Manufacturing process of silicon carbide substrate based on DBA and DPC processes

Abstract

The invention discloses a manufacturing process of a silicon carbide substrate based on DBA and DPC processes, and relates to the technical field of semiconductors. The silicon carbide substrate is prepared by cleaning semi-insulating silicon carbide, sputtering a seed layer for the first time, performing DBA aluminum plating and sintering, sputtering the seed layer for the second time, performing pattern transfer for the first time, electroplating a lead, performing pattern transfer for the second time, electroplating and thickening a copper seed layer, performing surface treatment, electroplating nickel and gold, electroplating a metal layer and performing scribing and forming. According to the manufacturing process, a semi-insulating silicon carbide substrate and a negative film process are adopted for manufacturing, a layer of aluminum film is additionally arranged on the basis to serve as a connecting layer between copper and the substrate, and the service life of the whole heat sink is greatly prolonged while efficient heat conduction transmission is guaranteed; the silicon carbide has excellent thermal conductivity and strength, and has good performance in coping with high temperature and high pressure when the laser works, so that the service life of the laser is greatly prolonged, and the performance of the laser is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a process for fabricating silicon carbide substrates based on DBA and DPC processes. Background Technology

[0002] With the widespread application of semiconductor laser technology in communications, industrial processing, medical aesthetics, and scientific research, the market demands for the performance of semiconductor lasers are constantly increasing, especially in terms of output power, integration density, and long-term operating life, where more stringent standards are being imposed. However, with the continuous increase in power, the heat generated by the laser accumulates rapidly during operation, especially in high-power continuous or pulsed operating modes, where the heat flux density per unit area increases significantly. At the same time, the miniaturization and integration of packaging structures further compresses the internal heat dissipation path and heat conduction space, making it difficult to effectively control the temperature of the active region, and highlighting the growing importance of thermal management. Heat accumulation in the active region not only causes a significant decrease in laser conversion efficiency but also leads to a series of negative effects such as increased threshold current, lasing wavelength drift, and unstable output beam patterns, severely restricting the performance and practicality of lasers under high-power conditions.

[0003] In existing laser heat sink packaging technologies, material and process bottlenecks further limit their applicability and reliability under high heat load scenarios. First, while conventional metal heat sinks (such as copper and aluminum) possess good thermal conductivity, their mechanical strength and thermal matching performance are limited. Commonly used ceramic heat sinks, such as aluminum nitride, while offering excellent insulation, struggle to achieve an ideal balance between thermal conductivity and structural strength, making it difficult to simultaneously meet the dual requirements of high-power lasers for efficient heat dissipation and structural stability. Second, silicon carbide (SiC) is considered an ideal thermal management material due to its high thermal conductivity, high hardness, and good chemical stability. However, it differs significantly from commonly used conductive layer materials (such as copper) in its coefficient of thermal expansion, easily leading to substrate warping and interface delamination during temperature cycling, thus interfering with the laser's polarization state and beam quality, affecting output characteristics. Furthermore, traditional DC electroplating of thick copper often introduces significant internal stress when forming conductive and heat dissipation pathways, which can severely lead to microcracks or even breakage of brittle substrates (such as SiC), seriously affecting the integrity and long-term reliability of the packaging structure.

[0004] In summary, the aforementioned limitations in materials and processes exacerbate the performance degradation and failure risk of semiconductor lasers under high-temperature and high-power operating environments, significantly shortening their lifespan. Therefore, to address these issues, this invention proposes a silicon carbide substrate fabrication process based on DBA and DPC technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a manufacturing process for silicon carbide substrates based on DBA and DPC processes, in order to solve the problems raised in the prior art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A fabrication process for silicon carbide substrates based on DBA and DPC processes includes the following steps: S1: Semi-insulating silicon carbide is used as the substrate. After cleaning and baking, a metal seed layer is sputtered for the first time to obtain the substrate. S2: After DBA (Direct Aluminum Plating) and pressure sintering on the substrate surface, a second copper seed layer is sputtered; then after the first pattern transfer, electroplating leads are performed; after the second pattern transfer, DPC (Direct Copper Plating) is used to thicken the copper seed layer. S3: After surface treatment, the substrate obtained in S2 is electroplated with nickel and gold, then electroplated with a metal layer, and finally diced and shaped to obtain a silicon carbide substrate.

