Electroplating process based on ceramic through hole filling

Abstract

The invention discloses a hole-filling electroplating process based on ceramic through holes, and relates to the field of advanced packaging of semiconductors. The hole-filling electroplating process based on the ceramic through hole comprises the following steps that a copper-clad substrate is subjected to laser through hole drilling through an optical fiber laser, after primary cleaning, grinding and polishing, soaking, secondary cleaning and blow-drying are carried out, the laser is used for repeatedly punching the punched position to the position of a copper sheet, and a drilled sample is obtained; and performing titanium-copper magnetron sputtering on the drilling sample, placing the drilling sample in a hole-filling electroplating solution for pulse electroplating, and grinding and polishing to obtain the hole-filling ceramic substrate. Raw materials of the hole-filling electroplating liquid comprise CuSO4, H2SO4, Cl <->, a brightening agent, a leveling agent and a wetting agent. The brightener is a composite heterocyclic brightener; the leveling agent comprises one or two of 1, 2, 4-triazole and 5-amino-1, 3, 4-thiadiazole-2-mercaptan, and the curing agent comprises one or two of 1, 2, 4-triazole and 5-amino-1, 3, 4-thiadiazole-2-mercaptan. And the wetting agent is a fatty amine ethyoxyl sulfonated substance.

Description

Technical Field

[0001] The present invention relates to the field of advanced semiconductor packaging, and in particular to a ceramic through-hole filling electroplating process. Background Art

[0002] In the field of electronic packaging, ceramic substrates, due to their excellent thermal conductivity and insulation properties, have become a popular interconnect carrier for high-frequency devices. They are widely used in new energy vehicle electronic control systems, photovoltaic inverters, and quantum dot display backplanes. Furthermore, the continued expansion of ceramic substrates in UV LED packaging and automotive radar is driving the evolution of electronic packaging towards higher density and multifunctionality, placing higher demands on through-hole filling in ceramic substrates.

[0003] However, the through-hole filling process for ceramic substrates faces multiple technical bottlenecks. First, conventional acidic copper plating systems often use a single brightener compounded with a leveling agent. This leads to an imbalance in the adsorption competition between the additives, hindering the transfer of copper ions at the bottom of the hole, often resulting in voids and incomplete hole filling. Inadequate optimization of pulse electroplating process parameters can easily lead to stress concentration within the coating and excessive surface roughness. Furthermore, the plating solution system is sensitive to fluctuations in Cl- concentration and has a low tolerance for impurities, making it difficult to meet the consistent filling requirements for high-aspect-ratio through-holes. Secondly, ceramic surface metallization typically utilizes a single chemical plating or sputtering process, which suffers from insufficient coating adhesion and high interface resistance. Laser drilling, due to the high hardness of ceramic materials, makes it difficult to achieve precise through-hole processing, resulting in microcracks and molten residue on the hole wall. These technical limitations restrict the application of ceramic substrates in high-density interconnect packaging, and breakthroughs are urgently needed in pretreatment processes, electroplating solution formulation design, and coordinated optimization of electroplating parameters.

[0004] In summary, in order to solve the above problems, it is of great practical significance to develop a ceramic through-hole filling electroplating process. Summary of the Invention

[0005] The object of the present invention is to provide a ceramic through-hole filling electroplating process to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A ceramic through-hole filling electroplating process comprises the following steps:

[0008] S1: Use a fiber laser to drill through holes in the copper-clad substrate. After cleaning, polishing, soaking and cleaning for a second time, and drying, use the laser to repeatedly drill holes at the drilled position to the copper sheet to obtain a drilled sample.

[0009] S2: The drilled sample is magnetron sputtered with titanium copper, placed in a hole-filling plating solution for pulse electroplating, and polished to obtain a hole-filling ceramic substrate.

[0010] More optimally, the raw materials of the hole filling electroplating solution include CuSO4, H2SO4, Cl - , brightener, leveling agent, wetting agent.

[0011] More optimally, the brightener is a complex heterocyclic brightener; the leveler includes one or two of 1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol; and the wetting agent is a fatty amine ethoxy sulfonate.

[0012] More optimally, the preparation method of the composite heterocyclic brightener is as follows: S1: at room temperature, dissolving NaOH in methanol as a solvent; sequentially adding 2-mercapto-4-aminopyrimidine and 1,3-propane sultone to the solvent, stirring and dissolving; washing and drying to obtain a heterocyclic brightener;

[0013] S2: Add methacryloyloxyethyl trimethylammonium chloride-acrylamide copolymer into deionized water, then add heterocyclic brightener, and stir for 30 to 40 minutes to obtain a composite heterocyclic brightener.

