Manufacturing method for high-thermal-conductivity silicon nitride copper-clad substrate
By laminating a high-strength copper foil metal underlayer onto a ceramic substrate and combining photolithography and electroplating processes, the problem of the inability to fabricate precision circuits in existing technologies has been solved, enabling the fabrication of a high thermal conductivity silicon nitride copper-clad substrate, which improves the thermal conductivity and solderability of the substrate.
Patent Information
- Application Number
- CN202511617398.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-06
- Publication Date
- 2026-01-09
AI Technical Summary
Precision circuits cannot be fabricated on ceramic substrates bonded with copper foil using existing technologies.
A high-strength copper foil metal substrate is laminated onto a ceramic substrate using copper brazing technology. The copper foil metal substrate is then patterned using photolithography and electroplating processes, and excess material is removed by etching to form a high thermal conductivity silicon nitride copper-clad substrate.
This technology enables the fabrication of precision circuits on ceramic substrates, solving the problem of the inability to process circuits in existing technologies, and also improves the thermal conductivity and solderability of the substrate.
Smart Images
Figure CN121310422A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application relates to a manufacturing method, in particular to a manufacturing method for a high-thermal-conductivity silicon nitride copper-clad substrate, and belongs to the technical field of ceramic electronic device design and manufacturing. BACKGROUND
[0002] AMB ceramic substrate, full name Active Metal Brazing, is a technology for realizing metallurgical combination of ceramic and copper foil through active metal brazing technology. The technology takes active metal brazing as the core, reacts Ag-Cu filler containing active elements such as Ti and Zr with the ceramic substrate in a vacuum high-temperature environment (about 800 DEG C) to form a copper-filler-ceramic composite structure, and realizes high-strength metallurgical bonding of the ceramic and the copper foil.
[0003] However, how to prepare a precise circuit on the ceramic substrate bonded with the copper foil, there is no technical means for reference in the prior art. SUMMARY
[0004] The application aims to solve the technical problem of providing a manufacturing method for a high-thermal-conductivity silicon nitride copper-clad substrate which can effectively prepare a precise circuit on the ceramic substrate bonded with the copper foil.
[0005] The technical scheme adopted to solve the above technical problem is as follows: a manufacturing method for a high-thermal-conductivity silicon nitride copper-clad substrate, comprising a ceramic bottom plate, the manufacturing method first adopts a copper brazing process to composite a high-strength copper foil metal bottom layer on two sides of the ceramic bottom plate, then adopts a photoetching process to perform patterning processing on the high-strength copper foil metal bottom layer to remove at least part of the high-strength copper foil metal bottom layer outside the pattern, then adopts an electroplating process to perform copper dam layer thickening on the high-strength copper foil metal bottom layer obtained through the photoetching, and finally adopts an etching process to remove a process solder layer and / or a process electroplated conductive layer outside the pattern to obtain a high-thermal-conductivity silicon nitride copper-clad substrate with a pattern meeting the requirements.
[0006] Further, when the copper brazing process is adopted to composite the high-strength copper foil metal bottom layer on the two sides of the ceramic bottom plate, Ag-Cu filler containing Ti and Zr type active elements is used as the welding material, the copper foil is reacted with the ceramic bottom plate in a high-temperature vacuum brazing furnace with a temperature not lower than 750 DEG C, a high-strength metallurgical bonding ceramic copper foil composite structure of copper-filler-ceramic is formed, and the composite work of the high-strength copper foil metal bottom layer is completed.
[0007] The preferred mode of the above scheme is that the Ag-Cu filler containing Ti and Zr type active elements is used as the welding material, and the copper brazing process is adopted to composite the high-strength copper foil metal bottom layer according to the following steps, First, the ceramic base plate and copper foil are cleaned by surface pretreatment, then active metal brazing paste is printed or sprayed on both sides of the ceramic base plate and dried, then a piece of cleaned copper foil is arranged on both sides of each piece of ceramic base plate with brazing material, and finally the ceramic base plate with copper foil is placed in the brazing furnace for high-temperature welding to form a copper-brazing material-ceramic high-strength metallurgical bonding ceramic copper foil composite structure.
