A high-reliability nickel-silver-plated aluminized ceramic substrate and a preparation method thereof

Abstract

The application discloses a kind of high reliability nickel silver-plated aluminized ceramic substrates and preparation method, it is related to semiconductor technical field, comprising the following steps: aluminized ceramic substrate surface is pretreated, and then in turn shot peening, chemical nickel plating, sand blasting, nickel activation and chemical silver plating are handled.The application introduces residual stress on the surface of aluminized ceramic substrate by shot peening, improves surface roughness, improves the adhesion of nickel layer and silver layer by sand blasting, nickel activation, and effectively inhibits silver migration by nickel-silver composite coating.Therefore, the reliability of the aluminized ceramic substrate prepared by the application is high, the adhesion of the coating is strong, and the silver migration resistance is good.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a high-reliability nickel-silver plated aluminum-coated ceramic substrate and its preparation method. Background Technology

[0002] Aluminum-clad ceramic substrates, as packaging substrates for IGBTs, possess excellent thermal conductivity, good resistance to thermal shock fatigue, outstanding thermal stability, lightweight structure, and good aluminum wire bonding capability.

[0003] Currently, silver plating on the surface of aluminized ceramic substrates is a common method to improve their solderability. In traditional silver plating processes, the surface of the aluminized ceramic substrate is pretreated before silver plating. This results in several drawbacks: First, the surface of the aluminized ceramic substrate has high flatness and insufficient roughness, making it prone to silver migration when soldering to the silver film of the chip after silver plating, leading to soldering failure. Second, the substrate surface is not effectively strengthened, resulting in poor reliability in power cycling tests. Third, direct silver plating after nickel plating can easily lead to plating peeling due to the poor adhesion between the nickel and silver layers. Fourth, silver migration within a single silver layer can degrade the substrate's insulation performance, affecting the normal operation of electronic devices.

[0004] Therefore, it is of great significance to develop a nickel-silver-clad aluminum ceramic substrate with high reliability, high adhesion and resistance to silver migration. Summary of the Invention

[0005] The purpose of this invention is to provide a highly reliable nickel-silver plated aluminum-coated ceramic substrate and its preparation method, so as to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate includes the following steps: S1: The surface of the aluminum-clad ceramic substrate is pretreated and then shot peening is performed. S2: Perform chemical nickel plating on the aluminum-coated ceramic substrate prepared in step S1; S3: Sandblast the aluminum-coated ceramic substrate prepared in step S2; S4: Perform nickel activation treatment on the aluminum-coated ceramic substrate prepared in step S3; S5: Perform chemical silver plating on the aluminum-coated ceramic substrate prepared in step S4.

[0007] Further, in step S1, the pretreatment steps are as follows: degreasing solution treatment for 1-5 minutes, water washing, alkaline etching solution treatment for 30-90 seconds, water washing, acid pickling solution treatment for 50-150 seconds, and water washing. The degreasing solution comprises the following components, by weight: 0.5-2 g / L sodium hydroxide, 10-20 g / L sodium carbonate, 5-10 g / L sodium phosphate, and 1-3 g / L nonionic surfactant; The alkaline etching solution comprises the following components, by weight: 30-40 g / L sodium hydroxide, 2-5 g / L sodium citrate; The pickling solution is a nitric acid solution with a mass fraction of 20%-40%; The nonionic surfactant is one or more of Tween-20, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

[0008] Further, in step S1, the shot peening parameters are as follows: the shot material is spherical alumina ceramic shot with a particle size of 50-150 mesh, the shot peening pressure is 0.7-1MPa, the shot peening distance is 10-15cm, the shot peening angle is 30-60°, and the shot peening linear velocity is 1000-1500mm / min; the surface roughness Ra value of the aluminized ceramic substrate after shot peening is 0.6-0.8μm.

[0009] Further, in step S2, the electroless nickel plating process is as follows: electroless nickel plating is performed on the shot-peened aluminum-coated ceramic substrate with electroless nickel plating solution, and air stirring is performed at 75-85℃ for 20-25 minutes to make the nickel layer thickness 4-6μm, thereby obtaining the electroless nickel-plated aluminum-coated ceramic substrate. The electroless nickel plating solution comprises the following components by weight: 25-30 g / L nickel sulfate heptahydrate, 25-30 g / L sodium hypophosphite monohydrate, 15-20 g / L sodium acetate, and 10-20 g / L sodium citrate dihydrate.

