A gold palladium plating solution for copper wire electroplating and an electroplating process

Abstract

The application provides a gold-palladium plating solution for copper wire electroplating and an electroplating process, wherein the gold-palladium plating solution for copper wire electroplating is characterized by comprising the following raw material components: 0.3-20 g / L of water-soluble gold salt, 0.1-12 g / L of water-soluble palladium salt, 10-20 mg / L of graphene quantum dots, 20-30 g / L of ethylenediamine, 50-110 g / L of a complexing agent, 15-25 g / L of a conductive salt, 15-25 g / L of a buffering agent, 25-35 g / L of a stabilizing agent, and the rest is solvent. The electroplating process is as follows: the copper wire to be plated is placed into an electroplating tank containing the gold-palladium plating solution, an electrode plate is used as an anode, and the copper wire is used as a cathode to perform electroplating, and after the electroplating is completed, the copper wire is subjected to a post-plating treatment process. The gold-palladium plating solution and the electroplating process have the advantages of simple process, high conductivity, wear resistance, strong corrosion resistance, uniform plating layer distribution, precise size, aging resistance and the like of the obtained gold-palladium alloy plating layer.

Description

Technical Field

[0001] This invention relates to the field of electroplating technology, and in particular to a gold-palladium plating solution for copper wire electroplating and an electroplating process. Background Technology

[0002] In traditional packaging processes, gold wire is a commonly used material due to its advantages such as high conductivity, corrosion resistance, good toughness, and ease of soldering. However, with the continuous rise in gold prices and the continuous decrease in electronic product prices, finding other more suitable metals to replace gold wire has become an urgent problem to solve. Copper wire is less expensive and has better electrical and thermal conductivity than gold wire, so it has gradually been adopted to reduce material costs. However, copper wire is prone to oxidation and corrosion, has high hardness, and poor solderability, which limits its application range. Therefore, people have begun to use copper wire with a metal plating on its surface.

[0003] Palladium-plated copper wire uses relatively inexpensive palladium as the plating layer, controlling costs while also addressing the issues of copper wire's susceptibility to oxidation and corrosion. However, palladium's conductivity is still insufficient, resulting in significant heat generation in very small chip packages. Furthermore, palladium's relatively high hardness can easily damage the chip. While gold-plated copper wire overcomes the drawbacks of high hardness and high resistance found in palladium-plated copper wire, the bonding strength between gold and copper is not as strong as that between palladium and copper, leading to inherently lower stability. Therefore, compared to the two types of plated copper wire mentioned above, gold-palladium-plated copper wire has become the primary choice.

[0004] Currently, gold-palladium-plated copper wire is typically produced by immersing the copper wire to be plated in a plating solution for electroplating. However, using commercially available gold-palladium plating solutions inevitably leads to peeling and delamination of the plating layer on the surface of the electroplated copper wire, resulting in product defects. Therefore, overcoming this problem has become a major research direction in this industry. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, this invention provides a gold-palladium plating solution for copper wire electroplating and an electroplating process. The process is simple, and the resulting gold-palladium alloy plating layer has advantages such as high conductivity, wear resistance, strong corrosion resistance, uniform coating distribution, precise dimensions, and aging resistance. This invention is achieved through the following technical solution:

[0006] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 0.3-20 g / L of water-soluble gold salt, 0.1-12 g / L of water-soluble palladium salt, 10-20 mg / L of graphene quantum dots, 20-30 g / L of ethylenediamine, 50-110 g / L of complexing agent, 15-25 g / L of conductive salt, 15-25 g / L of buffer, 25-35 g / L of stabilizer, with the balance being solvent.

[0007] In implementing the above embodiments, preferably, the water-soluble gold salt is any one of potassium gold sulfite, sodium gold sulfite, ammonium gold sulfite, sodium gold thiosulfate, potassium gold thiosulfate, and ammonium gold thiosulfate.

[0008] In implementing the above embodiments, preferably, the water-soluble palladium salt is any one of palladium acetylacetonate, palladium dichlorotetramine, or palladium dichlorodimine.

[0009] In implementing the above embodiments, preferably, the graphene quantum dots are modified with imidazole.

[0010] In implementing the above embodiments, preferably, the complexing agent is any one of guanidinoacetic acid, dimethylthiourea, dithioethylene glycol, mercaptochitosan, or triethanolamine.

[0011] In implementing the above embodiments, preferably, the conductive salt is any one of potassium sulfate, sodium sulfate, and ammonium sulfate.

