Dpc ceramic substrate after plating in-situ target sealing hole passivation integrated structure and process

Abstract

The application discloses a DPC ceramic substrate post-plating in-situ targeted hole sealing and passivation integrated structure and process, and belongs to the technical field of electronic packaging surface treatment. The plating layer structure is sequentially composed of a DPC ceramic substrate body, a copper diffusion barrier layer, a thin noble metal functional layer and a passivation layer from bottom to top. The passivation layer is a non-continuous discrete structure, is only distributed in the nanometer pores and grain boundary defects of the plating layer, has no continuous covering film on the surface, has a thickness increment of less than or equal to 10 nm, and completely retains the pure metal properties of the surface. In the process, a hole sealing and passivation agent is injected into a plating tank in-situ at the end of gold plating / silver plating main plating, the agent is directionally diffused and adsorbed at high-activity pores, and the plating and hole sealing are completed in the same tank, without the need of tank switching. The passivation agent comprises an alkyl-modified benzotriazole derivative, surface-modified nano-silicon dioxide, a dispersion stabilizer and a pH buffer. The application solves the problem that a traditional passivation film destroys the bonding and welding interface, guarantees the packaging reliability, and significantly improves the corrosion resistance of the plating layer.

Description

Technical Field

[0001] This invention relates to the field of ceramic substrates, and in particular to an integrated structure and process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating. Background Technology

[0002] DPC ceramic substrates are widely used in high-end electronic packaging fields such as semiconductor lighting, 5G communication, automotive electronics, and aerospace due to their excellent thermal conductivity, matching coefficient of thermal expansion with chips, and good high-frequency characteristics. The DPC process involves sputtering a seed layer and patterning copper lines on a ceramic substrate, followed by the sequential deposition of a diffusion barrier layer and a thin noble metal functional layer (such as a chemical immersion gold layer or a chemical immersion silver layer) on the surface of the copper pads to protect the copper lines and provide excellent solderability and bonding performance.

[0003] However, existing technologies have the following prominent problems: (1) High porosity of thin noble metal coatings: Chemical immersion gold or chemical immersion silver processes deposit thin layers of noble metals through displacement reactions. Due to the displacement deposition mechanism, nanoscale micropores, pinholes and grain boundary gaps are inevitable in the coating. When the gold layer thickness is only 0.05-0.1 μm or the silver layer thickness is 0.2-0.5 μm, the porosity is more significant. Corrosive media (moisture, sulfides, chlorides, etc.) can penetrate into the underlying metal along the pores, causing micro-galvanic corrosion, resulting in discoloration of the pads, increased contact resistance and even bonding failure.

[0004] (2) Conflict between traditional passivation technology and packaging performance: Existing surface passivation treatments (such as chromate passivation, organic thick film coating, etc.) usually transfer the substrate to an independent passivation tank for processing after plating to form a continuous cover film. Although this kind of "thick film, offline, heavy corrosion protection" solution can seal the pores, it will form an insulating layer or organic thin film on the surface of precious metals, which will seriously affect the subsequent solder wettability, gold wire / aluminum wire bonding strength and probe contact reliability, and cannot meet the electrical connection requirements of high-density packaging.

[0005] (3) Increasing the thickness of the gold layer is costly and carries the risk of gold embrittlement: The traditional practice in the industry is to simply increase the thickness of the gold layer to reduce porosity, but this not only significantly increases the cost of materials (as gold prices continue to rise), but an excessively thick gold layer may also cause gold embrittlement during welding, reducing the mechanical strength of the weld joint.

[0006] (4) The offline post-processing process is complex: the existing sealing process requires the substrate to be taken out of the plating tank, washed, transferred to the passivation tank, and then washed and dried again. The multi-step transfer not only increases the complexity of the process and the production cycle, but also the exposure of the substrate to air during the process may lead to oxidation of the coating surface, affecting the bonding effect between the sealing agent and the coating.

