A method for preparing a high-strength copper-clad ceramic substrate

Abstract

This invention discloses a method for preparing a high-strength copper-clad ceramic substrate, relating to the field of copper-clad ceramic substrate processing. The method mainly includes: preparing an alumina ceramic substrate with surface-treated silicon carbide as the reinforcing phase and sputtering copper; then, using a three-step progressive laser processing technology to prepare high-quality through-holes on the substrate; the three-step laser process specifically includes: first, thinning the pre-treated substrate by making multiple concentric circular cuts according to the target hole diameter to form pre-drilled pits; second, cutting through and trimming the pits; and finally, refining the holes. By optimizing the laser power, scanning path, and speed, high-quality through-holes are processed on the substrate to obtain the copper-clad ceramic substrate. This invention combines material modification and process innovation to produce copper-clad ceramic substrates with high-quality through-holes, excellent mechanical properties, and high reliability, suitable for high-power, high-integration semiconductor modules.

Description

Technical Field

[0001] This invention relates to the field of copper-clad ceramic substrate processing technology, specifically to a method for preparing a high-strength copper-clad ceramic substrate. Background Technology

[0002] Sputtered copper ceramic substrates are core components of power semiconductor modules, playing a crucial role in electrical interconnection, insulation and heat dissipation, and mechanical support. As semiconductor devices evolve towards higher power and miniaturization, a large number of microvias need to be fabricated on the substrate to achieve three-dimensional vertical interconnection. This places extremely high demands on the mechanical properties of the substrate itself and the quality of the via fabrication.

[0003] Currently, laser processing is mainly used for ceramic through-holes. However, the inherent high hardness, high brittleness, and poor thermal conductivity of ceramic materials (especially traditional alumina ceramics) pose serious challenges to laser processing: 1. The instantaneous high energy input of the laser generates significant thermal stress, which can easily induce microcracks and macroscopic edge chipping on the hole wall and exit edge, severely affecting the geometric accuracy and electrical reliability of the hole; 2. Traditional alumina ceramics have low fracture toughness and weak resistance to laser thermal shock, making them prone to damage during processing.

[0004] Therefore, in order to solve the above problems, the present invention proposes a method for preparing a high-strength copper-clad ceramic substrate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a high-strength copper-clad ceramic substrate 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-strength copper-clad ceramic substrate includes the following steps: (1) The surface of the sputtered copper ceramic substrate is ground flat, polished, ultrasonically cleaned and dried to obtain a pretreated sputtered copper ceramic substrate; (2) Using a laser, on the pre-treated sputtered copper ceramic substrate, set a multi-circle concentric scanning path according to the preset target aperture, control the laser to scan from the outside to the inside circle by circle, cut the target area thin, form a pre-drilled pit, and obtain a pre-drilled sputtered copper ceramic substrate. (3) Using a laser, the concentric circle scanning path described in step (2) is used to control the laser to scan from the outside to the inside in turn to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate (rough trimming) to obtain a drilled sputtered copper ceramic substrate. (4) Using a laser, the concentric circle scanning path described in step (2) is used to control the laser to scan from the outside to the inside in turn to trim (fine trim) the holes of the sputtered copper ceramic substrate to obtain a copper-clad ceramic substrate.

[0007] Furthermore, the thinning process conditions are as follows: a 300W fiber laser is used, a multi-circle concentric scanning path is set with the target aperture as the center, the distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 120-130W, and the laser is scanned from the outside to the inside at a speed of 1000mm / s, and the thinning is performed in 20-30 cycles. The thinning depth is 85-95% of the thickness of the pre-treated sputtered copper ceramic substrate.

[0008] Furthermore, the process conditions for cutting and trimming (rough finishing) are as follows: a 300W fiber laser is used, and a multi-circle concentric scanning path is set with the target aperture as the center. The distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 90-100W, and the laser is scanned circle by circle from the outside to the inside at a speed of 500mm / s. The cutting and trimming (rough finishing) is performed 10-20 times.

[0009] Furthermore, the trimming (fine finishing) process conditions are as follows: a 300W fiber laser is used, a multi-circle concentric scanning path is set with the target aperture as the center, the distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 270-280W, and the laser is scanned circle by circle from the outside to the inside at a speed of 1500mm / s, and the trimming (fine finishing) is performed 5-10 times.