[0007] Furthermore, in step S1, the semi-insulating silicon carbide has a thickness of 0.3-0.5 mm, a size of 3-5 inches, a thermal conductivity of >200 W / (m·K), a surface roughness of 10-60 nm, and a warpage of 10-50 μm.

[0008] Preferably, the semi-insulating silicon carbide has a thickness of 0.35-0.40 mm, a size of 4-5 inches, a thermal conductivity of 230-400 W / (m·K), a surface roughness of 10-50 nm, and a warpage of 10-40 μm.

[0009] Furthermore, in step S1, the cleaning conditions for the semi-insulating silicon carbide substrate are: ultrasonic acid removal cleaning in a Class 1000 cleanroom environment, and pure water ultrasonic cleaning in a Class 100 cleanroom environment.

[0010] Furthermore, in step S1, the process conditions for the first magnetron sputtering of the metal seed layer are: sputtering pressure 0.2-0.5 Pa, sputtering temperature 200-300 °C, sputtering current 10-30 A, sputtering voltage 400-800 V, and sputtering power 10-30 kW; the metal seed layer is a TiCu layer with a thickness of 50-600 nm.

[0011] Preferably, the process conditions for the first magnetron sputtering of the metal seed layer are: sputtering pressure 0.2-0.4 Pa, sputtering temperature 200-250 °C, sputtering current 10-20 A, sputtering voltage 500-800 V, and sputtering power 10-25 kW; the metal seed layer is a TiCu layer with a thickness of 50-500 nm.

[0012] Furthermore, in step S2, the process conditions for DBA (Direct Aluminum Plating) are: ambient temperature, sputtering power of 5-10kW, vacuum degree of 0.1-0.2Pa, pure oxygen flow rate of 30-50ppm; aluminum plating thickness of 100-130μm, and sputtered aluminum layer thickness of 5-8μm.

[0013] Preferred process conditions for DBA (Direct Aluminum Plating) are: ambient temperature, sputtering power of 5-9kW, vacuum degree of 0.18-0.2Pa, pure oxygen flow rate of 30ppm; aluminum plating thickness of 100-110μm, and sputtered aluminum layer thickness of 5-6μm.

[0014] Furthermore, in step S2, the process conditions for pressure sintering are: pressure 100-150 kgf, sintering temperature 1200-1500℃; after the aluminum layer is sintered, it is thinned to 10-30 μm using a 1200-mesh ceramic brush and a non-woven brush, then wet sandblasted, and finally polished to a surface roughness of 10-120 nm using a velvet pad and neutral fine polishing abrasive.

[0015] Preferably, the pressure sintering process conditions are: pressure 100-120 kgf, sintering temperature 1200-1300℃; after the aluminum layer is sintered, it is thinned to 10-20 μm using a 1200-mesh ceramic brush and a non-woven brush, then wet sandblasted, and finally polished to a surface roughness of 30-100 nm using a velvet pad and neutral fine polishing abrasive.

[0016] Furthermore, in step S2, the process conditions for the second sputtering of the copper seed layer are as follows: first, the aluminum layer is cleaned using ICP (inductively coupled plasma), and then... -4 A copper seed layer is sputtered at Pa, a temperature of 300-400℃, and a sputtering power of 9-15kW; the thickness of the copper seed layer is 1-3μm.

[0017] Preferably, the process conditions for the second sputtering of the copper seed layer are as follows: first, the aluminum layer is cleaned using ICP (inductively coupled plasma), and then... -4 A copper seed layer is sputtered at a temperature of 300-350℃ and a sputtering power of 9-13kW; the thickness of the copper seed layer is 1-2μm.

[0018] Furthermore, in step S2, the plating layer of the electroplated lead is a nickel layer with a thickness of 1-5 μm.