[0014] More optimally, in the solvent raw material, the mass ratio of NaOH to methanol is 1:(12-25); in the heterocyclic brightener raw material, the mass ratio of 2-mercapto-4-aminopyrimidine to 1,3-propane sultone is (1-3):(2-4); in the composite heterocyclic brightener raw material, the mass ratio of methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer, deionized water, and heterocyclic brightener is (1-3):(5-10):(1.5-4.5).

[0015] More optimally, the raw materials of the hole filling electroplating solution include the following components in terms of mass-volume concentration: CuSO4 200-260 g / L, H2SO4 50-90 g / L, Cl - 30-100 ppm, 1,2,4-triazole 0.5-1 ppm, 5-amino-1,3,4-thiadiazole-2-thiol 0.8-1.2 mg / L, complex heterocyclic brightener 3-5 mg / L, fatty amine ethoxysulfonate 30-50 ppm. Optimally, during the laser drilling process, the aperture is 0.02-0.3 mm, the ceramic thickness to aperture ratio is (2-6):1; the fiber laser has a maximum power of 140-160 W, a wavelength of 1050-1100 nm, a power of 18-22%, a frequency of 450-550 Hz, a speed of 75-85 mm / s, and a drilling rate of 750-850 holes / min.

[0016] More optimally, in the magnetron sputtering titanium copper process, the process parameters are as follows: the target material is titanium, the sputtering thickness of the titanium layer is 0.04-0.08 μm, and the sputtering power is 4-6 kW; the target material is copper, the copper layer thickness is 0.06-1.0 μm, and the sputtering power is 4-8 kW.

[0017] More optimally, the pulse plating operation process is as follows: the sputtered ceramic substrate is placed in the hole-filling plating solution, with the titanium-iridium-ruthenium mesh as the anode, the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 1-2ASD, the plating time is 100-140 minutes, and the plating surface coating thickness is 2-6μm.

[0018] In the preparation process of the composite heterocyclic brightener, a nucleophilic substitution-ring-opening reaction occurs in S1, and a sodium sulfonate group is introduced to obtain a heterocyclic brightener; in S2, a methacryloyloxyethyl trimethyl ammonium chloride-acrylamide copolymer and a heterocyclic brightener are compounded by electrostatic action to obtain a composite heterocyclic brightener; the sodium sulfonate group dissociates into an anionic form in the electroplating solution, and the methacryloyloxyethyl trimethyl ammonium chloride-acrylamide copolymer is a cationic polymer. The two form a complex through electrostatic attraction, which can construct an alternating adsorption layer on the cathode surface to regulate the copper ion The local concentration of ions and the reducing environment; and the long-chain structure of the methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer can form a physical barrier at the pore mouth, inhibiting the rapid deposition of copper at the pore mouth; the pyridine ring and the amino group can be directionally adsorbed, preferentially accelerating the deposition of copper at the bottom of the pore. The combination of the two can achieve a dynamic balance of "pore mouth inhibition-pore bottom acceleration" to meet the pore filling requirements, and the amino group can enhance the adsorption activity of sulfur atoms through the electron donor effect, while forming a hydrogen bond network with the amide group of the copolymer, stabilizing the interface between the two and improving the ability to regulate the copper deposition process.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention proposes a ceramic through-hole filling electroplating process method, which innovatively constructs a single-sided plated through-hole structure and adopts a single-sided plated through-hole technology to avoid the core-wrapped phenomenon. At the same time, it realizes direct through-hole plating in one time, simplifies the traditional complex process steps, and solves the problems of low efficiency and poor reliability of multi-layer vertical circuit interconnection.

[0021] (2) The present invention effectively solves the problems of high-diameter through-hole filling defects, electroplating "dog-bone effect", and interface thermal stress through innovative formula and precise configuration of the hole-filling electroplating solution, thereby achieving an overall improvement in the performance of the ceramic substrate; effectively reduces the electroplating time, and significantly optimizes the electroplating hole-filling effect.