[0010] Furthermore, the sputtered copper ceramic substrate is prepared by the following process: Step 1: Mix alumina, silicon carbide, sintering aid, dispersant and water to obtain a mixture; Step 2: Add binder to the mixture and mix, then cast and dry to obtain ceramic green sheets; Step 3: Take the ceramic green sheet, remove the glue and sinter it to obtain an alumina ceramic substrate; Step 4: Take an alumina ceramic substrate, clean it, perform plasma treatment, and vacuum sputtering to obtain a sputtered copper ceramic substrate.

[0011] Furthermore, the alumina ceramic substrate comprises the following components by weight: 70-80 parts alumina, 15-20 parts silicon carbide, 3-5 parts sintering aid, 3-5 parts dispersant, 6-8 parts binder, and 55-60 parts water.

[0012] Furthermore, the sintering aid is a mixture of magnesium oxide, zirconium oxide and yttrium oxide, with a mass ratio of (3-5):(1-2):(1-2); The dispersant is one or a mixture of sodium tripolyphosphate, polyacrylamide, and sodium citrate.

[0013] Furthermore, the binder is one of polyvinyl alcohol or sodium carboxymethyl cellulose.

[0014] Furthermore, the silicon carbide undergoes surface treatment, which includes the following processes: S1: At 50-60℃, silicon carbide, anhydrous ethanol and deionized water are mixed, and then silane coupling agent KH-550 is added. After ultrasonic vibration, centrifugation, washing and drying, aminated silicon carbide is obtained. S2: Hydroxylated hexagonal boron nitride was added to a citric acid solution, sodium sulfite was added, and the mixture was stirred at 100-120℃ for 8-10 hours. After filtration, washing and drying, carboxylated hexagonal boron nitride was obtained. S3: Aminated silicon carbide and carboxylated hexagonal boron nitride were added to N-methylpyrrolidone, a catalyst was added, and the mixture was stirred for 12-15 h to obtain a hexagonal boron nitride-silicon carbide complex. S4: Add concentrated nitric acid to deionized water and stir until homogeneous. Add aluminum isopropoxide and stir at 85-95℃ for 1-2 hours. While stirring, add hexagonal boron nitride-silicon carbide composite. After ultrasonic dispersion for 30-45 minutes, stir at 70-80℃ for 2-4 hours and dry at 100-120℃ for 12-24 hours to obtain surface-treated silicon carbide.

[0015] Furthermore, the mass-to-volume ratio of silicon carbide, anhydrous ethanol, deionized water, and silane coupling agent KH-550 is 1g:(2.6-2.8)mL:(3.2-3.5)mL:(0.7-0.75)mL.

[0016] Furthermore, the citric acid solution has a mass concentration of 5-10%, and the solvent is deionized water; The mass-to-volume ratio of hydroxylated hexagonal boron nitride, citric acid solution, and sodium sulfite is 1 g:(50-100) mL:(0.05-0.1) g.

[0017] Furthermore, the mass-to-volume ratio of aminated silicon carbide, carboxylated hexagonal boron nitride, N-methylpyrrolidone, and catalyst is 1 g:(0.3-0.5) g:(20-30) mL:(0.05-0.1) g; The catalyst is N-hydroxysuccinimide.

[0018] Furthermore, the mass-to-volume ratio of concentrated nitric acid, deionized water, aluminum isopropoxide, and hexagonal boron nitride-silicon carbide composite is (0.03-0.05) mL:(8-10) mL:1 g:(0.2-0.3) g; The concentration of concentrated nitric acid is 68%.

[0019] Furthermore, the process conditions for tape casting are: temperature of 60-80℃, speed of 0.3-0.5m / min, and squeegee gap of 300-400μm.

[0020] Furthermore, the process conditions for debinding are as follows: debinding temperature is 700-800℃, debinding time is 4-6h, debinding atmosphere is argon or nitrogen, and gas flow rate is 6-8L / min.

[0021] Furthermore, the sintering process conditions are as follows: sintering temperature is 1400-1500℃, sintering time is 2-4h, sintering atmosphere is argon or nitrogen, gas flow rate is 6-8L / min, and sintering pressure is 4-6MPa.