[0007] Therefore, there is an urgent need for a new type of sealing and passivation technology that can be completed in situ during the plating process without adding extra steps, without changing the metallic properties of the plating surface, and at the same time effectively sealing the pore corrosion channels, in order to meet the application requirements of DPC ceramic substrates in high-reliability electronic packaging. Summary of the Invention

[0008] In view of this, the present invention addresses the deficiencies of the existing technology, and its main objective is to provide an integrated structure and process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating. This effectively resolves the fundamental contradiction between traditional passivation processes and the packaging performance of thin noble metal plating on DPC ceramic substrates. Specifically, it addresses how to efficiently seal the nanopores of the plating layer and block corrosion penetration channels while avoiding the formation of a continuous covering film on the plating surface, thereby fully preserving its pure metallic properties and ensuring high reliability of chip packaging bonding and soldering.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: An integrated structure for in-situ targeted sealing and passivation of a DPC ceramic substrate after plating includes a DPC ceramic substrate body, which includes a ceramic base layer and a copper substrate. The copper substrate is formed on the surface of the ceramic base layer by a DPC process. A copper diffusion barrier layer is formed on the surface of the copper substrate. A thin noble metal functional layer is formed on the surface of the copper diffusion barrier layer. A passivation layer is formed on the surface of the thin noble metal functional layer by targeted pore filling.

[0010] As a preferred embodiment, the copper substrate surface undergoes pretreatment micro-etching, with a roughness Ra of 0.05–0.15 μm.

[0011] As a preferred embodiment, the copper diffusion barrier layer is a chemically plated nickel layer or a copper barrier layer with a thickness of 0.5 to 5 μm. This copper diffusion barrier layer is used to prevent copper atoms from diffusing into the thin noble metal functional layer.

[0012] As a preferred embodiment, the thin noble metal functional layer is a chemical immersion gold layer or a chemical immersion silver layer. The thickness of the chemical immersion gold layer is 0.05 to 0.1 μm, and the purity of the chemical immersion gold layer is ≥99.9%. The thickness of the chemical immersion silver layer is 0.2 to 0.5 μm, and the purity of the chemical immersion silver layer is ≥99.9%.

[0013] As a preferred embodiment, the passivation layer has a discontinuous discrete structure without a continuous surface covering film. The passivation layer is distributed within the nanopores and grain boundary defects of the thin noble metal functional layer, forming a physical blockage and chemical passivation of the corrosion channels. The overall thickness increment of the passivation layer is ≤10nm.

[0014] As a preferred embodiment, the passivation layer comprises an alkyl-modified benzotriazole derivative and surface-modified nano-silica particles.

[0015] As a preferred embodiment, the alkyl-modified benzotriazole derivative is methylbenzotriazole (TTA) or carboxyl-modified benzotriazole, wherein carboxyl-modified benzotriazole is preferred when the thin noble metal functional layer is a chemical immersion gold system, and methylbenzotriazole is preferred when the thin noble metal functional layer is a chemical immersion silver system; the surface-modified nano silica particles are hydroxyl-modified monodisperse nano silica sols with a particle size of 10-20 nm.

[0016] An integrated process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating, used to fabricate the aforementioned integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating, includes the following steps: Step S1: The DPC ceramic substrate body is subjected to micro-etching, activation and water washing pretreatment to remove the oxide layer and contaminants on the surface of the copper substrate, and a copper diffusion barrier layer is formed on the surface of the copper substrate. Step S2: Immerse the DPC ceramic substrate body with the copper diffusion barrier layer into the electroless gold or electroless silver plating bath for the main plating reaction until the plating thickness reaches 90% to 95% of the target value to form a thin noble metal functional layer. Step S3: When the main plating reaction is 30-60 seconds remaining, a sealing passivating agent is uniformly injected into the plating solution to make the final mass concentration of the passivating agent in the plating solution reach 0.1-0.3 g / L. By utilizing the original temperature of the plating solution and the high activity of the coating surface, the passivating components diffuse in a direction and are adsorbed at the pores and grain boundaries of the coating, thus completing the plating finishing and pore sealing simultaneously. The entire process is completed in the same tank to form a passivation layer. Step S4: After the reaction is complete, remove the DPC ceramic substrate, wash it with two stages of countercurrent pure water, and then dry it with hot air circulation at 100-110℃ for 8-12 minutes.

