A method for making a ceramic carrier plate for matching embedded packages

Abstract

This invention discloses a method for fabricating a ceramic substrate for embedded packaging, relating to the field of ceramic substrate technology. The method provides a method for fabricating a ceramic substrate for embedded packaging that, relying on precise design drawings, ensures high dimensional matching across all layers. Simultaneously, stable control of the etching line speed ensures that the cavity depth meets requirements. Based on the original planar pattern, a selective cavity is added; this structure provides precise spatial positioning and physical support for the subsequent installation of chips or devices, improving the overall assembly adaptability of the module. Furthermore, to avoid the risk of silver migration within the cavity, a secondary selective pattern fabrication is performed before silver plating, ensuring that silver migration does not occur at the edges of the silver surface.

Description

Technical Field

[0001] This invention relates to the field of ceramic substrate technology, specifically a method for manufacturing a ceramic substrate that is compatible with embedded packaging. Background Technology

[0002] In the field of electronic packaging, traditional planar surface-mount packaging is gradually evolving towards embedded packaging. In ceramic packaging, traditional power modules are also slowly moving towards P2 packaging. These new packaging methods can significantly reduce switching losses and inverter power losses, improve system power density and integration, and greatly increase module reliability. Initially, this packaging method was only suitable for PCB-type packaging substrates because they are generally embedded between multi-layer boards and need to balance the conductivity between upper and lower layers. Later, as more and more packaging substrates shifted to ceramic substrates, the special cavity fabrication on the ceramic surface became a major challenge restricting the development of this technology. Some established European PCB companies, having started earlier, have maintained a leading position globally in this field. Although they have accumulated significant research achievements in packaging technology, they still face difficulties in cavity fabrication because it requires specific dimensions, depths, and surface treatment methods. Therefore, providing a ceramic substrate fabrication method suitable for embedded packaging is of great significance in solving these problems. Summary of the Invention

[0003] The purpose of this invention is to provide a method for manufacturing a ceramic substrate that is compatible with embedded packaging, so as to solve the problems mentioned in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for fabricating a ceramic substrate compatible with embedded packaging includes the following steps: S1: Preliminary pattern making: On the copper-clad ceramic substrate semi-finished product, pretreatment, film application, exposure, development, etching, film removal, solder etching, cleaning and drying, and inspection are carried out in sequence to form surface circuits. S2: Single-stage selection: Pre-etching pretreatment, wet film printing, single-stage selection pattern exposure, development, and etching are performed sequentially on the surface lines to form Cavity; S3: Secondary selection: The Cavity is sequentially subjected to film removal, pretreatment, wet film printing, secondary selection pattern exposure, development, and chemical silver plating. S4: Slicing and Packaging: The ceramic substrates that have completed step S3 are sequentially subjected to film removal, post-processing, laser cutting, slicing, final inspection, and packaging to obtain ceramic carrier plates; Wherein, the area of ​​the graphic region exposed by the secondary selection graphic is smaller than the area of ​​the Cavity.

[0005] In a more optimized manner, in step S2, the etching system adopts a hydrochloric acid / sodium chlorate system; in the hydrochloric acid / sodium chlorate system, the acid equivalent is 1.7~2.1N, the copper ion concentration is 115~155g / L, the specific gravity is 1.28~1.31, and the sodium chlorate potential is 15~60V.

[0006] In step S2, the pre-etching process flow is as follows: first stage degreasing - second stage micro-etching - overflow rinsing - acid pickling - overflow rinsing - drying; the degreasing agent concentration in the first stage is 10~20%, and the degreasing temperature is 25~35℃; the second stage micro-etching system is a sulfuric acid / sodium persulfate system, with a sulfuric acid concentration of 4~6% and a sodium persulfate concentration of 5.5~10%, and the micro-etching temperature is 25~35℃; the acid pickling solution is a sulfuric acid solution with a concentration of 3~5%; the drying temperature is 70~80℃; and the total linear velocity of the pre-etching process is 1~1.2m / min. The process parameters for the single-stage selective pattern exposure are: film vacuum level: -10~-50kPa, A-stage vacuum level: -10~-40kPa, B-stage vacuum level: -10~-40kPa, alignment accuracy: 40~90μm, energy grid: 6-8 grids, exposure uniformity: 90~99%; During the development process, the concentration of the developer is 0.8~1.2%, the development temperature is 28~32℃, the pH is 10~13, and the linear velocity is 0.9~1.1m / min.

[0007] In a more optimized manner, in step S2, the etching rate is 0.5~2.1 m / min, and the upward spraying pressure is 2.4~3.0 kg / cm². 2 The downward spray pressure is 1.6~2.2 kg / cm². 2 The temperature is 45~55℃ and the depth is 150~180μm.

[0008] In a more optimized manner, in step S3, the edge of the Cavity is covered with selective ink after secondary selective pattern exposure and before development, and then chemical silver plating is performed. The raw materials of the selected ink are composed of the following components, by mass percentage: epoxy resin 49-53%, diethylene glycol ethyl ether acetate 4.8-5.2%, photoinitiator 3.8-4.2%, silicon dioxide 1.8-2.2%, barium sulfate 8.8-9.2%, talc 8.8-9.2%, pigment 0.8-1.2%, and additives 18-20%.