[0022] Among them, in the hole filling electroplating solution system, on the basis of the traditional formula, a multi-component formula of brightener composite heterocyclic brightener, composite leveling agent 1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol, and brightener dithiocarbamate is added, and the titanium iridium ruthenium mesh anode pulse electroplating process is coupled to achieve super-conformal hole filling of ceramic through holes; the thiol and amino groups of 2-mercapto-4-aminopyrimidine in the composite heterocyclic brightener, the sulfonic acid group of 1,3-propane sultone, and the quaternary ammonium salt group and amide group of methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer work synergistically. During the electroplating process, the thiol and amino groups form coordination compounds with copper ions through lone pairs of electrons, reducing the overpotential of copper deposition and promoting the uniform reduction of copper ions; the sulfonic acid group enhances the ion conductivity of the electroplating solution by virtue of its strong hydrophilicity and inhibits the precipitation of hydrogen bubbles; and the quaternary ammonium salt group acts as a cationic active center to attract SO4 2- or Cl - , synergistically enhance the activity of heterocyclic brighteners and accelerate the deposition of copper at the bottom of the pores; the amide group stabilizes the copper ion complex and effectively regulates the deposition rate; these active groups work synergistically to not only improve the uniformity and density of copper deposition, but also enhance the interfacial bonding strength between the coating and the ceramic substrate, thereby reducing the resistivity and improving the overall performance.

[0023] In addition, the heterocyclic nitrogen atoms in the composite leveler 1,2,4-triazole are adsorbed at the pore mouth, hindering copper deposition, and the thiol group of 5-amino-1,3,4-thiadiazole-2-thiol enhances the adsorption force, making the deposition rate inside the pore greater than that at the pore mouth, thus achieving bottom-up filling. The wetting agent fatty amine ethoxy sulfonate can reduce the surface tension of the pore-filling electroplating solution, and the polyether chain is embedded in the pore wall to ensure that the electroplating solution fully infiltrates deep holes and micropores. The above components work synergistically, the leveler inhibits pore mouth deposition and the brightener promotes the reaction at the bottom of the pore to achieve two-way regulation, realizing a filling effect from the bottom of the ceramic upwards, avoiding pore mouth closure and causing voids. The wetting agent ensures that the plating solution penetrates to the bottom of the deep hole, providing a site for the brightener and leveler to act, preventing local concentration imbalance. Cl- acts as a bridge to form a complex with the brightener, enhancing cathode adsorption and improving pore filling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the through hole of the tile;

[0025] Figure 2 This is a schematic diagram of porcelain sheet-thin copper;

[0026] Figure 3 This is a schematic diagram of drilling holes in a copper-clad substrate;

[0027] Figure 4 Schematic diagram of substrate sputtering;

[0028] Figure 5 Schematic diagram of electroplating of hole-filled ceramic substrate. DETAILED DESCRIPTION

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] It should be noted that, in parts by weight, all raw materials involved in the present invention are purchased from manufacturers without any special restrictions and exemplarily include: in the following embodiments, 1,2,4-triazole (CAS: 288-88-0), 5-amino-1,3,4-thiadiazole-2-thiol (CAS: 2349-67-9), 2-mercapto-4-aminopyrimidine (CAS: 333-49-3), 1,3-propane sultone (CAS: 1120-71-4), methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer (CAS: 67504-24-9), fatty amine ethoxy sulfonate (provided by Wuhan Chifei Chemical Co., Ltd.), and other raw materials are commercially available.

[0031] Example 1:

[0032] 1. Preparation of composite heterocyclic brightener: S1: Dissolve 1 part of NaOH in 18 parts of methanol as solvent at room temperature; add 2 parts of 2-mercapto-4-aminopyrimidine and 2 parts of 1,3-propane sultone to the solvent in sequence, stir and dissolve; wash and dry to obtain a heterocyclic brightener;

[0033] S2: Add 2 parts of methacryloyloxyethyl trimethyl ammonium chloride-acrylamide copolymer to 6 parts of deionized water, then add 3 parts of heterocyclic brightener, stir for 30 minutes, wash and dry to obtain a composite heterocyclic brightener.

[0034] 2. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 200g / L and stir for 10 minutes; slowly add H2SO4 to a concentration of 50g / L, stir and cool to room temperature; add 30ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0035] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them, respectively, to a concentration of 0.5 ppm and 0.8 mg / L, and add them to the base electrolyte in turn; then mix the brightener (3 mg / L composite heterocyclic brightener) and wetting agent (30 ppm fatty amine ethoxy sulfonate) with them, stir for 30 minutes, and obtain the hole-filling plating solution.