[0010] Furthermore, in step S3, the sandblasting parameters are as follows: the sandblasting abrasive is spherical white corundum with a particle size of 180-260 mesh, the sandblasting pressure is 0.3-0.5 MPa, and the sandblasting linear velocity is 500-1000 mm / min.

[0011] Further, in step S4, the nickel activation process is as follows: the sandblasted aluminum-coated ceramic substrate is subjected to nickel activation treatment with an activation solution, and activated at room temperature for 30-60 seconds to obtain a nickel-activated aluminum-coated ceramic substrate. The activation solution comprises the following components: nitric acid at a volume fraction of 2%-5%, imidazole at a mass fraction of 12%-15%, and palladium chloride at a mass fraction of 0.1-0.3 g / L.

[0012] Further, in step S5, the chemical silver plating process is as follows: the nickel-activated aluminum-clad ceramic substrate is treated with a chemical silver plating solution at 45-55°C for 10-15 minutes to make the silver layer thickness 0.4-0.8μm, thereby obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0013] Further, the electroless silver plating solution comprises the following components: by parts, 28-32 ml / L complexing agent, 4-6 ml / L wetting agent; 0.6-1.5 ml / L dispersant; 0.6-0.9 g / L silver nitrate; 0.05-0.5 g / L brightener; 0.04-0.08 g / L modified graphene oxide; The complexing agent is one or more of triethanolamine, ethylenediaminetetraacetic acid, sodium citrate, potassium sodium tartrate, and ethylenediamine; The wetting agent is an alkynyl alcohol-modified organosilicon polymer; The dispersant is one or more of sodium dodecyl diphenyl sulfonate and sodium dodecyl sulfonate; The brightener is one or more of 3-S-thiourea-propanesulfonate, 3-(benzothiazole-2-mercapto)-propanesulfonate, sodium N,N-dimethyldithiocarbamate propanesulfonate, phenyldithiopropanesulfonic acid, 2,3-dimercapto-1-propanesulfonate, and disodium 4,4-dithiobenzenedisulfonate.

[0014] Further, the preparation method of the modified graphene oxide is as follows: graphene oxide is added to deionized water and ultrasonically dispersed for 30-60 min. Methyl orange and ferric chloride are added sequentially and ultrasonically dispersed. Aniline is added while stirring. The mixture is allowed to stand at 0-5℃ for 12-24 h. After washing, drying and grinding, the modified graphene oxide is obtained. In the preparation of modified graphene oxide, the mass ratio of graphene oxide, methyl orange, ferric chloride and aniline is 1:(1.5-2.5):(15-25):(4-10).

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention introduces shot peening into the surface treatment of aluminized ceramic substrates. Compared with the traditional nickel-silver plating process involving degreasing, alkaline washing, and acid washing of the aluminized ceramic substrate surface, shot peening strengthens the substrate surface and introduces residual stress to offset the tensile stress generated by power cycling and thermal shock, improving reliability during power cycling and preventing cracking and failure of the substrate under long-term alternating hot and cold conditions. Furthermore, shot peening effectively increases the surface roughness of the aluminized ceramic substrate, creating a uniformly rough bonding surface. This enhances the adhesion between the substrate and the silver film on the chip after subsequent silver plating, effectively preventing silver drift during the welding process and improving welding reliability.

[0016] 2. This invention introduces a synergistic treatment of sandblasting and activation after nickel plating on an aluminum-coated ceramic substrate. Compared to the traditional nickel-silver plating process where electroless nickel plating is followed directly by electroless silver plating, this invention introduces sandblasting and nickel activation treatment after electroless nickel plating. Sandblasting removes the oxide film, impurities, and porous layer from the nickel layer surface, increasing its surface roughness; activation further enhances the surface activity of the nickel layer and removes residual oxides. The synergistic effect of these two treatments significantly improves the adhesion between the nickel layer and the subsequent electroless silver plating layer, preventing silver layer detachment and peeling during use, and improving the overall stability of the plating layer. Furthermore, imidazole and palladium chloride are introduced into the activation solution. The nitrogen atoms on the imidazole can coordinate with nickel atoms and adsorb onto the nickel layer surface, preventing excessive corrosion of the nickel layer by nitric acid and capturing silver ions in the subsequent silver plating solution, promoting silver layer formation. Simultaneously, palladium chloride promotes silver deposition and, synergistically with imidazole, promotes uniform silver layer formation.

