Activating solution for chemical nickel-palladium plating ion of copper bonding pad of display panel and preparation method of activating solution

Abstract

The invention provides a chemical nickel-palladium plating ion activating solution for a copper bonding pad of a display panel. The activating solution comprises the following components in concentration content: 5-100 mg / L of soluble palladium salt, 0.5-20 g / L of a complexing agent, 0.5-50 mg / L of a stabilizer, 5-100 mg / L of a wetting agent, 1-20 g / L of a copper corrosion inhibitor, 3-10 g / L of a cosolvent and a pH regulator. According to the chemical nickel-plating palladium ion activating solution, the copper corrosion inhibitor and the cosolvent are added, so that the chemical nickel-plating palladium ion activating solution can be coordinated with copper, a compact protective film is formed on the surface of the copper, a corrosion medium is prevented from being in contact with the copper, and inactivation caused by instability of the activating solution due to precipitation generated by coordination of the copper corrosion inhibitor and palladium ions is prevented. Safety risks of short circuit, poor contact, poor heat dissipation and the like caused by corrosion of a copper bonding pad are effectively avoided, functional problems of storage information loss, logic function interference and the like are solved, meanwhile, the stability of the activating solution is guaranteed by adding the stabilizer, skip plating or diffusion plating of chemical nickel plating is effectively prevented, the service life of the activating solution is prolonged, and the service life of the activating solution is prolonged. And the application of the method in the field of display panel copper bonding pad metallization is expanded.

Description

Technical Field

[0001] The invention belongs to the technical field of metallization of copper pads of display panels, and in particular relates to an activation solution for chemical nickel-palladium ion plating of copper pads of display panels and a preparation method thereof. Background Art

[0002] The metallization of copper pads of display panels is an important process in the production of display panels. As the key connection part in the display panel, the copper pad can be metallized by chemical nickel plating and other methods. Its purpose is to improve the conductivity of the pad to make signal transmission more efficient; prevent copper from diffusing to other material layers to cause performance problems; improve corrosion resistance to cope with the corrosive environment in production and use; at the same time, enhance the hardness and wear resistance of the pad, reduce physical damage in manufacturing, transportation, assembly and other links, and ensure the stability, reliability and service life of the display panel. Since copper is easily oxidized in the air, a layer of copper oxide will form on the surface of the oxidized copper, resulting in decreased conductivity and difficulty in welding. The metallization layer can effectively block the contact between copper and air and prevent the copper pad from being oxidized. In addition, the metallized copper pad can ensure the efficient transmission of electrical signals inside the display panel, reduce resistance, and improve the conductivity of the circuit. After metallization, the solderability can be enhanced, and the pad is easier to be soldered with external leads or other circuit components, ensuring the reliability of the connection and avoiding problems such as cold soldering and desoldering. The electroless plating metallization method of copper pads uses a chemical reaction to deposit a layer of metal on the surface of the copper pad. For example, in the electroless plating of nickel-phosphorus / palladium (NiP-Pd), in a solution containing nickel ions and a reducing agent, nickel ions are reduced to metallic nickel and deposited on the surface of the copper pad. At the same time, phosphorus elements are also co-deposited to form a nickel-phosphorus alloy layer, and then a layer of palladium and gold is plated. This method can be selectively deposited on the bonding pad, the cost is relatively low, and uniform metallization can be achieved on pads of complex shapes. It has good solderability, strong oxidation resistance, and good bonding strength. Therefore, the role of electroless plating pad metallization mainly includes improving the conductivity of the display panel to ensure stable signal transmission, acting as a barrier layer to prevent metal diffusion, enhancing corrosion resistance to extend service life, improving fingerprint recognition sensitivity, and improving surface hardness and wear resistance, which can improve the quality, performance and stability of the display panel.