[0036] 3. Pre-preparation of copper-clad substrate: Coat the surface of a 3-inch, 0.38mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in 8% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes and dry to obtain a copper-clad substrate.

[0037] 4. A ceramic through-hole filling electroplating process

[0038] S1: A fiber laser is used to laser drill a through hole in a copper-clad substrate, with a hole diameter of 0.1 mm and a ceramic thickness to hole diameter ratio of 3.8:1. The fiber laser has a maximum power of 150 W, a wavelength of 1064 nm, a power of 20%, a frequency of 500 Hz, a speed of 80 mm / s, and a drilling rate of 800 holes / min. A laser through hole 302 is formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0039] S2: The drilled ceramic piece is cleaned and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the fiber laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, artificially constructing blind holes, and the above cleaning, polishing, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0040] S3: magnetron sputtering titanium copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the target material is titanium, the titanium layer is sputtered to a thickness of 0.06 μm, and the sputtering power is 5 kW; the target material is copper, the copper layer is 0.8 μm thick, and the sputtering power is 6 kW, to obtain a ceramic substrate with a sputtering seed layer;

[0041] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 1.5ASD, the plating time is 120min, and the thickness of the electroplated surface coating is 4μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0042] Example 2:

[0043] 1. Preparation of a composite heterocyclic brightener: S1: Dissolve 1 part of NaOH in 12 parts of methanol as a solvent at room temperature; add 1 part of 2-mercapto-4-aminopyrimidine and 2 parts of 1,3-propane sultone to the solvent in sequence, stir and dissolve; wash and dry to obtain a heterocyclic brightener;

[0044] S2: Add 1 part of methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer to 5 parts of deionized water, then add 1.5 parts of heterocyclic brightener, stir for 35 minutes, wash and dry to obtain a composite heterocyclic brightener.

[0045] 2. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 220g / L and stir for 10 minutes; slowly add H2SO4 to a concentration of 60g / L, stir and cool to room temperature; add 50ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0046] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them, respectively, to a concentration of 0.75 ppm and 1.0 mg / L, and add them to the base electrolyte in turn; then mix the brightener (4 mg / L composite heterocyclic brightener) and wetting agent (40 ppm fatty amine ethoxy sulfonate) with them, stir for 35 minutes, and obtain the hole-filling electroplating solution.

[0047] 3. Preparing the copper-clad substrate: Coat the surface of a 4-inch, 0.1mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in a 2% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes to obtain the copper-clad substrate.

[0048] 4. A ceramic through-hole filling electroplating process

[0049] S1: Laser drilling a through hole in a copper-clad substrate with a hole diameter of 0.05 mm and a ceramic thickness to hole diameter ratio of 2:1. The fiber laser has a maximum power of 140 W, a wavelength of 1050 nm, a power of 18%, a frequency of 450 Hz, a speed of 75 mm / s, and a drilling rate of 750 holes / min. Laser through holes 302 are formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0050] S2: The drilled ceramic piece is cleaned, ground and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, and blind holes are artificially constructed. The above cleaning, grinding, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0051] S3: magnetron sputtering titanium and copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the titanium layer is sputtered to a thickness of 0.04 μm and the sputtering power is 4 kW; the copper layer is 0.4 μm thick and the sputtering power is 4 kW, thereby obtaining a ceramic substrate with a sputtering seed layer;

[0052] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC electroplating current is 1ASD, the electroplating time is 100min, and the electroplating surface coating thickness is 2μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0053] Example 3:

[0054] 1. Preparation of a composite heterocyclic brightener: S1: Dissolve 1 part of NaOH in 25 parts of methanol as a solvent at room temperature; add 3 parts of 2-mercapto-4-aminopyrimidine and 4 parts of 1,3-propane sultone to the solvent in sequence, stir and dissolve; wash and dry to obtain a heterocyclic brightener;

[0055] S2: 3 parts of methacryloyloxyethyl trimethyl ammonium chloride-acrylamide copolymer were added to 10 parts of deionized water, and then 4.5 parts of heterocyclic brightener were added, and stirred for 40 minutes to obtain a composite heterocyclic brightener.