[0022] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention describes a method for preparing a high-strength copper-clad ceramic substrate. The invention employs a three-step laser processing technology: thinning-through cutting and edge trimming (rough trimming)-edge trimming (fine trimming). This process decomposes and optimizes the total heat input, effectively overcoming the problem of thermal stress concentration in laser processing of ceramic materials. Thinning quickly removes most of the material while simultaneously forming a preheating zone below the hole area. Then, based on the preheating, through cutting and edge trimming (rough trimming) are performed with lower energy, greatly reducing tearing stress caused by instantaneous explosion at the exit point. Finally, edge trimming (fine trimming) is performed with high power and high speed. The process quickly removes the small amount of slag and microcracks generated in the first two steps, resulting in smooth, highly perpendicular hole walls and clear exit edges. Furthermore, in the three-step laser processing, a multi-circle concentric path centered on the target hole diameter is set up and scanned circle by circle from the outside in, allowing laser energy to be gradually transferred and accumulated from the outer region to the center. This scanning method forms a preheating zone, ensuring that the material in the central region is fully preheated before final penetration, thereby avoiding severe thermal shock and splashing caused by sudden energy acting on cold material, and significantly reducing exit edge chipping and the generation of hole wall microcracks.

[0023] 2. The present invention describes a method for preparing a high-strength copper-clad ceramic substrate. The silicon carbide used in this invention undergoes surface treatment, reacting the amino groups of aminated silicon carbide with the carboxyl groups of carboxylated hexagonal boron nitride to form a chemically bonded hexagonal boron nitride-silicon carbide composite, which is then encapsulated in alumina. The silicon carbide particles, as rigid particles, are uniformly dispersed in the alumina matrix, effectively pinning cracks, forcing cracks to deflect and circumvent, consuming crack propagation energy, thereby improving the bending strength and fracture toughness of the material. The lamellar structure of the hexagonal boron nitride... The structure can induce energy dissipation mechanisms such as crack deflection, bridging, and delamination in the alumina matrix, further improving the fracture toughness of the composite ceramic. Finally, an alumina coating layer is formed on the surface of the silicon carbide-boron nitride composite, which significantly improves the wettability and compatibility between the silicon carbide reinforcing phase and the alumina matrix, promotes the uniform dispersion of silicon carbide in the alumina matrix, and reduces the interfacial stress caused by the mismatch of thermal expansion coefficients. In the subsequent high-temperature sintering process, the coating layer is more tightly bonded to the alumina matrix, which helps to obtain a more dense ceramic matrix.

[0024] 3. The present invention describes a method for preparing a high-strength copper-clad ceramic substrate. The sintering aid used in this invention, magnesium oxide as a highly efficient sintering promoter, generates lattice vacancies through solid solution, significantly accelerating the material transport and diffusion process of the alumina matrix, achieving low-temperature high densification of the ceramic. Yttrium oxide reacts with alumina to generate a high-melting-point, high-thermal-conductivity yttrium aluminum garnet tough grain boundary phase, greatly improving the high-temperature strength and heat dissipation of the substrate. Simultaneously, yttrium oxide also stabilizes the tetragonal phase of zirconia. The metastable tetragonal phase of zirconia undergoes a martensitic phase transformation under stress, absorbing crack energy and achieving phase transformation toughening. This, combined with the bridging and deflection toughening mechanisms of silicon carbide-boron nitride, produces a synergistic effect, improving the fracture toughness of the substrate. Furthermore, its coefficient of thermal expansion, intermediate between that of the alumina matrix and the silicon carbide reinforcing phase, helps to mitigate thermal mismatch stress within the system. The synergistic effect of these three factors enhances the overall performance of the alumina ceramic substrate. Detailed Implementation

[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the following specific implementation: All numbers of parts mentioned below refer to parts by weight, unless otherwise specified.

[0027] The average particle size of alumina is 1 μm; the average particle size of silicon carbide is 50 nm; the average particle size of magnesium oxide is 40 nm; the average particle size of zirconium oxide is 50 nm; the average particle size of yttrium oxide is 50 nm; the CAS number for sodium tripolyphosphate is 7758-29-4, and its purity is 99%; the CAS number for anhydrous ethanol is 64-17-5, and its purity is 99.8%; the CAS number for sodium carboxymethyl cellulose is 9004-32-4, and its purity is 99%; the CAS number for silane coupling agent KH-550 is 919-30-2, and its purity is 99%. %; the particle size of hydroxylated hexagonal boron nitride is 5 μm; the CAS number of citric acid is 77-92-9, and the purity is 98%; the CAS number of sodium sulfite is 7757-83-7, and the purity is 99%; the CAS number of N-methylpyrrolidone is 872-50-4, and the purity is 99%; the CAS number of aluminum isopropoxide is 555-31-7, and the purity is 99%; the CAS number of concentrated nitric acid is 7697-37-2, and the concentration is 68%; the CAS number of N-hydroxysuccinimide is 6066-82-6, and the purity is 99%.