[0008] Further, the Ag-Cu brazing material containing Ti and Zr active elements is used as the welding material, and the high-strength copper foil metal bottom layer is compounded by the copper brazing process, which is performed as follows, First, qualified brazing solid welding pieces are prepared, at the same time, the ceramic base plate and copper foil are cleaned by surface pretreatment, then the brazing solid welding pieces and copper foil are arranged on both sides of the ceramic base plate from inside to outside, then the ceramic base plate with brazing solid welding pieces and copper foil is placed in the brazing furnace for high-temperature welding to form a copper-brazing material-ceramic high-strength metallurgical bonding ceramic copper foil composite structure.
[0009] The preferred mode of the above scheme is that when the copper dam layer is thickened by the pattern plating process, the copper metallization dam layer on the surface of the ceramic base plate is thickened by vacuum sputtering combined with pattern plating for one or more times.
[0010] Further, after the copper metallization dam layer on the surface of the ceramic base plate is thickened, the oxidation resistance and weldability of the ceramic copper-clad substrate are improved by surface treatment to improve the precision of the circuit.
[0011] The preferred mode of the above scheme is that each pattern process includes the following steps: surface cleaning, making a photosensitive film, exposure, development, copper plating, copper surface grinding and polishing, and fading the photosensitive film.
[0012] Further, the photoetching process includes the following steps: cleaning, making a photosensitive film, exposure, development, copper etching, and fading the photosensitive film.
[0013] The preferred mode of the above scheme is that when the patterned high-strength copper foil metal bottom layer is partially or completely removed by photoetching, the brazing material layer with conductive properties can be retained or the brazing material layer can be completely removed.
[0014] Further, when the brazing material layer is completely removed, the conductive layer required for subsequent pattern plating process is re-made by chemical deposition or physical deposition before the copper metallization layer is thickened by electroplating.
[0015] The application has the advantages that the manufacturing method provided by the application is based on the existing ceramic substrate, a high-strength copper foil metal layer is first compounded on the ceramic substrate by using copper soldering process, then a preliminary circuit is obtained by removing at least part of the high-strength copper foil metal layer on the high-strength copper foil metal layer by using photoetching process, then the copper dam layer on the preliminary circuit left by photoetching is thickened by using electroplating process, finally, the process soldering material layer and / or the process electroplating conductive layer outside the circuit are removed by using etching process to obtain a high-thermal-conductivity silicon nitride copper-clad substrate with a required pattern. Thus, the technical problem that the high-strength copper foil metal can only be compounded on the ceramic substrate by copper soldering and the circuit cannot be processed in the prior art is effectively solved, and the above technical solution of the application can also effectively prepare a precise circuit on the ceramic substrate bonded with the copper foil. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 A cross-sectional view of the high-strength copper foil metal layer compounded by the manufacturing method for the high-thermal-conductivity silicon nitride copper-clad substrate of the application; Figure 2 A photoetching cross-sectional view related to the manufacturing method for the high-thermal-conductivity silicon nitride copper-clad substrate of the application; Figure 3 A cross-sectional view after electroplating and development related to the manufacturing method for the high-thermal-conductivity silicon nitride copper-clad substrate of the application; Figure 4 A cross-sectional view after copper electroplating related to the manufacturing method for the high-thermal-conductivity silicon nitride copper-clad substrate of the application; Figure 5 A cross-sectional view of the C ceramic substrate product obtained by the manufacturing method for the high-thermal-conductivity silicon nitride copper-clad substrate of the application.