[0056] 2. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 260g / L and stir for 10 minutes; slowly add H2SO4 with a concentration of 90g / L, stir and cool to room temperature; add 100ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0057] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them respectively, making the concentrations of 1.0 ppm and 1.2 mg / L, and add them to the base electrolyte in turn; then mix the brightener (5 mg / L composite heterocyclic brightener) and wetting agent (50 ppm fatty amine ethoxy sulfonate) with them, stir for 40 minutes, and obtain the hole filling electroplating solution.

[0058] 3. Pre-preparation of copper-clad substrate: Coat the surface of a 4.5-inch, 1.5mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 280°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in a 15% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes to obtain a copper-clad substrate.

[0059] 4. A ceramic through-hole filling electroplating process

[0060] S1: Laser drilling a through hole in a copper-clad substrate with a hole diameter of 0.25 mm and a ceramic thickness to hole diameter ratio of 6:1. The fiber laser has a maximum power of 160 W, a wavelength of 1100 nm, a power of 22%, a frequency of 550 Hz, a speed of 85 mm / s, and a drilling rate of 850 holes / min. Laser through holes 302 are formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0061] S2: The drilled ceramic piece is cleaned, ground and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, and blind holes are artificially constructed. The above cleaning, grinding, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0062] S3: magnetron sputtering titanium and copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the titanium layer is sputtered to a thickness of 0.08 μm and the sputtering power is 6 kW; the copper layer is 1.0 μm thick and the sputtering power is 8 kW, thereby obtaining a ceramic substrate with a sputtered seed layer;

[0063] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 2ASD, the plating time is 140min, and the electroplating surface coating thickness is 6μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0064] Comparative Example 1: Based on Example 1, the hole-filling electroplating solution is a base electroplating solution, comprising the following steps:

[0065] 1. Basic electroplating solution configuration: Dissolve CuSO4 in deionized water at a concentration of 200g / L and stir for 10 minutes; slowly add H2SO4 at a concentration of 50g / L, stir and cool to room temperature; add 30ppm of Cl - , stir for 5 minutes to obtain the basic electroplating solution.

[0066] 2. Pre-preparation of copper-clad substrate: Coat the surface of a 3-inch, 0.38mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in 8% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes and dry to obtain a copper-clad substrate.

[0067] 3. A ceramic through-hole filling electroplating process

[0068] S1: A fiber laser is used to laser drill a through hole in a copper-clad substrate, with a hole diameter of 0.1 mm and a ceramic thickness to hole diameter ratio of 3.8:1. The fiber laser has a maximum power of 150 W, a wavelength of 1064 nm, a power of 20%, a frequency of 500 Hz, a speed of 80 mm / s, and a drilling rate of 800 holes / min. A laser through hole 302 is formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0069] S2: The drilled ceramic piece is cleaned and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the fiber laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, artificially constructing blind holes, and the above cleaning, polishing, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0070] S3: magnetron sputtering titanium copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the target material is titanium, the titanium layer is sputtered to a thickness of 0.06 μm, and the sputtering power is 5 kW; the target material is copper, the copper layer is 0.8 μm thick, and the sputtering power is 6 kW, to obtain a ceramic substrate with a sputtering seed layer;

[0071] S4: Place the ceramic substrate with the sputtered seed layer in the basic electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, with the hole position facing the titanium-iridium-ruthenium anode; the DC electroplating current is 1.5ASD, the electroplating time is 120min, and the electroplating surface coating thickness is 4μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface, thereby obtaining a hole-filled ceramic substrate.

[0072] Comparative Example 2: Based on Example 1, the composition of the composite heterocyclic brightener was adjusted, and 2-mercapto-4-aminopyrimidine and 1,3-propane sultone were added in a ratio of 2:1, comprising the following steps:

[0073] 1. Preparation of a composite heterocyclic brightener: S1: Dissolve 1 part of NaOH in 18 parts of methanol as a solvent at room temperature; add 4 parts of 2-mercapto-4-aminopyrimidine and 2 parts of 1,3-propane sultone to the solvent in sequence, stir and dissolve; wash and dry to obtain a heterocyclic brightener;

[0074] S2: Add 2 parts of methacryloyloxyethyl trimethyl ammonium chloride-acrylamide copolymer to 6 parts of deionized water, then add 3 parts of heterocyclic brightener, stir for 30 minutes, wash and dry to obtain a composite heterocyclic brightener.