[0019] Preferably, in the electroplated leads, the plating layer of the leads is a nickel layer with a thickness of 1-3 μm.

[0020] Furthermore, in step S2, the process conditions for thickening the copper seed layer using DPC (Direct Copper Plating) are as follows: the method is pulse and DC electroplating, and copper plating is thickened by electrochemical deposition. In the copper plating solution, pulse pre-plating of copper to 10-25μm is used, followed by DC electroplating to 20-35μm. The current density on the front side is 15-20% higher than that on the back side to ensure the copper thickness on the front side. The copper plating solution is an acidic copper sulfate solution, a high-copper, low-acid electroplating system, including the following components: 200-280g / L copper sulfate pentahydrate, 30-90g / L sulfuric acid, 40-80ppm chloride ions, 10-20mL / L wetting agent, 0.6-1.5mL / L copper plating brightener, and 25-40mL / L leveling agent.

[0021] Preferred process conditions for DPC (Direct Copper Plating) thickening of the copper seed layer are as follows: the method is pulse and DC electroplating, and copper thickening is achieved by electrochemical deposition of copper. In the copper plating solution, pulse pre-plating of copper to 10-20μm is used, followed by DC electroplating to 20-30μm. The current density on the front side is 15% higher than that on the back side to ensure the copper thickness on the front side. The copper plating solution is an acidic copper sulfate solution, a high-copper, low-acid electroplating system, including the following components: 200-260g / L copper sulfate pentahydrate, 40-90g / L sulfuric acid, 40-70ppm chloride ions, 10-15mL / L wetting agent, 0.6-1.4mL / L copper plating brightener, and 25-35mL / L leveling agent.

[0022] Furthermore, in step S3, the surface treatment process includes rough polishing, film removal, flash etching, sandblasting, and fine polishing. First, the substrate is pre-polished to remove surface protrusions, etc., and then polished using double-sided polyurethane pads and alumina abrasives. Film removal uses an organic film removal solution and is soaked for 1 hour at a temperature of 80-90℃. Flash etching uses a hydrochloric acid-ferric chloride system. Fine polishing uses a velvet pad and a neutral polishing solution for 20-30 minutes, with a single-piece pressure of 8-10 kgf.

[0023] Furthermore, in step S3, the process of electroplating nickel and gold includes wet sandblasting, electroplating nickel and gold, and electroplating a thickened gold layer; the electroplated nickel and gold layer is one or a mixture of two of the nickel and gold layers, with a layer thickness of 3-6 μm, and the electroplated thickened gold layer is 1-3 μm.

[0024] Preferably, the electroplated nickel-gold coating is one or a mixture of nickel and gold layers, with a coating thickness of 3-4 μm and an electroplated gold layer thickness of 1-2 μm.

[0025] Furthermore, in step S3, the electroplated metal layer is one or more of platinum, gold-tin, and gold, and the coating thickness is 10-40 μm.

[0026] Preferably, the thickness of the electroplated metal layer is 10-20 μm.

[0027] Furthermore, in step S3, the process conditions for dicing are as follows: using a metal resin blade and a dicing machine, dicing is performed at 28,000-30,000 rpm and 3-5 mm / s.

[0028] Preferably, the process conditions for dicing are as follows: a dicing machine is used, a metal resin blade is used, and dicing is performed at 28,000 rpm and 3 mm / s.

[0029] Compared with the prior art, the beneficial effects of the present invention are: 1. The present invention describes a fabrication process for a silicon carbide substrate based on DBA and DPC processes. The present invention uses semi-insulating silicon carbide as the substrate. Compared with conventional metal heat sinks and ceramic heat sinks, silicon carbide substrates have better thermal conductivity, bending strength and surface roughness. By introducing the DBA (Direct Aluminum Bonding) process, an aluminum thin film is constructed between the silicon carbide substrate and the copper layer as a buffer and connection layer. This not only optimizes the interface heat conduction path and improves the overall heat dissipation efficiency, but also significantly alleviates the problem of thermal stress accumulation caused by the mismatch of the thermal expansion coefficients of copper and silicon carbide, thereby ensuring the wavelength stability and spot quality of the laser in high-temperature operating environments.