[0028] Example 1: A method for preparing a high-strength copper-clad ceramic substrate, comprising the following steps: Step 1: Surface treatment with silicon carbide S1: At 55℃, silicon carbide, anhydrous ethanol, and deionized water were mixed, and then silane coupling agent KH-550 was added. After ultrasonic vibration, centrifugation, washing, and drying, aminated silicon carbide was obtained. The mass-volume ratio of silicon carbide, anhydrous ethanol, deionized water, and silane coupling agent KH-550 was 1g:2.7mL:3.3mL:0.72mL. S2: Hydroxylated hexagonal boron nitride was added to a citric acid solution, followed by sodium sulfite. The mixture was stirred at 100-120℃ for 8-10 hours. After filtration, washing, and drying, carboxylated hexagonal boron nitride was obtained. The citric acid solution had a mass concentration of 8% and the solvent was deionized water. The mass-volume ratio of hydroxylated hexagonal boron nitride, citric acid solution, and sodium sulfite was 1 g: 80 mL: 0.08 g. S3: Aminated silicon carbide and carboxylated hexagonal boron nitride were added to N-methylpyrrolidone, and N-hydroxysuccinimide was added. The mixture was stirred and reacted for 13 h to obtain a hexagonal boron nitride-silicon carbide complex. The mass-volume ratio of aminated silicon carbide, carboxylated hexagonal boron nitride, N-methylpyrrolidone, and N-hydroxysuccinimide was 1 g:0.4 g:25 mL:0.08 g. S4: Concentrated nitric acid was added to deionized water and stirred until homogeneous. Aluminum isopropoxide was added and the mixture was stirred at 90°C for 1.5 h. Hexagonal boron nitride-silicon carbide composite was added while stirring. After ultrasonic dispersion for 40 min, the mixture was stirred at 75°C for 3 h and dried at 110°C for 18 h to obtain surface-treated silicon carbide. The mass-volume ratio of concentrated nitric acid, deionized water, aluminum isopropoxide, and hexagonal boron nitride-silicon carbide composite was 0.04 mL:9 mL:1 g:0.25 g. Step 2: Preparation of sputtered copper ceramic substrate S1: Alumina, silicon carbide, sintering aid, dispersant and water are mixed to obtain a mixture; a binder is added to the mixture and mixed; the mixture is cast into a ceramic green sheet at a temperature of 70℃, a speed of 0.4m / min and a scraper gap of 350μm, and then dried. S2: The ceramic green sheet is debonded for 5 hours at a debonding temperature of 750℃, a debonding atmosphere of argon, and a gas flow rate of 7L / min. Then, it is sintered for 3 hours at a sintering temperature of 1450℃, a sintering atmosphere of argon, a gas flow rate of 7L / min, and a sintering pressure of 5MPa to obtain an alumina ceramic substrate. After cleaning, plasma treatment, and vacuum sputtering, a sputtered copper ceramic substrate is obtained. The alumina ceramic substrate includes the following mass components: 75 parts alumina, 18 parts silicon carbide, 4 parts sintering aid, 4 parts dispersant, 7 parts binder, and 58 parts water. Step 3: Drilling holes S1: The surface of the sputtered copper ceramic substrate is ground flat, and then polished, ultrasonically cleaned and dried to obtain the pretreated sputtered copper ceramic substrate; S2: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set on the pre-treated sputtered copper ceramic substrate. The spacing between adjacent concentric circles is 0.02mm, the laser output power is 120W, and the laser scans from the outside to the inside at a speed of 1000mm / s, repeating 25 times to thin the target area, forming pre-drilled pits, thus obtaining a pre-drilled sputtered copper ceramic substrate. The thinning depth is 90% of the thickness of the pre-treated sputtered copper ceramic substrate. S3: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with an adjacent concentric circle spacing of 0.02mm and a laser output power of 90W. The laser scans from the outside to the inside at a speed of 500mm / s, repeating 15 times, to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate, thus obtaining a drilled sputtered copper ceramic substrate. S4: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with an adjacent concentric circle spacing of 0.02mm and a laser output power of 270W. The laser scans from the outside to the inside at a speed of 1500mm / s, repeating 8 times, to trim the holes in the sputtered copper ceramic substrate and obtain a copper-clad ceramic substrate.

