Electroplating method of semiconductor original device support, electroplating liquid medicine and support

Abstract

The invention discloses an electroplating method of a semiconductor original device support, electroplating liquid medicine and the support, and belongs to the technical field of semiconductor packaging and surface treatment. The method comprises the steps of base material pretreatment, nickel plating bottoming, nickel layer activation, silver pre-plating, local silver plating and the like, a nickel barrier layer is constructed on a copper base material, high-cyanide silver pre-plating and low-free-cyanide high-speed local silver plating are implemented after activation, and selective deposition of a silver layer in a functional area is achieved. A three-dimensional structure stabilizer is adopted to improve the aging resistance of the liquid medicine, and flame crystallization and annealing treatment are combined to strengthen interface bonding. According to the scheme, the replacement reaction between copper and silver is effectively inhibited, the silver dosage is remarkably reduced by 60% or above, the coating binding force, the reflective rate and the thermal stability are improved, the service life of the bath solution is prolonged, and the method is suitable for efficient and reliable manufacturing of high-power supports.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging and surface treatment technology, and in particular to an electroplating method, electroplating solution, and substrate for semiconductor components. Background Technology

[0002] As the carrier structure of LED chips, the mounting bracket undertakes multiple functions, including electrical connection, heat conduction, and optical reflection. The quality of its surface metal plating directly affects the luminous efficacy, heat dissipation performance, soldering reliability, and lifespan of the LED device. With the development of high-power, high-brightness LEDs, higher requirements are placed on the mounting bracket plating in terms of reflectivity, thermal conductivity, adhesion, and long-term stability. Traditional processes generally adopt the flow of "alkaline copper plating → acidic copper plating → pre-plating silver → full immersion silver plating," directly depositing a thick silver layer on a copper substrate to meet performance requirements. This process achieves silver layer deposition through full surface coverage and is suitable for early general-purpose LED products. However, this traditional process has significant drawbacks: the large potential difference between copper and silver makes them prone to displacement reactions, resulting in poor adhesion of the silver layer; to prevent copper diffusion at high temperatures from causing discoloration of the silver layer, a silver layer thicker than 80μm is required, leading to a serious waste of precious metals; simultaneously, the linear polymer additives in the silver plating solution are prone to breakage and aging, resulting in instability of the plating bath, frequent maintenance, a narrow process window, and difficulty in guaranteeing yield. These problems restrict the large-scale production of high-performance, low-cost LED products. Summary of the Invention

[0003] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electroplating method, electroplating solution, and substrate for semiconductor device substrates, which can solve the comprehensive technical problems of poor adhesion, easy discoloration of silver layer, high consumption of precious metals, and unstable solution in traditional copper-to-silver processes.

[0004] An electroplating method for a semiconductor device substrate according to a first aspect embodiment of the present invention includes the following sequential steps: S1. Substrate pretreatment: Electrolytic degreasing and activation treatment of the support substrate; S2. Nickel plating undercoat: The pretreated substrate is immersed in the first plating solution to electrodeposit a nickel layer. The concentrations of each component in the first plating solution are as follows: nickel sulfamate 70-110 g / L, nickel chloride 10-30 g / L, boric acid 30-50 g / L, pH 3.8-4.4, temperature 55-65℃, current density 5-20 A / dm², and electrodeposition time 15-30 seconds, forming a nickel layer with a thickness of 0.4-0.6 μm. S3. Nickel layer activation: The nickel-plated substrate is immersed in an activation solution containing potassium cyanide and sodium carbonate, both at a concentration of 3-20 g / L, and activation is performed at a current density of 0.3-1 A / dm². S4. Pre-plating silver: The activated substrate is immersed in the second plating solution to electrodeposit a pre-plated silver layer. The second plating solution contains 120-160 g / L potassium cyanide and 2.2-4 g / L silver cyanide, the temperature is 20-30℃, the current density is 1.5-2.5 A / dm², the electrodeposition time is 4-8 seconds, and a pre-plated silver layer with a thickness of 0.05-0.2 μm is formed. S5. Local silver plating: The non-functional areas of the substrate are masked using a mask, and the substrate is immersed in a third plating solution. Selective electrodeposition is performed on the exposed functional areas to form a functional silver layer with a thickness of 0.5-2 μm. The third plating solution contains 50-80 g / L of silver ions, 2-10 g / L of potassium cyanide, 1-5 ml / L of brightener and 4-6 ml / L of additives, with a pH of 9.0-9.5, a temperature of 50-70℃, a current density of 50-200 A / dm², and an electrodeposition time of 2-5 seconds. According to some embodiments of the present invention, in step S1, the electrolytic degreasing is carried out in an electrolyte containing 90-110 g / L of degreasing powder, the electrolysis temperature is 50-70°C, the current density is 5-20 A / dm², and the electrolysis time is 10-20 seconds; the activation treatment is to immerse the substrate in an acid salt solution containing 75-95 g / L of starter salt at room temperature for 5-10 seconds. According to some embodiments of the present invention, after step S5, step S6 is further included: desilvering of non-functional areas, in which the substrate with partially silvered substrate is used as the anode and immersed in a fourth plating solution containing 80-100 g / L of desilvering powder, and electrolyzed for 10-20 seconds at a current density of 2-6 A / dm² to remove the pre-plated silver layer in the non-functional areas. According to some embodiments of the present invention, after the silver plating step is completed, a step S7 is further included: post-processing, the post-processing including at least one of the following sub-steps: S7a, Silver protection treatment: Immerse the substrate in a silver protection agent aqueous solution with a concentration of 50-100 ml / L for 5-10 seconds; S7b, Coating crystallization treatment: Use a flame to uniformly sweep the surface of the silver layer in the functional area, so that the surface layer is slightly melted and then naturally cooled; S7c, Overall Annealing: Heat the entire substrate to 200-300℃ and hold for 3-5 minutes, then cool. According to some embodiments of the present invention, during the electrodeposition process in steps S2, S4 and / or S5, ultrasonic assistance is applied to the plating solution at an ultrasonic frequency of 20-40 kHz. According to a second aspect of the present invention, an electroplating solution for a bracket of an LED, integrated circuit, or optocoupler is at least one of the first plating solution, the second plating solution, or the third plating solution, wherein at least one plating solution contains a stabilizer and a surfactant. The stabilizer is a water-soluble polymer with a three-dimensional network structure or a star-shaped or dendritic structure; The surfactant comprises hydrophilic and hydrophobic groups, wherein the hydrophilic groups include nonpolar hydrocarbon long chains, and the hydrophobic groups include at least one of organic amine salts, quaternary ammonium salts, and polyoxyethylene long chains. According to some embodiments of the present invention, the third plating solution comprises the following components in parts by weight: 40-50 parts copper sulfate, 40-50 parts sodium sulfate, 100-120 parts potassium sodium tartrate, 40-60 parts sodium hydroxide solution, 1-8 parts stabilizer, 1-5 parts bisbenzenesulfonamide, 1-5 parts sodium cyanide, 1-5 parts surfactant, and 80-100 parts deionized water. According to a third aspect of the present invention, a support includes a substrate and a nickel layer, a pre-plated silver layer, and a thick silver layer sequentially formed on the surface of the substrate and located on a functional area; the thickness of the nickel layer is 0.4-0.6 μm, the thickness of the pre-plated silver layer is 0.05-0.2 μm, and the thickness of the thick silver layer on the functional area is 0.5-2 μm.