[0017] In the figure, 1 is a ceramic substrate, 2 is a high-strength copper foil metal layer, and 3 is a soldering material layer. DETAILED DESCRIPTION
[0018] As Figures 1-5The application provides a manufacturing method for high-thermal-conductivity silicon nitride copper-clad substrates, which can effectively manufacture fine circuits on ceramic substrates bonded with copper foils. The manufacturing method comprises a ceramic substrate 1. The manufacturing method first adopts copper soldering technology to combine a high-strength copper foil metal layer 2 on two sides of the ceramic substrate 1, then adopts photoetching technology to perform patterning processing on the high-strength copper foil metal layer 2 to remove the high-strength copper foil metal layer outside the pattern, then adopts electroplating technology to thicken the copper dam layer on the high-strength copper foil metal layer obtained by photoetching, and finally adopts etching technology to remove the process soldering material layer and / or the process electroplating conductive layer outside the pattern to obtain the high-thermal-conductivity silicon nitride copper-clad substrate with a required pattern. The manufacturing method provided by the application is based on the existing ceramic substrate, adopts copper soldering technology to combine a high-strength copper foil metal layer on the ceramic substrate, then adopts photoetching technology to remove a part of the high-strength copper foil metal layer to obtain a preliminary circuit on the high-strength copper foil metal layer, then adopts electroplating technology to thicken the copper dam layer on the preliminary circuit, and finally adopts etching technology to remove the process soldering material layer and / or the process electroplating conductive layer outside the circuit to obtain the high-thermal-conductivity silicon nitride copper-clad substrate with a required pattern. In this way, the technical problem that the existing technology can only combine a high-strength copper foil metal on a ceramic substrate by copper soldering but cannot perform circuit processing can be effectively solved. The above technical solution can also effectively manufacture fine circuits on ceramic substrates bonded with copper foils.
[0019] Correspondingly, in combination with the prior art, in order to fully utilize the existing process equipment and reduce the manufacturing cost, when the copper soldering technology is adopted to combine the high-strength copper foil metal layer on the two sides of the ceramic substrate 1, the Ag-Cu solder containing Ti and Zr active elements is used as the soldering material, the copper foil is reacted with the ceramic substrate 1 in a high-temperature vacuum soldering furnace at a temperature not lower than 750 DEG C, a high-strength copper-solder-ceramic metallurgical bonding ceramic copper foil composite structure is formed, and the combination of the high-strength copper foil metal layer 2 is completed. At this time, there are two ways to clad copper. One way is that the Ag-Cu solder containing Ti and Zr active elements is used as the soldering material, and the combination of the high-strength copper foil metal layer 2 is performed according to the following steps, First, the ceramic substrate 1 and the copper foil are cleaned by surface pretreatment, then the active metal soldering paste is printed or sprayed on the two sides of the ceramic substrate 1 and dried, then a piece of cleaned copper foil is arranged on each side of the ceramic substrate 1 with the soldering paste, finally the ceramic substrate 1 with the copper foil is placed in the soldering furnace for high-temperature soldering to form the high-strength copper-solder-ceramic metallurgical bonding ceramic copper foil composite structure. The other way is that the Ag-Cu solder containing Ti and Zr active elements is used as the soldering material, and the combination of the high-strength copper foil metal layer 2 is performed according to the following steps, First, qualified brazing solid sheets are prefabricated. At the same time, the ceramic base plate 1 and copper foil are cleaned through surface pretreatment. Then, brazing solid sheets and copper foil are sequentially set on both sides of the ceramic base plate 1 from the inside out. Next, the ceramic base plate with brazing solid sheets and copper foil is placed into the brazing furnace for high-temperature welding to form a high-strength metallurgically bonded ceramic copper foil composite structure of copper-brazing filler metal-ceramic.
[0020] Similarly, when using pattern electroplating to thicken the copper dam layer in this application, the copper metallization dam layer on the ceramic substrate surface is thickened by vacuum sputtering combined with pattern electroplating through one or more copper plating operations. After the copper metallization dam layer on the ceramic substrate surface is thickened, surface treatment is performed to improve the oxidation resistance and solderability of the ceramic copper-clad substrate 1, thereby improving the precision of its circuitry. Accordingly, each pattern electroplating process includes the following steps: surface cleaning, photosensitive film fabrication, exposure, development, copper plating, copper surface grinding and polishing, and photosensitive film removal. The photolithography process sequentially includes the following steps: cleaning, photosensitive film fabrication, exposure, development, copper etching, and photosensitive film removal.
[0021] A further preferred embodiment is that when the high-strength copper foil metal substrate 2, excluding the pattern, is partially or completely removed during photolithography, the conductive solder material layer 3 can be retained or completely removed. When the solder material layer 3 is completely removed, the conductive layer required for the subsequent pattern electroplating process is re-fabricated by chemical deposition or physical deposition before electroplating to thicken the copper metallization layer.
[0022] The technical solution of this application will be further described below through specific embodiments: This invention provides a method for fabricating a ceramic substrate using a composite AMB and DPC process. The ceramic substrate is first bonded to an underlying copper layer using the AMB process, then patterned using photolithography, and finally thickened with copper at desired locations using a DPC patterning electroplating process. The ceramic substrate fabricated using this invention combines the high bonding strength and high performance of the AMB process with the dammed structure of the DPC process.