[0009] In a more optimized manner, the chemical silver plating process is as follows: micro-etching stage 1, micro-etching stage 2, pre-immersion, and silver plating; The micro-etching stage employs a sulfuric acid / hydrogen peroxide system, with a sulfuric acid concentration of 4-7%, a temperature of 25-35℃, and an upper and lower spray pressure of 1.5-2.5 kg / cm². 2 The micro-etching stage uses a sulfuric acid / sodium persulfate system, with a sodium persulfate concentration of 40-80 g / L, a sulfuric acid concentration of 2-4%, a temperature of 25-35℃, and an upper and lower spray pressure of 1.5-2.5 kg / cm². 2 .

[0010] In step S3, the process parameters for the secondary selective pattern exposure are as follows: film vacuum degree: -10~-50kPa, A stage vacuum degree: -10~-40kPa, B stage vacuum degree: -10~-40kPa, alignment accuracy: 40~90μm, energy grid: 6~8 grids, exposure uniformity: 90~99%; during the development process, the concentration of the developer is 0.8~1.2%, the development temperature is 28~32℃, the pH is 10~13, and the overall linear velocity is 0.9~1.1m / min.

[0011] More preferably, the pre-impregnation is carried out in a pre-impregnation solution, the raw materials of which are composed of the following components by mass percentage: 15~20% YZF-317B, 4~8% YZF-318C, 0.5~1.8% nitric acid, and 0.1~0.2% copper ions; the pre-impregnation temperature is 35~45℃.

[0012] The raw materials for YZF-317B, by mass percentage, consist of: 98% deionized water, 1% copper nitrate, and 1% nitric acid; the raw materials for YZF-318C, by weight percentage, consist of: 99% deionized water and 1% copper nitrate.

[0013] More preferably, the silver plating is carried out in a chemical silver plating solution, the raw materials of which consist of the following components by mass percentage: 2~4% YZF-316A, 20~30% YZF-317B, 4~6% YZF-318C, 0.5~1.8% nitric acid, and 0.1~0.5% copper ions; The silver plating thickness is 0.3~1.0μm, and the temperature is 50~55℃.

[0014] The raw materials for YZF-316A, by mass percentage, are: 92% deionized water, 6% silver nitrate, and 2% nitric acid.

[0015] In step S4, the post-treatment process is as follows: primary micro-etching - secondary micro-etching - acid washing - anti-oxidation - post-washing - drying; the primary micro-etching system is a sulfuric acid / sodium persulfate micro-etching system, with a sulfuric acid concentration of 2-6% and a sodium persulfate concentration of 1.9-6%, and the primary micro-etching temperature is 25-35℃; the secondary micro-etching system is a sulfuric acid / hydrogen peroxide micro-etching system, with a sulfuric acid concentration of 40-75 g / L, a copper ion concentration of 5-12 g / L, a temperature of 25-35℃, and an upper and lower spray pressure of 1-2 kg / cm. 2 The pickling solution is a sulfuric acid solution with a concentration of 0.5-1.5%; the antioxidant solution has a concentration of 80-90 ml / L and a temperature of 30-40℃; the conductivity of the subsequent water wash is 0.5-2 μs / cm; and the drying temperature is 80-90℃.

[0016] In step S4, the laser cutting process parameters are as follows: laser power is 150W, cutting power output rate is 30~37%, frequency is 3~3.5kHz, pulse width is 60~80μs, moving speed is 80~120mm / s, and cutting depth is 80~130μm.

[0017] In a more optimized manner, in step S1, the etching system is a hydrochloric acid / sodium chlorate system, wherein the acid equivalent is 1.7~2.1N, the copper ion concentration is 115~155g / L, the specific gravity is 1.28~1.31, the sodium chlorate potential is 15~60V, and the temperature is 45~55℃.

[0018] In step S1, the pretreatment includes a first micro-etching and a second micro-etching; the solution system for the first micro-etching is a sulfuric acid / hydrogen peroxide system, with a sulfuric acid concentration of 8-12% and a micro-etching temperature of 25-35℃; the solution system for the second micro-etching is a sulfuric acid / sodium persulfate system, with a sulfuric acid concentration of 4-6%, a sodium persulfate concentration of 5.5-10%, and a micro-etching temperature of 25-35℃. The film is applied at a temperature of 100~120℃, and the film type is a photosensitive dry film, which consists of a PE layer, a photosensitive layer, and a PET layer in sequence. The exposure energy grid is 6 to 8 grids, the exposure uniformity is 90 to 99%, and the vertical alignment accuracy is 10 to 50 μm; The developing solution is sodium carbonate with a concentration of 0.8-1.2%, a pH of 10.5-11.5, a temperature of 28-32℃, and a speed of 0.9-1.1 m / min; The etching solution system is a hydrochloric acid / sodium chlorate system with an acid equivalent of 1.7~2.1N, a copper ion concentration of 115~155g / L, a specific gravity of 1.28~1.31, a sodium chlorate potential of 15~60V, and a temperature of 45~55℃. During the cleaning and drying process, the drying temperature is 80~90℃.