[0005] According to an embodiment of the present invention, an electroplating method, electroplating solution, and a substrate for semiconductor components have at least the following beneficial effects: by first electrodepositing a dense nickel layer on a copper substrate as a barrier layer and a bonding optimization layer, the displacement reaction between copper and silver is avoided, the bonding force is improved, and high-temperature discoloration is suppressed; the use of a high-cyanide, low-silver system for pre-plating silver effectively controls the silver ion reduction potential and achieves uniform transition layer deposition; local high-current-density silver plating is achieved through a mask, significantly reducing the amount of silver used; and with the use of a special anti-aging solution and post-treatment process, the plating quality and process stability are significantly improved, thereby solving the technical problems of precious metal waste, poor bonding force, and rapid plating aging in traditional processes, and achieving a balance between high performance and low cost.

[0006] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Detailed Implementation

[0007] 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. 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.

[0008] Example 1: As a key structural component of high-power semiconductor light-emitting devices, the mounting bracket undertakes multiple functions, including chip fixation, light reflection and guidance, heat conduction, and electrical connection. With the development of LEDs towards higher brightness and higher reliability, higher requirements are placed on the performance of the mounting bracket surface plating: it not only needs excellent reflectivity and electrical and thermal conductivity, but also needs to remain stable under high-temperature reflow soldering and long-term service conditions to avoid device failure due to silver layer discoloration, blistering, or peeling. However, the current technology, which commonly uses a direct full-immersion silver plating process on a copper substrate, has many drawbacks. For example, due to the significant difference in standard electrode potentials between copper and silver (Cu²⁺ / Cu: +0.34V, Ag⁺ / Ag: +0.80V), a displacement reaction (2Ag⁺ + Cu → 2Ag + Cu²⁺) is easily generated without an effective barrier layer, resulting in a loose and porous initial deposition layer with poor adhesion. To prevent the silver layer from yellowing or even blackening due to high-temperature oxidation diffusion, a silver layer with a thickness exceeding 80μm is often required, leading to a huge consumption of precious metals. In addition, the residual silver layer in non-functional areas after full-area silver plating is difficult to remove, wasting materials and potentially causing short circuit risks. Therefore, there is an urgent need for a new electroplating method that can significantly reduce silver consumption while ensuring high-quality plating, and improve adhesion strength and process controllability.

[0009] Based on this, this application provides an electroplating method for semiconductor device substrates, comprising the following sequential steps: S1. Substrate pretreatment: Electrolytic degreasing and activation treatment of the support substrate; The substrate is typically made of copper alloy (such as C194, C7025, etc.), which is widely used in lead frame manufacturing due to its good conductivity and machinability. The electrolytic degreasing process aims to thoroughly remove grease, polishing paste, and other organic contaminants adhering to the substrate surface to ensure good adhesion of subsequent plating layers. Specifically, the substrate, acting as either the cathode or anode, is immersed in an alkaline electrolyte containing 90-110 g / L of degreasing powder and electrolyzed for 10-20 seconds at a temperature of 50-70℃ and a current density of 5-20 A / dm². During this process, microbubbles generated by hydrogen evolution at the cathode or oxygen evolution at the anode mechanically remove contaminants, while the surfactants in the degreasing powder emulsify and saponify, synergistically achieving efficient decontamination. Optionally, using a periodic commutation current mode can further improve cleaning uniformity and reduce edge over-corrosion. Activation treatment is used to remove naturally formed oxide films (such as Cu2O) on the substrate surface, exposing a clean metal lattice. The etching process can be completed by immersing the substrate in an acidic solution containing 75-95 g / L of bath salt (the main components of which are a composite system of dilute sulfuric acid and corrosion inhibitors) for 5-10 seconds at room temperature. This step should be timed precisely to avoid over-etching, which could cause surface roughness or pitting.

[0010] S2. Nickel plating undercoat: The pretreated substrate is immersed in the first plating solution to electrodeposit a nickel layer. The concentrations of each component in the first plating solution are as follows: nickel sulfamate 70-110 g / L, nickel chloride 10-30 g / L, boric acid 30-50 g / L, pH 3.8-4.4, temperature 55-65℃, current density 5-20 A / dm², and electrodeposition time 15-30 seconds, forming a nickel layer with a thickness of 0.4-0.6 μm. Nickel sulfamate (Ni(SO3NH2)2) serves as the main salt, providing the Ni²⁺ ion source. Compared to the traditional nickel sulfate system, it allows for higher current densities without easily causing scorching, thus promoting rapid film formation. Nickel chloride (NiCl2) acts as a conductive salt and promotes anodic dissolution, maintaining the metal ion balance in the plating bath. Boric acid (H3BO3) acts as a buffer, stabilizing the pH of the plating bath within the weakly acidic range (3.8-4.4) to prevent localized pH increases that could lead to nickel hydroxide co-deposition. Maintaining the plating bath temperature within the range of 55-65℃ helps improve ion migration rate and crystal density. A current density of 5-20 A / dm², combined with short pulse energizing of 15-30 seconds, can form a dense, fine-grained, low-stress nickel transition layer on the copper substrate, with a thickness strictly controlled between 0.4-0.6 μm. This nickel layer not only fills the microscopic depressions in the copper substrate but also acts as an effective diffusion barrier, inhibiting the migration of Cu atoms to the silver layer and thus preventing discoloration of the silver layer during high-temperature aging. An alternative solution is to use the Watts nickel system (nickel sulfate + nickel chloride + boric acid), but this requires stricter filtration and additive management to ensure coating quality.

[0011] S3. Nickel layer activation: The nickel-plated substrate is immersed in an activation solution containing potassium cyanide and sodium carbonate, both at a concentration of 3-20 g / L, and the activation treatment is carried out at a current density of 0.3-1 A / dm². Despite the deposition of a nickel layer, a thin layer of nickel oxide (NiO) rapidly forms in the air, affecting the adhesion of the subsequent silver layer. To address this, a weakly alkaline activation solution containing 3-20 g / L potassium cyanide (KCN) and 3-20 g / L sodium carbonate (Na2CO3) is used for pretreatment. Cyanide ions (CN⁻) can form a stable tetracyanonitrile(II) complex [Ni(CN)4]²⁻ with Ni²⁺, thereby dissolving the surface oxide film (NiO + 4CN⁻ + H2O → [Ni(CN)4]²⁻ + 2OH⁻). Simultaneously, a cathode current of 0.3-1 A / dm² is applied to promote hydrogen evolution at the cathode. The physical agitation of hydrogen bubbles enhances the cleaning effect and reduces residual high-valence nickel species. Sodium carbonate is used to adjust the solution pH to an alkaline environment (approximately pH 9-10), enhancing cyanide stability and preventing acidic side reactions. The entire activation process takes only a few seconds and can be directly transferred to the next process without additional rinsing, thus reducing the risk of secondary contamination. As a cyanide-free alternative, a complexing activation solution containing citrate or tartrate can be used, supplemented by ultrasonic-assisted mass transfer enhancement.

[0012] S4. Pre-plating silver: The activated substrate is immersed in the second plating solution to electrodeposit a pre-plated silver layer. The second plating solution contains 120-160 g / L potassium cyanide and 2.2-4 g / L silver cyanide. The temperature is 20-30℃, the current density is 1.5-2.5 A / dm², and the electrodeposition time is 4-8 seconds to form a pre-plated silver layer with a thickness of 0.05-0.2 μm. Pre-plating with silver is the core step in achieving high-quality silver deposition on nickel. A strong complexing system composed of high-concentration potassium cyanide (120-160 g / L) and low-concentration silver cyanide (AgCN 2.2-4 g / L) is used, ensuring that silver exists primarily in the form of [Ag(CN)2]⁻, significantly reducing the concentration of free Ag⁺. This shifts the silver deposition potential negatively to a range lower than that of nickel, thermodynamically preventing displacement reactions (i.e., avoiding spontaneous reduction and deposition of Ag⁺ on Ni). Based on this, a moderate current density of 1.5-2.5 A / dm² is applied, and through the cathodic reduction reaction [Ag(CN)2]⁻ + e⁻ → Ag + 2CN⁻, uniform nucleation and continuous coverage of silver on the nickel layer are achieved. Maintaining a temperature of 20-30℃ helps stabilize the complexation equilibrium and prevents cyanide decomposition. By controlling the electrodeposition time within 4-8 seconds, a dense, thin silver layer of 0.05-0.2 μm thickness can be obtained, serving as the basis for subsequent thick silver deposition. This pre-plating layer possesses both electrochemical inertness and good conductivity, providing an ideal starting interface for the next step of high-current-density silver plating. Under environmentally conscious principles, cyanide-free pre-plating silver processes using sulfite or thiosulfate systems can also be explored, but specialized stabilizers and complexing agents are required to ensure the integrity of the plating layer.