[0017] As a preferred embodiment, the sealing and passivating agent is an aqueous system with a pH value consistent with that of the plating solution, wherein the pH of the gold plating system is 4.5–5.5 and the pH of the silver plating system is 4.0–5.0; the sealing and passivating agent comprises, by mass percentage: 40%–50% alkyl-modified benzotriazole derivative, 20%–30% surface-modified monodisperse nano-silica sol, 5%–10% low molecular weight nonionic surfactant, and 10%–20% weak organic acid salt pH buffer adjuster.

[0018] As a preferred embodiment, the low molecular weight nonionic surfactant is PEG-400, PEG-600, or a citrate ester; the weak organic acid salt is sodium citrate or sodium borate; the pore-sealing passivating agent also contains nano-palladium catalytic particles with a particle size of 2-5 nm, added at an amount of 0.01-0.03 g / L, to simultaneously improve the nucleation rate of gold wire bond synthesis.

[0019] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, as can be seen from the above technical solution: 1. In-situ integrated process with zero additional steps: The sealing and passivating agent is injected at the time when the surface activity of the coating is at its highest at the end of the plating process. The entire process is completed in the same tank without the need to change tanks or expose air. No additional process steps or equipment investment are required, and the production efficiency is comparable to that of conventional plating processes.

[0020] 2. Targeted filling, preserving surface metallic properties: The passivation component only fills the pores and grain boundary defects of the coating, without forming a continuous covering film on the flat surface. The coating surface still maintains pure metallic properties, and has almost no adverse effects on solderability (wetting time ≤1.5s), bonding strength (tensile strength increase ≥10%) and contact resistance (change rate ≤5%).

[0021] 3. Dual sealing mechanism for significant corrosion protection: Benzotriazole derivatives form a molecular-level passivation film through chemical coordination bonds, while nano-silica particles fill the pore channels through physical sealing. The two work synergistically to effectively block the penetration path of corrosive media and greatly improve salt spray and sulfur resistance.

[0022] 4. Excellent plating solution compatibility: The sealing and passivating agent is an aqueous system with pH pre-adjusted to match the main plating solution. After injection, it does not disturb the acid-base balance of the plating solution and does not affect the main plating reaction rate or the coating quality.

[0023] 5. Wide applicability: It is applicable to both chemical immersion gold and chemical immersion silver systems, and can be flexibly selected according to different application requirements; the optional addition of nano-palladium catalyst particles further expands its application in high-end bonding and encapsulation scenarios.

[0024] 6. Controllable cost: Reliable protection can be achieved with only a low concentration (0.1-0.3 g / L) of sealing passivating agent without increasing the gold layer thickness, resulting in minimal increase in material cost.

[0025] To more clearly illustrate the structural features and effects of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0026] Figure 1 This is a cross-sectional schematic diagram of the integrated structure of in-situ targeted sealing and passivation of DPC ceramic substrate after plating according to the present invention.

[0027] Explanation of reference numerals in the attached diagram: 10. DPC ceramic substrate body 11. Ceramic base layer 12. Copper substrate; 20. Copper diffusion barrier layer 30. Thin precious metal functional layer; 40. Passivation layer. Detailed Implementation

[0028] Please refer to Figure 1 As shown, it illustrates the specific structure of the integrated structure of in-situ targeted sealing and passivation of DPC ceramic substrate after plating according to the present invention, which includes a DPC ceramic substrate body 10.

[0029] The DPC ceramic substrate body 10 includes a ceramic base layer 11 and a copper base layer 12. The copper base layer 12 is formed on the surface of the ceramic base layer 11 by DPC process. A copper diffusion barrier layer 20 is formed on the surface of the copper base layer 12. A thin noble metal functional layer 30 is formed on the surface of the copper diffusion barrier layer 20. A passivation layer 40 is formed on the surface of the thin noble metal functional layer 30 by targeted pore filling.

