on the surface of a glass substrate

Abstract

The present invention relates to a method for preparing a conductive circuit on the surface of a glass substrate, comprising the following steps: 1) using metal salts and NaH2PO2 as raw materials to prepare a catalytically active metal element mixed solution; 2) pre-placing the metal element mixed solution on the surface of a clean glass substrate and drying it; 3) placing the glass substrate with the side covered with the metal element film facing downward and tightly superimposing it on the surface of a smooth and clean copper plate, then placing it on a laser processing table and processing the overlap between the glass and the copper plate using a laser according to a set electronic circuit pattern; 4) cleaning the glass substrate; and 5) placing the glass substrate in a chemical plating solution to deposit a metal layer, thereby completing the preparation of the conductive circuit on the surface of the glass substrate. The preparation method of the present invention not only has a simple preparation process, but also can obtain a metal coating with high bonding strength on the surface of the glass substrate.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive application of laser surface treatment, chemical plating and electroplating technology, and particularly relates to a method for preparing a conductive circuit on the surface of a glass substrate. Background Art

[0002] Glass is an amorphous material. Due to its high optical transparency, strong hardness, good chemical stability and heat dissipation, as well as low price, it is widely used in the field of microelectronic devices as a substitute for circuit substrates.

[0003] Glass circuit board electronic products typically require a high bond strength between the glass substrate and the metal layer of the electronic circuitry on its surface, as this directly determines the lifespan and reliability of the circuit board. However, due to the relatively smooth surface of glass, the bond strength between the glass substrate and the metal layer is weak, which greatly limits its application in printed circuit boards. Therefore, it is particularly important to improve the bond strength between the glass substrate and the metal layer through surface modification technology.

[0004] Currently, numerous methods have been used to improve the bonding strength between glass substrates and surface metal layers. For example, patent document CN110225664A discloses a method for preparing a glass-based conductive circuit board. The method involves first using epoxy resin as a binder and laminating glass and copper foil together under vacuum hot pressing to obtain a glass-based copper-clad laminate. The glass-based copper-clad laminate is then pressed, and then the electronic circuit portion is fabricated on the glass-based copper-clad laminate using a circuit board manufacturing process. Finally, laser ablation is used to ablate the resin outside the electronic circuit. While this method can achieve the fabrication of conductive circuits on the glass surface, the preparation process requires vacuum hot pressing, which is relatively complex. Furthermore, since the glass surface is relatively smooth, this method has a certain impact on improving the bonding strength between the glass and the surface electronic circuits. Hanada et al. proposed in the journal (Applied Physics A, 2008, 90(4): 603-607) to prepare a metal copper layer circuit on the glass surface by combining femtosecond laser direct writing etching technology with chemical plating technology. However, the acquisition of the metal copper layer is based on the premise that lithium aluminosilicate glass doped with trace amounts of silver and cerium is used as the substrate, rather than ordinary glass. At the same time, the bonding strength between the metal copper layer on the surface after chemical plating and the glass substrate is only tested by transparent tape, and the bonding strength is not very high. Summary of the Invention

[0005] In order to improve the defects of the prior art in preparing conductive circuits on the surface of glass substrates, such as complicated process, harsh preparation conditions, low bonding strength, and low industrial application value, the present invention provides a method for preparing conductive circuits on the surface of glass substrates.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A method for preparing a conductive circuit on the surface of a glass substrate comprises the following steps:

[0008] 1) Preparation of a metal activation mixed solution: using a metal salt and NaH2PO2 as raw materials, respectively, to prepare a metal salt solution and a NaH2PO2 solution, and then mixing the metal salt solution and the NaH2PO2 solution to obtain a catalytically active metal element mixed solution;

[0009] 2) Pre-depositing a thin film containing a metal element: Pre-depositing the mixed solution containing the metal element in step 1) on the surface of a clean glass substrate, and drying it to obtain a solid thin film glass substrate with one side covered with the metal element;

[0010] 3) Laser processing: The glass substrate from step 2) is placed with the metal film-coated side facing downward and tightly superposed on a smooth and clean copper plate. The substrate is then placed on a laser processing table and the overlap between the glass and copper plate is processed using a laser according to a predetermined electronic circuit pattern, yielding a laser-processed glass substrate.