[0013] S5. Localized silver plating: The non-functional areas of the substrate are masked using a mask, and the substrate is immersed in the third plating solution. Selective electrodeposition is performed on the exposed functional areas to form a functional silver layer with a thickness of 0.5-2μm. The third plating solution contains 50-80g / L of silver ions, 2-10g / L of potassium cyanide, 1-5ml / L of brightener and 4-6ml / L of additives. The pH value is 9.0-9.5, the temperature is 50-70℃, the current density is 50-200A / dm², and the electrodeposition time is 2-5 seconds. The "functional area" refers to the region within the support structure that requires high reflectivity and good weldability, such as the inner wall of the reflector cup and solder pads. The "non-functional area" includes parts that do not require silver plating, such as pin connections and frame support structures. Non-functional areas are completely shielded using physical masks (such as acid- and alkali-resistant engineering plastic masks, ceramic molds, or flexible film patches), exposing only the target area for electroplating. The third plating solution used is a low-free-cyanide high-speed silver plating solution: the total silver ion concentration reaches 50-80 g / L, while the free potassium cyanide is only 2-10 g / L, significantly increasing the effective concentration of Ag⁺, enabling rapid deposition at ultra-high current densities of 50-200 A / dm² without scorching or dendritic crystal formation. Brighteners (such as selenium compounds, tellurium compounds, or organosulfur derivatives) are used to refine the grains and improve the gloss of the plating layer; composite additives (such as polyethylene glycol and polyethyleneimine) improve the dispersion ability of the plating solution and prevent current concentration at the edges of the fixture. The plating bath pH is maintained in a slightly alkaline range of 9.0-9.5, and the temperature is raised to 50-70℃ to enhance ionic activity. Under this combination of high-intensity parameters, a 0.5-2μm thick silver layer can be constructed in just 2-5 seconds, greatly improving production efficiency. The mask material is reusable and easy to automate loading and unloading, making it suitable for mass production lines. As an alternative implementation, non-contact local deposition techniques such as spraying, brushing, or laser-induced selective electroplating can also be used to achieve higher precision patterning control.

[0014] The aforementioned technical features are closely integrated in terms of spatial layout and process sequence: substrate pretreatment lays the foundation for all subsequent steps; nickel plating as the underlayer changes the unfavorable interface of traditional direct copper-silver contact, constructing a copper-nickel-silver gradient structure; nickel layer activation ensures that the nickel surface is in a highly active state; the pre-plated silver layer establishes a continuous conductive bridge under thermodynamically controlled conditions; and finally, precise spatial distribution of precious metals is achieved through localized silver plating. The parameters of each step are matched to each other, jointly serving the overall goal of "high performance, low cost, and high efficiency".

[0015] Through the above-described steps, this application achieves a technological leap from traditional full-immersion plating to selective composite electroplating. The introduction of a dense nickel barrier layer effectively prevents copper atoms from diffusing into the silver layer, solving the technical challenge of silver discoloration under high-temperature conditions. The high-cyanide complexation pre-plating silver process bypasses the substitution reaction pathway between nickel and silver, ensuring the metallurgical bond between the silver layer and the nickel base. Utilizing mask shielding and low-cyanide high-speed silver plating technology, the required silver thickness is rapidly deposited only in functional areas, reducing silver usage by more than 60% compared to traditional processes. The overall process is compact, with short dwell times at each step, making it suitable for integration into continuous production lines, improving product consistency and yield. This method is particularly suitable for surface treatment of high-power LED and Mini / Micro LED packaging brackets, offering significant economic and technological advantages.

[0016] Example 2: Based on the above embodiments, this embodiment further provides: Electrolytic degreasing is carried out in an electrolyte containing 90-110 g / L of degreasing powder, at an electrolysis temperature of 50-70℃, a current density of 5-20 A / dm², and an electrolysis time of 10-20 seconds; the activation treatment involves immersing the substrate in an acid salt solution containing 75-95 g / L of starter salt at room temperature for 5-10 seconds.

[0017] Step 1: Electrolytic degreasing is carried out in an electrolyte containing 90-110 g / L of degreasing powder. The electrolysis temperature is 50-70℃, the current density is 5-20 A / dm², and the electrolysis time is 10-20 seconds. The degreasing powder is a mixture of alkaline composite surfactants and detergent builders, with its main components being sodium metasilicate, sodium carbonate, trisodium phosphate, and nonionic emulsifiers (such as fatty alcohol polyoxyethylene ether). The electrolyte is strongly alkaline (pH 10-12), effectively saponifying grease and reducing the interfacial tension between oil and the metal surface. Under energized conditions, an electrolytic reaction of water occurs at the cathode or anode (depending on the process settings, either anodic or cathodic degreasing), generating hydrogen or oxygen microbubbles. These microbubbles mechanically agitate and peel away the oil film and particulate contaminants adhering to the substrate surface. Controlling the electrolysis temperature within the range of 50-70℃ significantly improves ion migration rate and chemical reaction kinetics efficiency, enhancing decontamination capabilities while preventing excessive moisture evaporation or localized overheating damage to the substrate due to excessively high temperatures. The current density is controlled between 5-20 A / dm² to ensure sufficient gas generation for efficient physical cleaning without triggering severe gas evolution that could cause roughness or pitting on the coating precursor surface. The electrolysis time is limited to 10-20 seconds, which is the result of optimizing the process cycle while ensuring cleaning effect. Too short a time will result in incomplete degreasing, while too long a time may cause slight corrosion of the copper substrate or increase energy consumption. In an optional embodiment, the concentration of degreasing powder can be adjusted to 95±5 g / L, the electrolysis temperature can be set to 60±5℃, the current density can be 10-15 A / dm², and the time can be 15 seconds, which is suitable for online cleaning processes in large-scale continuous production.

[0018] Step 2: Activation treatment involves immersing the substrate in an acid salt solution containing 75-95 g / L of starter salt for 5-10 seconds at room temperature. The "opening salt" is an acidic composite salt used for metal surface activation, typically containing copper sulfate, copper chloride, fluoroboric acid, etc. It can be a dilute acid system containing 75-95 g / L copper chloride (CuCl2) or copper sulfate (CuSO4) (with a small amount of hydrochloric acid or sulfuric acid added to adjust the pH to 2.0-4.0). The solution selectively dissolves naturally formed cuprous oxide (Cu2O) or other passivation films on the surface of the copper alloy substrate, exposing fresh metal lattices with high surface energy, thereby improving the adhesion of the subsequent nickel layer. Performing this treatment at room temperature helps control the reaction rate and prevents excessive acid etching that could damage the microstructure. Immersion time should be controlled within 5-10 seconds to complete surface activation quickly without causing substrate dissolution. Too low a concentration (<75 g / L) will result in insufficient activation capacity, and residual oxides will affect adhesion; too high a concentration (>95 g / L) may cause rapid copper ion deposition or displacement reactions, forming a loose and porous displacement copper layer, which will actually reduce the coating quality. In an optional embodiment, an activation solution consisting of 80 g / L CuCl2 and 10 mL / L hydrochloric acid can be used to treat the surface at 25°C for 8 seconds to obtain a stable and uniform activated surface.