[0012] In implementing the above embodiments, preferably, the buffer is at least one of boric acid or its salt, acetic acid or its salt, or aminoacetic acid or its salt.

[0013] In implementing the above embodiments, preferably, the stabilizer is any one of tridecyl phosphite, trioctyl phosphite, thionyl diacetic acid, or dithioglycolic acid.

[0014] In implementing the above embodiments, preferably, the solvent is deionized water.

[0015] The present invention also provides an electroplating process using the gold-palladium plating solution described above, the steps of which are as follows: placing the copper wire to be plated into an electroplating tank containing the gold-palladium plating solution, using the electrode plate as the anode and the copper wire as the cathode for electroplating, and washing with hot water and drying after electroplating; wherein, the electroplating parameters during the electroplating process are: pH 7-9, temperature 18-70℃, current density 1-15ASD, Baumé degree 5-30, and electroplating time 0.5-300s.

[0016] Compared with the prior art, the present invention has the following advantages:

[0017] 1. The copper wire obtained by electroplating according to the present invention has a uniformly distributed, precisely sized, and aging-resistant electroplated layer with low hardness and good ductility. It maintains a high gold content to ensure that the alloy coating has excellent properties such as high conductivity, good solderability, and strong corrosion resistance.

[0018] 2. The gold-palladium plating solution of the present invention contains graphene quantum dots and ethylenediamine in its raw material components. During the electroplating process, it eliminates different areas with uneven charge on the surface of the workpiece, so that the gold-palladium plating layer is evenly distributed on the surface of the copper wire of the workpiece, thereby eliminating the internal stress of the plating layer and solving the problem of plating peeling on the copper wire.

[0019] 3. The electroplating process of the present invention is simple and has a wide range of applications. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0022] To facilitate implementation of the present invention by those skilled in the art, descriptions of some of the reagents used in the embodiments and comparative examples are provided below:

[0023] Water-soluble gold salt: Potassium gold sulfite;

[0024] Water-soluble palladium salt: dichlorotetraamminepalladium;

[0025] Graphene quantum dots: Imidazole-modified graphene quantum dots;

[0026] Complexing agent: ethylene dithioglycol;

[0027] Conductive salt: Ammonium sulfate;

[0028] Buffer: Glycine;

[0029] Stabilizer: thionodiacetic acid;

[0030] Solvent: Deionized water.

[0031] Example 1

[0032] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 30g of water-soluble gold salt, 10g of water-soluble palladium salt, 1g of imidazole-modified graphene quantum dots, 2000g of ethylenediamine, 5000g of complexing agent, 1500g of conductive salt, 1500g of buffer, 2500g of stabilizer, and the remainder is diluted to 100L with solvent.

[0033] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0034] The steps for electroplating copper wires using the above plating solution are as follows:

[0035] Step 1: Clean the outer surface of the copper wire to be plated;

[0036] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 0.5ASD, Baumé degree 15, line speed 3m / min, and electroplating time 120sec.

[0037] Example 2

[0038] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 400g of water-soluble gold salt, 200g of water-soluble palladium salt, 2g of imidazole-modified graphene quantum dots, 2200g of ethylenediamine, 6000g of complexing agent, 1700g of conductive salt, 1700g of buffer, 2700g of stabilizer, and the balance is made up to 100L with solvent.

[0039] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0040] The steps for electroplating copper wires using the above plating solution are as follows:

[0041] Step 1: Clean the outer surface of the copper wire to be plated;

[0042] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0043] Example 3

[0044] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 800g of water-soluble gold salt, 400g of water-soluble palladium salt, 4g of imidazole-modified graphene quantum dots, 2400g of ethylenediamine, 7000g of complexing agent, 1900g of conductive salt, 1900g of buffer, 2900g of stabilizer, with the remainder diluted to 100L with solvent.

[0045] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0046] The steps for electroplating copper wires using the above plating solution are as follows:

[0047] Step 1: Clean the outer surface of the copper wire to be plated;

[0048] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0049] Example 4

[0050] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 1200g of water-soluble gold salt, 600g of water-soluble palladium salt, 6g of imidazole-modified graphene quantum dots, 2600g of ethylenediamine, 8000g of complexing agent, 2100g of conductive salt, 2100g of buffer, 3100g of stabilizer, and the balance is made up to 100L with solvent.