[0075] 2. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 200g / L and stir for 10 minutes; slowly add H2SO4 to a concentration of 50g / L, stir and cool to room temperature; add 30ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0076] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them, respectively, to a concentration of 0.5 ppm and 0.8 mg / L, and add them to the base electrolyte in turn; then mix the brightener (3 mg / L composite heterocyclic brightener) and wetting agent (30 ppm fatty amine ethoxy sulfonate) with them, stir for 30 minutes, and obtain the hole-filling plating solution.

[0077] 3. Pre-preparation of copper-clad substrate: Coat the surface of a 3-inch, 0.38mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in 8% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes and dry to obtain a copper-clad substrate.

[0078] 4. A ceramic through-hole filling electroplating process

[0079] S1: A fiber laser is used to laser drill a through hole in a copper-clad substrate, with a hole diameter of 0.1 mm and a ceramic thickness to hole diameter ratio of 3.8:1. The fiber laser has a maximum power of 150 W, a wavelength of 1064 nm, a power of 20%, a frequency of 500 Hz, a speed of 80 mm / s, and a drilling rate of 800 holes / min. A laser through hole 302 is formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0080] S2: The drilled ceramic piece is cleaned, ground and polished; soaked in 0.1molH2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the fiber laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, artificially constructing blind holes, and the above cleaning, grinding, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0081] S3: magnetron sputtering titanium copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the target material is titanium, the titanium layer is sputtered to a thickness of 0.06 μm, and the sputtering power is 5 kW; the target material is copper, the copper layer is 0.8 μm thick, and the sputtering power is 6 kW, to obtain a ceramic substrate with a sputtering seed layer;

[0082] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 1.5ASD, the plating time is 120min, and the thickness of the electroplated surface coating is 4μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0083] Comparative Example 3: Based on Example 1, only a heterocyclic brightener was added, comprising the following steps:

[0084] 1. Preparation of heterocyclic brightener: Under room temperature, dissolve 1 part of NaOH in 18 parts of methanol as a solvent; add 2 parts of 2-mercapto-4-aminopyrimidine and 2 parts of 1,3-propane sultone to the solvent in sequence, stir and dissolve; wash and dry to obtain a heterocyclic brightener.

[0085] 2. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 200g / L and stir for 10 minutes; slowly add H2SO4 to a concentration of 50g / L, stir and cool to room temperature; add 30ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0086] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them, respectively, to a concentration of 0.5 ppm and 0.8 mg / L, and add them to the base electrolyte in turn; then mix the brightener (3 mg / L heterocyclic brightener) and wetting agent (30 ppm fatty amine ethoxy sulfonate) with them, stir for 30 minutes, and obtain the hole-filling plating solution.

[0087] 3. Pre-preparation of copper-clad substrate: Coat the surface of a 3-inch, 0.38mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in 8% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes and dry to obtain a copper-clad substrate.

[0088] 4. A ceramic through-hole filling electroplating process

[0089] S1: A fiber laser is used to laser drill a through hole in a copper-clad substrate, with a hole diameter of 0.1 mm and a ceramic thickness to hole diameter ratio of 3.8:1. The fiber laser has a maximum power of 150 W, a wavelength of 1064 nm, a power of 20%, a frequency of 500 Hz, a speed of 80 mm / s, and a drilling rate of 800 holes / min. A laser through hole 302 is formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0090] S2: The drilled ceramic piece is cleaned and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the fiber laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, artificially constructing blind holes, and the above cleaning, polishing, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0091] S3: magnetron sputtering titanium copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the target material is titanium, the titanium layer is sputtered to a thickness of 0.06 μm, and the sputtering power is 5 kW; the target material is copper, the copper layer is 0.8 μm thick, and the sputtering power is 6 kW, to obtain a ceramic substrate with a sputtering seed layer;

[0092] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 1.5ASD, the plating time is 120min, and the thickness of the electroplated surface coating is 4μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0093] Comparative Example 4: Based on Example 1, the brightener composition was adjusted and commercially available sodium thiopropane sulfonate was added, comprising the following steps:

[0094] 1. Hole filling plating solution configuration: S1: Dissolve CuSO4 in deionized water to a concentration of 200g / L and stir for 10 minutes; slowly add H2SO4 to a concentration of 50g / L, stir and cool to room temperature; add 30ppm of Cl - , stirring for 5 minutes to obtain a basic electroplating solution;

[0095] S2: Add leveling agents (1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol) to hot water to dissolve them, respectively, to a concentration of 0.5 ppm and 0.8 mg / L, and add them to the base electrolyte in turn; then mix the brightener (3 mg / L sodium thiopropane sulfonate) with them and stir for 30 minutes to obtain a hole-filling electroplating solution.