[0019] Through the above-described steps, this application achieves refined control over the pretreatment process of the substrate. By employing a specific concentration range of degreasing powder combined with precisely matched electrolytic parameters, organic contaminants can be efficiently removed without excessively corroding the substrate, ensuring surface cleanliness meets electroplating requirements. Simultaneously, by limiting the initial salt concentration and short immersion conditions, selective removal of the oxide layer on the metal surface is achieved, avoiding the substrate corrosion risk associated with traditional strong acid activation. These process parameters have been verified through systematic experiments and are within the optimal process window, not only improving the initial bonding strength of the plating layer but also enhancing batch-to-batch consistency and process stability, making it particularly suitable for high-precision, high-reliability, high-power LED packaging applications.

[0020] Example 3: Based on the above embodiments, this embodiment further provides: For desilvering of non-functional areas, the substrate with partial silver plating is used as the anode and immersed in a fourth plating solution containing 80-100 g / L of desilvering powder. Electrolysis is performed for 10-20 seconds at a current density of 2-6 A / dm² to remove the pre-plated silver layer in the non-functional areas.

[0021] This step is a crucial process for selectively removing the silver layer from non-functional areas of the substrate that has already undergone partial silver plating. Its purpose is to address the problem in existing technologies where, even with mask-based selective silver plating of functional areas, a thin silver layer (0.05–0.2 μm) remains in non-functional areas if full-area silver deposition is performed on the entire substrate surface during the initial "pre-silver plating" step. While this residual silver layer does not affect electrical performance, it leads to unnecessary consumption of precious silver, increases material costs, and may pose an unnecessary risk of short circuits during subsequent processing or use. Therefore, by introducing anodic electrolysis to selectively remove the pre-plated silver layer from non-functional areas, extreme silver resource conservation and precise allocation of structural functions can be achieved.

[0022] Step S6: Silver removal from non-functional areas The substrate with partial silver plating is used as the anode and immersed in a fourth plating solution containing 80-100 g / L of silver removal powder. Electrolysis is performed for 10-20 seconds at a current density of 2-6 A / dm² to remove the pre-plated silver layer in the non-functional areas.

[0023] in, "Using the partially silver-plated substrate as the anode" means that during the entire electrochemical silver removal process, the scaffold is connected to the positive electrode of the power supply, causing the surface metal to undergo an oxidation reaction. This is because silver has a low standard electrode potential (Ag → Ag⁺ + e⁻, E...). 0 (≈ +0.8 V), under appropriate applied voltage conditions, the silver layer is selectively oxidized and dissolved preferentially over the copper or nickel substrate, thus avoiding damage to the underlying nickel layer or exposed copper substrate. This design utilizes the differences in electrochemical activity between different metals to ensure good selectivity and controllability in the silver removal process.

[0024] The silver-removing powder mentioned in the "immersion in the fourth plating solution containing 80-100 g / L of silver-removing powder" is a composite chemical agent specifically used for silver anode dissolution. Its main components are a mixture of nitrate-based oxidation promoters and complexed cyanides (such as sodium cyanide and potassium cyanide). Nitrates provide the initial oxidation driving force, accelerating the loss of electrons from silver atoms; while free cyanide ions (CN⁻) rapidly form a stable [Ag(CN)₂]⁻ complex with the generated Ag⁺, reducing the concentration of free silver ions in the solution and driving the reaction to continue to the right (Ag + 2CN⁻ → [Ag(CN)₂]⁻ + e⁻). The fourth plating solution is a weakly alkaline system with a pH controlled between 9.0 and 10.5 to mitigate the risk of corrosion to the nickel underlayer. When the silver-removing powder concentration is below 80 g / L, the oxidation-complexing ability is insufficient, and the silver removal efficiency decreases; exceeding 100 g / L may lead to over-dissolution or fogging corrosion, affecting surface quality. In an alternative embodiment, the silvering powder can be replaced by a cyanide-free, environmentally friendly silvering solution containing sodium thiosulfate (Na2S2O3) and sodium sulfite (Na2SO3), which is suitable for production environments with strict restrictions on cyanide emissions.

[0025] The kinetic parameter window for electrolytic silver removal is defined as "electrolysis for 10-20 seconds at a current density of 2-6 A / dm²". Too low a current density (<2 A / dm²) leads to a slow reaction rate, prolonging the process cycle and reducing throughput; too high a current density (>6 A / dm²) easily causes intensified electrode polarization, resulting in localized over-dissolution or the formation of black silver oxide precipitates, affecting surface cleanliness. Controlling the electrolysis time within the range of 10-20 seconds ensures complete removal of the pre-plated silver layer in non-functional areas while preventing diffusion corrosion at the mask edges or slight loss of the silver layer edges in functional areas due to prolonged dwell time. In an optional embodiment, a pulsed current mode (e.g., 0.5 seconds of forward current followed by 0.2 seconds of de-current cycling) can be used instead of DC electrolysis to further improve silver removal uniformity and reduce energy consumption.

[0026] The synergistic effect among the various technical features is manifested in the following ways: the electrochemical oxidation mechanism driven by the "anodine as the connection method," combined with the chemical complexation ability of the "specific concentration of silver removal powder," enables rapid, selective, and non-destructive stripping of the ultra-thin pre-plated silver layer in non-functional areas under dynamic control of "limited current density and time." The entire process requires no change of fixtures or re-masking, is simple to operate, and is compatible with automated production lines.

[0027] Through the above-described steps, this application achieves the technical effect of efficiently removing residual silver layers in non-functional areas without affecting the integrity of the thick silver layer in functional areas. Because it employs an electrochemical anodic dissolution combined with complexation stabilization, it solves the problems of precious metal waste and potential electrical interference in the prior art. Therefore, it achieves comprehensive benefits including significantly reducing silver usage (saving more than 60% compared to traditional full-immersion plating processes), improving material utilization, enhancing product reliability, and increasing environmental friendliness. Simultaneously, the removed silver ions can be enriched and extracted through a recycling system, achieving resource recycling and aligning with the trend of green manufacturing development.

[0028] Example 4: Based on the above embodiments, this embodiment further provides: Post-processing, the post-processing comprising at least one of the following sub-steps: S7a, Silver protection treatment: Immerse the substrate in a silver protection agent aqueous solution with a concentration of 50-100 ml / L for 5-10 seconds; S7b, Coating crystallization treatment: Use a flame to uniformly sweep the surface of the silver layer in the functional area, so that the surface layer is slightly melted and then naturally cooled; S7c, Overall Annealing: Heat the entire substrate to 200-300℃ and hold for 3-5 minutes, then cool.

[0029] The S7a silver protection treatment involves immersing the partially silver-plated substrate in an aqueous solution of a silver protectant containing organic corrosion inhibitors, forming a dense chemically adsorbed film on the silver surface. This protectant is typically a benzotriazole (BTA) or its derivatives, which coordinate with silver atoms at room temperature to form a complex film insoluble in water and air, effectively blocking the corrosion of the silver layer by sulfides (such as H2S), chloride ions, and oxygen in the environment. Maintaining the protectant concentration within the range of 50-100 ml / L and the treatment time between 5-10 seconds achieves high-efficiency protection without significantly increasing the process cycle. Too low a concentration may result in incomplete film formation, while too high a concentration may cause residue problems affecting subsequent welding performance. As an alternative, nitrogen-containing heterocyclic compounds such as thiazoles and imidazoles can be used instead of benzotriazole, achieving similar anti-discoloration effects.