[0051] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0052] The steps for electroplating copper wires using the above plating solution are as follows:

[0053] Step 1: Clean the outer surface of the copper wire to be plated;

[0054] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0055] Example 5

[0056] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 1600g of water-soluble gold salt, 800g of water-soluble palladium salt, 8g of imidazole-modified graphene quantum dots, 2800g of ethylenediamine, 9000g of complexing agent, 2300g of conductive salt, 2300g of buffer, 3300g of stabilizer, and the balance is made up to 100L with solvent.

[0057] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0058] The steps for electroplating copper wires using the above plating solution are as follows:

[0059] Step 1: Clean the outer surface of the copper wire to be plated;

[0060] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0061] Example 6

[0062] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 2000g of water-soluble gold salt, 1200g of water-soluble palladium salt, 10g of imidazole-modified graphene quantum dots, 3000g of ethylenediamine, 11000g of complexing agent, 2500g of conductive salt, 2500g of buffer, 3500g of stabilizer, and the balance is made up to 100L with solvent.

[0063] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0064] The steps for electroplating copper wires using the above plating solution are as follows:

[0065] Step 1: Clean the outer surface of the copper wire to be plated;

[0066] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0067] Comparative Example 1

[0068] Commercially available gold-palladium electroplating solution.

[0069] The steps for electroplating copper wires using the above plating solution are as follows:

[0070] Step 1: Clean the outer surface of the copper wire to be plated;

[0071] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 5ASD, Baumé degree 20, line speed 30m / min, and electroplating time 12sec.

[0072] Comparative Example 2

[0073] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 30g of water-soluble gold salt, 10g of water-soluble palladium salt, 2000g of ethylenediamine, 5000g of complexing agent, 1500g of conductive salt, 1500g of buffer, 2500g of stabilizer, and the remainder is diluted to 100L with solvent.

[0074] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0075] The steps for electroplating copper wires using the above plating solution are as follows:

[0076] Step 1: Clean the outer surface of the copper wire to be plated;

[0077] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 0.5ASD, Baumé degree 15, line speed 3m / min, and electroplating time 120sec.

[0078] Comparative Example 3

[0079] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 30g of water-soluble gold salt, 10g of water-soluble palladium salt, 1g of imidazole-modified graphene quantum dots, 5000g of complexing agent, 1500g of conductive salt, 1500g of buffer, 2500g of stabilizer, and the remainder is diluted to 100L with solvent.

[0080] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside.

[0081] The steps for electroplating copper wires using the above plating solution are as follows:

[0082] Step 1: Clean the outer surface of the copper wire to be plated;

[0083] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 0.5ASD, Baumé degree 15, line speed 3m / min, and electroplating time 120sec.

[0084] Comparative Example 4

[0085] A gold-palladium plating solution for copper wire electroplating comprises the following raw materials: 30g of water-soluble gold salt, 10g of water-soluble palladium salt, 5000g of complexing agent, 1500g of conductive salt, 1500g of buffer, 2500g of stabilizer, and the remainder is diluted to 100L with solvent.

[0086] The preparation method includes: mixing water-soluble gold salt and water-soluble palladium salt according to the above-mentioned raw material composition ratio, then adding imidazole-modified graphene quantum dots, ethylenediamine, complexing agent, conductive salt, buffer, and stabilizer, and finally adjusting the volume to 100L with solvent, mixing well, and setting aside for later use.

[0087] The steps for electroplating copper wires using the above plating solution are as follows:

[0088] Step 1: Clean the outer surface of the copper wire to be plated;

[0089] Step 2: Place the copper wire to be plated into an electroplating tank containing a gold-palladium plating solution. Electroplating is performed using the electrode plate as the anode and the copper wire as the cathode. After electroplating, rinse with hot water and dry to obtain a copper wire plated with a gold-palladium coating. The electroplating parameters are as follows: pH 8.0, temperature 50℃, current density 0.5ASD, Baumé degree 15, line speed 3m / min, and electroplating time 120sec.

[0090] The gold-plated palladium-copper wires of Examples 1-6 and Comparative Examples 1-4 were subjected to the following tests:

[0091] Appearance test: Place the sample under a microscope and observe whether there are peeling defects on the sample surface; no peeling defects indicate that the sample is qualified, otherwise it is unqualified.

[0092] Thermal shock test: 15 cycles of thermal shock from -40℃ to 85℃. After the test, observe the sample surface under a microscope to see if it cracks, partially or completely peels off, or blisters, and judge it according to the following standards: No defects at all are qualified, and any one or more of the above defects are unqualified.