[0019] In a more optimized manner, the solder etching operation method in step S1 is as follows: the ceramic substrate after the film removal step in step S1 is placed in a self-made solder etching system, and then transferred to a sulfuric acid / hydrogen peroxide micro-etching system with a concentration of 4~6% for micro-etching treatment. The self-made solder etching system consists of: 18-22 kg of caustic soda, 4-6 kg of heavy metal salts, 140-160 L of hydrogen peroxide, 8-12 kg of silicate, and 140-160 L of deionized water.

[0020] A ceramic substrate prepared by a method for fabricating ceramic substrates for embedded packaging.

[0021] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. The present invention provides a method for manufacturing a ceramic substrate for embedded packaging. Based on the original planar pattern, the selected Cavity is added. This structure provides precise spatial positioning and physical support for the subsequent installation of chips or devices, and improves the overall assembly adaptability of the module.

[0022] 2. The present invention provides a method for manufacturing a ceramic substrate that matches embedded packaging. In order to avoid the risk of silver migration inside the cavity, a secondary pattern selection process is added before silver plating to ensure that silver migration does not occur at the edge of the silver surface.

[0023] 3. The present invention provides a method for manufacturing a ceramic substrate that matches embedded packaging. Relying on precise drawing design data, it can ensure that the dimensions of each layer are highly matched; at the same time, by stably controlling the etching line speed, it ensures that the cavity depth meets the requirements. Attached Figure Description

[0024] Figure 1 This is a structural diagram of a ceramic substrate for traditional packaging methods. Figure 2 This is a structural diagram of the ceramic carrier plate for embedded packaging according to the present invention; Figure 3 This is a schematic diagram of the product of the present invention; Figure 4 This is a schematic diagram showing the dimensions of the product of this invention; Figure 5 This is a preliminary schematic diagram of the product design in this invention; Figure 6 This is a product state diagram after the preliminary graphic creation steps are completed in this invention; Figure 7 This is a schematic diagram of etching depth measurement in a single selection step of the present invention; Figure 8This is a product state diagram after a single selection step in this invention; Figure 9 This is a product state diagram after the secondary selection step is completed in this invention; Figure 10 This is a distribution diagram of the chemical silver plating area and the cavity area in the secondary selection step of this invention; Figure 11 This is a product state diagram after the slicing and packaging step is completed in this invention; Figure 12 This is a structural diagram of the final product in this invention; Figure 13 This is a single-selection graphic design diagram in the present invention; Figure 14 This is a design diagram for the chemical silver plating process in the secondary selection step of this invention. 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 embodiments, the parts are by weight; it should be noted that there are no special restrictions on the purchase manufacturers of all the raw materials involved in this invention, and they include, for example: photosensitive dry film (model: AQ-6238), degreasing agent (model: PDH439), wet film (model: IC600-BL2), and developer (model: PDH-20).

[0027] Selected ink: 50% epoxy resin (BASF Laromer LR-9004), 5% diethylene glycol ethyl ether acetate, 4% photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone), 2% silica, 9% barium sulfate, 9% talc, 1% pigment, and 20% additives (19% diluent tripropylene glycol diacrylate, 0.8% dispersant BYK-163, and 0.2% leveling agent BYK-331).

[0028] YZF-316A: 92% deionized water, 6% silver nitrate, 2% nitric acid.

[0029] YZF-317B: 98% deionized water, 1% copper nitrate, 1% nitric acid.

[0030] YZF-318C: 99% deionized water, 1% copper nitrate.

[0031] Etching system for solder pads: 20kg caustic soda, 5kg heavy metal salt (copper sulfate pentahydrate), 150L hydrogen peroxide, 10kg silicate, 150L deionized water.