[0030] The S7b coating crystallization treatment involves instantaneously heating the surface of the silver layer in the functional area using an external heat source. This raises the surface metal to a state above its melting point but not completely melted. Surface tension drives the liquid metal to redistribute and rapidly cool and solidify, thereby optimizing the microstructure. The flame used is a low-temperature oxy-fuel flame or a plasma torch, with the temperature controlled between 800-1200℃ and the sweeping speed controlled between 10-50 mm / s, ensuring a short treatment time and concentrated heat within a few micrometers of the surface layer. This process transforms the columnar crystal structure formed by the original electrodeposition into fine equiaxed crystals, closing micropores and cracks, and significantly improving the coating density, reflectivity (up to 95% or more), and thermal and electrical conductivity. Furthermore, the micro-melting process releases some residual stress, reducing the risk of interface peeling due to thermal expansion mismatch during service. As an optional implementation, a laser beam can be used instead of a flame for local scanning, with the energy density adjusted to 10-30 J / cm² and the pulse width 1-10 ms, achieving similar controllable remelting and grain refinement.

[0031] The S7c overall annealing process involves placing the entire support in an inert or reducing protective atmosphere (such as a N2 / H2 mixture), heating it to 200-300℃ and holding it at that temperature for 3-5 minutes, followed by slow furnace cooling or air cooling to room temperature. This heat treatment activates the atomic diffusion ability at the interface between the nickel and silver layers, promoting the formation of Ni-Ag solid solution or intermetallic compounds, and constructing a diffusion bonding layer of a certain thickness. This upgrades the interface connection, which was originally mainly mechanically interlocked, to a metallurgical bonding state. This not only significantly enhances the adhesion of the coating and improves its resistance to high-temperature aging and thermal cycling shock, but also helps to eliminate residual stress inside the substrate and improve the overall structural stability. The annealing temperature is lower than the recrystallization temperature of the copper substrate to avoid softening or dimensional deformation of the substrate. As an optional implementation, induction heating or infrared radiation can also be used for rapid heating and cooling to shorten the processing cycle, making it suitable for continuous production lines.

[0032] The three post-processing methods mentioned above are complementary in function and can be flexibly selected for use individually or in combination depending on the actual product application scenario. For example, for high-power LED devices with high reliability requirements, the entire process of S7a→S7b→S7c can be executed sequentially to achieve comprehensive improvement from surface protection and structural densification to interface strengthening; while for cost-sensitive low-end products, only S7c annealing can be selected to balance performance and economy.

[0033] Through the above-described steps, this application achieves multi-dimensional enhancement of the silver plating layer on the support: Silver protection treatment forms a stable chemical adsorption film on the silver surface, effectively preventing sulfidation and blackening caused by environmental media and extending its lifespan; plating crystallization treatment utilizes flame sweeping to initiate surface micro-melting and self-quenching processes, eliminating microscopic defects and improving plating density, reflectivity, and thermal conductivity; overall annealing promotes atomic interdiffusion at the nickel-silver interface, forming a diffusion bonding layer, significantly enhancing interlayer bonding and thermal shock resistance. Multiple post-treatment methods can be combined and applied according to requirements to comprehensively improve the long-term stability and overall performance of the support under complex working conditions.

[0034] Example 5: Based on the above embodiments, this embodiment further provides: During the electrodeposition process in steps S2, S4 and / or S5, ultrasonic assistance is applied to the plating solution at a frequency of 20-40 kHz.

[0035] Among these, introducing ultrasonic-assisted treatment into the electrodeposition process is a key enhancement measure to address problems such as limited mass transfer at the cathode interface, bubble retention, and uneven additive distribution under high current densities. This technology achieves dynamic control of the electrochemical deposition process by integrating an ultrasonic generation system into the plating bath.

[0036] During the electrodeposition process in steps S2, S4, and / or S5, ultrasonic assistance is applied to the plating bath at a frequency of 20-40 kHz. The phrase "electrodeposition process in steps S2, S4, and / or S5" refers to the application of ultrasound covering one or more key electroplating steps in nickel undercoating (S2), pre-plating silver (S4), and partial silver plating (S5). These steps all involve the reduction deposition of metal ions on the substrate surface, and in practice, they often face the risk of plating defects caused by high current densities. For example, when using a high current density of 5-20 A / dm² to rapidly form a nickel layer in S2, the cathodic hydrogen evolution reaction is exacerbated; when using a current density as high as 50-200 A / dm² for instantaneous thick silver deposition in S5, problems such as scorching, burrs, or increased porosity are highly likely to occur. Therefore, simultaneously introducing an ultrasonic field into these steps can effectively improve process stability and coating quality consistency.

[0037] "Applying ultrasonic assistance to the plating solution" refers to installing piezoelectric ultrasonic transducers at the bottom or sidewalls of the electroplating tank. These transducers convert high-frequency electrical signals into mechanical vibrations, which are then transmitted to the plating solution, generating an ultrasonic field of controllable intensity. The ultrasonic energy propagates in the liquid as longitudinal waves, triggering a cavitation effect. This effect involves the formation and rapid collapse of microbubbles in localized low-pressure areas, releasing high-temperature, high-pressure shock waves and high-speed microjets. This physical action effectively strips hydrogen bubbles adhering to the cathode surface, preventing their aggregation and formation of shielding areas that lead to pinholes, pitting, and other defects. Simultaneously, it enhances solution convection, reduces the diffusion layer thickness, and increases the transport rate of metal ions to the electrode surface, thereby supporting uniform deposition at higher current densities.

[0038] The "ultrasonic frequency of 20-40kHz" is an optimized operating window. Below 20kHz, excessive cavitation intensity may lead to coarsening of the coating grains or even damage to the substrate; above 40kHz, the cavitation effect weakens, defoaming ability decreases, and energy consumption increases. Optionally, the frequency can be adjusted in different steps according to the properties of the plating bath and process requirements: for example, 30-40kHz is used in the S2 nickel plating stage to balance mass transfer enhancement and gentle stirring; 20-30kHz is used in the S5 high-speed silver plating stage to obtain stronger defoaming ability and faster ion replenishment rate. Furthermore, the ultrasonic power density can be controlled within the range of 0.3-1.0 W / cm³ to avoid excessive disturbance affecting mask sealing or causing coating roughness.

[0039] As an optional implementation, the ultrasonic device can be configured for intermittent operation, such as shutting off for 10 seconds after every 30 seconds of operation, to reduce heat accumulation and extend equipment life; it can also be integrated into the filtration loop in conjunction with a plating solution circulation system to achieve a synergistic purification effect of simultaneous filtration and ultrasonic degassing. Furthermore, the ultrasonic radiation direction can be designed to be vertically upward or obliquely incident to ensure that energy is concentrated on the workpiece suspension area, thereby improving energy utilization efficiency.

[0040] There is a functional progression among the various technical features: by defining the application stage (S2 / S4 / S5), the mode of action (applying ultrasonic assistance), and the core parameters (20-40kHz frequency), a general enhancement mechanism applicable to multiple types of electrodeposition processes is constructed. This mechanism not only solves local problems in specific processes but also achieves a systematic improvement in coating density, uniformity, and production efficiency throughout the entire process chain.