[0030] 2. The present invention describes a silicon carbide substrate fabrication process based on DBA and DPC processes. After sintering, the aluminum layer is polished to a surface roughness of less than 100nm. Combined with pattern transfer and electroplating thickening technology, good perpendicularity of the circuit sidewalls and pattern positioning accuracy are achieved, effectively avoiding the misalignment and step problems that may be caused by multiple pattern transfers. By electroplating leads, the step problem caused by misalignment after multiple pattern transfers is avoided. Pulse and DC electroplating are used to thicken the copper seed layer, avoiding the huge stress caused by DC electroplating of thick copper, which could lead to substrate damage.

[0031] 3. The present invention describes a silicon carbide substrate fabrication process based on DBA and DPC processes. The present invention uses the DBA process to achieve high-strength bonding between the aluminum layer and the silicon carbide substrate, effectively overcoming the problems of looseness, unevenness and poor bonding caused by traditional paste printing of aluminum layers.

[0032] 4. The present invention describes a manufacturing process for a silicon carbide substrate based on DBA and DPC processes. The present invention uses DPC process, which significantly reduces the internal stress of the coating, prevents the substrate from developing microcracks or chipping due to stress concentration, and improves the long-term reliability of the substrate under thermal cycling and mechanical vibration environments. Attached Figure Description

[0033] Figure 1 This is a schematic flowchart of the manufacturing process of the silicon carbide substrate of the present invention. Figure 2This is a cross-sectional schematic diagram of the silicon carbide substrate prepared according to the present invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] Example 1: A fabrication process for a silicon carbide substrate based on DBA and DPC processes, comprising the following steps: S1: Semi-insulating silicon carbide was used as the substrate. It was ultrasonically deacidified in a Class 1000 cleanroom environment, ultrasonically cleaned with pure water in a Class 100 cleanroom environment, and baked. Then, a 100nm thick TiCu layer was sputtered under sputtering pressure of 0.2Pa, sputtering temperature of 200℃, sputtering current of 15A, sputtering voltage of 600V, and sputtering power of 15kW to obtain the substrate. The semi-insulating silicon carbide was 0.35mm thick, 100.5×0.37mm in size, had a thermal conductivity of 250W / (m·K), a surface roughness of 30nm, and a warpage of 30μm. S2: Aluminum is deposited on the substrate surface using the DBA process, with an aluminum thickness of 100μm; under the conditions of 5kW sputtering power in the early stage, 9kW sputtering power in the later stage, vacuum degree of 0.18Pa, pure oxygen flow rate of 30ppm, and room temperature, an aluminum layer with a thickness of 5μm is sputtered; then pressure sintering is performed at a pressure of 100kgf and a sintering temperature of 1200℃. After sintering, the surface is treated by thinning to 15μm using a 1200-mesh ceramic brush and a non-woven brush, followed by wet sandblasting, and then polishing to a surface roughness of 50nm using a velvet pad and neutral fine polishing abrasive. After sintering, the aluminum layer is cleaned by ICP and then subjected to a vacuum pressure of 10. -4 At Pa, a temperature of 350℃, and a sputtering power of 9kW, a 2μm thick copper seed layer was sputtered. After the first pattern transfer, electroplating of the leads is performed, with a nickel plating layer and a thickness of 1.5 μm. After the second pattern transfer, a thickened copper seed layer is electroplated using pulse and DC electroplating methods. Copper is thickened by electrochemical deposition. In the copper plating solution, a 15μm pre-plating of copper is performed using pulse electroplating, followed by DC electroplating to a thickness of 25μm. The current density on the front side is 15% higher than that on the back side to ensure the thickness of the copper on the front side. The copper plating solution is an acidic copper sulfate solution, a high-copper, low-acid electroplating system, comprising the following components: 220g / L copper sulfate pentahydrate, 50g / L sulfuric acid, 50ppm chloride ions, 12mL / L wetting agent sodium dodecyl sulfate, 0.8mL / L copper plating brightener sodium dimethylformamide sulfonate, and 30mL / L leveling agent sodium mercaptoimidazolium propanesulfonate. S3: The substrate obtained in S2 is subjected to surface treatment. The surface treatment process includes rough polishing, film removal, flash etching, sandblasting, and fine polishing. First, the substrate is pre-polished to remove surface protrusions, etc., and then polished using double-sided polyurethane pads and alumina abrasives. Film removal is performed using an organic film removal solution, which is soaked at 80°C for 1 hour. Flash etching is performed using a hydrochloric acid-ferric chloride system. Fine polishing is performed using a velvet pad and a neutral polishing solution for 30 minutes, with a single-piece pressure of 8 kgf. Next, nickel-gold plating is performed, with a nickel-gold layer of 3μm thickness, followed by electroplating to thicken the gold layer by 1μm. Then, an electroplated metal layer is applied. The metal layer is a gold-tin layer with a thickness of 20μm. Finally, the silicon carbide substrate was obtained by dicing. The dicing process conditions were as follows: a dicing machine was used with a metal resin blade at 28,000 rpm and 3 mm / s.