[0017] 3. This invention employs a nickel-silver composite plating layer on an aluminum-clad ceramic substrate to enhance its resistance to silver migration. Compared to a single silver layer, the composite plating structure of a nickel layer and a silver layer, with the nickel layer as an intermediate transition layer, forms an effective diffusion barrier layer. This effectively prevents the migration of silver atoms from the silver layer, avoiding problems such as decreased substrate insulation performance and short circuits caused by silver migration. Simultaneously, the nickel layer improves the substrate's corrosion resistance and mechanical strength, while the silver layer ensures excellent conductivity and solderability. The synergistic effect of these two layers significantly reduces silver migration, resulting in a substantial improvement in insulation reliability and overall performance. Furthermore, during the preparation of the chemical silver plating solution, conductive polymer polyaniline-modified graphene oxide is added. The nitrogen atoms in polyaniline can complex silver ions, not only improving the interfacial compatibility between graphene oxide and the silver substrate but also effectively inhibiting silver atom migration. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating the fabrication process of a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to the present invention. Figure 2 This is a schematic diagram of the coating adhesion test of the aluminum-coated ceramic substrate corresponding to Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the coating adhesion test of the aluminum-coated ceramic substrate corresponding to Embodiment 2 of the present invention; Figure 4 This is a schematic diagram of the coating adhesion test on the aluminum-coated ceramic substrate corresponding to Comparative Example 1 of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0020] In the following embodiments, the aluminum-clad ceramic substrate has a size of 138*190; the spherical alumina ceramic pellets have a particle size of 100 mesh; the spherical white corundum has a particle size of 225 mesh; and the graphene oxide has a particle size of 50 nm.