[0030] The copper substrate 12 undergoes pretreatment micro-etching, resulting in a roughness Ra of 0.05–0.15 μm. The copper diffusion barrier layer 20 is an electroless nickel plating layer or a copper barrier layer, with a thickness of 0.5–5 μm. This layer prevents copper atoms from diffusing into the thin noble metal functional layer. The thin noble metal functional layer 30 is an electroless gold immersion layer or an electroless silver immersion layer. The electroless gold immersion layer has a thickness of 0.05–0.1 μm and a purity ≥99.9%; the electroless silver immersion layer has a thickness of 0.2–0.5 μm and a purity ≥99.9%. The passivation layer 40 has a discontinuous discrete structure without a continuous surface coating. It is distributed within the nanopores and grain boundary defects of the thin noble metal functional layer 30, physically blocking and chemically passivating corrosion channels. The overall thickness increment of the passivation layer 40 is ≤10 nm. The passivation layer 40 comprises an alkyl-modified benzotriazole derivative and surface-modified nano-silica particles. The alkyl-modified benzotriazole derivative is methylbenzotriazole (TTA) or carboxyl-modified benzotriazole, with a small molecular size. It preferentially adsorbs onto pores / grain boundaries through coordination bonds to form a monomolecular passivation film. When the thin noble metal functional layer is a chemical immersion gold system, carboxyl-modified benzotriazole is preferred, and when the thin noble metal functional layer is a chemical immersion silver system, methylbenzotriazole is preferred. The surface-modified nano-silica particles are hydroxyl-modified monodisperse nano-silica sol with a particle size of 10-20 nm. The hydroxyl-modified monodisperse nano-silica sol diffuses into the pores with the plating solution and anchors with the corrosion inhibitor molecules to form a physical seal.

[0031] This invention also discloses an integrated process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating, used to fabricate the aforementioned integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating, comprising the following steps: Step S1 involves micro-etching, activation, and water washing pretreatment of the DPC ceramic substrate body 10 to remove the oxide layer and contaminants on the surface of the copper substrate 12, and forming a copper diffusion barrier layer 20 on the surface of the copper substrate 12.

[0032] Step S2: Immerse the DPC ceramic substrate body 10 with the copper diffusion barrier layer 20 into the electroless gold or electroless silver plating bath for the main plating reaction until the plating thickness reaches 90% to 95% of the target value, so as to form a thin noble metal functional layer 30.

[0033] Step S3: When the main plating reaction has 30-60 seconds remaining, a sealing passivating agent is uniformly injected into the plating solution to achieve a final mass concentration of 0.1-0.3 g / L. Utilizing the original temperature of the plating solution and the high activity of the plating surface, the passivating components diffuse directionally and adsorb onto the pores and grain boundaries of the plating layer, simultaneously completing the plating process and sealing the pores. The entire process is completed in the same tank to form a passivation layer 40. This sealing passivating agent is an aqueous system with a pH value consistent with the pH value of the plating solution. The pH of the gold plating system is 4.5-5.5, and the pH of the silver plating system is 4.0-5.0. The sealing passivating agent, by mass percentage, comprises: 40%-50% alkyl-modified benzotriazole derivative, 20%-30% surface-modified monodisperse nano-silica sol, 5%-10% low molecular weight nonionic surfactant, and 10%-20% weak organic acid salt pH buffer adjuster. The low molecular weight nonionic surfactant is PEG-400, PEG-600, or a citrate ester to prevent the agglomeration of nano-silicon particles and ensure uniform miscibility between the agent and the plating bath. The weak organic acid salt is sodium citrate or sodium borate to pre-adjust the pH of the sealing passivation agent to match that of the main plating bath, ensuring that the acid-base balance is not disturbed after injection. The sealing passivation agent also contains nano-palladium catalyst particles with a particle size of 2-5 nm, added at a rate of 0.01-0.03 g / L, to simultaneously improve the nucleation rate of gold wire bond synthesis and increase the bond pull force by ≥10%. Furthermore, during the injection of the sealing passivation agent, the plating bath temperature is maintained at the main plating reaction temperature, the injection rate is uniform and continuous, and the injection time is controlled within 10-30 seconds. Moreover, the passivation layer 40 does not form a continuous covering film on the surface of the thin noble metal functional layer 30, the surface contact resistance change rate is ≤5%, and the solderability wetting time is ≤1.5 seconds.