[0096] 2. Pre-preparation of copper-clad substrate: Coat the surface of a 3-inch, 0.38mm ceramic sheet with a layer of nano-silver paste. Set the temperature to 250°C and vacuum-sinter a 100μm thick copper sheet on one side. Clean the surface in 8% dilute hydrochloric acid solution for 2 minutes, then ultrasonicate in an alcohol solution for 3 minutes and dry to obtain a copper-clad substrate.

[0097] 3. A ceramic through-hole filling electroplating process

[0098] S1: A fiber laser is used to laser drill a through hole in a copper-clad substrate, with a hole diameter of 0.1 mm and a ceramic thickness to hole diameter ratio of 3.8:1. The fiber laser has a maximum power of 150 W, a wavelength of 1064 nm, a power of 20%, a frequency of 500 Hz, a speed of 80 mm / s, and a drilling rate of 800 holes / min. A laser through hole 302 is formed by irradiating a high-power density laser beam; and a drilled ceramic tile is obtained.

[0099] S2: The drilled ceramic piece is cleaned and polished; soaked in 0.1 mol H2SO4 for 1 hour, ultrasonically cleaned in ultrapure water for 5 minutes, ultrasonically cleaned in alcohol for 3 minutes, and blown dry; laser drilling is performed using the fiber laser in S2, and holes are repeatedly drilled from the punched position of the ceramic piece to the position of the copper piece, artificially constructing blind holes, and the above cleaning, polishing, soaking, secondary cleaning, and blow-drying processes are repeated to obtain a ceramic substrate;

[0100] S3: magnetron sputtering titanium copper on the surface of the ceramic substrate and the hole wall as a seed layer for copper plating; the target material is titanium, the titanium layer is sputtered to a thickness of 0.06 μm, and the sputtering power is 5 kW; the target material is copper, the copper layer is 0.8 μm thick, and the sputtering power is 6 kW, to obtain a ceramic substrate with a sputtering seed layer;

[0101] S4: Place the ceramic substrate with the sputtered seed layer in the hole-filling electroplating solution, with the titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position facing the titanium-iridium-ruthenium anode; the DC plating current is 1.5ASD, the plating time is 120min, and the thickness of the electroplated surface coating is 4μm; use a high-precision semiconductor grinding and polishing machine with a speed of 30 rpm and cerium oxide as the grinding medium for 20min to obtain a smooth and flat surface to obtain a hole-filling ceramic substrate.

[0102] sample Bonding strength (N / mm) Resistivity (Ω·m) Example 1 13.2 <![CDATA[1.62×10 -8 ]]> Example 2 12.4 <![CDATA[1.76×10 -8 ]]> Example 3 12.6 <![CDATA[1.74×10 -8 ]]> Comparative Example 1 8.6 <![CDATA[2.07×10 -8 ]]> Comparative Example 2 10.6 <![CDATA[1.89×10 -8 <!-- 8 -->]]> Comparative Example 3 9.5 <![CDATA[1.92×10 -8 ]]> Comparative Example 4 11.4 <![CDATA[1.94×10 -8 ]]>

[0103] Performance testing: Based on IPC-TM-650 2.4.8 "Peel Strength Test" standard, a 180° peel tester is used to peel the copper foil from the surface of the ceramic substrate and measure the peel force per unit width. In accordance with IPC-TM-650 2.5.17 "Sheet Resistance Test Method", the four-probe method is used to test the resistivity of the coating.

[0104] Conclusion: The data from the examples and comparative examples show that the optimization of the via-filling plating solution formulations and process parameters in Examples 1-3 significantly improved the performance of ceramic substrates. The synergistic effects of the composite leveler in the plating solution, which inhibits deposition at the via openings, the brightener catalyzes the reduction of copper ions at the via bottoms, and the wetting agent ensures wetting of deep vias, along with the interfacial strengthening effect of the magnetron sputtering titanium-copper seed layer, achieve excellent coating bonding strength and electrical conductivity, demonstrating the adaptability and stability of the process system.