[0021] Example 1: A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate: Taking an aluminum-coated ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 1: Shot peening treatment: S1: Add 1 g / L sodium hydroxide, 15 g / L sodium carbonate, 7 g / L sodium phosphate and 1 g / L Tween-20 to deionized water and stir to obtain an oil-removing solution; add 30 g / L sodium hydroxide and 2 g / L anhydrous sodium citrate to deionized water to obtain an alkaline etching solution; S2: The aluminum-clad ceramic substrate is sequentially treated with degreasing solution for 3 min, washed with water, treated with alkaline etching solution for 1 min, washed with water, treated with acid pickling solution for 90 s, and washed with water to obtain the pretreated aluminum-clad ceramic substrate. S3: The pretreated aluminum-coated ceramic substrate was shot-peened with spherical alumina ceramic pellets. The shot-peening pressure was 0.8 MPa, the shot-peening distance was 13 cm, the shot-peening angle was 40°, and the linear speed was 1200 mm / min, so that the surface roughness was 0.7 μm, and the shot-peened aluminum-coated ceramic substrate was obtained. Step Two: Electroless Nickel Plating Treatment S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Electroless nickel plating is performed on the shot-peened aluminum-clad ceramic substrate using electroless nickel plating solution, followed by air stirring treatment at 80°C for 20 min to achieve a nickel layer thickness of 4.3 μm, thus obtaining an electroless nickel-plated aluminum-clad ceramic substrate. Step 3: Sandblasting treatment: Under a pressure of 0.4 MPa and a linear speed of 750 mm / min, a spherical white corundum was used to sandblast an alumina-coated ceramic substrate that had been chemically nickel-plated, resulting in a sandblasted alumina-coated ceramic substrate. Step 4: Nickel activation treatment: S1: Add 120 g / L imidazole to a 3% (v / v) nitric acid solution, stir and mix well to obtain the activation solution; S2: The sandblasted aluminum-clad ceramic substrate was subjected to nickel activation treatment with an activation solution and activated at room temperature for 40 seconds to obtain a nickel-activated aluminum-clad ceramic substrate. Step 5: Chemical silver plating treatment: S1: Add silver nitrate, 30 ml / L sodium citrate, 5 ml / L alkynyl alcohol modified organosilicon polymer, 1 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to deionized water to make the concentration of silver ions 0.7 g / L, stir and mix well to obtain chemical silver plating solution. S2: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 50°C for 10 min to make the silver layer thickness 0.5 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0022] Example 2: A method for preparing a high-reliability nickel-silver plated aluminum-clad ceramic substrate: Taking an aluminum-clad Si3N4 ceramic substrate with an aluminum layer thickness of 0.6 mm as an example: Step 1: Shot peening treatment: S1: Add 1 g / L sodium hydroxide, 15 g / L sodium carbonate, 7 g / L sodium phosphate and 1 g / L Tween-20 to deionized water and stir to obtain an oil-removing solution; add 30 g / L sodium hydroxide and 2 g / L anhydrous sodium citrate to deionized water to obtain an alkaline etching solution. S2: The aluminum-clad ceramic substrate is sequentially treated with degreasing solution for 3 min, washed with water, treated with alkaline etching solution for 1 min, washed with water, treated with acid pickling solution for 90 s, and washed with water to obtain the pretreated aluminum-clad ceramic substrate. S3: The pretreated aluminum-coated ceramic substrate is shot-peened with spherical alumina ceramic pellets. The shot-peening pressure is 0.7MPa, the shot-peening distance is 15cm, the shot-peening angle is 40°, and the linear speed is 1400mm / min, so that the surface roughness is 0.8μm, and the shot-peened aluminum-coated ceramic substrate is obtained. Step Two: Electroless Nickel Plating Treatment S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Electroless nickel plating was performed on the shot-peened aluminum-clad ceramic substrate using an electroless nickel plating solution, followed by air stirring at 82°C for 23 min to achieve a nickel layer thickness of 5.1 μm, thus obtaining an electroless nickel-plated aluminum-clad ceramic substrate. Step 3: Sandblasting treatment: Under a pressure of 0.4 MPa and a linear speed of 750 mm / min, a spherical white corundum was used to sandblast an alumina-coated ceramic substrate that had been chemically nickel-plated, resulting in a sandblasted alumina-coated ceramic substrate. Step 4: Nickel activation treatment: S1: Add 120 g / L imidazole to a 3% (v / v) nitric acid solution, stir and mix well to obtain the activation solution; S2: The sandblasted aluminum-clad ceramic substrate was subjected to nickel activation treatment with an activation solution and activated at room temperature for 40 seconds to obtain a nickel-activated aluminum-clad ceramic substrate. Step 5: Chemical silver plating treatment: S1: Add silver nitrate, 30 ml / L sodium citrate, 5 ml / L alkynyl alcohol modified organosilicon polymer, 1 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to deionized water to make the concentration of silver ions 0.7 g / L, stir and mix well to obtain chemical silver plating solution. S2: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 52°C for 12 min to achieve a silver layer thickness of 0.6 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0023] Example 3: A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate: Taking an aluminum-coated ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 1: Shot peening treatment: S1: Add 1 g / L sodium hydroxide, 15 g / L sodium carbonate, 7 g / L sodium phosphate and 1 g / L Tween-20 to deionized water and stir to obtain an oil-removing solution; add 30 g / L sodium hydroxide and 2 g / L anhydrous sodium citrate to deionized water to obtain an alkaline etching solution. S2: The aluminum-clad ceramic substrate is sequentially treated with degreasing solution for 3 min, washed with water, treated with alkaline etching solution for 1 min, washed with water, treated with acid pickling solution for 90 s, and washed with water to obtain the pretreated aluminum-clad ceramic substrate. S3: The pretreated aluminum-coated ceramic substrate was shot-peened with spherical alumina ceramic pellets. The shot-peening pressure was 0.8 MPa, the shot-peening distance was 13 cm, the shot-peening angle was 40°, and the linear speed was 1200 mm / min, so that the surface roughness was 0.7 μm, and the shot-peened aluminum-coated ceramic substrate was obtained. Step Two: Electroless Nickel Plating Treatment S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Electroless nickel plating is performed on the shot-peened aluminum-clad ceramic substrate using electroless nickel plating solution, followed by air stirring treatment at 80°C for 20 min to achieve a nickel layer thickness of 4.3 μm, thus obtaining an electroless nickel-plated aluminum-clad ceramic substrate. Step 3: Sandblasting treatment: Under a pressure of 0.4 MPa and a linear speed of 750 mm / min, a spherical white corundum was used to sandblast an alumina-coated ceramic substrate that had been chemically nickel-plated, resulting in a sandblasted alumina-coated ceramic substrate. Step 4: Nickel activation treatment: S1: Add 120 g / L imidazole and 0.1 g / L palladium chloride