[0036] Comparative Example 1: Based on Example 1, the DBA process was modified to print aluminum coating using paste, including the following steps: S1: Semi-insulating silicon carbide was ultrasonically acid-reduced in a Class 1000 cleanroom environment, ultrasonically cleaned with pure water in a Class 100 cleanroom environment, and baked. Then, a 100nm thick TiCu layer was sputtered under sputtering conditions of 0.2Pa, sputtering temperature of 200℃, sputtering current of 15A, sputtering voltage of 600V, and sputtering power of 15kW to obtain the substrate. The semi-insulating silicon carbide has a thickness of 0.35mm, dimensions of 100.5×0.37mm, thermal conductivity of 250W / (m·K), surface roughness of 30nm, and warpage of 30μm. S2: Aluminum sintering with paste printing is performed on the substrate surface. Vacuum pressure sintering process is used to bond the substrate and aluminum layer. Printing is done with a 120-mesh screen to print 30μm aluminum paste. Vacuum sintering is performed at a sintering temperature of 800℃. Surface treatment is done with wet sandblasting and fine polishing. Fine polishing is done with a velvet pad and neutral fine polishing abrasive to a surface roughness of 50nm. After sintering, the aluminum layer is cleaned by ICP and then subjected to a vacuum pressure of 10. -4At Pa, a temperature of 350℃, and a sputtering power of 9kW, a 2μm thick copper seed layer was sputtered. After the first pattern transfer, electroplating of the leads is performed, with a nickel plating layer and a thickness of 1.5 μm. After the second pattern transfer, a thickened copper seed layer is electroplated using pulse and DC electroplating methods. Copper is thickened by electrochemical deposition. In the copper plating solution, a 15μm pre-plating of copper is performed using pulse electroplating, followed by DC electroplating to a thickness of 25μm. The current density on the front side is 15% higher than that on the back side to ensure the thickness of the copper on the front side. The copper plating solution is an acidic copper sulfate solution, a high-copper, low-acid electroplating system, comprising the following components: 220g / L copper sulfate pentahydrate, 50g / L sulfuric acid, 50ppm chloride ions, 12mL / L wetting agent sodium dodecyl sulfate, 0.8mL / L copper plating brightener sodium dimethylformamide sulfonate, and 30mL / L leveling agent sodium mercaptoimidazolium propanesulfonate. S3: The substrate obtained in S2 is subjected to surface treatment. The surface treatment process includes rough polishing, film removal, flash etching, sandblasting, and fine polishing. First, the substrate is pre-polished to remove surface protrusions, etc., and then polished using double-sided polyurethane pads and alumina abrasives. Film removal is performed using an organic film removal solution, which is soaked at 80°C for 1 hour. Flash etching is performed using a hydrochloric acid-ferric chloride system. Fine polishing is performed using a velvet pad and a neutral polishing solution for 30 minutes, with a single-piece pressure of 8 kgf. Next, nickel-gold plating is performed, with a nickel-gold layer of 3μm thickness, followed by electroplating to thicken the gold layer by 1μm. Then, an electroplated metal layer is applied. The metal layer is a gold-tin layer with a thickness of 20μm. Finally, the silicon carbide substrate was obtained by dicing. The dicing process conditions were as follows: a dicing machine was used with a metal resin blade at 28,000 rpm and 3 mm / s.