[0011] 4) Cleaning: Use diluted aqua regia, tap water or distilled water to clean the glass substrate after laser processing in step 3);

[0012] 5) Chemical plating: The glass substrate cleaned in step 4) is placed in a chemical plating solution to deposit a metal layer, thereby completing the preparation of the conductive circuit on the surface of the glass substrate.

[0013] On the basis of the above technical solution, the present invention can also be improved as follows.

[0014] Furthermore, in step 1), the metal elements contained in the mixed solution are one or more ions of palladium, gold, tungsten, molybdenum, rhodium, ruthenium, silver and nickel.

[0015] Furthermore, in step 1), the concentration of metal ions in the metal salt solution is 0.10 to 2.0 mol / L, the concentration of the NaH2PO2 solution is 2 to 4 times the concentration of the metal ions in the metal salt solution, and the metal salt solution and the NaH2PO2 solution are mixed in a volume ratio of 1:1.

[0016] Furthermore, in step 2), a cleaning method is used to obtain clean glass, and the specific steps are as follows: first, the glass substrate is placed in acetone for ultrasonic treatment for 1 to 5 minutes, and then the glass substrate is placed in distilled water for ultrasonic treatment for 1 to 5 minutes.

[0017] Furthermore, in step 2), the metal activation mixed solution in step 1) is pre-placed on the surface of a clean glass substrate by spin coating, spray coating or brush coating.

[0018] Furthermore, in step 2), the glass substrate pre-applied with the metal activation mixed solution is dried by air drying, low temperature drying or infrared drying.

[0019] Furthermore, the laser used in step 3) is a pulsed laser with a wavelength selected from the ultraviolet band or the visible light band, a pulsed laser power of 3W to 8W, a laser scanning rate of 150 to 800 mm / s, a scanning spacing of 5 to 30 μm, and a laser pulse frequency of 50 KHz to 1 MHz.

[0020] Furthermore, the cleaning in step 4) includes the following specific steps: placing the glass substrate after laser processing in step 3) in dilute aqua regia for ultrasonic treatment for 5 to 30 seconds, and then ultrasonically treating it in tap water or distilled water for 0.5 to 2 minutes; wherein the dilute aqua regia is prepared by mixing aqua regia and water in a volume ratio of 1:5 to 1:8.

[0021] Further, in step 5), the chemical plating solution is composed of 10g / L CuSO4·5H2O, 15ml / L formaldehyde, 30g / LEDTA·2Na, 40g / L potassium sodium tartrate, 10mg / Lα,α′-bipyridine, 100mg / L potassium ferrocyanide and 10mg / L polyethylene glycol. When performing chemical plating, the temperature is controlled at 55°C, the pH value is 12.5, and the chemical plating time is 60 to 120min.

[0022] The beneficial effects of the present invention are:

[0023] (1) Compared with the preparation of conductive circuits on glass substrates by bonding with adhesives, the present invention does not require vacuum hot pressing, has a simple process, is easy to operate, has strong universality, and is more conducive to application in the field of industrial production.

[0024] (2) The preparation method of the present invention not only has a simple preparation process, but also can obtain a metal coating with high bonding strength on the surface of the glass substrate.

[0025] In practice, the traditional process for preparing metal coatings on glass substrates involves first using a laser to etch the glass surface pre-coated with a metal salt film, followed by chemical plating. However, due to the relatively smooth glass surface, if the laser power is too high during processing, the metal salt layer on the glass surface will be completely etched away, making subsequent chemical plating impossible. On the other hand, if the laser power is too low, the micro-nanostructure formed by the etching of the glass surface will be insufficient, resulting in low bonding strength of the subsequent metal coating. Therefore, in order to successfully perform chemical plating on the glass substrate surface and achieve a high bonding strength of the metal coating, the glass substrate is usually subjected to two laser processing steps. The purpose of the first laser processing is to roughen the glass surface, and the purpose of the second laser processing is to impact the active metal elements into the micro-nanostructure formed by the first laser processing. At the same time, during these two processing, the metal salt solution needs to be pre-placed on the surface of the glass substrate and dried. This process usually requires the glass substrate to be removed from the laser processing table before it is implemented. However, when the glass substrate is placed on the laser processing table again, before the second laser processing is implemented, in order to ensure that the second laser etching scanning area coincides with the first laser processing area, the position of the glass substrate needs to be precisely positioned before the second processing, which undoubtedly increases the complexity of the preparation technology. The present invention chooses to pre-place a copper plate under the glass substrate, and the side of the glass substrate covered with the metal salt film faces the copper plate. Then, only one laser etching process is required at the overlapping part, which not only greatly simplifies the preparation process, but also effectively improves the bonding strength of the metal coating on the surface of the glass substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the principle of laser constructing an electronic circuit on a glass substrate in Example 1 of the present invention;

[0027] Figure 2 This is an electronic circuit diagram of the copper plating layer prepared on the surface of the glass substrate after chemical plating in Example 1 of the present invention.