to a 3% nitric acid solution, stir and mix well to obtain an activation solution; S2: The sandblasted aluminum-clad ceramic substrate was subjected to nickel activation treatment with an activation solution and activated at room temperature for 40 seconds to obtain a nickel-activated aluminum-clad ceramic substrate. Step 5: Chemical silver plating treatment: S1: Add 1 g / L graphene oxide to deionized water and ultrasonically disperse for 30-60 min. Then add 1.5 g / L methyl orange and 15 g / L ferric chloride sequentially and ultrasonically disperse. While stirring, add 6 g / L aniline and let stand at 4℃ for 24 h. Wash, dry and grind to obtain modified graphene oxide. S2: Add 0.04 g / L modified graphene oxide to deionized water, mix ultrasonically, add silver nitrate, 30 ml / L triethanolamine, 5 ml / L alkynyl alcohol modified organosilicon polymer, 0.6 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to make the concentration of silver ions 0.7 g / L, stir and mix to obtain chemical silver plating solution; S3: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 50°C for 10 min to make the silver layer thickness 0.5 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0024] Example 4: A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate: Taking an aluminum-coated ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 1: Shot peening treatment: S1: Add 1 g / L sodium hydroxide, 15 g / L sodium carbonate, 7 g / L sodium phosphate and 1 g / L Tween-20 to deionized water and stir to obtain an oil-removing solution; add 30 g / L sodium hydroxide and 2 g / L anhydrous sodium citrate to deionized water to obtain an alkaline etching solution. S2: The aluminum-clad ceramic substrate is sequentially treated with degreasing solution for 3 min, washed with water, treated with alkaline etching solution for 1 min, washed with water, treated with acid pickling solution for 90 s, and washed with water to obtain the pretreated aluminum-clad ceramic substrate. S3: The pretreated aluminum-coated ceramic substrate was shot-peened with spherical alumina ceramic pellets. The shot-peening pressure was 0.8 MPa, the shot-peening distance was 13 cm, the shot-peening angle was 40°, and the linear speed was 1200 mm / min, so that the surface roughness was 0.7 μm, and the shot-peened aluminum-coated ceramic substrate was obtained. Step Two: Electroless Nickel Plating Treatment S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Electroless nickel plating is performed on the shot-peened aluminum-clad ceramic substrate using electroless nickel plating solution, followed by air stirring treatment at 80°C for 20 min to achieve a nickel layer thickness of 4.3 μm, thus obtaining an electroless nickel-plated aluminum-clad ceramic substrate. Step 3: Sandblasting treatment: Under a pressure of 0.4 MPa and a linear speed of 750 mm / min, a spherical white corundum was used to sandblast an alumina-coated ceramic substrate that had been chemically nickel-plated, resulting in a sandblasted alumina-coated ceramic substrate. Step 4: Nickel activation treatment: S1: Add 120 g / L imidazole and 0.15 g / L palladium chloride to a 3% (v / v) nitric acid solution, stir and mix well to obtain an activation solution; S2: The sandblasted aluminum-clad ceramic substrate was subjected to nickel activation treatment with an activation solution and activated at room temperature for 40 seconds to obtain a nickel-activated aluminum-clad ceramic substrate. Step 5: Chemical silver plating treatment: S1: Add 1 g / L graphene oxide to deionized water and ultrasonically disperse for 60 min. Then add 2 g / L methyl orange and 20 g / L ferric chloride in sequence, ultrasonically disperse, and add 8 g / L aniline while stirring. Let stand at 4℃ for 24 h, wash, dry and grind to obtain modified graphene oxide. S2: Add 0.04 g / L modified graphene oxide to deionized water, mix ultrasonically, add silver nitrate, 30 ml / L triethanolamine, 5 ml / L alkynyl alcohol modified organosilicon polymer, 0.9 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to make the silver ion concentration 0.7 g / L, stir and mix to obtain the chemical silver plating solution; S3: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 50°C for 10 min to make the silver layer thickness 0.5 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0025] Example 5: A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate: Taking an aluminum-coated ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 1: Shot peening treatment: S1: Add 1 g / L sodium hydroxide, 15 g / L sodium carbonate, 7 g / L sodium phosphate and 1 g / L Tween-20 to deionized water and stir to obtain an oil-removing solution; add 30 g / L sodium hydroxide and 2 g / L anhydrous sodium citrate to deionized water to obtain an alkaline etching solution. S2: The aluminum-clad ceramic substrate is sequentially treated with degreasing solution for 3 min, washed with water, treated with alkaline etching solution for 1 min, washed with water, treated with acid pickling solution for 90 s, and washed with water to obtain the pretreated aluminum-clad ceramic substrate. S3: The pretreated aluminum-coated ceramic substrate was shot-peened with spherical alumina ceramic pellets. The shot-peening pressure was 0.8 MPa, the shot-peening distance was 13 cm, the shot-peening angle was 40°, and the linear speed was 1200 mm / min, so that the surface roughness was 0.7 μm, and the shot-peened aluminum-coated ceramic substrate was obtained. Step Two: Electroless Nickel Plating Treatment S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Electroless nickel plating is performed on the shot-peened aluminum-clad ceramic substrate using electroless nickel plating solution, followed by air stirring treatment at 80°C for 20 min to achieve a nickel layer thickness of 4.3 μm, thus obtaining an electroless nickel-plated aluminum-clad ceramic substrate. Step 3: Sandblasting treatment: Under a pressure of 0.4 MPa and a linear speed of 750 mm / min, a spherical white corundum was used to sandblast an alumina-coated ceramic substrate that had been chemically nickel-plated, resulting in a sandblasted alumina-coated ceramic substrate. Step 4: Nickel activation treatment: S1: Add 120 g / L imidazole and 0.25 g / L palladium chloride to a 3% (v / v) nitric acid solution, stir and mix well to obtain an activation solution; S2: The sandblasted aluminum-clad ceramic substrate was subjected to nickel activation treatment with an activation solution and activated at room temperature for 40 seconds to obtain a nickel-activated aluminum-clad ceramic substrate. Step 5: Chemical silver plating treatment: S1: Add 1 g / L graphene oxide to deionized water and ultrasonically disperse for 30-60 min. Then add 2.5 g / L methyl orange and 25 g / L ferric chloride in sequence and ultrasonically disperse. While stirring, add 10 g / L aniline and let stand at 4℃ for 24 h. Wash, dry and grind to obtain modified graphene oxide. S2: Add 0.04 g / L modified graphene oxide to deionized water, mix ultrasonically, add silver nitrate, 30 ml / L triethanolamine, 5 ml / L alkynyl alcohol modified organosilicon polymer, 1.3 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to make the concentration of silver ions 0.7 g / L, stir and mix to obtain chemical silver plating solution; S3: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 50°C for 10 min to make the silver layer thickness 0.5 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

