A method of additive copper material on ceramic substrate

Abstract

The application discloses a method for adding copper material on a ceramic substrate, comprising the following steps: ultrasonic cleaning and surface metallization treatment of the ceramic substrate; air replacement in the bin; copper material powder is laid on the ceramic substrate after heating; a laser is started after laying a layer of powder, and the powder is melted and fused with the ceramic substrate by the laser; the laser power is increased, and the copper material part is started to be printed; the powder laying and printing steps are repeatedly executed until the printing is finished. The application can process copper-ceramic forming parts with high interface bonding strength, thereby meeting the application requirements of insulation, heat conduction and the like.

Description

Technical Field

[0001] This invention relates to a method for additive manufacturing of metallic materials, and more particularly to a method for additively manufacturing copper materials on a ceramic substrate. Background Technology

[0002] In existing technologies, laser-based powder bed melting (L-PBF) is an advanced additive manufacturing technology that uses high-energy lasers to melt metal powder layer by layer to create complex three-dimensional parts. In recent years, with the development of laser technology, shorter wavelength green lasers (typically 515nm or 532nm) have attracted much attention due to their higher absorption rate for metal materials such as copper, gold, and aluminum, which have high reflectivity to infrared lasers, further expanding the application scope of L-PBF technology.

[0003] In the traditional green laser powder bed fusion technology for printing copper or copper alloys, stainless steel is the most commonly used substrate material. However, in some products involving applications such as conductivity and insulation, metal substrates cannot meet the requirements for insulation, thermal conductivity, and other related applications. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a method for adding copper material on a ceramic substrate to meet the application requirements of the prior art, thereby enabling the processing of copper-ceramic molded parts with high interfacial bonding strength and thus satisfying the application requirements such as insulation and thermal conductivity.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0006] A method for additively manufacturing copper material on a ceramic substrate includes the following steps: Step S1, preparing a ceramic substrate; Step S2, performing surface metallization treatment on the ceramic substrate; Step S3, fixing the ceramic substrate in a molding chamber; Step S4, filling the molding chamber with inert gas to replace the air inside the chamber; Step S5, heating the ceramic substrate and then spreading copper material powder; Step S6, after spreading one layer of powder, starting a laser to melt the powder and fuse it with the ceramic substrate; Step S7, increasing the laser power and starting to print copper material parts; repeating the powder spreading and printing steps until printing is completed.

[0007] Preferably, the ceramic substrate is an alumina or aluminum nitride substrate.

[0008] Preferably, in step S2, the ceramic substrate is surface-metallized by direct copper plating.

[0009] Preferably, in step S4, during the process of replacing the air inside the chamber, the oxygen content inside the chamber is reduced to less than 100 ppm.

[0010] Preferably, in step S5, the ceramic substrate is heated to 200°C.

[0011] Preferably, the method includes: step S8, pausing powder application when printing reaches the 50th layer, and using a laser to perform an overall scan of the cross-section of the part so that the part is heated evenly.

[0012] Preferably, in step S7, after the powder fuses with the ceramic substrate to form an "adhesion layer", the laser power is increased to 200W and the scanning speed is 800mm / s to start printing copper material parts.

[0013] Preferably, the ceramic substrate is a silicon carbide or silicon dioxide substrate.

[0014] Preferably, in step S2, titanium material is sputtered onto the surface of a ceramic substrate using a PVD process to form a reaction layer.

[0015] Preferably, the ceramic substrate is a silicon nitride substrate.

[0016] Preferably, in step S4, during the process of replacing the air in the chamber, the oxygen content in the chamber is reduced to less than 100 ppm; in step S7, a layer of copper powder is first laid on the surface of the ceramic substrate, and then a laser is used to scan the surface of the ceramic substrate. The laser power is 300W and the scanning speed is 10 mm / s, so that a metal-like silicon layer is formed on the surface of the ceramic substrate.