[0003] The pre-treatment steps of copper-based chemical nickel plating mainly include pickling and oil removal, micro-etching, and activation. The pre-treatment steps are the key steps of chemical nickel plating. The pre-treatment can remove surface oil, oxide layer and rust, make the surface activation uniform, improve surface performance, enhance the corrosion resistance and wear resistance of the coating, thereby ensuring the coating bonding force, ensuring the coating uniformity, improving the quality of the coating, and extending the service life of the coating. Among them, the activation process is mainly to form sites with catalytic activity on the surface of the substrate to trigger the chemical nickel plating reaction. The activation step can ensure the coating bonding force and uniformity, improve the quality of the coating, and the currently commonly used method is mainly palladium ion activation. However, at present, chemical nickel plating palladium ion activation will have uneven activation, resulting in copper pads with undesirable problems such as leakage plating and infiltration plating, poor stability of the activation solution, and high cost. At the same time, the palladium ions in the activation solution will corrode the copper pads, thereby causing safety risks such as excessive circuit resistance, poor contact, leakage and poor heat dissipation, thereby causing poor chip signal transmission, storage data loss, logical function interference and other functional problems, and may also cause chip packaging failure and other problems. In order to solve the corrosion problem of the activation solution to the copper substrate, the present invention adds a copper corrosion inhibitor that suppresses copper corrosion in the activation solution, but the conventional alcohol amines, azoles and phosphonic acid copper corrosion inhibitors are easy to coordinate with the palladium ions in the activation solution to generate palladium ion complex precipitation during use, which will affect the stability and activation performance of the activation solution, and it is necessary to add a cosolvent to ensure the stability and activation performance of the activation solution. In addition, the commonly used inorganic iodide stabilizing effect is insufficient, so that the life of the activation solution is not long. Therefore, the palladium ion activation solution formula is optimized, the corrosion of the activation solution to the copper pad is suppressed, and the pad is prevented from leaking and plating, and the stability, activation performance and activation uniformity of the activation solution are improved, which become the problems that the current copper-based chemical nickel plating palladium ion activation solution is concerned about. Summary of the invention

[0004] The main purpose of the present invention is to provide an activation solution for chemical nickel plating of copper pads of display panels and a preparation method thereof, which solves the problems in the prior art that copper pads are easily corroded during chemical nickel plating of copper pads, and the pads have defects such as infiltration plating and leakage plating, which lead to safety risks such as circuit short circuit, poor contact, leakage and poor heat dissipation, and the palladium ions in the activation solution are easily coordinated with the copper corrosion inhibitor to form insoluble precipitates, thereby affecting the stability and activation performance of the activation solution. In addition, the commonly used inorganic iodide has insufficient stabilizing effect, which makes the activation solution have a short life. In order to solve the above problems, the technical solution adopted by the present invention is: An activation solution for chemical nickel-palladium ion plating of copper pads of display panels, the activation solution comprising the following components in concentration: 5-100 mg / L of soluble palladium salt, 0.5-20 g / L of complexing agent, 0.5-50 mg / L of stabilizer, 5-100 mg / L of wetting agent, 1-20 g / L of copper corrosion inhibitor, 3-10 g / L of cosolvent and pH regulator.

[0005] Furthermore, the soluble palladium salt is one of palladium chloride, palladium sulfate, palladium sulfate dihydrate and tetraamminepalladium sulfate.

[0006] Further preferably, the soluble palladium salt is palladium sulfate, palladium sulfate dihydrate, tetraamminepalladium sulfate and palladium chloride.

[0007] Furthermore, the complexing agent is one or more of disodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, trisodium citrate dihydrate, ammonium citrate and ethylenediamine.

[0008] Further preferably, the complexing agent is disodium ethylenediaminetetraacetate and ammonium citrate.

[0009] Furthermore, the stabilizer is one or more of iodobenzene, methyl iodide, ethyl iodide, methyl o-iodobenzoate, trimethyl silyl iodide, iodoform, potassium iodide and potassium iodate.

[0010] More preferably, the stabilizer is any one or more of iodobenzene, methyl iodide, ethyl iodide, potassium iodide and methyl o-iodobenzoate.

[0011] Furthermore, the wetting agent is one or more of nonylphenol polyoxyethylene ether, TC-EHS, MA-80, PEG-400, OP-10, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium methane sulfonate and sodium isooctyl sulfate.

[0012] Further preferably, the wetting agent includes nonylphenol polyoxyethylene ether, sodium lauryl sulfate and OP-10.

[0013] Furthermore, the copper corrosion inhibitor is one or more of benzotriazole (BTA), toluenetriazole (TTA), mercaptobenzothiazole sodium salt (MBT), hydroxybenzotriazole, 2-mercaptobenzimidazole, ethylenediamine trimethylenephosphonic acid, diethylenetriamine pentamethylphosphonic acid, hydroxyethylenediphosphonic acid, aminotrimethylenephosphonic acid, octadecylamine, morpholine, monoethanolamine, diethanolamine and triethanolamine.

[0014] Further preferably, the copper corrosion inhibitor is benzotriazole, hydroxybenzotriazole, triethanolamine and aminotrimethylenephosphonic acid.