[0028] Figure 3 This is a schematic diagram of measuring the bonding strength of the copper plating layer on the glass surface using the solder welding vertical tensile method in Example 1 of the present invention. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0030] Unless otherwise specified, the raw materials used in the present invention are conventional raw materials in the art and can be purchased on the market. The experimental methods and detection methods in the following examples are all conventional methods unless otherwise specified, and the instruments and equipment used in the experiments can be obtained through commercial channels.

[0031] The present invention provides a method for preparing a conductive circuit on the surface of a glass substrate, comprising the following steps:

[0032] 1) Preparation of a metal activation mixed solution: using a metal salt and NaH2PO2 as raw materials, respectively, to prepare a metal salt solution and a NaH2PO2 solution, and then mixing the metal salt solution and the NaH2PO2 solution to obtain a catalytically active metal element mixed solution;

[0033] 2) Pre-depositing a thin film containing a metal element: Pre-depositing the mixed solution containing the metal element in step 1) on the surface of a clean glass substrate, and drying it to obtain a solid thin film glass substrate with one side covered with the metal element;

[0034] 3) Laser processing: The glass substrate from step 2) is placed with the metal film-coated side facing downward and tightly superposed on a smooth and clean copper plate. The substrate is then placed on a laser processing table and the overlap between the glass and copper plate is processed using a laser according to a predetermined electronic circuit pattern, yielding a laser-processed glass substrate.

[0035] 4) Cleaning: Use diluted aqua regia, tap water or distilled water to clean the glass substrate after laser processing in step 3);

[0036] 5) Chemical plating: The glass substrate cleaned in step 4) is placed in a chemical plating solution to deposit a metal layer, thereby completing the preparation of the conductive circuit on the surface of the glass substrate.

[0037] In step 1), the metal elements contained in the mixed solution are one or more ions of palladium, gold, tungsten, molybdenum, rhodium, ruthenium, silver and nickel. After laser etching, these metal salts will form active centers that catalyze chemical plating reactions in the laser etched area. Preferably, in step 1), the concentration of metal ions in the configured metal salt solution is 0.10-2.0 mol / L, the concentration of NaH2PO2 solution is 2-4 times the concentration of metal ions in the metal salt solution, and the metal salt solution and NaH2PO2 solution are mixed in a volume ratio of 1:1 to ensure that the amount of NaH2PO2 in the mixed solution is 2-4 times the amount of metal element substances. Under the thermal effect of laser etching, the metal ions or Cu in the metal salt 2+ Ions pass through H2PO2 - Oxidation-reduction reaction occurs. Although theoretically, it reacts in a 1:1 ratio of mass, in order to ensure that the metal ions or Cu 2+ The ions are fully reduced, so the amount of NaH2PO2 used should be higher than 1:1.

[0038] When the inventors conducted experimental research on the concentration of metal ions in the metal salt solution, they found that a concentration of 0.10 to 2.0 mol / L was more suitable. If the concentration of metal ions was too low, there would be fewer active species in the subsequent laser etching area, which would affect the quality of subsequent chemical plating and the bonding strength between the metal coating and the glass substrate. At the same time, the concentration of metal ions should not be too high. The main reason is that some metal salt solutions have a certain color. If the concentration is too high, it will increase its absorption of laser energy and cause more laser light to scatter, thereby weakening the laser's ability to etch and roughen the lower surface of the glass substrate, ultimately affecting the bonding strength between the subsequent metal coating and the glass substrate.

[0039] H2PO2 in NaH2PO2 solution - Under the influence of laser etching thermal effect, it will react with metal ions or Cu in metal salts. 2+ A redox reaction occurs between the two, and more metal element particles or copper particles with catalytic activity are generated on the surface of the roughened glass substrate after etching. These particles serve as catalytic active centers, making the laser-etched area of the glass substrate more conducive to chemical plating.