[0037] Comparative Example 2: Based on Example 1, the DBA process was modified to aluminum plating, including the following steps: S1: Semi-insulating silicon carbide was ultrasonically acid-reduced in a Class 1000 cleanroom environment, ultrasonically cleaned with pure water in a Class 100 cleanroom environment, and baked. Then, a 100nm thick TiCu layer was sputtered under sputtering conditions of 0.2Pa, sputtering temperature of 200℃, sputtering current of 15A, sputtering voltage of 600V, and sputtering power of 15kW to obtain the substrate. The semi-insulating silicon carbide has a thickness of 0.35mm, dimensions of 100.5×0.37mm, thermal conductivity of 250W / (m·K), surface roughness of 30nm, and warpage of 30μm. S2: The substrate is sintered with aluminum and bonded to the aluminum film using a vacuum pressure sintering process. The vacuum pressure sintering process conditions are: pressure 100 kgf, sintering temperature 1200 °C. Then, surface treatment is carried out. After thinning to 15μm using a 1200-mesh ceramic brush and a non-woven brush, wet sandblasting is performed. Then, a velvet pad and neutral fine polishing abrasive are used to polish the surface to a roughness of 50nm. After sintering, the aluminum layer is cleaned by ICP and then subjected to a vacuum pressure of 10. -4 At Pa, a temperature of 350℃, and a sputtering power of 9kW, a 2μm thick copper seed layer was sputtered. After the first pattern transfer, electroplating of the leads is performed, with a nickel plating layer and a thickness of 1.5 μm. After the second pattern transfer, a thickened copper seed layer is electroplated using pulse and DC electroplating methods. Copper is thickened by electrochemical deposition. In the copper plating solution, a 15μm pre-plating of copper is performed using pulse electroplating, followed by DC electroplating to a thickness of 25μm. The current density on the front side is 15% higher than that on the back side to ensure the thickness of the copper on the front side. The copper plating solution is an acidic copper sulfate solution, a high-copper, low-acid electroplating system, comprising the following components: 220g / L copper sulfate pentahydrate, 50g / L sulfuric acid, 50ppm chloride ions, 12mL / L wetting agent sodium dodecyl sulfate, 0.8mL / L copper plating brightener sodium dimethylformamide sulfonate, and 30mL / L leveling agent sodium mercaptoimidazolium propanesulfonate. S3: The substrate obtained in S2 is subjected to surface treatment. The surface treatment process includes rough polishing, film removal, flash etching, sandblasting, and fine polishing. First, the substrate is pre-polished to remove surface protrusions, etc., and then polished using double-sided polyurethane pads and alumina abrasives. Film removal is performed using an organic film removal solution, which is soaked at 80°C for 1 hour. Flash etching is performed using a hydrochloric acid-ferric chloride system. Fine polishing is performed using a velvet pad and a neutral polishing solution for 30 minutes, with a single-piece pressure of 8 kgf. Next, nickel-gold plating is performed, with a nickel-gold layer of 3μm thickness, followed by electroplating to thicken the gold layer by 1μm. Then, an electroplated metal layer is applied. The metal layer is a gold-tin layer with a thickness of 20μm. Finally, the silicon carbide substrate was obtained by dicing. The dicing process conditions were as follows: a dicing machine was used with a metal resin blade at 28,000 rpm and 3 mm / s.