[0105] By comparing Example 1 with Comparative Examples 1 to 4, it can be seen that the use of only the basic electroplating solution, without the coordinated regulation of the brightener, leveler and wetting agent, will lead to disordered copper deposition, loose coating structure and insufficient interface bonding strength; after adjusting the composition of the brightener, a single active group or a key group is missing, and the copper deposition process cannot be precisely regulated, which affects the quality of the coating, resulting in a loose coating structure and weak interface bonding; the use of commercially available brighteners cannot meet the requirements for fine regulation of the deposition process, and ultimately leads to a decrease in coating bonding strength and conductive properties.

[0106] 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 embodied 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 illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A ceramic through-hole filling electroplating process, characterized by: The following steps are involved: S1: Use a fiber laser to drill through holes in the copper-clad substrate. After cleaning, polishing, soaking, secondary cleaning, and drying, use the laser to repeatedly drill holes at the drilled position to the copper sheet to obtain a drilled sample. S2: The drilled sample is magnetron sputtered with titanium copper, placed in a hole-filling plating solution for pulse electroplating, and polished to obtain a hole-filling ceramic substrate.

2. The ceramic through-hole filling electroplating process according to claim 1, characterized in that: The raw materials of the hole filling electroplating solution include CuSO4, H2SO4, Cl - , brightener, leveling agent, wetting agent.

3. The ceramic through-hole filling electroplating process according to claim 2, characterized in that: The brightener is a composite heterocyclic brightener; the leveler includes one or two of 1,2,4-triazole and 5-amino-1,3,4-thiadiazole-2-thiol; and the wetting agent is a fatty amine ethoxy sulfonate.

4. The ceramic through-hole filling electroplating process according to claim 3, characterized in that: The preparation method of the composite heterocyclic brightener is as follows: S1: dissolving NaOH in methanol as a solvent at room temperature; adding 2-mercapto-4-aminopyrimidine and 1,3-propane sultone to the solvent in sequence, stirring and dissolving; washing and drying to obtain the heterocyclic brightener; S2: Add methacryloyloxyethyl trimethylammonium chloride-acrylamide copolymer into deionized water, then add heterocyclic brightener, and stir for 30 to 40 minutes to obtain a composite heterocyclic brightener.

5. The ceramic through-hole filling electroplating process according to claim 4, characterized in that: In the solvent raw material, the mass ratio of NaOH to methanol is 1:(12-25); in the heterocyclic brightener raw material, the mass ratio of 2-mercapto-4-aminopyrimidine to 1,3-propane sultone is (1-3):(2-4); in the composite heterocyclic brightener raw material, the mass ratio of methacryloyloxyethyltrimethylammonium chloride-acrylamide copolymer, deionized water, and heterocyclic brightener is (1-3):(5-10):(1.5-4.5).

6. The ceramic through-hole filling electroplating process according to claim 1, characterized in that: The raw materials of the hole filling electroplating solution include the following components in terms of mass-volume concentration: CuSO4 200-260 g / L, H2SO4 50-90 g / L, Cl - 30~100ppm, 1,2,4-triazole 0.5~1ppm, 5-amino-1,3,4-thiadiazole-2-thiol 0.8~1.2mg / L, complex heterocyclic brightener 3~5mg / L, fatty amine ethoxy sulfonate 30~50ppm.

7. The ceramic through-hole filling electroplating process according to claim 1, characterized in that: During the laser drilling process, the aperture is 0.02-0.3 mm, the ceramic thickness to aperture ratio is (2-6):1; the maximum power of the fiber laser is 140-160 W, the wavelength is 1050-1100 nm, the power is 18-22%, the frequency is 450-550 Hz, the speed is 75-85 mm / s, and the drilling rate is 750-850 holes / min.

8. The ceramic through-hole filling electroplating process according to claim 1, characterized in that: During the magnetron sputtering of titanium copper, the process parameters are as follows: when the target material is titanium, the sputtering thickness of the titanium layer is 0.04-0.08 μm, and the sputtering power is 4-6 kW; when the target material is copper, the copper layer thickness is 0.06-1.0 μm, and the sputtering power is 4-8 kW.

9. The ceramic through-hole filling electroplating process according to claim 1, characterized in that: The pulse electroplating operation process is as follows: the sputtered ceramic substrate is placed in a hole-filling electroplating solution, with a titanium-iridium-ruthenium mesh as the anode and the ceramic substrate as the cathode, and the hole position faces the titanium-iridium-ruthenium anode; the DC electroplating current is 1-2ASD, the electroplating time is 100-140 minutes, and the electroplated surface coating thickness is 2-6μm.

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