[0093] Under a microscope, observe the sample surface for any of the following defects: pinholes, cracks, partial or complete peeling, discoloration, and judge according to the following criteria: no defects at all are acceptable, and any one or more of the above defects are unacceptable.

[0094] Corrosion test: Immerse the sample in a mixed aqueous solution of iodine and potassium iodide (iodine concentration of 60 g / L, potassium iodide concentration of 220 g / L) for 3 min, then clean it with ultrasonication in pure water for 15 min and dry it in a 50℃ oven. After the operation, observe the sample under a microscope and estimate the proportion of the corroded area to the total area under the microscope. Judge according to the following standards: less than 10% of the corroded area is excellent, 10-30% is qualified, and more than 30% is unqualified.

[0095] Coating ductility test: The plated copper wire is drawn using a 5% reduction rate until the deformation rate reaches 90%. The surface coating is then inspected. The coating should be free of peeling, flaking, and cracking. The following criteria should be used for evaluation: No defects at all are considered qualified; any one or more of the above defects are considered unqualified.

[0096] Note: For thermal shock testing, corrosion testing, and coating ductility testing, it is necessary to first observe whether there are defects on the surface of the plated part and mark the location of the defects. During the test, the defects appearing at the marked locations are not observed.

[0097] The test results are shown in Table 1:

[0098] Table 1

[0099]

[0100] According to the data in Table 1, Examples 1-6 of the present invention passed the thermal shock test and corrosion test, proving that the copper wire electroplated using the gold-palladium plating solution of the present invention has the advantages of good adhesion and corrosion resistance. Moreover, after external observation, there are no peeling defects on the surface. In contrast, the plated parts of Comparative Examples 1-4 all showed peeling defects to varying degrees. Among them, Comparative Example 2, compared with Examples 1-6, does not contain graphene quantum dots in its plating solution composition; Comparative Example 3, compared with Examples 1-6, does not contain ethylenediamine in its plating solution composition; Comparative Example 4, compared with Examples 1-6, does not contain graphene quantum dots and ethylenediamine in its plating solution composition. Therefore, it can be inferred that the plating solutions of the present invention contain both graphene quantum dots and ethylenediamine, which is why the plating layers of the present invention do not show peeling defects.

[0101] The above description is merely an exemplary 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 within the protection scope of the present invention.

Claims

1. A gold-palladium plating solution for copper wire electroplating, characterized in that, Its raw material composition includes: water-soluble gold salt 0.3-20 g / L, water-soluble palladium salt 0.1-12 g / L, graphene quantum dots 10-20 mg / L, ethylenediamine 20-30 g / L, complexing agent 50-110 g / L, conductive salt 15-25 g / L, buffer 15-25 g / L, stabilizer 25-35 g / L, with the balance being solvent; The graphene quantum dots are modified with imidazole; The water-soluble gold salt is potassium gold sulfite; The water-soluble palladium salt is dichlorotetraamminepalladium.

2. The gold-palladium plating solution for copper wire electroplating according to claim 1, characterized in that, The complexing agent is any one of guanidinoacetic acid, dimethylthiourea, dithioethylene glycol, mercaptochitosan, or triethanolamine.

3. The gold-palladium plating solution for copper wire electroplating according to claim 1, characterized in that, The conductive salt is any one of potassium sulfate, sodium sulfate, and ammonium sulfate.

4. The gold-palladium plating solution for copper wire electroplating according to claim 1, characterized in that, The buffer is at least one of boric acid or its salt, acetic acid or its salt, or aminoacetic acid or its salt.

5. The gold-palladium plating solution for copper wire electroplating according to claim 1, characterized in that, The stabilizer is any one of tridecyl phosphite, trioctyl phosphite, thionyl diacetic acid, or dithioglycolic acid.

6. The gold-palladium plating solution for copper wire electroplating according to claim 1, characterized in that, The solvent is deionized water.

7. An electroplating process using the gold-palladium plating solution as described in any one of claims 1-6, characterized in that, The copper wire to be plated is placed in an electroplating tank containing the gold-palladium plating solution. Electroplating is performed with the electrode plate as the anode and the copper wire as the cathode. After electroplating, the copper wire is washed with hot water and dried. The electroplating parameters are as follows: pH 7-9, temperature 18-70℃, current density 1-15ASD, Baumé degree 5-30, and electroplating time 0.5-300s.

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