[0038] Conclusion: The silicon carbide substrate fabrication process based on DBA and DPC proposed in this invention exhibits excellent process adaptability and structural stability during specific implementation. The silicon carbide substrate prepared by Example 1 demonstrates outstanding performance in key indicators: its copper plating layer thickness is uniform and controllable, surface roughness is significantly reduced, the gold-tin plating layer is densely bonded and has uniform composition, and the overall structure meets the requirements for high-power semiconductor laser packaging in terms of thermal conductivity, interface bonding strength, and dimensional accuracy, showing good engineering applicability. In contrast, Comparative Example 1 uses a traditional paste printing process to prepare the aluminum layer. The resulting aluminum layer has a loose structure and poor density, with obvious thickness unevenness and interface defects. This makes it difficult for subsequent polishing processes to effectively improve the surface condition. The surface roughness of the prepared substrate fails to meet the process specifications, which seriously affects its heat dissipation efficiency and interface reliability as a heat sink substrate. In contrast, Comparative Example 2 uses a vacuum pressure sintering process to bond the substrate and aluminum film together. The resulting substrate has a significant overall misalignment, with a misalignment of 5-10 μm. This seriously affects the dimensional accuracy and positional consistency of the circuit pattern, and the structure cannot meet the assembly requirements of high-density integrated lasers. In summary, this invention, through a process route combining DBA (Direct Aluminum Plating) and DPC (Direct Copper Plating), achieves high thermal conductivity and high bonding strength while also ensuring pattern accuracy and surface quality, providing a reliable and efficient silicon carbide substrate solution for packaging and heat dissipation of high-power, long-life semiconductor lasers.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A fabrication process for silicon carbide substrates based on DBA and DPC processes, characterized in that: Includes the following steps: S1: Semi-insulating silicon carbide is used as the substrate. After cleaning and baking, a metal seed layer is sputtered for the first time to obtain the substrate. S2: After aluminum sputtering and pressure sintering on the substrate surface, a second copper seed layer is sputtered; then after the first pattern transfer, the leads are electroplated; after the second pattern transfer, the thickened copper seed layer is electroplated. S3: After surface treatment, the substrate obtained in S2 is electroplated with nickel and gold, then electroplated with a metal layer, and finally diced and shaped to obtain a silicon carbide substrate.

2. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In S1, the process conditions for the first magnetron sputtering of the metal seed layer are: sputtering pressure 0.2-0.5 Pa, sputtering temperature 200-250 °C, sputtering current 10-20 A, sputtering voltage 500-800 V, and sputtering power 10-25 kW.

3. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In S2, the process conditions for aluminum sputtering are: sputtering power 5-9kW, vacuum degree 0.18-0.2Pa, and pure oxygen flow rate 30ppm.

4. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In S2, the process conditions for pressure sintering are: pressure 100-120 kgf, sintering temperature 1200-1300 °C.

5. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In step S2, the process conditions for the second sputtering of the copper seed layer are: vacuum pressure 10... -4 Pa, temperature 300-350℃, sputtering power 9-13kW.

6. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In step S2, the plating thickness of the electroplated lead is 1-3 μm.

7. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In S2, the method for thickening the copper seed layer by electroplating is pulse and DC electroplating; the process conditions for pulse and DC electroplating are as follows: in the copper electroplating solution, after pulse preplating of copper to 10-20μm, switch to DC electroplating to plate copper to 20-30μm.

8. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 7, characterized in that: The copper plating solution comprises the following components: 200-260 g / L copper sulfate pentahydrate, 40-90 g / L sulfuric acid, 40-70 ppm chloride ions, 10-15 mL / L wetting agent, 0.6-1.4 mL / L copper plating brightener, and 25-35 mL / L leveling agent.

9. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In step S3, the electroplated nickel-gold coating is one or a mixture of nickel and gold layers, and the coating thickness is 3-4 μm.

10. The fabrication process of a silicon carbide substrate based on DBA and DPC processes according to claim 1, characterized in that: In step S3, the electroplated metal layer is one or more of platinum, gold-tin, and gold, with a thickness of 15-30 μm.

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