[0026] Comparative Example 1: A method for preparing a high-reliability nickel-silver plated aluminum-clad ceramic substrate: Taking an aluminum-clad ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 1: Chemical nickel plating treatment: S1: Add 25 g / L nickel sulfate heptahydrate, 30 g / L sodium hypophosphite monohydrate, 15 g / L sodium acetate, and 15 g / L sodium citrate dihydrate to deionized water to obtain a chemical nickel plating solution. S2: Place the aluminum-clad ceramic substrate in a chemical nickel plating solution and plate it at 82°C for 22 minutes to make the nickel layer thickness 5.2μm, thus obtaining the chemically nickel-plated aluminum-clad ceramic substrate; Step Two: Chemical Silver Plating Treatment S1: Add silver nitrate, 30 ml / L sodium citrate, 5 ml / L alkynyl alcohol modified organosilicon polymer, 1 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to deionized water to make the concentration of silver ions 0.7 g / L, stir and mix well to obtain chemical silver plating solution. S2: Treat the electroless nickel-plated aluminum-clad ceramic substrate with electroless silver plating solution at 50°C for 11 min to make the silver layer thickness 0.5 μm, thus obtaining the nickel-silver-plated aluminum-clad ceramic substrate.

[0027] Comparative Example 2: A method for preparing a high-reliability nickel-silver plated aluminum-clad ceramic substrate: Taking an aluminum-clad ALN ceramic substrate with an aluminum layer thickness of 0.3 mm as an example: Step 5: Chemical silver plating treatment: S1: Add 0.04 g / L graphene oxide to deionized water, sonicate to mix, then add silver nitrate, 30 ml / L triethanolamine, 5 ml / L alkynyl alcohol modified organosilicon polymer, 1.3 ml / L sodium dodecyl sulfonate and 0.15 g / L 3-S-thiourea-propanesulfonate to make the silver ion concentration 0.7 g / L, stir to mix, and obtain the chemical silver plating solution; S3: Treat the nickel-activated aluminum-clad ceramic substrate with chemical silver plating solution at 50°C for 10 min to make the silver layer thickness 0.5 μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate. The remaining steps are the same as in Example 5. Testing and Experiment