[0032] Example 1: A method for fabricating a ceramic substrate for embedded packaging, comprising the following steps: S1: Preliminary graphic design: S1-1: Pretreatment: On the copper-clad ceramic substrate semi-finished product, the first micro-etching is performed at a temperature of 30℃ using a sulfuric acid / hydrogen peroxide system (sulphuric acid concentration of 10%); then the second micro-etching is performed at a temperature of 30℃ using a sulfuric acid / sodium persulfate system (sulphuric acid concentration of 5% and sodium persulfate concentration of 8%); then routine overflow water washing is performed, followed by acid washing with 4% sulfuric acid, and then routine overflow water washing is performed again. Finally, drying is carried out at a temperature of 75℃, with the line speed controlled at 1.1m / min throughout the process. S1-2: Film application: Apply AQ-6238 photosensitive dry film to the substrate surface at 110℃; S1-3: Exposure: Exposure is performed using an automatic double-sided LED exposure system. The exposure parameters are: 7 energy bars, 95% uniformity, and 35μm vertical alignment accuracy. S1-4: Development: A sodium carbonate solution with a concentration of 1.0% and a pH of 11 is used as the developing solution. Development is carried out at 30°C, and the linear velocity of the entire process is 1.0 m / min. S1-5: Etching: Etching was performed using a hydrochloric acid / sodium chlorate system at a temperature of 50°C, where the acid equivalent was 1.9N, the copper ion concentration was 135g / L, the specific gravity was 1.295, and the sodium chlorate potential was 40V. S1-6: Film removal: Use a 4% sodium hydroxide solution to remove the film at 50°C, then rinse with overflow water and dry at 85°C; S1-7: Solder etching: Use a solder etching system (20kg caustic soda, 5kg copper sulfate pentahydrate, 150L hydrogen peroxide, 10kg silicate, 150L deionized water) for etching, and then prepare a sulfuric acid / hydrogen peroxide system (5% sulfuric acid concentration) for micro-etching. S1-8: Cleaning and drying: Perform overflow water washing, dry at a temperature of 85℃, and then inspect to form surface circuits; S2: First-order selection: S2-1: Pre-etching treatment: The first stage of degreasing is carried out at 30°C using a 15% concentration of PDH439 degreasing agent; the second stage of micro-etching is carried out at 30°C using a sulfuric acid / sodium persulfate system (5% sulfuric acid concentration, 7% sodium persulfate concentration), followed by overflow rinsing, acid pickling (using a 4% concentration of sulfuric acid solution), overflow rinsing again, and drying at 75°C. The linear speed is controlled at 1.1m / min throughout the process. S2-2: Wet film printing: Use IC600-BL2 wet film printing on the surface circuitry; print all the grooves of the product. S2-3: Single-stage pattern exposure: Exposure is performed, with vacuum level controlled at -30kPa, A / B stage vacuum level at -25kPa, alignment accuracy at 65μm, energy grid at 7 grids, and exposure uniformity at 95%; S2-4: Development: Use a 1.0% concentration PDH-20 developer solution with a pH of 11.5, and develop at 30°C and a linear velocity of 0.9~1.1m / min to expose the area where cavity needs to be formed. S2-5: Etching: Using a hydrochloric acid / sodium chlorate system (acid equivalent 1.9N, copper ion concentration 135g / L, specific gravity 1.295, sodium chlorate potential 40V), etching was performed at 50℃ with a speed of 1.3m / min and an upward spraying pressure of 2.7kg / cm². 2 The downward spray pressure is 1.9 kg / cm². 2 Under these conditions, the etching depth is controlled to 165μm to form the required