[0017] The method for additive manufacturing of copper materials on a ceramic substrate disclosed in this invention involves directly additively manufacturing copper or copper alloys onto the ceramic substrate, thereby achieving additive manufacturing of copper or copper alloy components, such as the integrated molding of "insulation-thermal conductivity-electrical conductivity" functional structural components. Compared to existing technologies that print copper and copper alloy components on stainless steel substrates, the ceramic substrate approach of this invention is more suitable for the manufacturing of high-end electronic devices such as 5G base station power amplifier modules, new energy vehicle IGBT substrates, and satellite power supply heat sinks, and can effectively promote the technological development in the fields of heterogeneous integration and high-performance functional components. Attached Figure Description

[0018] Figure 1 A schematic diagram of the device structure for performing the method of the present invention. Detailed Implementation

[0019] The present invention will now be described in more detail with reference to the accompanying drawings and embodiments.

[0020] This invention discloses a method for additive copper material on a ceramic substrate. Please refer to [link to relevant documentation]. Figure 1 It includes the following steps: Step S1: Prepare the ceramic substrate; Step S2: Perform surface metallization treatment on the ceramic substrate; Step S3: Fix the ceramic substrate in the molding chamber; Step S4: Inert gas, specifically argon, is introduced into the molding chamber to replace the air inside the chamber. Step S5: After heating the ceramic substrate, powder is spread on it. The powder spread is copper material powder. Step S6: After a layer of powder is laid, the laser is activated to melt the powder and fuse it with the ceramic substrate. Step S7: Increase laser power and begin printing copper parts; Step S8: When printing reaches the 50th layer, pause the powder application and use a laser to scan the cross-section of the part to ensure that the part is heated evenly. Step S9: Repeat the steps of toner application, printing, and overall scanning until printing is complete.

[0021] The above method employs green laser L-PBF technology to directly print copper and copper alloys onto a ceramic substrate, aiming to meet the needs of certain products for insulation, heat dissipation, and heterogeneous integration. Specifically, the ceramic material refers to advanced ceramics, which can be one of the five advanced ceramics: alumina, aluminum nitride, silicon carbide, silicon nitride, and silicon dioxide. Before use, the ceramic substrate needs to be cleaned by ultrasonic cleaning in acetone, ethanol, and deionized water in sequence to remove contaminants.

[0022] Furthermore, adding copper or copper alloys to ceramics is a combination of dissimilar materials. Ceramic and metal have significant differences in physical and chemical properties such as melting point, thermal conductivity, wettability, and thermal expansion. Therefore, the bonding of these two materials requires different surface treatment methods depending on the specific ceramic material. For alumina (Al2O3) and aluminum nitride (AlN) ceramics, surface metallization can be achieved through the Direct Bonded Copper (DBC) method. For silicon carbide (SiC) ceramics, the PVD method can be used to sputter a metal thin film such as W, Ni, or Ti onto the surface as an intermediate layer, depending on the application requirements. For silicon nitride (Si3N4) ceramics, direct bonding between silicon nitride and copper can be achieved through laser surface modification. Specifically, a laser scans the silicon nitride surface, causing a copper-silicon eutectic reaction that allows copper to form a metallurgical bond with the modified surface. Alternatively, active metal brazing (AMB) can be used to bond silicon nitride and copper. For silicon dioxide (SiO2) ceramics, a PVD method can be used to sputter an intermediate layer on the surface as a transition.

[0023] Please see Figure 1 The equipment configuration employs an L-PBF system with a green laser of approximately 515 nm wavelength, while the scanning system uses a high-speed galvanometer mirror corresponding to the green laser in conjunction with an f-theta field mirror. During the printing process, the forming chamber is filled with high-purity argon gas (oxygen content < 100 ppm) and maintained inert. Before the actual printing, the ceramic plate is preheated, with an overall preheating temperature of no less than 200℃, and if necessary, heated to 300-400℃ to reduce the temperature difference at the copper / ceramic interface and suppress the risk of cracking.

[0024] During the printing process, the first few layers require a lower laser energy density for "adhesion layer" deposition, depending on the material selection, to ensure a strong intermediate phase layer is formed between the copper or copper alloy and the ceramic. Subsequent layers gradually increase the laser energy density until the optimal range for printing copper or copper alloy is reached.