[0023] The technical solution adopted by this invention to solve its technical problem is: The DPC ceramic substrate is manufactured using a composite process of AMB and DPC, combining the high bonding strength and high strength of the AMB process with the damming structure of the DPC process.
[0024] First, the AMB process is used to metallize both sides of the ceramic sheet to create the bottom metallization layer.
[0025] The AMB process first involves cleaning the ceramic and copper sheets through surface pretreatment. Then, active metal brazing paste is printed or sprayed onto both sides of the ceramic sheets and dried. Next, a cleaned copper sheet is placed on each side of each ceramic sheet with brazing paste. The entire assembly is then placed in a brazing furnace for high-temperature welding. Alternatively, the brazing paste can be applied by placing pre-made solid brazing paste sheets between each layer of ceramic and copper sheets.
[0026] Secondly, photolithography is used to pattern the underlying copper layer of the ceramic substrate fabricated by the AMB process to obtain the required underlying pattern.
[0027] The photolithography process sequentially includes cleaning, fabrication of a photosensitive film, exposure, development, copper etching, and removal of the photosensitive film. During patterning, the solder layer created on the ceramic surface using the AMB process is retained as the conductive layer for subsequent DPC pattern copper plating.
[0028] Finally, the desired copper thickness is achieved by applying a DPC pattern electroplating process to the areas where copper plating is needed. This DPC pattern electroplating process includes cleaning, fabrication of a photosensitive film, exposure, development, copper plating, copper surface grinding and polishing, and removal of the photosensitive film. Multiple DPC pattern electroplating processes can be performed as needed to achieve the required copper layer thickness. After DPC pattern electroplating is completed, the photosensitive film is removed, and then the solder layer created on the ceramic surface using the AMB process is etched away using solder etching to obtain the final product.
[0029] The DPC process involved in this invention refers to DPC ceramic substrate, or Direct Plated Copper Ceramic, a technique for directly electroplating a copper layer onto the surface of a ceramic substrate. This technique achieves ceramic surface metallization through vacuum sputtering and patterned electroplating, and then improves the oxidation resistance and solderability of the substrate through surface treatment, thereby realizing precision circuitry.
[0030] Example
[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.
[0032] like Figure One As shown, the ceramic and copper sheets are first cleaned through surface pretreatment. Then, active metal brazing paste is printed or sprayed on both sides of the ceramic sheet and dried. Next, a cleaned copper sheet is placed on each side of each ceramic sheet with brazing paste. The whole assembly is then placed in a brazing furnace for high-temperature welding. After welding, it becomes a whole, and the ceramic and copper sheets have a strong bonding force.
[0033] like Figure TwoAs shown, the ceramic substrate obtained by the AMB process is then patterned, which can be performed using photolithography. The photolithography process sequentially includes cleaning, fabrication of a photosensitive film, exposure, development, copper etching, and removal of the photosensitive film. During the patterning process, the solder layer fabricated on the ceramic surface by the AMB process is retained as the conductive layer for subsequent DPC pattern copper plating.
[0034] Finally, the desired copper layer thickness is achieved by applying a DPC pattern electroplating process to the areas where copper plating is needed. Multiple DPC pattern electroplating processes can be performed as required to achieve the desired copper layer thickness. The DPC pattern electroplating process sequentially includes cleaning, fabrication of a photosensitive film, exposure, development, copper plating, copper surface grinding and polishing, and removal of the photosensitive film. After the DPC pattern electroplating is completed, the solder layer created on the ceramic surface using the AMB process is etched away using solder etching.
[0035] like Figure Three The diagram shown is a cross-sectional view of the DPC pattern after electroplating and development. The substrate patterned by the AMB process is obtained by sequentially performing cleaning, photosensitive film fabrication, exposure, and development processes.
[0036] like Figure Four The diagram shows a cross-section of a DPC pattern after copper electroplating. The developed substrate is then electroplated with copper, with the copper thickness being equal to or slightly lower than the thickness of the photosensitive film. After copper plating, the top of the plated area is ground and polished. Multiple copper plating processes can be performed, each involving a sequential process of cleaning, photosensitive film fabrication, exposure, development, copper plating, and grinding / polishing, until the desired copper thickness is achieved.