Cavity; S3: Secondary selection: S3-1: Membrane removal: Use a 4% sodium hydroxide solution at 50°C to remove the wet membrane from step S2-5, then perform overflow washing and drying at 85°C; S3-2: Pretreatment: The first micro-etching is performed on the ceramic substrate at 30°C using a sulfuric acid / hydrogen peroxide system (sulphuric acid concentration of 10%); then the second micro-etching is performed at 30°C using a sulfuric acid / sodium persulfate system (sulphuric acid concentration of 5% and sodium persulfate concentration of 7%), followed by routine overflow rinsing, acid washing with 4% sulfuric acid, and then routine overflow rinsing. Finally, the substrate is dried at 75°C, with the line speed controlled at 1.1m / min throughout the process. S3-3: Wet film printing: On the surface circuit, use IC600-BL2 wet film printing to fill all the grooves of the product; S3-4: Secondary selective pattern exposure: Exposure is performed using film, with the film vacuum level controlled at -30kPa, the A / B stage vacuum level at -25kPa, the alignment accuracy at 65μm, the energy grid at 7 grids, and the exposure uniformity at 95%. The area of ​​the secondary selective pattern should be smaller than that of the primary selective pattern, and the area of ​​the exposed pattern area should be smaller than the area of ​​the cavity. Selective ink should also be applied to the edge of the cavity. S3-5: Development: Use a 1.0% concentration PDH-20 developer solution with a pH of 11.5 to develop the area where cavity needs to be formed at 30°C and a linear velocity of 1.0 m / min. S3-6: Chemical silver plating: A first-stage micro-etching operation is performed using a sulfuric acid / hydrogen peroxide system (5.5% sulfuric acid concentration), at 30℃, with an upper and lower spray pressure of 2 kg / cm². A second-stage micro-etching operation is performed using a sulfuric acid / sodium persulfate system (3% sulfuric acid concentration, 5.8% sodium persulfate concentration), at 30℃, with an upper and lower spray pressure of 2 kg / cm². Pre-immersion treatment is performed in a pre-immersion solution (containing 17.5% YZF-317B, 6% YZF-318C, 1.1% nitric acid, and 0.15% copper ions) at 40℃. Then, chemical silver plating is performed in a chemical silver plating solution (containing 3% YZF-316A, 25% YZF-317B, 5% YZF-318C, 1.1% nitric acid, and 0.3% copper ions) at 52℃, controlling the silver plating layer thickness to be 0.65 μm. S4: Fragmented Packaging: S4-1: Film removal: Use a 4% sodium hydroxide solution to remove the film at 50°C, then rinse with overflow water and dry at 85°C; S4-2: Post-treatment: A micro-etching process was performed at 30°C using a sulfuric acid / sodium persulfate system (4% sulfuric acid and 4% sodium persulfate). Then, a sulfuric acid / hydrogen peroxide system (57.5 g / L sulfuric acid and 8.5 g / L copper ion concentration) was used at 30°C with an upper and lower spray pressure of 1.2 kg / cm². 2 Under the following conditions, secondary micro-etching was performed; then acid washing was performed using a 1.0% sulfuric acid solution; then anti-oxidation treatment was performed in an 85 ml / L anti-oxidation solution at 35°C, followed by water washing while controlling the conductivity to 1.2 μs / cm, and finally drying at 85°C. S4-3: Laser cutting: Cutting is performed using a laser with the following parameters: laser power 150W, cutting power output rate 33.5%, frequency 3.2kHz, pulse width 70μs, moving speed 100mm / s, and cutting depth 105μm. S4-4: Slicing: The cut substrate is separated into individual ceramic carrier plates. The finished products are then inspected and packaged to obtain ceramic carrier plates.