[0015] Furthermore, the co-solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

[0016] More preferably, the co-solvent is dimethyl sulfoxide or N,N-dimethylformamide.

[0017] Furthermore, the pH adjusting agent is one or more of hydrochloric acid, sulfuric acid, sodium hydroxide, and potassium hydroxide, and the pH value of the activation solution is adjusted to a corresponding pH.

[0018] Another aspect of the present invention provides a method for preparing the copper corrosion inhibiting chemical nickel-palladium ion plating activation solution, comprising the following steps: (1) adding the co-solvent, copper corrosion inhibitor, complexing agent and soluble palladium salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding sodium hydroxide or sulfuric acid solution to the second mixed solution to adjust the pH of the plating solution to 1.0-3.0, thereby obtaining the chemical nickel-palladium ion activation solution.

[0019] Another aspect of the present invention provides the use of the chemical nickel plating palladium ion activation solution in chemical nickel plating of copper pads of display panels.

[0020] Furthermore, a copper pad substrate is selected as a workpiece for chemical nickel plating. First, a stripping solution is used to remove residual glue on the surface of the copper pad substrate to ensure its surface cleanliness and good wettability.

[0021] Furthermore, after the copper pad substrate is subjected to degreasing, pickling and micro-etching steps, its surface cleanliness, activation uniformity and good bonding strength of the nickel plating layer can be ensured.

[0022] Furthermore, the copper pad substrate is activated by the palladium ion activation solution to ensure uniform palladium catalytic active sites on the surface of the copper pad, thereby ensuring a good chemical nickel plating speed, uniform thickness of the nickel plating layer, and good bonding strength of the nickel plating layer.

[0023] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention optimizes the composition of copper-based chemical nickel-palladium ion activation solution, and on this basis, adds a copper corrosion inhibitor, which can coordinate with copper to form a dense protective film on the copper surface to prevent the corrosive medium from contacting the copper. This protective film has good stability, can effectively prevent copper corrosion and electrochemical corrosion in environments such as the atmosphere, water, and soil, and effectively avoids the copper pad being corroded by the activation solution to cause circuit short circuits, poor contact and poor heat dissipation and other safety risks, as well as functional problems such as loss of stored information and interference with logical functions. The cosolvent can effectively maintain the stability and activation performance of the activation solution. At the same time, the organic iodine stabilizer in the activation solution can keep the activation solution stable, effectively prevent defects such as leakage plating and permeation plating in the copper pad chemical nickel plating, and extend the life of the activation solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings: Figure 1 This is a FIB image of the nickel-plated part of Example 5 of the present invention.

[0025] Figure 2 This is an ultra-depth-of-field microscope image of the nickel-plated part of Example 5 of the present invention.

[0026] Figure 3 This is the FIB image of the nickel-plated part of Comparative Example 1 of the present invention.

[0027] Figure 4 This is an ultra-depth-of-field microscope image of the nickel-plated part of Comparative Example 2 of the present invention.

[0028] Figure 5 This is an ultra-depth-of-field microscope image of the nickel-plated part of Comparative Example 3 of the present invention. DETAILED DESCRIPTION

[0029] In the copper pad chemical nickel-palladium ion activation solution of the present invention, since the complexing agent can react with Pd 2+ A stable complex is formed to maintain the stability of the activation solution and extend the activation life. In addition, the addition of a stabilizer can also maintain the stability of the activation solution. At the same time, the copper corrosion inhibitor can coordinate with copper to form a dense protective film on the copper surface to prevent the corrosive medium from contacting the copper. This protective film has good stability and can effectively prevent copper corrosion and electrochemical corrosion in the atmosphere, water, soil and other environments. The co-solvent can effectively maintain the stability and activation performance of the activation solution. In addition, the organic iodine stabilizer in the activation solution can keep the activation solution stable, effectively prevent defects such as leakage and permeation of chemical nickel plating on copper pads, and extend the life of the activation solution.

[0030] The invention provides an activation solution for chemical nickel-palladium ion plating of a copper pad of a display panel. The activation solution contains 5-100 mg / L of a soluble palladium salt, 0.5-20 g / L of a complexing agent, 0.5-50 mg / L of a stabilizer, 5-100 mg / L of a wetting agent, 1-20 g / L of a copper corrosion inhibitor, 3-10 g / L of a cosolvent and a certain amount of a pH regulator.