[0029] Example 2: A method for preparing a high-strength copper-clad ceramic substrate, comprising the following steps: Step 1: Surface treatment with silicon carbide S1: At 50℃, silicon carbide, anhydrous ethanol, and deionized water were mixed, and then silane coupling agent KH-550 was added. After ultrasonic vibration, centrifugation, washing, and drying, aminated silicon carbide was obtained. The mass-volume ratio of silicon carbide, anhydrous ethanol, deionized water, and silane coupling agent KH-550 was 1g:2.6mL:3.2mL:0.7mL. S2: Hydroxylated hexagonal boron nitride was added to a citric acid solution, followed by sodium sulfite. The mixture was stirred at 100-120℃ for 8-10 hours. After filtration, washing, and drying, carboxylated hexagonal boron nitride was obtained. The citric acid solution had a mass concentration of 5% and the solvent was deionized water. The mass-volume ratio of hydroxylated hexagonal boron nitride, citric acid solution, and sodium sulfite was 1 g: 100 mL: 0.05 g. S3: Aminated silicon carbide and carboxylated hexagonal boron nitride were added to N-methylpyrrolidone, followed by N-hydroxysuccinimide. The mixture was stirred for 12 hours to obtain a hexagonal boron nitride-silicon carbide complex. The mass-to-volume ratio of aminated silicon carbide, carboxylated hexagonal boron nitride, N-methylpyrrolidone, and N-hydroxysuccinimide was 1 g:0.3 g:20 mL:0.05 g. S4: Concentrated nitric acid was added to deionized water and stirred until homogeneous. Aluminum isopropoxide was added and stirred at 85°C for 1 hour. Hexagonal boron nitride-silicon carbide composite was added while stirring. After ultrasonic dispersion for 45 minutes, the mixture was stirred at 70°C for 4 hours and dried at 100°C for 24 hours to obtain surface-treated silicon carbide. The mass-volume ratio of concentrated nitric acid, deionized water, aluminum isopropoxide, and hexagonal boron nitride-silicon carbide composite was 0.03 mL: 8 mL: 1 g: 0.3 g. Step 2: Preparation of sputtered copper ceramic substrate S1: Alumina, silicon carbide, sintering aid, dispersant and water are mixed to obtain a mixture; a binder is added to the mixture and mixed; the mixture is cast and dried at a temperature of 60℃, a speed of 0.3m / min and a scraper gap of 300μm to obtain a ceramic green sheet; S2: The ceramic green sheet is debonded for 6 hours at a debonding temperature of 700℃, a debonding atmosphere of nitrogen, and a gas flow rate of 6L / min. Then, it is sintered for 4 hours at a sintering temperature of 1400℃, a sintering atmosphere of nitrogen, a gas flow rate of 6L / min, and a sintering pressure of 4MPa to obtain an alumina ceramic substrate. After cleaning, plasma treatment, and vacuum sputtering, a sputtered copper ceramic substrate is obtained. The alumina ceramic substrate includes the following mass components: 70 parts alumina, 15 parts silicon carbide, 3 parts sintering aid, 3 parts dispersant, 6 parts binder, and 55 parts water. Step 3: Drilling holes S1: The surface of the sputtered copper ceramic substrate is ground flat, and then polished, ultrasonically cleaned and dried to obtain the pretreated sputtered copper ceramic substrate; S2: A 300W fiber laser is used, with a multi-circle concentric scanning path centered on the target aperture. The spacing between adjacent concentric circles is 0.03mm, and the laser output power is 125W. The laser scans from the outside inward at a speed of 1000mm / s, repeating 20 times to thin the target area, forming pre-drilled pits to obtain a pre-drilled sputtered copper ceramic substrate. The thinning depth is 85% of the thickness of the pre-treated sputtered copper ceramic substrate. S3: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with an adjacent concentric circle spacing of 0.03mm and a laser output power of 95W. The laser is scanned from the outside to the inside at a speed of 500mm / s, and the process is repeated 10 times to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate, thus obtaining a drilled sputtered copper ceramic substrate. S4: Using a 300W fiber laser, a multi-circle concentric scanning path is set with the target aperture as the center. The distance between adjacent concentric circles is 0.03mm, the laser output power is 275W, and the laser is scanned from the outside to the inside at a speed of 1500mm / s, and the cycle is repeated 5 times to trim the holes of the sputtered copper ceramic substrate to obtain the copper-clad ceramic substrate.