[0033] Example 2: A method for fabricating a ceramic substrate for embedded packaging, comprising the following steps: S1: Preliminary graphic design: S1-1: Pretreatment: On the copper-clad ceramic substrate semi-finished product, the first micro-etching is performed at 25°C using a sulfuric acid / hydrogen peroxide system (sulphuric acid concentration of 8%); then the second micro-etching is performed at 25°C using a sulfuric acid / sodium persulfate system (sulphuric acid concentration of 4% and sodium persulfate concentration of 5.5%); then routine overflow rinsing is performed, followed by acid washing with 3% sulfuric acid, and then routine overflow rinsing is performed again. Finally, drying is carried out at 70°C, with the line speed controlled at 1m / min throughout the process. S1-2: Film application: Apply AQ-6238 photosensitive dry film to the substrate surface at 100℃; S1-3: Exposure: Exposure is performed using an automatic double-sided LED exposure device. The exposure parameters are: 6 energy bars, 90% uniformity, and 10μm vertical alignment accuracy. S1-4: Development: A sodium carbonate solution with a concentration of 0.8% and a pH of 10.5 is used as the developing solution. Development is carried out at 28°C, and the linear velocity of the entire process is 0.9 m / min. S1-5: Etching: Etching was performed using a hydrochloric acid / sodium chlorate system at a temperature of 45°C, where the acid equivalent was 1.7N, the copper ion concentration was 115g / L, the specific gravity was 1.28, and the sodium chlorate potential was 15V. S1-6: Film removal: Use a 3% sodium hydroxide solution to remove the film at 45°C, then rinse with overflow water and dry at 80°C; S1-7: Solder etching: Use a solder etching system (20kg caustic soda, 5kg heavy metal salt (copper sulfate pentahydrate), 150L hydrogen peroxide, 10kg silicate, 150L deionized water) for etching, and then prepare a sulfuric acid hydrogen peroxide system (4% sulfuric acid concentration) for micro-etching. S1-8: Cleaning and drying: Perform overflow water washing, dry at a temperature of 80℃, and then inspect to form surface circuits; S2: First-order selection: S2-1: Pre-etching treatment: The first stage of degreasing is carried out at 25°C using 10% PDH439 degreasing agent; the second stage of micro-etching is carried out at 25°C using a sulfuric acid / sodium persulfate system (4% sulfuric acid concentration, 5.5% sodium persulfate concentration), followed by overflow rinsing, acid pickling (using 3% sulfuric acid solution), overflow rinsing again, and drying at 70°C. The linear speed is controlled at 1.0 m / min throughout the process. S2-2: Wet film printing: Use IC600-BL2 wet film printing on the surface circuitry; print all the grooves of the product. S2-3: Single-stage selective pattern exposure: Exposure is performed, with vacuum level controlled at -50kPa, A / B stage vacuum level at -40kPa, alignment accuracy at 40μm, energy grid at 6 grids, and exposure uniformity at 90%; S2-4: Development: Use PDH-20 developer with a concentration of 0.8% and a pH of 10 to develop the area where cavity needs to be formed at 28°C and a linear velocity of 0.9~1.1m / min. S2-5: Etching: Using a hydrochloric acid / sodium chlorate system (acid equivalent 1.7N, copper ion concentration 115g / L, specific gravity 1.28, sodium chlorate potential 15V), etching was performed at 45℃ with a speed of 0.5m / min and an upward spraying pressure of 2.4kg / cm. 2 The downward spray pressure is 1.6 kg / cm². 2 Under these conditions, the etching depth is controlled to 150 μm to form the required Cavity; S3: Secondary selection: S3-1: Membrane removal: Use a 3% sodium hydroxide solution at 45°C to remove the wet membrane from step S2-5, then rinse with overflow water and dry at 80°C. S3-2: Pretreatment: The first micro-etching is performed on the ceramic substrate at 25°C using a sulfuric acid / hydrogen peroxide system (8% sulfuric acid concentration); then the second micro-etching is performed at 25°C using a sulfuric acid / sodium persulfate system (4% sulfuric acid concentration, 5.5% sodium persulfate concentration); then routine overflow rinsing is performed, followed by acid washing with 3% sulfuric acid, and then routine overflow rinsing is performed again. Finally, the substrate is dried at 70°C, with the line speed controlled at 1.0 m / min throughout the process. S3-3: Wet film printing: On the surface circuit, use IC600-BL2 wet film printing to fill all the grooves of the product; S3-4: Secondary Selective Pattern Exposure: Exposure is performed using film, with the film vacuum level controlled at -50 kPa, A / B stage vacuum level at -40 kPa, alignment accuracy at 40 μm, energy grid at 6 divisions, and exposure uniformity at 90%. The area of ​​the secondary selective pattern must be smaller than the area of ​​the primary selective pattern, and the area of ​​the exposed pattern region must be smaller than the area of ​​the cavity. Furthermore, selective ink is applied to the edge of the cavity. S3-5: Development: Use PDH-20 developer with a concentration of 0.8% and a pH of 10 to develop the area where cavity needs to be formed at 28°C and a linear velocity of 0.9 m / min. S3-6: Chemical silver plating: Micro-etching is performed using a sulfuric acid / hydrogen peroxide system (4% sulfuric acid concentration), at 25℃, with an upper and lower spray pressure of 1.5 kg / cm². Alternatively, a sulfuric acid / sodium persulfate system (2% sulfuric acid concentration, 3.8% sodium persulfate concentration) is used, at 25℃, with an upper and lower spray pressure of 1.5 kg / cm². 2A two-stage micro-etching process was performed: pre-immersion treatment was carried out at 35°C in a pre-immersion solution (containing 15% YZF-317B, 4% YZF-318C, 0.5% nitric acid, and 0.1% copper ions); then, electroless silver plating was carried out at 50°C in a chemical silver plating solution (containing 2% YZF-316A, 20% YZF-317B, 4% YZF-318C, 0.5% nitric acid, and 0.1% copper ions), controlling the silver plating layer thickness to be 0.3 μm. S4: Fragmented Packaging: S4-1: Film removal: Use a 3% sodium hydroxide solution to remove the film at 45°C, then rinse with overflow water and dry at 80°C; S4-2: Post-treatment: A micro-etching process is performed at 25°C using a sulfuric acid / sodium persulfate system (2% sulfuric acid concentration, 1.9% sodium persulfate concentration); followed by a sulfuric acid / hydrogen peroxide system (40g / L sulfuric acid concentration, 5g / L copper ion concentration) at 25°C and an upper and lower spray pressure of 1kg / cm. 2 Under the following conditions, secondary micro-etching is performed; then acid washing is performed using a 0.5% sulfuric acid solution; then anti-oxidation treatment is performed in an 80 ml / L anti-oxidation solution at 30°C, followed by water washing while controlling the conductivity to 0.5 μs / cm, and finally drying at 80°C. S4-3: Laser cutting: Cutting is performed using a laser with the following parameters: laser power 150W, cutting power output rate 30%, frequency 3kHz, pulse width 60μs, moving speed 80mm / s, and cutting depth 80μm. S4-4: Slicing: The cut substrate is separated into individual ceramic carrier plates. The finished products are then inspected and packaged to obtain ceramic carrier plates.