[0031] In the present invention, the soluble palladium salt is palladium sulfate, palladium sulfate dihydrate, tetraamminepalladium sulfate and palladium chloride.

[0032] In the present invention, the copper corrosion inhibitor is one or more of benzotriazole (BTA), toluene triazole (TTA), sodium mercaptobenzothiazole (MBT), hydroxybenzotriazole, 2-mercaptobenzimidazole, ethylenediamine tris(methylenephosphonic acid), diethylenetriamine penta(methylenephosphonic acid), hydroxyethylenediphosphonic acid, aminotrimethylenephosphonic acid, octadecylamine, morpholine, monoethanolamine, diethanolamine and triethanolamine. With the addition of the copper corrosion inhibitor, the copper corrosion inhibitor can coordinate with copper to form a dense protective film on the copper surface to prevent the corrosive medium from contacting the copper. This protective film has good stability and can effectively prevent copper corrosion and electrochemical corrosion in environments such as the atmosphere, water and soil. Under preferred conditions, the copper corrosion inhibitor is benzotriazole, hydroxybenzotriazole, triethanolamine, diethylenetriamine penta(methylenephosphonic acid) and aminotrimethylenephosphonic acid.

[0033] In the present invention, the cosolvent is dimethyl sulfoxide or N,N-dimethylformamide. Solvents with strong polarity can better dissolve the complex formed by palladium ions and copper corrosion inhibitors, thereby reducing the formation of precipitation.

[0034] In the present invention, the stabilizer is iodobenzene, methyl iodide, ethyl iodide, potassium iodide and methyl o-iodobenzoate. The addition of the stabilizer can inhibit the self-catalytic decomposition of the chemical nickel plating palladium ion activation solution, maintain the stability of the activated nickel plating solution, and avoid economic losses.

[0035] In the present invention, the complexing agent is disodium ethylenediaminetetraacetate and ammonium citrate. The addition of the complexing agent can form a stable complex with palladium ions, improve the stability of the palladium ion activation solution, and prevent adverse reactions such as precipitation or hydrolysis of palladium ions in the solution.

[0036] In the present invention, the wetting agent is nonylphenol polyoxyethylene ether, sodium lauryl sulfate and OP-10. The wetting agent can reduce the surface tension of the contact surface between the activation solution and the substrate, so that the activation solution can better wet the substrate surface, thereby ensuring that palladium ions are uniformly adsorbed on the substrate surface to form a uniform catalytic active layer.

[0037] In the present invention, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, sodium hydroxide, and potassium hydroxide, and the pH of the activation solution is adjusted to the corresponding pH so that the activation solution is kept within a suitable pH range to ensure the activity and stability of palladium ions and the smooth progress of the activation reaction.

[0038] The present invention provides an activation solution for chemical nickel-palladium ion plating of a display panel copper pad and a preparation method thereof, comprising the following steps: (1) adding the co-solvent, copper corrosion inhibitor, complexing agent and soluble palladium salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding sodium hydroxide or sulfuric acid solution to the second mixed solution to adjust the pH of the plating solution to 1.0-3.0, thereby obtaining the chemical nickel-palladium ion activation solution.

[0039] In order to better understand the present invention, the present invention is further described in detail below in conjunction with embodiments and comparative examples, but the scope of protection claimed in the present invention is not limited to the following embodiments and comparative examples.

[0040] Example 1 The composition and content of the chemical nickel-palladium ion activation solution of this embodiment are shown in Table 1: Table 1 Example 1 Activation Solution Components and Contents

[0041] The preparation method of the chemical nickel-palladium ion activation solution comprises the following steps: S1. In 100 mL of ultrapure water, dimethyl sulfoxide, palladium chloride, ammonium citrate and methyl o-iodobenzoate were added in sequence and stirred until completely dissolved to obtain a first mixed solution; S2. OP-10 and benzotriazole were added to the first mixed solution and stirred until completely dissolved to obtain a second mixed solution; S3. Add ultrapure water to the second mixed solution to make the volume to 200 mL, then add sulfuric acid solution to adjust the pH of the plating solution to 1.0, so as to obtain the activation solution.

[0042] Embodiment 2: The composition and content of the chemical nickel-palladium ion activation solution of this embodiment are shown in Table 2: Table 2 Example 2 Activation Solution Components and Contents

[0043] The preparation method is the same as Example 1.