[0030] Example 3: A method for preparing a high-strength copper-clad ceramic substrate, comprising the following steps: Step 1: Surface treatment with silicon carbide S1: At 60℃, silicon carbide, anhydrous ethanol, and deionized water were mixed, and then silane coupling agent KH-550 was added. After ultrasonic vibration, centrifugation, washing, and drying, aminated silicon carbide was obtained. The mass-volume ratio of silicon carbide, anhydrous ethanol, deionized water, and silane coupling agent KH-550 was 1g:2.8mL:3.5mL:0.75mL. S2: Hydroxylated hexagonal boron nitride was added to a citric acid solution, followed by sodium sulfite. The mixture was stirred at 100-120℃ for 8-10 hours. After filtration, washing, and drying, carboxylated hexagonal boron nitride was obtained. The citric acid solution had a mass concentration of 10% and was dissolved in deionized water. The mass-volume ratio of hydroxylated hexagonal boron nitride, citric acid solution, and sodium sulfite was 1 g: 50 mL: 0.1 g. S3: Aminated silicon carbide and carboxylated hexagonal boron nitride were added to N-methylpyrrolidone, and N-hydroxysuccinimide was added. The mixture was stirred and reacted for 15 h to obtain a hexagonal boron nitride-silicon carbide complex. The mass-volume ratio of aminated silicon carbide, carboxylated hexagonal boron nitride, N-methylpyrrolidone, and N-hydroxysuccinimide was 1 g: 0.5 g: 30 mL: 0.1 g. S4: Concentrated nitric acid was added to deionized water and stirred until homogeneous. Aluminum isopropoxide was added and stirred at 95°C for 2 hours. Hexagonal boron nitride-silicon carbide composite was added while stirring. After ultrasonic dispersion for 30 minutes, the mixture was stirred at 80°C for 2 hours and dried at 120°C for 12 hours to obtain surface-treated silicon carbide. The mass-volume ratio of concentrated nitric acid, deionized water, aluminum isopropoxide, and hexagonal boron nitride-silicon carbide composite was 0.05 mL: 10 mL: 1 g: 0.2 g. Step 2: Preparation of sputtered copper ceramic substrate S1: Alumina, silicon carbide, sintering aid, dispersant and water are mixed to obtain a mixture; a binder is added to the mixture and mixed; the mixture is cast and dried at a temperature of 80℃, a speed of 0.5m / min and a scraper gap of 400μm to obtain a ceramic green sheet; S2: The ceramic green sheet is debonded for 4 hours at a debonding temperature of 800℃, a debonding atmosphere of argon, and a gas flow rate of 8L / min. Then, it is sintered for 2 hours at a sintering temperature of 1500℃, a sintering atmosphere of nitrogen, a gas flow rate of 8L / min, and a sintering pressure of 6MPa to obtain an alumina ceramic substrate. After cleaning, plasma treatment, and vacuum sputtering, a sputtered copper ceramic substrate is obtained. The alumina ceramic substrate includes the following mass components: 80 parts alumina, 20 parts silicon carbide, 5 parts sintering aid, 5 parts dispersant, 8 parts binder, and 60 parts water. Step 3: Drilling holes S1: The surface of the sputtered copper ceramic substrate is ground flat, and then polished, ultrasonically cleaned and dried to obtain the pretreated sputtered copper ceramic substrate; S2: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set on the pre-treated sputtered copper ceramic substrate. The spacing between adjacent concentric circles is 0.04mm, the laser output power is 130W, and the laser scans from the outside to the inside at a speed of 1000mm / s, repeating 30 times to thin the target area, forming pre-drilled pits, thus obtaining a pre-drilled sputtered copper ceramic substrate. The thinning depth is 95% of the thickness of the pre-treated sputtered copper ceramic substrate. S3: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with a spacing of 0.04mm between adjacent concentric circles and a laser output power of 100W. The laser scans from the outside to the inside at a speed of 500mm / s, repeating 20 times, to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate, thus obtaining a drilled sputtered copper ceramic substrate. S4: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with an adjacent concentric circle spacing of 0.04mm and a laser output power of 280W. The laser scans from the outside to the inside at a speed of 1500mm / s, repeating 10 times to trim the holes in the sputtered copper ceramic substrate, thus obtaining a copper-clad ceramic substrate.

[0031] Comparative Example 1: Based on Example 1, the three-step laser processing technology was replaced with a traditional single-parameter laser direct perforation process. The only difference from Example 1 is that: Step 3: Drilling holes S1: The surface of the sputtered copper ceramic substrate is ground flat, and then polished, ultrasonically cleaned and dried to obtain the pretreated sputtered copper ceramic substrate; S2: Using a 300W fiber laser, a multi-circle concentric scanning path centered on the target aperture is set, with an adjacent concentric circle spacing of 0.02mm. The laser output power is 120W, and the laser is scanned 25 times at a speed of 1000mm / s to drill holes in the pre-treated sputtered copper ceramic substrate, thus obtaining a copper-clad ceramic substrate.