[0034] Example 3: A method for fabricating a ceramic substrate for embedded packaging, comprising the following steps: S1: Preliminary graphic design: S1-1: Pretreatment: On the copper-clad ceramic substrate semi-finished product, the first micro-etching is performed at a temperature of 35℃ using a sulfuric acid / hydrogen peroxide system (sulphuric acid concentration of 12%); then the second micro-etching is performed at a temperature of 35℃ using a sulfuric acid / sodium persulfate system (sulphuric acid concentration of 6% and sodium persulfate concentration of 10%); then routine overflow water washing is performed, followed by acid washing with 5% sulfuric acid, and then routine overflow water washing is performed again. Finally, drying is carried out at a temperature of 80℃, with the line speed controlled at 1.2m / min throughout the process. S1-2: Film application: Apply AQ-6238 photosensitive dry film to the substrate surface at 120℃; S1-3: Exposure: Exposure is performed using an automatic double-sided LED exposure system. The exposure parameters are: 8 energy bars, 99% uniformity, and 50μm vertical alignment accuracy. S1-4: Development: A sodium carbonate solution with a concentration of 1.2% and a pH of 11.5 was used as the developing solution, and development was carried out at 32°C. The linear velocity of the entire process was 1.1 m / min. S1-5: Etching: Etching was performed using a hydrochloric acid / sodium chlorate system at a temperature of 55°C, where the acid equivalent was 2.1N, the copper ion concentration was 155g / L, the specific gravity was 1.31, and the sodium chlorate potential was 60V. S1-6: Film removal: Use a 3-5% sodium hydroxide solution to remove the film at 55°C, then rinse with overflow water and dry at 90°C; S1-7: Solder etching: Use a solder etching system (20kg caustic soda, 5kg heavy metal salt (copper sulfate pentahydrate), 150L hydrogen peroxide, 10kg silicate, 150L deionized water) for etching, and then prepare a sulfuric acid hydrogen peroxide system (6% sulfuric acid concentration) for micro-etching. S1-8: Cleaning and drying: Perform overflow water washing, dry at a temperature of 90℃, and then inspect to form surface circuitry; S2: First-order selection: S2-1: Pre-etching treatment: The first stage of degreasing is carried out at 35°C using a 20% concentration of PDH439 degreasing agent; the second stage of micro-etching is carried out at 35°C using a sulfuric acid / sodium persulfate system (6% sulfuric acid concentration, 10% sodium persulfate concentration), followed by overflow rinsing, acid pickling (using a 5% sulfuric acid solution), overflow rinsing again, and drying at 80°C. The linear speed is controlled at 1.2m / min throughout the process. S2-2: Wet film printing: Use IC600-BL2 wet film printing on the surface circuitry; print all the grooves of the product. S2-3: Single-stage selective pattern exposure: Exposure is performed, with vacuum level controlled at -10kPa, A / B stage vacuum level at -10kPa, alignment accuracy at 90μm, energy grid at 8 grids, and exposure uniformity at 99%; S2-4: Development: Use PDH-20 developer with a concentration of 1.2% and a pH of 13 to develop the area where cavity needs to be formed at 2°C and a linear velocity of 1.1 m / min. S2-5: Etching: Using a hydrochloric acid / sodium chlorate system (acid equivalent 2.1N, copper ion concentration 155g / L, specific gravity 1.31, sodium chlorate potential 60V), etching was performed at 55℃ with a speed of 2.1m / min and an upward spraying pressure of 3.0kg / cm². 2 The downward spray pressure is 2.2 kg / cm².2 The etching depth is 180μm to form the required cavity; S3: Secondary selection: S3-1: Membrane removal: Use a 5% sodium hydroxide solution at 55°C to remove the wet membrane from step S2-5, then perform overflow washing and drying at 90°C; S3-2: Pretreatment: The first micro-etching is performed on the ceramic substrate at 35°C using a sulfuric acid / hydrogen peroxide system (sulphuric acid concentration of 12%); then the second micro-etching is performed at 35°C using a sulfuric acid / sodium persulfate system (sulphuric acid concentration of 6% and sodium persulfate concentration of 10%), followed by routine overflow rinsing, acid washing with 5% sulfuric acid, and then routine overflow rinsing. Finally, the substrate is dried at 80°C, with the line speed controlled at 1.2 m / min throughout the process. S3-3: Wet film printing: On the surface circuit, use IC600-BL2 wet film printing to fill all the grooves of the product; S3-4: Secondary selective pattern exposure: Exposure is performed using film, with film vacuum level controlled at -10kPa, A / B stage vacuum level at -10kPa, alignment accuracy at 90μm, energy grid at 8 grids, and exposure uniformity at 99%. The area of ​​the secondary selective pattern should be smaller than that of the primary selective pattern, and the area of ​​the exposed pattern region should be smaller than the area of ​​the cavity. Selective ink is then applied to the edge of the cavity. S3-5: Development: Use PDH-20 developer with a concentration of 1.2% and a pH of 13 to develop the area where cavity needs to be formed, at 32°C and a linear velocity of 1.1 m / min. S3-6: Chemical silver plating: Micro-etching is performed in one stage using a sulfuric acid / hydrogen peroxide system (7% sulfuric acid concentration), at 35℃, with an upper and lower spray pressure of 2.5 kg / cm²; or using a sulfuric acid / sodium persulfate system (4% sulfuric acid concentration, 7.9% sodium persulfate concentration), at 35℃, with an upper and lower spray pressure of 1.5~2.5 kg / cm². 2 A two-stage micro-etching process was performed: pre-immersion treatment was carried out at 45°C in a pre-immersion solution (containing 20% ​​YZF-317B, 8% YZF-318C, 1.8% nitric acid, and 0.2% copper ions); then, electroless silver plating was carried out at 55°C in a chemical silver plating solution (containing 4% YZF-316A, 30% YZF-317B, 6% YZF-318C, 1.8% nitric acid, and 0.5% copper ions), with the silver plating layer thickness controlled at 1.0 μm. S4: Fragmented Packaging: S4-1: Film removal: Use a 5% sodium hydroxide solution to remove the film at 55°C, then rinse with overflow water and dry at 85°C; S4-2: Post-treatment: A micro-etching process is performed at 35°C using a sulfuric acid / sodium persulfate system (6% sulfuric acid concentration and 6% sodium persulfate concentration); followed by a sulfuric acid / hydrogen peroxide system (75g / L sulfuric acid concentration and 12g / L copper ion concentration) at 35°C and an upper and lower spray pressure of 2kg / cm. 2 Under these conditions, secondary micro-etching is performed; then acid washing is carried out using a 1.5% sulfuric acid solution; then anti-oxidation treatment is carried out in an anti-oxidation solution with a concentration of 90 ml / L at 40°C, followed by water washing while controlling the conductivity to 2 μs / cm, and finally drying at 90°C. S4-3: Laser cutting: Cutting is performed using a laser with the following parameters: laser power 150W, cutting power output rate 37%, frequency 3.5kHz, pulse width 80μs, moving speed 120mm / s, and cutting depth 130μm. S4-4: Slicing: The cut substrate is separated into individual ceramic carrier plates. The finished products are then inspected and packaged to obtain ceramic carrier plates.