[0044] Embodiment 3: The composition and content of the chemical nickel-palladium ion activation solution of this embodiment are shown in Table 3: Table 3 Example 3 Activation Solution Components and Contents

[0045] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 2.0.

[0046] Embodiment 4: The composition and content of the chemical nickel-palladium ion activation solution of this embodiment are shown in Table 4: Table 4 Example 4 Activation Solution Components and Contents

[0047] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0048] Embodiment 5: The composition and content of the chemical nickel-palladium ion activation solution of this embodiment are shown in Table 5: Table 5 Example 5 Activation Solution Components and Contents

[0049] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0050] Example 6 The composition and content of the palladium ion activation solution of the chemical nickel plating solution of this comparative example are shown in Table 6: Table 6 Example 6 Activation Solution Components and Contents

[0051] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0052] Comparative Example 1 The composition and content of the palladium ion activation solution of the chemical nickel plating solution of this comparative example are shown in Table 7: Table 7 Comparative Example 1 Activation Solution Composition and Content

[0053] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0054] Comparative Example 2 The composition and content of the palladium ion activation solution of the chemical nickel plating solution of this comparative example are shown in Table 8: Table 8 Comparative Example 2 Activation Solution Composition and Content

[0055] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0056] Comparative Example 3 The composition and content of the palladium ion activation solution of the chemical nickel plating solution of this comparative example are shown in Table 9: Table 9 Comparative Example 4 Activation Solution Composition and Content

[0057] The preparation method is the same as that of Example 1, and in S3, sulfuric acid is used to adjust the pH of the plating solution to 1.5.

[0058] Effect example: The chemical nickel plating solutions of Examples 1-5 and Comparative Examples 1-4 are respectively used for chemical nickel plating on LED display copper pad substrates, specifically comprising the following steps: S1. For the copper pad substrate (10mm*15mm) selected as the workpiece for chemical nickel plating, first use the stripping liquid to remove the residual glue on the surface of the copper pad substrate; S2. The copper pad substrate is cleaned with degreasing acid solution for 3 minutes, micro-etched with micro-etching solution for 20 seconds, and then cleaned with ultrapure water; S3. The copper pad substrate is activated by the palladium ion activation solution for 3 minutes and then washed with ultrapure water; S4. The pretreated copper pad substrate is placed in a chemical nickel plating solution and plated at 85° C. for 9 minutes; S5. Clean and dry the nickel-plated silicon wafer with ultrapure water to obtain a nickel-plated part.

[0059] S6. The surface condition of the nickel plating on the copper pad substrate and the corrosion condition of the bottom copper substrate were characterized by FIB (focused ion beam) and ultra-depth microscopy.

[0060] Table 10 Nickel coating surface, bottom copper substrate corrosion and activation solution stability of nickel-plated parts of Examples 1-6 and Comparative Examples 1-3

[0061] Note: No leakage plating means that each unit copper pad (6 small pads) is plated normally, and there is no extension of the plating layer to the non-copper pad area (such as Figure 2 As shown, taking Example 5 as an example); Severe leakage plating means that only some of the small pads of each unit copper pad (6 small pads) are plated normally, and the other pads are black or not plated (such as Figure 5 As shown, taking comparative example 3 as an example); severe infiltration means that the nickel plating extends to the non-copper pad area except the copper substrate (such as Figure 4 As shown, taking Comparative Example 2 as an example); No corrosion means that no corrosion holes appear on the bottom copper substrate after electroless nickel plating (such as Figure 1 As shown, taking Example 5 as an example); severe corrosion means that obvious corrosion holes appear on the bottom copper substrate after chemical nickel plating (such as Figure 3 As shown, taking Comparative Example 1 as an example); the activation liquid is stable, no precipitation means that the activation liquid is clear, no precipitation occurs, and it can be used normally; the activation liquid is unstable, precipitation means that the activation liquid is turbid, obvious precipitation occurs, and it cannot be used normally.