[0040] In fact, in the present invention, even if a mixed solution of metal elements is not used, the copper plate is directly placed under the glass plate, and then a laser is used to etch the bonding surface of the glass and the copper plate. During the etching process, trace copper elemental particles sputtered from the surface of the copper plate to the roughened area of the glass substrate can induce the successful realization of subsequent chemical copper plating because of their certain catalytic activity. However, since the copper elemental particles are not very active and their number is small, the bonding strength between the final glass substrate and the surface copper layer will be poor.

[0041] Based on this, in order to improve the defect of poor bonding strength between the glass substrate and the surface copper layer, the inventors deliberately added metal salts as catalytic active species in step 1) to enhance its catalytic activity, and added H2PO2 in NaH2PO2 - Under the influence of laser etching thermal effect, it shows good reducibility, which can not only reduce metal salts into metal element particles, but also etch more Cu splashed on the surface of copper plate. 2+ It is reduced to Cu metal particles. Under the synergistic effect of the dual catalytic activity of these different metal particles, the bonding strength between the glass substrate and the surface coating can be effectively improved.

[0042] In step 2), the surface of the glass substrate must be clean, because the cleanliness of its surface will directly affect the adhesion strength between the metal element-containing film and the glass substrate, thereby affecting the subsequent laser processing and the bonding strength between the glass substrate and the copper plating layer.

[0043] In step 2), the mixed solution containing the metal elements needs to be pre-distributed uniformly; the drying method is preferably air drying, low-temperature drying or infrared drying, wherein the low-temperature drying temperature is preferably set to 50-80°C.

[0044] In step 3), the focus of the etching laser needs to be placed at the junction of the glass substrate and the copper plate. At this time, taking advantage of the high light transmittance of the glass, the laser will penetrate the glass and etch a pit structure covered with micro-nano structures on the lower surface of the glass at the junction of the glass substrate and the copper plate. At the same time, part of the laser energy will also etch the metal salt film and the upper surface of the copper plate, and reduce the etched particulate material of the metal salt and the copper plate surface to a metal element, which is splashed onto the surface of the glass substrate, thereby providing a large amount of catalytic active species for the subsequent chemical copper plating.

[0045] In step 3), the side of the glass substrate surface covered with the metal element film is selected to face downward, and is tightly superimposed on the surface of a smooth and clean copper plate, and then a laser is used to process it. The reason for choosing this processing method is that compared with the traditional technology of directly using a laser to process the glass covered with a metal film on one side, the present invention simplifies the preparation process while also obtaining a metal coating with higher bonding strength. Because the acquisition of a high bonding strength metal coating on the glass surface is mainly determined by the roughness of the glass surface, that is, when the micron and nano structures on the glass surface are richer, the corresponding bonding strength is higher. However, the premise for obtaining the high bonding strength coating is that there must be a large number of active species with catalytic activity in the inner wall of the micro-nanostructure pit formed by laser etching, which can induce subsequent chemical plating reactions, so that the interior of the micro-nanostructure is tightly filled with metal substances and there is no void structure. However, in the traditional technology of directly using laser to process the glass covered with metal film on one side, if the laser power used is high, although deeper grooves can be etched on the glass surface, the etched area has richer micro-nanostructures, which is beneficial to improving the bonding strength between the glass and the surface coating, but at the same time, the high-power laser will completely etch and impact and remove the metal film on the glass surface, resulting in a lack of catalytically active species inside the micro-nanostructure formed by etching, which makes it difficult to achieve subsequent chemical plating, or even if chemical plating is possible, the bonding strength of the coating will be reduced due to the loose bonding between the coating and the micro-nanostructure; of course, if the laser power used is low, the bonding strength of the final coating will not be high due to the shallow grooves etched by the laser. Compared with this technology, the present invention chooses to face down the side of the glass substrate covered with the metal element film and tightly overlap it with the surface of the copper plate. Then, the laser is used to process the overlapping surface. It can not only etch a richer micro-nano structure on the lower surface of the glass, but also utilize the anti-impact properties of the laser etching splashing particles and the good reflectivity of the copper plate to reflect part of the laser energy and impact a large number of active species into the micro-nano structure in the roughened area of the glass substrate, ultimately obtaining a coating with higher bonding strength.

[0046] In step 4), the purpose of washing with dilute aqua regia is to remove active species outside the laser-etched area. Preferably, the glass substrate, after laser processing in step 3), is first ultrasonically treated in dilute aqua regia for 5 to 30 seconds, and then ultrasonically treated in tap water or distilled water for 0.5 to 2 minutes; wherein the dilute aqua regia is prepared by mixing aqua regia and water in a volume ratio of 1:5 to 1:8.