[0037] like Figure Five As shown, after copper plating is completed, the photosensitive film is first removed, and then the solder layer made on the ceramic surface by the AMB process is etched away by solder etching to obtain the final product.
Claims
1. A method for fabricating a high thermal conductivity silicon nitride copper-clad substrate, comprising a ceramic substrate (1), characterized in that: The manufacturing method first uses copper brazing to laminate a high-strength copper foil metal substrate (2) on both sides of a ceramic substrate (1). Then, photolithography is used to pattern the high-strength copper foil metal substrate (2), at least partially removing the high-strength copper foil metal substrate outside the pattern. Next, electroplating is used to thicken the copper dam layer on the high-strength copper foil metal substrate obtained by photolithography. Finally, etching is used to remove the process solder layer and / or process electroplated conductive layer outside the pattern to obtain a high thermal conductivity silicon nitride copper-clad substrate with a pattern that meets the requirements.
2. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 1, characterized in that: When using copper brazing process to composite high-strength copper foil metal underlayer on both sides of ceramic substrate (1), Ag-Cu brazing filler metal containing Ti and Zr active elements is used as brazing material. The copper foil is reacted with the ceramic substrate (1) in a high-temperature vacuum brazing furnace at a temperature not lower than 750℃ to form a high-strength metallurgically bonded ceramic copper foil composite structure of copper-brazing filler metal-ceramic to complete the composite work of high-strength copper foil metal underlayer (2).
3. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 2, characterized in that: Using Ag-Cu solder containing active elements such as Ti and Zr as the soldering material, the composite high-strength copper foil metal underlayer (2) is carried out in the following steps: First, the ceramic substrate (1) and copper foil are cleaned through surface pretreatment. Then, active metal brazing slurry is printed or sprayed on both sides of the ceramic substrate (1) and dried. Next, a cleaned copper foil is placed on each side of each ceramic substrate (1) with brazing material. Finally, the ceramic substrate (1) with copper foil is placed in the brazing furnace for high-temperature welding to form a high-strength metallurgically bonded ceramic copper foil composite structure of copper-brazing material-ceramic.
4. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 2, characterized in that: Using Ag-Cu solder containing active elements such as Ti and Zr as the soldering material, the composite high-strength copper foil metal underlayer (2) is carried out in the following steps: First, qualified brazing solid welding sheets are prefabricated. At the same time, the ceramic base plate (1) and copper foil are cleaned through surface pretreatment. Then, brazing solid welding sheets and copper foil are set on both sides of the ceramic base plate (1) from the inside to the outside. Next, the ceramic base plate with brazing solid welding sheets and copper foil is placed into the brazing furnace for high-temperature welding to form a high-strength metallurgical bonded ceramic copper foil composite structure of copper-brazing filler metal-ceramic.
5. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 1, 2, 3 or 4, characterized in that: When using pattern electroplating to thicken the copper dam layer, the copper metallization dam layer on the surface of the ceramic substrate is thickened by one or more copper plating processes using vacuum sputtering combined with pattern electroplating.
6. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 5, characterized in that: After the copper metallization dam layer on the surface of the ceramic substrate is thickened, the oxidation resistance and solderability of the ceramic copper-clad substrate (1) are improved by surface treatment to enhance the precision of its circuit.
7. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 6, characterized in that: Each pattern electroplating process includes the following steps: surface cleaning, photosensitive film preparation, exposure, development, copper plating, copper surface grinding and polishing, and photosensitive film removal.
8. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 5, characterized in that: The photolithography process includes several steps in sequence: cleaning, making a photosensitive film, exposure, development, copper etching, and removing the photosensitive film.
9. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 5, characterized in that: When the high-strength copper foil metal underlayer (2) other than the pattern is partially or completely removed by photolithography, the conductive brazing material layer (3) can be retained or the brazing material layer (3) can be completely removed.
10. The method for fabricating a high thermal conductivity silicon nitride copper-clad substrate according to claim 9, characterized in that: When the solder material layer is completely removed (3), the conductive layer required for the subsequent pattern electroplating process is remade by chemical deposition or physical deposition before electroplating to thicken the copper metallization layer.