[0034] Step S4: After the reaction is complete, remove the DPC ceramic substrate, wash it with two stages of countercurrent pure water, and then dry it with hot air circulation at 100-110℃ for 8-12 minutes.

[0035] The present invention will be further described in detail below with reference to several embodiments and comparative examples: Example 1: In-situ targeted passivation of DPC ceramic substrates using chemical immersion gold system (1) Substrate preparation: Alumina (Al2O3) ceramic substrate with dimensions of 114.3mm×114.3mm×0.38mm is selected. The surface is formed with copper substrate 12 (copper lines and copper pads) by DPC process. The surface of copper pads is micro-etched and the roughness Ra is about 0.10μm.

[0036] (2) Copper diffusion barrier layer: Nickel is chemically plated on the surface of the copper pad with a thickness of 2μm, which serves as the copper diffusion barrier layer 20.

[0037] (3) Main plating reaction: Immerse the DPC ceramic substrate body 10 into a chemical immersion gold plating bath (pH 5.0, temperature 85℃) to carry out the immersion gold reaction. The target thickness of the gold layer is 0.08μm (about 3.15μin). When the gold layer thickness reaches about 0.072μm (90% of the target value), proceed to the next step.

[0038] (4) In-situ sealing and passivation in the same plating tank: When the main plating reaction has about 45 seconds remaining, a concentrated solution of the sealing and passivating agent is injected into the plating tank at a constant rate and completed within 20 seconds, so that the final mass concentration of the passivating agent in the plating solution reaches 0.2 g / L. The sealing and passivating agent formula used is: 45 wt% carboxyl-modified benzotriazole, 25 wt% hydroxyl-modified nano silica sol (particle size 15 nm), 8 wt% PEG-400, 17 wt% sodium citrate, and the balance is deionized water, with the pH pre-adjusted to 5.0. After injection, the reaction continues until the total time is reached, and the final thickness of the gold layer reaches 0.08 μm.

[0039] (5) Post-processing: Take out the DPC ceramic substrate and wash it with two stages of countercurrent pure water (resistivity ≥15MΩ•cm) for 30s each to remove residual agents on the surface; then dry it in a 105℃ hot air circulating oven for 10min to complete the entire process.

[0040] In the obtained coating structure, the thickness increment of the pore-targeted passivation layer is about 5-8 nm, distributed in the grain boundaries of the gold layer and inside the nanopores. The surface of the gold layer still exhibits a pure metallic luster, and XPS analysis confirms that the surface gold element accounts for ≥99.5%.

[0041] Example 2: In-situ targeted passivation of DPC ceramic substrates using a chemical silver impregnation system (1) Substrate preparation: Aluminum nitride (AlN) ceramic substrate with dimensions of 50mm×50mm×0.25mm is selected. The surface is formed with copper substrate 12 (copper lines and copper pads) by DPC process. The surface of the copper pads is micro-etched and the roughness Ra is about 0.08μm.

[0042] (2) Main plating reaction: The DPC ceramic substrate body 10 is immersed in a chemical silver plating bath (pH 4.5, temperature 50℃) to carry out the silver plating reaction. The target thickness of the silver layer is 0.3μm. When the silver layer thickness reaches about 0.27μm (90% of the target value), proceed to the next step.

[0043] (3) In-situ sealing and passivation in the same plating tank: When the main plating reaction has about 40 seconds remaining, a concentrated solution of the sealing and passivating agent is injected into the plating tank at a uniform rate, and the injection is completed within 15 seconds, so that the final mass concentration of the passivating agent in the plating solution reaches 0.15 g / L. The sealing and passivating agent formula used is: 48 wt% methylbenzotriazole (TTA), 22 wt% hydroxyl-modified nano silica sol (particle size 12 nm), 7 wt% PEG-600, 15 wt% sodium borate, and the balance is deionized water, with the pH pre-adjusted to 4.5. After injection, the reaction continues until the total time is reached, and the final thickness of the silver layer reaches 0.3 μm.

[0044] (4) Post-processing: Take out the DPC ceramic substrate, wash it with two stages of countercurrent pure water for 30s each, and then dry it in a 100℃ hot air circulating oven for 12min.