[0032] Comparative Example 2: Based on Example 1, the scanning path was adjusted. The only difference from Example 1 is that: Step 3: Drilling holes S1: The surface of the sputtered copper ceramic substrate is ground flat, and then polished, ultrasonically cleaned and dried to obtain the pretreated sputtered copper ceramic substrate; S2: Using a 300W fiber laser, a single-circle scanning path is set, the laser output power is 120W, and the laser is scanned 25 times at a speed of 1000mm / s to thin the pre-treated sputtered copper ceramic substrate, forming pre-drilled pits to obtain a pre-drilled sputtered copper ceramic substrate; the thinning depth is 90% of the thickness of the pre-treated sputtered copper ceramic substrate. S3: Using a 300W fiber laser, a single-circle scanning path is set, the laser output power is 90W, and it scans 15 times at a speed of 500mm / s to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate to obtain a drilled sputtered copper ceramic substrate. S4: Using a 300W fiber laser, a single-circle scanning path is set, the laser output power is 270W, and the laser is scanned 8 times from the outside to the inside at a speed of 1500mm / s to trim the holes of the sputtered copper ceramic substrate and obtain the copper-clad ceramic substrate.

[0033] Comparative Example 3: Based on Example 1, the silicon carbide was not surface treated.

[0034] Experiment: Alumina ceramic substrates and copper-clad ceramic substrates obtained in Examples 1-3 and Comparative Examples 1-3 were used as samples. Their performance was tested and the test results were recorded. Fracture toughness test: The fracture toughness of the alumina ceramic substrate was tested according to the test method specified in the standard GB / T 23806-2025 "Fine Ceramics Fracture Toughness Test Method - Single-sided Precracked Beam (SEPB) Method". Bending strength test: The bending strength of the alumina ceramic substrate was tested according to the test method (three-point bending method) specified in standard GB / T 6569-2006 "Test method for bending strength of fine ceramics". Hole edge chipping width test: The width of the chipping at the edge of the copper-clad ceramic substrate is observed under a microscope; Crack detection: Visually inspect the copper-clad ceramic substrate for cracks.

[0035] Conclusion: As can be seen from the comparison of data in Table 1, the technical solution of the present invention is significantly superior to the comparative example in terms of substrate mechanical properties and through-hole processing quality; Comparative Example 1 uses the traditional one-step laser perforation method. Although the substrate is the same, the width of the ceramic chipping at the hole edge is significantly increased and visible cracks are generated. This proves that the three-step progressive laser process of the present invention is the key to avoiding processing damage and obtaining high-quality through holes.

[0036] In Comparative Example 2, after changing the multi-circle scan to a single-circle scan, the edge breakage width was still greater than that in the embodiment, proving that the multi-circle concentric circle scanning path from the outside to the inside can further optimize the energy distribution and is an effective means to reduce edge breakage. Comparative Example 3 uses untreated silicon carbide, which significantly reduces fracture toughness and flexural strength, confirming that the surface-treated silicon carbide reinforcement prepared in this invention plays an important role in improving the fracture toughness and flexural strength of the substrate.

[0037] In summary, this invention achieves high-quality through-holes in copper-clad ceramic substrates with excellent mechanical properties through the synergy of material modification (surface treatment of silicon carbide) and process innovation (three-step progressive multi-circuit scanning laser processing).

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for preparing a high-strength copper-clad ceramic substrate, characterized in that: Includes the following steps: (1) The surface of the sputtered copper ceramic substrate is ground flat, polished, ultrasonically cleaned and dried to obtain a pretreated sputtered copper ceramic substrate; (2) Using a laser, on the pre-treated sputtered copper ceramic substrate, set a multi-circle concentric scanning path according to the preset target aperture, control the laser to scan from the outside to the inside circle by circle, cut the target area thin, form a pre-drilled pit, and obtain a pre-drilled sputtered copper ceramic substrate. (3) Using a laser, the laser is controlled to scan from the outside to the inside in a concentric circle scanning path as described in step (2) to cut through and trim the pre-drilled pits of the pre-drilled sputtered copper ceramic substrate to obtain a drilled sputtered copper ceramic substrate. (4) Using a laser, the concentric circle scanning path described in step (2) is used to control the laser to scan from the outside to the inside in turn to trim the holes of the sputtered copper ceramic substrate and obtain a copper-clad ceramic substrate.