[0041] Through the above-described steps, this application achieves effective control over the cathode interface state in key electrodeposition stages such as nickel undercoating, pre-silver plating, and localized silver plating. The introduction of ultrasonic assistance at a frequency of 20-40 kHz significantly reduces bubble retention caused by hydrogen evolution at the cathode, lowering the pinhole rate and surface defect density of the coating. Enhanced solution mass transfer reduces the diffusion layer thickness, enabling stable deposition even under high current density conditions and improving deposition efficiency per unit time. Simultaneously, the ultrasonic action promotes the uniform adsorption of functional additives such as brighteners and stabilizers on the electrode surface, improving coating smoothness and gloss. Therefore, without altering the fundamental chemical system, this application significantly improves the quality consistency and process tolerance of the substrate coating through physical field assistance, making it particularly suitable for the high-reliability coating requirements of automated continuous production lines.

[0042] Example 6: In traditional electroplating processes, poor solution stability is a key bottleneck restricting production efficiency and product quality. The linear additives used in conventional electroplating solutions are prone to molecular chain breakage under shear forces during electrolysis, generating low-molecular-weight byproducts. This leads to a rapid decline in surface adsorption capacity, resulting in rough coating crystals, pinholes, or scorching defects. Furthermore, the continuous accumulation of decomposition products accelerates solution aging, requiring frequent replacement or complex purification treatments, increasing operating costs and environmental pressures. Especially in high-current-density, rapid electroplating scenarios (such as silver plating in localized functional areas), uneven mass transfer and exacerbated side reactions further amplify these problems. Therefore, improving the chemical and physical stability of electroplating solutions during long-term operation to ensure a uniform, dense coating with a wide process window has become an urgent technical challenge.

[0043] This application raises the following points: An electroplating solution for brackets used in LEDs, integrated circuits, and optocouplers is at least one of a first plating solution, a second plating solution, or a third plating solution, wherein at least one plating solution contains a stabilizer and a surfactant. The stabilizer is a water-soluble polymer with a three-dimensional network structure or a star-shaped or dendritic structure; Surfactants contain hydrophilic and hydrophobic groups. The hydrophilic groups include nonpolar hydrocarbon long chains, and the hydrophobic groups include at least one of organic amine salts, quaternary ammonium salts, and polyoxyethylene long chains.

[0044] Through the above technical solution, this application provides a composite electroplating solution system suitable for the electrodeposition process, aiming to overcome the performance instability problem caused by the easy degradation of additives in existing plating solutions. This solution can be applied to at least one of nickel sulfamate plating solution (first plating solution), pre-plated silver cyanide plating solution (second plating solution), or high-speed local silver plating solution (third plating solution), exhibiting good versatility and adaptability. The core lies in the introduction of two types of functional additives—a stabilizer with a specific structure and an amphiphilic surfactant—which work synergistically at the electrodeposition interface to significantly improve the anti-aging ability and film quality of the plating solution.

[0045] "Stabilizers" specifically refer to water-soluble polymers with a three-dimensional network structure, star-shaped or dendritic topology. Due to their highly branched molecular structure, these polymers, even when subjected to electrolyte shear or electric field disturbances, retain larger molecular fragments and multiple active adsorption sites, maintaining effective control over metal ion deposition behavior despite local chain breakage. For example, modified polyamide-amine (PAMAM) dendritic macromolecules, hyperbranched polyethyleneimine, or cross-linked sodium polyacrylate can all be used as options. These stabilizers anchor at multiple points on the cathode surface growth front, inhibiting abnormal grain growth, promoting fine grain deposition, and effectively blocking interference from impurity ions. Compared to traditional linear polyethylene glycol additives, their lifespan can be extended by more than three times, significantly reducing replenishment frequency and wastewater discharge.

[0046] "Surfactants" are organic compounds containing a clearly defined hydrophilic-hydrophobic amphiphilic structure. Their molecules possess both hydrophobic and hydrophilic portions, allowing them to align at gas-liquid and solid-liquid interfaces and regulate interfacial tension. Specifically, the "hydrophilic group" of this surfactant contains a nonpolar hydrocarbon chain (such as a C12-C18 alkyl chain). While this structure is usually considered a hydrophobic unit, in this context it should be interpreted as "the hydrophobic group contains a nonpolar hydrocarbon chain," while the "hydrophilic group" actually refers to strongly polar functional groups such as organic amine salts, quaternary ammonium salts, or long chains of polyoxyethylene. A reasonable explanation is that this surfactant uses a long-chain alkyl group as a hydrophobic tail, intercalated with a quaternary ammonium salt cationic head group or polyoxyethylene (—(CH2CH2O)). n —) Hydrophilic segments act as the head, forming typical cationic or nonionic surfactant structures. These substances can effectively reduce the surface tension of the plating solution, generate a stable and delicate foam layer, and inhibit the formation of harmful mists from the volatilization of cyanide or acidic components; at the same time, they improve wettability, promote the penetration of the plating solution into micro-areas, enhance coverage, and assist brighteners in achieving micro-leveling effects.

[0047] The stabilizers and surfactants mentioned above are dispersed together in the plating bath system, each performing its function while also exhibiting a synergistic effect. The stabilizers stabilize metal complex ions and control the reduction rate through steric hindrance and charge shielding; the surfactants optimize the interfacial environment, promote uniform adsorption of additives, and prevent excessively high local concentrations that could lead to inclusions. The combined use of these two agents ensures that the plating bath maintains a stable mass transfer state even under high current densities (e.g., 50–200 A / dm²), avoiding problems such as loose coatings and nodules caused by hydrogen bubble retention or concentration polarization. This is particularly suitable for the high-speed local silver plating process in step S5, supporting the deposition of thick silver layers in a short time (2–5 seconds) without burning.

[0048] As an alternative implementation, the stabilizer can be replaced with a hyperbranched polyester containing both carboxyl and hydroxyl groups, with a molecular weight distribution controlled between 5,000 and 20,000 Da, exhibiting good solubility and stability within a pH range of 4–9; the surfactant can also be a compound system of fatty alcohol polyoxyethylene ether (AEO series) and dodecyl dimethyl benzyl ammonium chloride, which combines defoaming and bactericidal functions, further extending the bath maintenance cycle.

[0049] Through the above technical solutions, this application achieves functional enhancement of the electroplating solution for the support: due to the use of stabilizers with three-dimensional network or dendritic structures, it can maintain a high ability to inhibit grain coarsening in a continuous electrolytic environment, delay the failure process of additives, and significantly extend the service life of the plating solution; due to the design of surfactants with specific amphiphilic structures, it can effectively regulate the gas-liquid interface behavior, inhibit acid mist escape, and improve the smoothness of the coating; the overall solution system not only improves the density and appearance quality of the coating, but also reduces chemical consumption and environmental treatment burden, constituting one of the core foundations supporting efficient and green electroplating processes.

[0050] Example 7: Based on the above embodiments, this embodiment further provides: An electroplating solution for brackets used in LEDs, integrated circuits, and optocouplers, which is a third plating solution, comprises the following components by weight: 40-50 parts copper sulfate, 40-50 parts sodium sulfate, 100-120 parts potassium sodium tartrate, 40-60 parts sodium hydroxide solution, 1-8 parts stabilizer, 1-5 parts bisbenzenesulfonamide, 1-5 parts sodium cyanide, 1-5 parts surfactant, and 80-100 parts deionized water.

[0051] This embodiment provides a functional electroplating solution for localized silver plating of a support structure, specifically a third plating solution. This solution, through optimized synergistic proportions of the main salt, complexing system, and functional additives, achieves rapid, uniform, and dense silver layer deposition at high current densities, while simultaneously ensuring the long-term stability of the plating bath. The components and their functions are as follows: Copper sulfate, as one of the metal ion sources, can participate in the co-deposition process or adjust the crystal structure of the coating under specific process conditions. Its dosage is controlled within the range of 40-50 parts to ensure sufficient metal supply capacity while avoiding excessive concentration that could lead to uncontrolled deposition rate or rough coating. In some optional embodiments, copper sulfate can be partially replaced by nickel sulfate or cobalt sulfate to introduce trace alloying elements to improve coating hardness and wear resistance.