[0045] In the obtained coating structure, the thickness increment of the pore-targeted filling passivation layer is about 3 to 6 nm, and the surface of the silver layer still retains the pure silver metal properties. TGA-DSC analysis confirms that the passivation components are only enriched inside the pores, and there is no continuous film covering the surface.

[0046] Example 3: Chemical immersion gold system containing nano-palladium catalyst particles The basic process is the same as in Example 1, except that palladium nanoparticles with a particle size of approximately 3 nm are additionally added to the pore-sealing passivating agent at a concentration of 0.02 g / L. The resulting coating simultaneously enriches palladium nanoparticles in the pores of the gold layer. Gold wire bonding tests (25 μm gold wire, ultrasonic + hot-press bonding) showed an average bonding pull force of 12.5 gf, an increase of approximately 11.6% compared to the control group without palladium (11.2 gf). Furthermore, the fracture mode was gold wire breakage (rather than interface peeling), indicating excellent bonding interface quality.

[0047] Comparative Example 1: Conventional chemical immersion gold (without pore sealing and passivation) Using the same DPC ceramic substrate and nickel plating process as in Example 1, conventional chemical immersion gold was applied to a thickness of 0.08 μm. After plating, the substrate was directly removed, washed, and dried without any sealing or passivation treatment.

[0048] Comparative Example 2: Traditional Offline Thick Film Passivation After the immersion gold process in Example 1 is completed, the substrate is transferred to a separate organic passivation tank and immersed in a conventional organic passivating agent (concentration 5g / L) for 60s. After being taken out, washed with water and dried, a continuous organic passivation film (thickness of about 50-100nm) is formed on the surface of the gold layer.

[0049] Performance Testing and Comparison The following performance tests were performed on the above-described embodiments and comparative samples:

[0050] Test results show that the coatings of Examples 1-3 of the present invention maintain excellent solderability and bonding performance, while their salt spray resistance and sulfurization resistance are significantly better than those of untreated conventional coatings (Comparative Example 1). Compared with traditional offline thick film passivation (Comparative Example 2), the present invention does not damage the surface metallic properties, and the wetting time, contact resistance and bonding pull force are all far superior to the traditional solution.

[0051] Process parameter optimization explanation: After extensive experimental verification, the preferred range of key process parameters for this invention is as follows: When the main plating completion is controlled at 90% to 95%, the sealing passivating agent is injected to ensure that the main structure of the plating layer has been formed and the surface still maintains high activity; the injection time is 30 to 60 seconds remaining. If the time is too short, the passivating agent will not diffuse sufficiently, and if the time is too long, the surface activity of the plating layer will decrease, resulting in a weakening of the targeted adsorption effect; the final concentration of the passivating agent is 0.1 to 0.3 g / L, which is the optimal range. If the concentration is too low, the sealing will not be complete, and if the concentration is too high, it may cause slight film formation on the surface.

[0052] The preferred method for injecting the sealing and passivating agent is continuous injection at a uniform rate, with the injection time controlled within 10–30 seconds. This avoids plating defects caused by excessively high local concentrations due to a single pour. During the injection process, the plating solution temperature remains constant at the main plating reaction temperature, eliminating the need for additional heating or cooling.

[0053] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are merely for explaining the principles of the invention and should not be construed as limiting the scope of protection of the invention in any way. Based on this explanation, those skilled in the art can readily conceive of other specific embodiments of the invention without inventive effort, and these embodiments will all fall within the scope of protection of the present invention.

Claims

1. An integrated structure for in-situ targeted sealing and passivation of a DPC ceramic substrate after plating, comprising a DPC ceramic substrate body, the DPC ceramic substrate body comprising a ceramic base layer and a copper substrate, the copper substrate being formed on the surface of the ceramic base layer by a DPC process; characterized in that: A copper diffusion barrier layer is formed on the surface of the copper substrate, a thin noble metal functional layer is formed on the surface of the copper diffusion barrier layer, and a passivation layer is formed on the surface of the thin noble metal functional layer by targeted filling of pores.

2. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 1, characterized in that: The copper substrate surface undergoes pretreatment micro-etching, with a roughness Ra of 0.05–0.15 μm.

3. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 1, characterized in that: The copper diffusion barrier layer is a chemically plated nickel layer or a copper barrier layer with a thickness of 0.5 to 5 μm. This copper diffusion barrier layer is used to prevent copper atoms from diffusing into the thin noble metal functional layer.

4. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 1, characterized in that: The thin noble metal functional layer is a chemical immersion gold layer or a chemical immersion silver layer. The thickness of the chemical immersion gold layer is 0.05 to 0.1 μm and the purity of the chemical immersion gold layer is ≥99.9%. The thickness of the chemical immersion silver layer is 0.2 to 0.5 μm and the purity of the chemical immersion silver layer is ≥99.9%.

5. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 1, characterized in that: The passivation layer has a discontinuous discrete structure and no continuous surface covering film. It is distributed in the nanopores and grain boundary defects of the thin noble metal functional layer, forming physical blockage and chemical passivation of corrosion channels. The overall thickness increment of the passivation layer is ≤10nm.

6. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrate after plating as described in claim 1, characterized in that: The passivation layer comprises alkyl-modified benzotriazole derivatives and surface-modified nano-silica particles.

7. The integrated structure for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 6, characterized in that: The alkyl-modified benzotriazole derivative is methylbenzotriazole (TTA) or carboxyl-modified benzotriazole, wherein carboxyl-modified benzotriazole is preferred when the thin noble metal functional layer is a chemical immersion gold system, and methylbenzotriazole is preferred when the thin noble metal functional layer is a chemical immersion silver system; the surface-modified nano silica particles are hydroxyl-modified monodisperse nano silica sol with a particle size of 10-20 nm.

8. An integrated process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating, characterized in that, To fabricate an integrated structure for in-situ targeted sealing and passivation of a DPC ceramic substrate as described in any one of claims 1 to 7, the following steps are included: Step S1: The DPC ceramic substrate body is subjected to micro-etching, activation and water washing pretreatment to remove the oxide layer and contaminants on the surface of the copper substrate, and a copper diffusion barrier layer is formed on the surface of the copper substrate. Step S2: Immerse the DPC ceramic substrate body with the copper diffusion barrier layer into the electroless gold or electroless silver plating bath for the main plating reaction until the plating thickness reaches 90% to 95% of the target value to form a thin noble metal functional layer. Step S3: When the main plating reaction is 30-60 seconds remaining, a sealing passivating agent is uniformly injected into the plating solution to make the final mass concentration of the passivating agent in the plating solution reach 0.1-0.3 g / L. By utilizing the original temperature of the plating solution and the high activity of the coating surface, the passivating components diffuse in a direction and are adsorbed at the pores and grain boundaries of the coating, thus completing the plating finishing and pore sealing simultaneously. The entire process is completed in the same tank to form a passivation layer. Step S4: After the reaction is complete, remove the DPC ceramic substrate, wash it with two stages of countercurrent pure water, and then dry it with hot air circulation at 100-110℃ for 8-12 minutes.

9. The integrated process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 8, characterized in that: The sealing and passivating agent is an aqueous system with a pH value consistent with that of the plating solution. The pH of the gold plating system is 4.5–5.5, and the pH of the silver plating system is 4.0–5.

0. The sealing and passivating agent comprises, by mass percentage: 40%–50% alkyl-modified benzotriazole derivative, 20%–30% surface-modified monodisperse nano-silica sol, 5%–10% low molecular weight nonionic surfactant, and 10%–20% weak organic acid salt pH buffer adjuster.

10. The integrated process for in-situ targeted sealing and passivation of DPC ceramic substrates after plating as described in claim 9, characterized in that: The low molecular weight nonionic surfactant is PEG-400, PEG-600 or citrate ester; the weak organic acid salt is sodium citrate or sodium borate; the pore-sealing passivating agent also contains nano-palladium catalytic particles with a particle size of 2-5 nm, added at an amount of 0.01-0.03 g / L, used to simultaneously improve the nucleation rate of gold wire bond synthesis.

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