[0062] As can be seen from the results of Examples 1-5 and Comparative Examples 1-4, the surface of the copper pad substrate is activated using the chemical nickel plating palladium ion activation solution provided by the present invention. Within a certain pH range, by adding a certain amount of copper corrosion inhibitor in the activation solution and adding a cosolvent to prevent palladium ions from coordinating and precipitating with the copper corrosion inhibitor, the corrosion of the copper substrate can be effectively suppressed, thereby avoiding the copper pad from being corroded and causing circuit short circuits, poor contact and poor heat dissipation and other safety risks, as well as functional problems such as loss of storage information and interference with logical functions. The best copper corrosion inhibitor and cosolvent combination is aminotrimethylenephosphonic acid and N, N-dimethylformamide. In addition, the addition of a certain amount of stabilizer can effectively maintain the stability of the activation solution and extend its service life. Compared with the inorganic iodide stabilizers such as potassium iodide commonly used at present, the stabilizing effect of organic iodides such as methyl iodide used in the present invention is better, and the activation solution effect can reach more than 160 days. Secondly, the addition of a certain amount of wetting agent can make the palladium ions in the activation solution evenly dispersed, effectively preventing defects such as leakage plating and permeation plating from chemical nickel plating of copper pads. The above advantages expand the application of the activation solution in the field of copper-based chemical nickel plating. In addition, if the copper corrosion inhibitor is not added, the copper substrate will react with the activation solution and cause serious corrosion. If the stabilizer is not added, the activation solution will be unstable, which will affect the chemical nickel plating and cause nickel plating to leak. If only the copper corrosion inhibitor is added without the co-solvent, the stability of the activation solution will be affected, thereby affecting its copper corrosion inhibition performance and activation performance, resulting in leakage plating of chemical nickel plating.

[0063] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. An activation solution for chemical nickel-palladium ion plating of display panel copper pads, characterized in that: Soluble palladium salt 5-100 mg / L, copper corrosion inhibitor 0.5-20 g / L, stabilizer 0.5-50 mg / L, wetting agent 5-100 mg / L, copper corrosion inhibitor 1-20 g / L, co-solvent 3-10 g / L and pH adjuster.

2. The activation solution according to claim 1, characterized in that: The soluble palladium salt is one of palladium chloride, palladium sulfate, palladium sulfate dihydrate and tetraamminepalladium sulfate.

3. The activation solution according to claim 1, characterized in that: The complexing agent is one or more of disodium ethylenediaminetetraacetate, disodium ethylenediaminetetraacetate, trisodium citrate dihydrate, ammonium citrate or ethylenediamine.

4. The activation solution according to claim 1, characterized in that: The stabilizer is one or more of iodobenzene, methyl iodide, ethyl iodide, methyl o-iodobenzoate, trimethyl silyl iodide, iodoform, potassium iodide or potassium iodate.

5. The activation solution according to claim 1, characterized in that: The copper corrosion inhibitor is one or more of benzotriazole, toluenetriazole, sodium mercaptobenzothiazole, hydroxybenzotriazole, 2-mercaptobenzimidazole, ethylenediamine trimethylenephosphonic acid, diethylenetriamine pentamethylphosphonic acid, hydroxyethylenediphosphonic acid, aminotrimethylenephosphonic acid, octadecylamine, morpholine, monoethanolamine, diethanolamine or triethanolamine.

6. The activation solution according to claim 1, characterized in that: The co-solvent is one or more of dimethyl sulfoxide, N,N-dimethylformamide and N-methylpyrrolidone.

7. The activation solution according to claim 1, characterized in that: The wetting agent is one or more of nonylphenol polyoxyethylene ether, TC-EHS, MA-80, PEG-400, OP-10, sodium dodecylbenzene sulfonate, sodium dodecyl sulfate, sodium methane sulfonate or sodium isooctyl sulfate.

8. The method for preparing the activation solution for chemical nickel-palladium ion plating of display panel copper pads according to any one of claims 1 to 7, characterized in that: The following steps are involved: (1) adding the co-solvent, copper corrosion inhibitor, complexing agent and soluble palladium salt to ultrapure water in sequence, stirring until completely dissolved, to obtain a first mixed solution; (2) adding a stabilizer and a wetting agent to the first mixed solution, stirring until completely dissolved, to obtain a second mixed solution; (3) Adding sodium hydroxide or sulfuric acid solution to the second mixed solution to adjust the pH of the plating solution to 1.0-3.0, thereby obtaining the chemical nickel-palladium ion activation solution.

9. Use of the palladium ion activation solution for chemical nickel plating of copper pads of display panels as claimed in any one of claims 1 to 8 in chemical nickel plating of copper pads of display panels.

10. The use according to claim 9, characterized in that: When the activation solution is used for chemical nickel plating, the activation temperature is 25-30° C. and the activation time is 3-5 minutes, which can improve the corrosion of the activation solution on the copper pad, prevent leakage plating and seepage plating on the pad, and improve the stability of the activation solution and the activation uniformity.

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