[0052] Sodium sulfate, as a conductive salt, is used to improve the conductivity of the plating solution, reduce the tank pressure and energy consumption. Its concentration is maintained at 40-50 parts to ensure uniform current distribution during electrolysis, which is especially suitable for supports with complex geometries. In alternative solutions, strong electrolytes such as sodium chloride or sodium nitrate can also be used to achieve similar effects, but a pH buffer system is required to prevent side reactions.

[0053] Sodium potassium tartrate, as a powerful complexing agent, has a good complexing ability for copper ions, which can effectively inhibit the concentration of free metal ions and prevent localized rapid deposition that could lead to burrs or dendrites. Its addition amount is 100-120 parts, which is within the high-efficiency complexing range. In other embodiments, sodium potassium tartrate can be replaced by disodium EDTA, trisodium citrate, or sodium gluconate to meet the complexing requirements of different metal systems.

[0054] Sodium hydroxide solution is used to adjust and stabilize the pH of the plating solution within the alkaline range (usually 9.0-9.5) to ensure the stability of the complex and the effectiveness of the additives. The dosage is 40-60 parts. This parameter can be dynamically adjusted according to the evaporation loss in actual production, or it can be automatically replenished by the metering pump linked to the online pH monitoring system to maintain a constant pH.

[0055] The stabilizer is a water-soluble polymer with a three-dimensional network structure or a star-shaped or dendritic structure, such as modified polyamide or hyperbranched polyethyleneimine, and is added at a rate of 1-8 parts. Due to its special molecular topology, this type of stabilizer is not easily broken into low-molecular-weight fragments under electrolytic oxidation conditions. Even if partial degradation occurs, it retains multiple adsorption sites, continuously inhibiting side reactions and impurity precipitation, and significantly extending the service life of the plating solution. Compared with traditional linear polymers, it has better anti-aging properties and can maintain good dispersion ability even after more than 300 hours of continuous operation.

[0056] Bisbenzenesulfonylimide, as a highly efficient stress reliever, is added in amounts of 1-5 parts. The sulfonyl groups in its molecular structure preferentially adsorb onto high-energy growth points on the cathode surface, inhibiting abnormal grain growth, promoting the formation of fine grain structures, and simultaneously alleviating stress accumulation in the coating, reducing the risk of microcracks and peeling. In modified embodiments, sodium saccharin or naphthalenesulfonic acid derivatives can be used as substitutes, but bisbenzenesulfonylimide exhibits more outstanding stability under high-temperature and high-current conditions.

[0057] Surfactants contain both hydrophilic and hydrophobic groups, and their typical structure is a nonionic or zwitterionic compound composed of long-chain alkyl groups and polyoxyethylene chains. The addition amount is 1-5 parts. Their main functions are to reduce liquid-solid interfacial tension, enhance wettability, and allow the plating bath to fully cover fine areas, improving deep plating and uniform plating capabilities. Simultaneously, the stable foam layer they form at the gas-liquid interface helps suppress cyanide volatilization and improves the safety of the working environment. Optional alternatives include fatty alcohol polyoxyethylene ethers and alkylphenol polyoxyethylene ethers, but care must be taken to control the cloud point temperature to adapt to operating conditions of 50-70℃.

[0058] Deionized water is used as the solvent carrier, with an amount of 80-100 parts, to ensure that all components are fully dissolved and form a homogeneous and stable aqueous phase system; the water quality requires a resistivity of not less than 15 MΩ·cm to avoid the introduction of impurities such as calcium and magnesium ions that may cause precipitation or interfere with the electrodeposition process.

[0059] The above components are added in the following order during preparation: first, deionized water is added to the plating tank, followed by the dissolution of sodium sulfate and copper sulfate, then potassium sodium tartrate is added and stirred until completely complexed. Next, sodium hydroxide solution is slowly added dropwise to adjust the pH. Finally, the stabilizer, bis(benzenesulfonyl)imide, sodium cyanide, and surfactant are added, and stirring is continued until the solution is clear and transparent. The newly prepared plating solution is allowed to mature for 24 hours before use, and is equipped with continuous filtration and ultrasonic-assisted devices to maintain cleanliness.

[0060] Through the above technical solution, this application achieves refined design and functional integration of the third plating solution formulation system. Due to the adoption of a wide-range controllable component ratio, the plating solution can operate stably at high current densities of 50-200 A / dm² without scorching or loosening, meeting the dual requirements of speed and quality for local silver plating of the support structure. The introduction of a three-dimensional stabilizer and highly efficient stress-relieving additives effectively inhibits the aging process of the plating solution, reducing maintenance frequency and waste liquid discharge. The formulation of a special surfactant enhances the spreadability and anti-fouling ability of the plating solution on complex surfaces, improving the consistency and appearance quality of the coating. Overall, this solution not only supports high-speed selective electrodeposition processes but also possesses excellent sustainable operating characteristics, making it suitable for mass production scenarios of high-power support structures.

[0061] Example 8: Traditional mounting brackets face multiple performance challenges in high-power, high-optical-effect applications. As chip power density continues to increase, higher demands are placed on the bracket's reflectivity, thermal management capabilities, soldering reliability, and long-term environmental stability. Current technologies commonly employ a process of directly immersing a thick silver layer onto a copper substrate. While this achieves certain optical and conductive functions, it has significant drawbacks: Firstly, the large potential difference between copper and silver makes them prone to displacement reactions without an intermediate layer, resulting in weak interfacial adhesion and easy blistering or peeling of the plating. Secondly, to prevent discoloration of the silver layer at high temperatures and ensure soldering performance, a silver layer thickness exceeding 80μm is often required, leading to a severe waste of precious metal resources and significantly increasing manufacturing costs. Furthermore, non-functional areas (such as pins and connecting bridges) are also covered with silver, which not only serves no practical purpose but also exacerbates material consumption and complicates subsequent recycling. Therefore, a novel structural design is urgently needed that effectively controls the silver layer distribution and overall usage while ensuring high performance in critical areas, balancing functionality and economy.

[0062] This application raises the following points: A scaffold includes a substrate and a nickel layer, a pre-plated silver layer, and a thick silver layer sequentially formed on the surface of the substrate and on a functional area; the nickel layer has a thickness of 0.4-0.6 μm, the pre-plated silver layer has a thickness of 0.05-0.2 μm, and the thick silver layer on the functional area has a thickness of 0.5-2 μm.

[0063] This application can be applied to reflective cup-shaped or planar support structures in the field of high-power LED packaging, and also to semiconductor device carrier platforms requiring high thermal conductivity and high reflectivity. This embodiment provides a multi-layer composite plating structure support, achieving a technical balance between functional zoning optimization and efficient material utilization by sequentially constructing a nickel layer, a pre-plated silver layer, and a locally thick silver layer on a substrate. Its core lies in assigning different functions to metal layers of specific thickness and location, enabling each layer to work synergistically to meet comprehensive performance requirements.

[0064] The substrate is typically made of copper or a copper alloy, serving as the mechanical support and conductive / thermal conductor for the entire support structure. Its surface, after pretreatment, exhibits good activity and cleanliness, laying the foundation for subsequent plating adhesion. First, a nickel layer with a thickness of 0.4-0.6 μm is formed on the substrate surface. This nickel layer is not merely a simple transition layer but plays multiple roles: firstly, it acts as a diffusion barrier between copper and silver, effectively suppressing discoloration and increased resistance caused by the migration of copper atoms to the silver layer during high-temperature processes; secondly, it improves the microscopic unevenness of the copper surface, providing a more uniform deposition interface and enhancing the adhesion of the subsequent silver layer. This thickness range has been experimentally verified to offer optimal cost-effectiveness—too thin a layer will fail to form a complete and dense barrier, while too thick a layer increases the risk of internal stress and unnecessarily raises costs.