[0028] Thermal cycling performance test: Aluminum-coated ceramic substrate samples prepared in the above examples and comparative examples were subjected to zinc immersion thermal cycling tests using a TSE-12-A high and low temperature cycling test chamber, according to the testing standard GB / T 2423.22-2012 "Environmental Testing Part 2: Test Methods Test N: Temperature Change". Parameter settings: Cycling temperature: -40℃ - 125℃. The surface roughness of the sample surface was measured before and after cycling.

[0029] Adhesion test: Take the aluminum-coated ceramic substrate samples prepared in the above examples and comparative examples, draw a grid on their surface, and then use adhesive tape to pull them apart. Observe the coating peeling off to determine the adhesion between the coating and the substrate.

[0030] The experimental results are shown in Table 1 below.

[0031] Table 1 Performance Test Data of Aluminum-Clad Ceramic Substrates

[0032] Conclusion: By optimizing the nickel-silver plating process on aluminum-clad ceramic substrates, the adhesion between the nickel and silver layers is improved, effectively inhibiting silver migration.

[0033] In Comparative Example 1, a conventional process was used to electroless plate nickel and silver on the surface of an aluminum-clad ceramic substrate. First, the surface of the aluminum-clad ceramic substrate was not shot-peened, which could not effectively offset the tensile stress generated by power cycling and thermal shock. The reliability during power cycling was lower than that of the embodiment. Second, the comparative example did not undergo sandblasting and nickel activation treatment. Compared with the embodiment, the surface roughness and surface activity of the nickel layer were reduced, thereby reducing the adhesion between the nickel layer and the silver layer.

[0034] In Comparative Example 2, the graphene oxide was not modified with aniline, which reduced its dispersibility in the electroless silver plating solution, affected the uniformity of the silver layer, and reduced the interfacial bonding force between the nickel layer and the silver layer.

[0035] 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 its spirit or essential characteristics. 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, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate, characterized in that: Includes the following steps: S1: The surface of the aluminum-clad ceramic substrate is pretreated and then shot peening is performed. S2: Perform chemical nickel plating on the aluminum-coated ceramic substrate prepared in step S1; S3: Sandblast the aluminum-coated ceramic substrate prepared in step S2; S4: Perform nickel activation treatment on the aluminum-coated ceramic substrate prepared in step S3; S5: Perform chemical silver plating on the aluminum-coated ceramic substrate prepared in step S4.

2. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S1, the pretreatment steps are as follows: degreasing solution treatment for 1-5 min, water washing, alkaline etching solution treatment for 30-90 s, water washing, acid pickling solution treatment for 50-150 s, water washing. The degreasing solution comprises the following components, by weight: 0.5-2 g / L sodium hydroxide, 10-20 g / L sodium carbonate, 5-10 g / L sodium phosphate, and 1-3 g / L nonionic surfactant; The alkaline etching solution comprises the following components, by weight: 30-40 g / L sodium hydroxide, 2-5 g / L sodium citrate; The pickling solution is a nitric acid solution with a mass fraction of 20%-40%; The nonionic surfactant is one or more of Tween-20, fatty alcohol polyoxyethylene ether, and alkylphenol polyoxyethylene ether.

3. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S1, the shot peening parameters are as follows: the shot material is spherical alumina ceramic shot with a particle size of 50-150 mesh, the shot peening pressure is 0.7-1MPa, the shot peening distance is 10-15cm, the shot peening angle is 30-60°, and the shot peening linear velocity is 1000-1500mm / min; after shot peening, the surface roughness Ra value of the aluminized ceramic substrate is 0.6-0.8μm.

4. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S2, the electroless nickel plating process is as follows: electroless nickel plating is performed on the shot-peened aluminum-coated ceramic substrate with electroless nickel plating solution, and air stirring is performed at 75-85℃ for 20-25 minutes to make the nickel layer thickness 4-6μm, so as to obtain the electroless nickel-plated aluminum-coated ceramic substrate. The electroless nickel plating solution comprises the following components by weight: 25-30 g / L nickel sulfate heptahydrate, 25-30 g / L sodium hypophosphite monohydrate, 15-20 g / L sodium acetate, and 10-20 g / L sodium citrate dihydrate.

5. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S3, the sandblasting parameters are as follows: the sandblasting abrasive is spherical white corundum with a particle size of 180-260 mesh, the sandblasting pressure is 0.3-0.5 MPa, and the sandblasting linear velocity is 500-1000 mm / min.

6. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S4, the nickel activation process is as follows: the sandblasted aluminum-coated ceramic substrate is subjected to nickel activation treatment with an activation solution, and activated at room temperature for 30-60 seconds to obtain a nickel-activated aluminum-coated ceramic substrate. The activation solution comprises the following components: nitric acid at a volume fraction of 2%-5%, imidazole at a mass fraction of 12%-15%, and palladium chloride at a mass fraction of 0.1-0.3 g / L.

7. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 1, characterized in that: In step S5, the chemical silver plating process is as follows: the nickel-activated aluminum-clad ceramic substrate is treated with a chemical silver plating solution at 45-55℃ for 10-15 minutes to make the silver layer thickness 0.4-0.8μm, thus obtaining a nickel-silver-plated aluminum-clad ceramic substrate.

8. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 7, characterized in that: The electroless silver plating solution comprises the following components: by parts, 28-32 ml / L complexing agent, 4-6 ml / L wetting agent; 0.6-1.5 ml / L dispersant; 0.6-0.9 g / L silver nitrate; 0.05-0.5 g / L brightener; 0.04-0.08 g / L modified graphene oxide; The complexing agent is one or more of triethanolamine, ethylenediaminetetraacetic acid, sodium citrate, potassium sodium tartrate, and ethylenediamine; The wetting agent is an alkynyl alcohol-modified organosilicon polymer; The dispersant is one or more of sodium dodecyl diphenyl sulfonate and sodium dodecyl sulfonate; The brightener is one or more of 3-S-thiourea-propanesulfonate, 3-(benzothiazole-2-mercapto)-propanesulfonate, sodium N,N-dimethyldithiocarbamate propanesulfonate, phenyldithiopropanesulfonic acid, 2,3-dimercapto-1-propanesulfonate, and disodium 4,4-dithiobenzenedisulfonate.

9. The method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to claim 8, characterized in that: The modified graphene oxide is prepared as follows: graphene oxide is added to deionized water and ultrasonically dispersed for 30-60 min. Methyl orange and ferric chloride are added sequentially and ultrasonically dispersed. Aniline is added while stirring. The mixture is allowed to stand at 0-5℃ for 12-24 h. After washing, drying and grinding, the modified graphene oxide is obtained. In the preparation of modified graphene oxide, the mass ratio of graphene oxide, methyl orange, ferric chloride and aniline is 1:(1.5-2.5):(15-25):(4-10).

10. An aluminum-coated ceramic substrate is prepared by a method for preparing a high-reliability nickel-silver plated aluminum-coated ceramic substrate according to any one of claims 1-9.

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