[0047] The above parameters ensure that active species outside the laser-etched area are completely removed while preserving most of the active species within the laser-etched area. The dilute aqua regia cleaning time should be neither too long nor too short. If the cleaning time is too long, the active species within the laser-etched area will be directly removed; if the cleaning time is too short, the active species outside the laser-etched area will not be completely removed.

[0048] The following are examples and comparative examples of the present invention.

[0049] Example 1

[0050] 1) Preparation of the metal activation mixed solution: Accurately measure 17.74g of PdCl2 and dissolve it in 1000ml of distilled water to obtain a 0.1mol / L PdCl2 solution. Accurately measure 8.8g of NaH2PO2 and dissolve it in 500ml of water to obtain a 0.2mol / L NaH2PO2 solution. Mix the PdCl2 solution and the NaH2PO2 solution in a 1:1 volume ratio to obtain a catalytically active metal element mixed solution.

[0051] 2) Pre-depositing a thin film containing metal elements: A 1.00mm thick glass substrate was cleaned under ultrasonic conditions in acetone and then in distilled water for 5 minutes each, resulting in a relatively clean surface. A prepared metal element mixed solution was sprayed onto one surface of the glass substrate. After drying, a metal-coated glass substrate was obtained.

[0052] 3) Laser processing: such as Figure 1 As shown, first, the side of the glass substrate covered with the metal element film is facing down and tightly overlapped with the surface of a smooth and clean copper plate. Then, it is placed on a laser processing table. Then, according to the set electronic circuit pattern, the laser focus is ensured to be placed at the junction of the glass and the copper plate, and the glass and the copper plate are processed using a laser. The laser used in this embodiment is a 355nm nanosecond pulse laser with a laser power of 3W, a laser scanning rate of 150mm / s, a scanning pitch of 5μm, and a laser pulse frequency of 50KHz, thus obtaining a glass substrate after laser processing.

[0053] 4) Cleaning: First, the laser-processed glass substrate was ultrasonically cleaned for 5 seconds using dilute aqua regia prepared by mixing aqua regia with water in a volume ratio of 1:5, and then ultrasonically cleaned for 2 minutes using distilled water.

[0054] 5) Electroless Plating: The glass substrate cleaned in step 4) is placed in an electroless plating solution for electroless copper plating, thereby completing the formation of conductive circuits on the surface of the glass substrate. The electroless plating solution consists of 10g / L CuSO4·5H2O, 15ml / L formaldehyde, 30g / L EDTA·2Na, 40g / L potassium sodium tartrate, 10mg / L α,α′-bipyridine, 100mg / L potassium ferrocyanide, and 10mg / L polyethylene glycol. The electroless plating is performed at a temperature of 50°C, a pH of 12.5, and a plating time of 60 minutes.

[0055] Figure 2 This is a circuit diagram of the copper plating layer prepared on the surface of the glass substrate after chemical plating.

[0056] like Figure 3 As shown, the bonding strength of the copper layer on the glass surface was measured using the solder welding vertical tensile method. The test results showed that the bonding strength of the copper layer on the glass surface was 6.25 MPa.

[0057] Example 2

[0058] 1) Preparation of the Metal Activation Mixed Solution: Accurately measure 17.00g of AgNO₃ and dissolve it in 50ml of water to obtain a 2.0mol / L AgNO₃ solution. Accurately measure 35.2g of NaH₂PO₂ and dissolve it in 50ml of water to obtain an 8.0mol / L NaH₂PO₂ solution. Mix the AgNO₃ solution and the NaH₂PO₂ solution in a 1:1 volume ratio to obtain a catalytically active metal element mixed solution.

[0059] 2) Pre-applying a thin film containing metal elements: Select a 1.5mm thick glass substrate and clean it under ultrasonication in acetone and then in distilled water for 1 minute each to obtain a relatively clean glass substrate. Apply the prepared metal element mixed solution to one surface of the glass substrate by brushing. Dry the glass substrate in an oven at 70°C to obtain a glass substrate covered with metal elements.