[0065] Next, a pre-plated silver layer with a thickness of 0.05-0.2 μm is deposited on top of the nickel layer. The key function of this layer is to act as a "bonding bridge," ensuring continuous and dense electrodeposition of the subsequent thick silver layer on the nickel substrate. Since the standard electrode potential of nickel is higher than that of silver, directly applying a high current density for silver deposition can easily trigger localized displacement reactions, resulting in a loose or porous coating. By introducing an extremely thin but complete pre-plated silver layer, stable silver nucleus growth points can be established without affecting the overall cost, avoiding direct exposure of the nickel surface to a high concentration of silver ions. This thickness range ensures film continuity without wasting silver resources due to excessive deposition.

[0066] Furthermore, the thick silver layer is only applied to functional areas, i.e., critical areas for light reflection or solder wetting, such as the inner wall of the reflector cup or the solder pad area, with a thickness of 0.5-2 μm. This design embodies the "as-needed" material usage philosophy: compared to traditional full-area silver plating, functional silver layers are deposited only in necessary areas, significantly reducing silver usage and lowering unit product costs. Simultaneously, this thickness is sufficient to meet the requirements of high reflectivity (>95%) and good solder wettability, and supports subsequent possible flame crystallization or annealing treatments to further improve performance. Non-functional areas are not covered by this thick silver layer, thus avoiding ineffective deposition.

[0067] The aforementioned layers are stacked in a hierarchical manner, with interlayer bonding achieved through electrochemical deposition and metallurgical adhesion or strong physical adsorption, resulting in clear interfaces yet robust bonds. The nickel layer achieves a tight bond with the substrate via electroplating; the pre-plated silver layer nucleates and grows on the activated nickel layer, resulting in a dense structure; the thick silver layer is selectively enhanced by deposition based on the pre-plated silver layer, ensuring performance in localized areas meets standards. The entire structure achieves a hierarchical progression from basic support to functional realization.

[0068] Through the above technical solution, this application achieves the following: by adopting a gradient composite structure consisting of a nickel layer, a pre-plated silver layer, and a thick silver layer in the functional area, the problems of poor silver layer bonding, serious material waste, and redundant plating in non-functional areas that exist in traditional brackets are solved. Therefore, while ensuring high reflectivity, excellent electrical and thermal conductivity, and welding reliability, the amount of precious metals used is significantly reduced, and the economic efficiency and environmental friendliness of the product are improved, which has clear industrial application value.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for electroplating a semiconductor device substrate, characterized in that, The process includes the following sequential steps: S1, Substrate pretreatment: Electrolytic degreasing and activation treatment of the support substrate; S2, Nickel plating undercoat: Immersing the pretreated substrate in a first plating solution to electrodeposit a nickel layer. The concentrations of each component in the first plating solution are as follows: nickel sulfamate 70-110 g / L, nickel chloride 10-30 g / L, boric acid 30-50 g / L, pH 3.8-4.4, temperature 55-65℃, current density 5-20 A / dm², and electrodeposition time 15-30 seconds, forming a nickel layer with a thickness of 0.4-0.6 μm; S3, Nickel layer activation: Immersing the nickel-plated substrate in an activation solution containing potassium cyanide and sodium carbonate, both at a concentration of 3-20 g / L, and performing activation treatment at a current density of 0.3-1 A / dm². S4. Pre-plating silver: The activated substrate is immersed in the second plating solution to electrodeposit a pre-plated silver layer. The second plating solution contains 120-160 g / L potassium cyanide and 2.2-4 g / L silver cyanide, the temperature is 20-30℃, the current density is 1.5-2.5 A / dm², the electrodeposition time is 4-8 seconds, and a pre-plated silver layer with a thickness of 0.05-0.2 μm is formed. S5. Local silver plating: The non-functional areas of the substrate are masked using a mask, and the substrate is immersed in a third plating solution. Selective electrodeposition is performed on the exposed functional areas to form a functional silver layer with a thickness of 0.5-2 μm. The third plating solution contains 50-80 g / L of silver ions, 2-10 g / L of potassium cyanide, 1-5 ml / L of brightener and 4-6 ml / L of additives, with a pH of 9.0-9.5, a temperature of 50-70℃, a current density of 50-200 A / dm², and an electrodeposition time of 2-5 seconds.

2. The electroplating method for a semiconductor component substrate according to claim 1, characterized in that, In step S1, the electrolytic degreasing is carried out in an electrolyte containing 90-110 g / L of degreasing powder, at an electrolysis temperature of 50-70°C, a current density of 5-20 A / dm², and an electrolysis time of 10-20 seconds; the activation treatment involves immersing the substrate in an acid salt solution containing 75-95 g / L of starter salt at room temperature for 5-10 seconds.

3. The electroplating method for a semiconductor component substrate according to claim 1, characterized in that, After step S5, step S6 is also included: silver removal from non-functional areas. The substrate with partial silver plating is used as the anode and immersed in a fourth plating solution containing 80-100 g / L of silver removal powder. Electrolysis is performed for 10-20 seconds at a current density of 2-6 A / dm² to remove the pre-plated silver layer in the non-functional areas.

4. The electroplating method for a semiconductor component substrate according to claim 3, characterized in that, After completing the silver plating step, step S7 is also included: post-treatment, which includes at least one of the following sub-steps: S7a, silver protection treatment: immersing the substrate in a silver protection agent aqueous solution with a concentration of 50-100 ml / L for 5-10 seconds; S7b, plating crystallization treatment: using a flame to uniformly sweep the surface of the silver layer in the functional area, so that the surface layer is slightly melted and then naturally cooled. S7c, Overall Annealing: Heat the entire substrate to 200-300℃ and hold for 3-5 minutes, then cool.

5. The electroplating method for a semiconductor component substrate according to claim 1, characterized in that, During the electrodeposition process in steps S2, S4 and / or S5, ultrasonic assistance is applied to the plating solution at a frequency of 20-40 kHz.

6. An electroplating solution for brackets used in LEDs, integrated circuits, and optocouplers, characterized in that, It is at least one of the first plating solution, the second plating solution, or the third plating solution, wherein at least one plating solution contains a stabilizer and a surfactant; the stabilizer is a water-soluble polymer having a three-dimensional network structure or a star-shaped or dendritic structure; the surfactant contains hydrophilic groups and hydrophobic groups, wherein the hydrophilic groups include nonpolar hydrocarbon long chains, and the hydrophobic groups include at least one of organic amine salts, quaternary ammonium salts, and polyoxyethylene long chains.

7. The electroplating solution for a bracket used in LEDs, integrated circuits, and optocouplers according to claim 6, characterized in that, The third plating solution comprises the following components by weight: 40-50 parts copper sulfate, 40-50 parts sodium sulfate, 100-120 parts potassium sodium tartrate, 40-60 parts sodium hydroxide solution, 1-8 parts stabilizer, 1-5 parts bisbenzenesulfonamide, 1-5 parts sodium cyanide, 1-5 parts surfactant, and 80-100 parts deionized water.

8. A stent, characterized in that, It includes a substrate and a nickel layer, a pre-plated silver layer, and a thick silver layer formed sequentially on the surface of the substrate and on the functional area; the thickness of the nickel layer is 0.4-0.6 μm, the thickness of the pre-plated silver layer is 0.05-0.2 μm, and the thickness of the thick silver layer on the functional area is 0.5-2 μm.