2. The method for preparing a high-strength copper-clad ceramic substrate according to claim 1, characterized in that: The thinning process conditions are as follows: a 300W fiber laser is used, a multi-circle concentric scanning path is set with the target aperture as the center, the distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 120-130W, and the laser is scanned from the outside to the inside at a speed of 1000mm / s, and the thinning is performed in 20-30 cycles. The thinning depth is 85-95% of the thickness of the pre-treated sputtered copper ceramic substrate.

3. The method for preparing a high-strength copper-clad ceramic substrate according to claim 1, characterized in that: The cutting and trimming process conditions are as follows: a 300W fiber laser is used, a multi-circle concentric scanning path is set with the target aperture as the center, the distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 90-100W, and the laser is scanned from the outside to the inside at a speed of 500mm / s, and the cutting and trimming are performed in 10-20 cycles.

4. The method for preparing a high-strength copper-clad ceramic substrate according to claim 1, characterized in that: The trimming process conditions are as follows: a 300W fiber laser is used, a multi-circle concentric scanning path is set with the target aperture as the center, the distance between adjacent concentric circles is 0.02-0.04mm, the laser output power is 270-280W, and the laser is scanned from the outside to the inside at a speed of 1500mm / s, and the trimming is performed in 5-10 cycles.

5. The method for preparing a high-strength copper-clad ceramic substrate according to claim 1, characterized in that: The sputtered copper ceramic substrate is prepared by the following process: Step 1: Mix alumina, silicon carbide, sintering aid, dispersant and water to obtain a mixture; Step 2: Add binder to the mixture and mix, then cast and dry to obtain ceramic green sheets; Step 3: Take the ceramic green sheet, remove the glue and sinter it to obtain an alumina ceramic substrate; Step 4: Take an alumina ceramic substrate, clean it, perform plasma treatment, and vacuum sputtering to obtain a sputtered copper ceramic substrate.

6. The method for preparing a high-strength copper-clad ceramic substrate according to claim 5, characterized in that: The silicon carbide undergoes a surface treatment process, which includes the following steps: S1: At 50-60℃, silicon carbide, anhydrous ethanol and deionized water are mixed, and then silane coupling agent KH-550 is added. After ultrasonic vibration, centrifugation, washing and drying, aminated silicon carbide is obtained. S2: Hydroxylated hexagonal boron nitride was added to a citric acid solution, followed by sodium sulfite. The mixture was stirred at 100-120°C for 8-10 hours. After filtration, washing, and drying, carboxylated hexagonal boron nitride was obtained. S3: Aminated silicon carbide and carboxylated hexagonal boron nitride were added to N-methylpyrrolidone, a catalyst was added, and the mixture was stirred for 12-15 h to obtain a hexagonal boron nitride-silicon carbide complex. S4: Add concentrated nitric acid to deionized water and stir until homogeneous. Add aluminum isopropoxide and stir at 85-95℃ for 1-2 hours. While stirring, add hexagonal boron nitride-silicon carbide composite. After ultrasonic dispersion for 30-45 minutes, stir at 70-80℃ for 2-4 hours and dry at 100-120℃ for 12-24 hours to obtain surface-treated silicon carbide.

7. The method for preparing a high-strength copper-clad ceramic substrate according to claim 5, characterized in that: The sintering aid is a mixture of magnesium oxide, zirconium oxide and yttrium oxide, with a mass ratio of (3-5):(1-2):(1-2).

8. The method for preparing a high-strength copper-clad ceramic substrate according to claim 5, characterized in that: The casting process conditions are as follows: temperature 60-80℃, speed 0.3-0.5m / min, and scraper gap 300-400μm.

9. The method for preparing a high-strength copper-clad ceramic substrate according to claim 5, characterized in that: The process conditions for degreasing are as follows: degreasing temperature is 700-800℃, degreasing time is 4-6h, degreasing atmosphere is argon or nitrogen, and gas flow rate is 6-8L / min.

10. The method for preparing a high-strength copper-clad ceramic substrate according to claim 5, characterized in that: The sintering process conditions are as follows: sintering temperature is 1400-1500℃, sintering time is 2-4h, sintering atmosphere is argon or nitrogen, gas flow rate is 6-8L / min, and sintering pressure is 4-6MPa.

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