[0035] Conclusion: The ceramic substrate prepared by this method, relying on precise design drawings, can ensure the dimensional matching of each layer and the required depth of the cavity, providing precise spatial positioning and physical support for the subsequent installation of chips or devices.

[0036] 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 fabricating a ceramic substrate for embedded packaging, characterized in that: Includes the following steps: S1: Preliminary pattern making: On the copper-clad ceramic substrate semi-finished product, pretreatment, film application, exposure, development, etching, film removal, solder etching, cleaning and drying, and inspection are carried out in sequence to form surface circuits. S2: Single-stage selection: Pre-etching pretreatment, wet film printing, single-stage selection pattern exposure, development, and etching are performed sequentially on the surface lines to form Cavity; S3: Secondary selection: The Cavity is sequentially subjected to film removal, pretreatment, wet film printing, secondary selection pattern exposure, development, and chemical silver plating. S4: Slicing and Packaging: The ceramic substrates that have completed step S3 are sequentially subjected to film removal, post-processing, laser cutting, slicing, final inspection, and packaging to obtain ceramic carrier plates; Wherein, the area of ​​the graphic region exposed by the secondary selection graphic is smaller than the area of ​​the Cavity.

2. The method for fabricating a ceramic substrate for embedded packaging according to claim 1, characterized in that: In step S2, the etching system is a hydrochloric acid / sodium chlorate system; in the hydrochloric acid / sodium chlorate system, the acid equivalent is 1.7~2.1N, the copper ion concentration is 115~155g / L, the specific gravity is 1.28~1.31, and the sodium chlorate potential is 15~60V.

3. The method for fabricating a ceramic substrate for embedded packaging according to claim 1, characterized in that: In step S2, the etching rate is 0.5~2.1 m / min, and the upward spraying pressure is 2.4~3.0 kg / cm². 2 The downward spray pressure is 1.6~2.2 kg / cm². 2 The temperature is 45~55℃ and the depth is 150~180μm.

4. The method for fabricating a ceramic substrate for embedded packaging according to claim 1, characterized in that: In step S3, the edge of the Cavity is covered with selective ink after secondary selective pattern exposure and before development, and then chemically silvered. The raw materials of the selected ink are composed of the following components, by mass percentage: epoxy resin 49-53%, diethylene glycol ethyl ether acetate 4.8-5.2%, photoinitiator 3.8-4.2%, silicon dioxide 1.8-2.2%, barium sulfate 8.8-9.2%, talc 8.8-9.2%, pigment 0.8-1.2%, and additives 18-20%.

5. The method for fabricating a ceramic substrate for embedded packaging according to claim 4, characterized in that: The process flow for the chemical silver plating is as follows: micro-etching stage 1, micro-etching stage 2, pre-immersion, and silver plating; The micro-etching stage employs a sulfuric acid / hydrogen peroxide system, with a sulfuric acid concentration of 4-7%, a temperature of 25-35℃, and an upper and lower spray pressure of 1.5-2.5 kg / cm². 2 The micro-etching stage uses a sulfuric acid / sodium persulfate system, with a sodium persulfate concentration of 40-80 g / L, a sulfuric acid concentration of 2-4%, a temperature of 25-35℃, and an upper and lower spray pressure of 1.5-2.5 kg / cm². 2 .

6. The method for fabricating a ceramic substrate for embedded packaging according to claim 5, characterized in that: The pre-impregnation is carried out in a pre-impregnation solution, the raw materials of which consist of the following components by mass percentage: 15~20% YZF-317B, 4~8% YZF-318C, 0.5~1.8% nitric acid, and 0.1~0.2% copper ions; the pre-impregnation temperature is 35~45℃.

7. The method for fabricating a ceramic substrate for embedded packaging according to claim 5, characterized in that: The silver plating is carried out in a chemical silver plating solution, the raw materials of which consist of the following components by mass percentage: 2~4% YZF-316A, 20~30% YZF-317B, 4~6% YZF-318C, 0.5~1.8% nitric acid, and 0.1~0.5% copper ions; The silver plating thickness is 0.3~1.0μm, and the temperature is 50~55℃.

8. The method for fabricating a ceramic substrate for embedded packaging according to claim 1, characterized in that: In step S1, the etching system is a hydrochloric acid / sodium chlorate system, wherein the acid equivalent is 1.7~2.1N, the copper ion concentration is 115~155g / L, the specific gravity is 1.28~1.31, the sodium chlorate potential is 15~60V, and the temperature is 45~55℃.

9. The method for fabricating a ceramic substrate for embedded packaging according to claim 1, characterized in that: In step S1, the solder etching operation method is as follows: the ceramic substrate after the film removal step in step S1 is placed in the solder etching system, and then transferred to a 4~6% sulfuric acid / hydrogen peroxide micro-etching system for micro-etching treatment. The etching system for the solder pads consists of: 18-22 kg of caustic soda, 4-6 kg of heavy metal salts, 140-160 L of hydrogen peroxide, 8-12 kg of silicate, and 140-160 L of deionized water.

10. The ceramic substrate prepared by the method for fabricating a ceramic substrate for matching embedded packaging according to any one of claims 1 to 9.

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