[0060] 3) Laser processing: First, the side of the glass substrate covered with the metal element film faces downward and is tightly overlapped with the surface of a smooth and clean copper plate. Then, it is placed on a laser processing table. Then, according to the set electronic circuit pattern, ensure that the laser focus is placed on the joint between the glass and the copper plate, and use laser processing to process it. The laser used in this embodiment is a 532nm picosecond pulse laser with a laser power of 8W, a laser scanning rate of 800mm / s, a scanning pitch of 30μm, and a laser pulse frequency of 1MHz, thus obtaining a glass substrate after laser processing.

[0061] 4) Cleaning: First, the laser-processed glass substrate was ultrasonically cleaned for 30 seconds using dilute aqua regia prepared by mixing aqua regia with water in a volume ratio of 1:8, and then ultrasonically cleaned for 0.5 minutes using distilled water.

[0062] 5) Electroless Plating: The glass substrate cleaned in step 4) is placed in an electroless plating solution for electroless copper plating, thereby completing the formation of conductive circuits on the surface of the glass substrate. The electroless plating solution consists of 10g / L CuSO4·5H2O, 15ml / L formaldehyde, 30g / L EDTA·2Na, 40g / L potassium sodium tartrate, 10mg / L α,α′-bipyridine, 100mg / L potassium ferrocyanide, and 10mg / L polyethylene glycol. The electroless plating is performed at a temperature of 50°C, a pH of 12.5, and a plating time of 120 minutes.

[0063] Similarly, the bonding strength of the copper layer on the glass surface was measured using the solder welding vertical tensile method. The test results showed that the bonding strength of the copper layer on the glass surface was 7.31 MPa.

[0064] Example 3

[0065] 1) Preparation of the Metal Activation Mixed Solution: Accurately measure 17.74g of PdCl2 and dissolve it in 125ml of water to obtain a 0.8mol / L PdCl2 solution. Accurately measure 8.8g of NaH2PO2 and dissolve it in 50ml of water to obtain a 2.0mol / L NaH2PO2 solution. Mix the PdCl2 solution and the NaH2PO2 solution in a 1:1 volume ratio to obtain a catalytically active metal element mixed solution.

[0066] 2) Pre-depositing a thin film containing metal elements: A 2.0 mm thick glass substrate was cleaned under ultrasonic conditions in acetone and then in distilled water for 3 minutes each, resulting in a relatively clean surface. A prepared metal element mixed solution was pre-deposited onto one surface of the glass substrate using spin coating. The glass substrate was then dried using infrared irradiation to obtain a glass substrate coated with the metal element.

[0067] 3) Laser processing: First, the side of the glass substrate covered with the metal element film faces downward and is tightly overlapped with the surface of a smooth and clean copper plate. Then, it is placed on a laser processing table. Then, according to the set electronic circuit pattern, ensure that the laser focus is placed at the junction of the glass and the copper plate, and use laser processing to process it. The laser used in this embodiment is a 355nm picosecond pulse laser with a laser power of 7W, a laser scanning rate of 600mm / s, a scanning pitch of 20μm, and a laser pulse frequency of 200kHz, thus obtaining a glass substrate after laser processing.

[0068] 4) Cleaning: First, the laser-processed glass substrate was ultrasonically cleaned for 15 seconds using dilute aqua regia prepared by mixing aqua regia with water in a volume ratio of 1:6, and then ultrasonically cleaned for 1 minute using distilled water.

[0069] 5) Electroless Plating: The glass substrate cleaned in step 4) is placed in an electroless plating solution for electroless copper plating, thereby completing the formation of conductive circuits on the surface of the glass substrate. The electroless plating solution consists of 10g / L CuSO4·5H2O, 15ml / L formaldehyde, 30g / L EDTA·2Na, 40g / L potassium sodium tartrate, 10mg / L α,α′-bipyridine, 100mg / L potassium ferrocyanide, and 10mg / L polyethylene glycol. During the electroless plating process, the temperature is controlled at 55°C, the pH is 12.5, and the plating time is 90 minutes.

[0070] Similarly, the bonding strength of the copper layer on the glass surface was measured using the solder welding vertical tensile method. The test results showed that the bonding strength of the copper layer on the glass surface was 10.52 MPa.

[0071] Comparative Example 1

[0072] To compare the effect of the metal activation mixed solution treatment on improving the bonding strength of the copper plating layer on the surface of a glass substrate in the present invention, based on Example 3, this comparative example tested a glass substrate (with the same raw materials and corresponding process parameters as Example 3). Without any metal activation solution pre-applied to its surface, it was directly superimposed on a copper plate. Then, the bonding area was processed using a laser. The laser used was also a 355nm picosecond pulse laser with a laser power of 7W, a laser scanning rate of 600mm / s, a scanning pitch of 20μm, and a laser pulse frequency of 200kHz. Subsequently, chemical copper plating was performed, and the bonding strength of the copper plating layer was tested. The results showed that the bonding strength of the copper layer on the glass substrate surface was 2.93Mpa.

[0073] It can be seen that compared with the bonding strength of the copper layer on the surface of the glass substrate in Comparative Example 1 of 2.93 MPa, the bonding strength of the copper layer on the surface of the glass substrate in Example 3 is 10.52 MPa, that is, the method of the present invention can increase the bonding strength of the copper plating layer on the surface of the glass substrate by about 3.6 times through the pre-treatment of the metal activation mixed solution.

[0074] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a conductive circuit on the surface of a glass substrate, characterized in that: The following steps are involved: 1) Preparation of a metal activation mixed solution: Using a metal salt and NaH2PO2 as raw materials, respectively, a metal salt solution and a NaH2PO2 solution are prepared, and the metal salt solution and the NaH2PO2 solution are then mixed to obtain a catalytically active metal element mixed solution; wherein the metal element contained in the mixed solution is one or more ions of palladium, gold, tungsten, molybdenum, rhodium, ruthenium, silver, and nickel; 2) Pre-depositing a thin film containing a metal element: Pre-depositing the mixed solution containing the metal element in step 1) on the surface of a clean glass substrate, and drying it to obtain a solid thin film glass substrate with one side covered with the metal element; 3) Laser Processing: The glass substrate from step 2) is placed with the metal film-coated side facing downward and tightly superimposed on a smooth and clean copper plate. The substrate is then placed on a laser processing table. The laser is used to process the overlap between the glass and copper plate according to the pre-set electronic circuit pattern, yielding a laser-processed glass substrate. 4) Cleaning: Use diluted aqua regia, tap water or distilled water to clean the glass substrate after laser processing in step 3); 5) Chemical plating: The cleaned glass substrate in step 4) is placed in a chemical plating solution to deposit a metal layer, thereby completing the preparation of a conductive circuit on the surface of the glass substrate; wherein the chemical plating solution is composed of 10 g / L CuSO4·5H2O, 15 ml / L formaldehyde, 30 g / L EDTA·2Na, 40 g / L potassium sodium tartrate, 10 mg / L α,α′-bipyridine, 100 mg / L potassium ferrocyanide, and 10 mg / L polyethylene glycol.

2. The method according to claim 1, characterized in that In step 1), the concentration of metal ions in the prepared metal salt solution is 0.10 to 2.0 mol / L, the concentration of the NaH2PO2 solution is 2 to 4 times the concentration of the metal ions in the metal salt solution, and the metal salt solution and the NaH2PO2 solution are mixed in a volume ratio of 1:

1.

3. The method according to claim 1, characterized in that In step 2), a cleaning method is used to obtain clean glass. The specific steps are as follows: first, the glass substrate is placed in acetone for ultrasonic treatment for 1 to 5 minutes, and then the glass substrate is placed in distilled water for ultrasonic treatment for 1 to 5 minutes.

4. The method according to claim 1, wherein In step 2), the metal activation mixed solution in step 1) is pre-placed on the surface of a clean glass substrate by spin coating, spray coating or brush coating.

5. The method according to claim 1, wherein In step 2), the glass substrate pre-filled with the metal activation mixed solution is dried by air drying, low-temperature drying or infrared drying.

6. The method according to claim 1, characterized in that The laser used in step 3) is a pulsed laser with a wavelength selected from the ultraviolet band or the visible light band, a pulsed laser power of 3W~8W, a laser scanning rate of 150~800mm / s, a scanning spacing of 5~30μm, and a laser pulse frequency of 50KHz~1MHz.

7. The method according to claim 1, characterized in that The cleaning in step 4) comprises the following specific steps: placing the glass substrate after the laser processing in step 3) in dilute aqua regia for ultrasonic treatment for 5 to 30 seconds, and then ultrasonically treating it in tap water or distilled water for 0.5 to 2 minutes; wherein the dilute aqua regia is prepared by mixing aqua regia and water in a volume ratio of 1:5 to 1:

8.

8. The method according to claim 1, characterized in that In step 5), when performing chemical plating, the temperature is controlled to be 55° C., the pH value is 12.5, and the chemical plating time is 60 to 120 minutes.

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