[0025] In addition, during the printing process, depending on the size and shape characteristics of the product, if necessary, an in-situ surface heating treatment can be performed after a certain number of layers have been printed (such as 50 layers). This involves turning off the powder spreading mechanism and allowing the laser to scan the current surface globally at low power to promote stress relaxation.

[0026] After printing, the product will be slowly cooled down under the temperature control module. In some cases, it can be slowly cooled to room temperature along with the oven. The purpose is to avoid interface cracking caused by rapid cooling. After that, heat treatment will be performed depending on the product.

[0027] This invention directly additively manufactures copper or copper alloys onto a ceramic substrate, thereby enabling the additive manufacturing of copper or copper alloy components, such as the integrated molding of "insulation-thermal conductivity-electrical conductivity" functional structural parts. Compared to existing technologies that print copper and copper alloy components on stainless steel substrates, this invention's ceramic substrate approach is more suitable for manufacturing high-end electronic devices such as 5G base station power amplifier modules, new energy vehicle IGBT substrates, and satellite power supply heat sinks, effectively promoting technological development in the fields of heterogeneous integration and high-performance functional components.

[0028] For different copper materials, the present invention provides the following embodiments. Example

[0029] In this embodiment, the ceramic substrate is an alumina or aluminum nitride substrate. Specifically, in step S2, the ceramic substrate is surface-metallized using a direct copper plating method. It should be noted that, for alumina or aluminum nitride substrates, in addition to the copper plating method, other methods can be used for surface metallization, such as directly printing a layer of another metal.

[0030] Accordingly, in step S4, during the process of replacing the air inside the chamber, the oxygen content inside the chamber is reduced to below 100 ppm.

[0031] Based on this, in step S5, the ceramic substrate is heated to 200°C.

[0032] In step S7, after the powder fuses with the ceramic substrate to form an "adhesion layer", the laser power is increased to 200W and the scanning speed is 800mm / s to start printing copper material parts.

[0033] This embodiment achieves additive copper fabrication on an alumina or aluminum nitride substrate. After ultrasonic cleaning, the ceramic substrate is surface metallized using the direct copper bonding (DBC) method. Then, as... Figure 1 As shown, the alumina plate is fixed in the molding chamber and the air inside the chamber is replaced with argon gas. The goal is to reduce the oxygen content in the molding chamber to less than 100 ppm. Then, the substrate heating is turned on to heat the alumina plate to 200°C.

[0034] Next, powder spreading begins, with a thickness of 30 μm. The powder material is pure copper. After one layer of powder is spread, a green laser, using a galvanometer and field lens, irradiates the powder surface with low power, melting the powder and fusing it with the substrate. After the "adhesion layer" appears, the laser power is gradually increased to a suitable process window, such as increasing the power to 200 W and the scanning speed to 800 mm / s, to begin normal copper material printing.

[0035] When printing reaches 50 layers, toner application is paused. The laser then scans the entire cross-section of the part, ensuring more even heating and reducing the risk of cracking. The toner application-printing-overall scanning process then continues until printing is complete.

[0036] Finally, after the parts have cooled down slowly, they can be removed for further post-processing. Example

[0037] The difference between this embodiment and Embodiment 1 is that the ceramic substrate is a silicon carbide or silicon dioxide substrate. In this embodiment, in step S2, titanium material is sputtered onto the surface of the ceramic substrate using a PVD process to form a reaction layer.

[0038] Specifically, in this embodiment, copper is added to a silicon carbide or silicon dioxide substrate. After ultrasonic cleaning of the ceramic substrate, Ti is sputtered onto the substrate surface using PVD to form a reaction layer, followed by... Figure 1 As shown, the plate is fixed in the molding chamber, and the subsequent steps are the same as in Example 1. Example

[0039] The difference in this embodiment is that the ceramic substrate is a silicon nitride substrate.

[0040] In step S4 of this embodiment, during the process of replacing the air in the chamber, the oxygen content in the chamber is reduced to less than 100 ppm; In addition, in step S7, a layer of copper powder is first laid on the surface of the ceramic substrate, and then the surface of the ceramic substrate is scanned by a laser with a laser power of 300W and a scanning speed of 10 mm / s, so that a metal-like silicon layer is formed on the surface of the ceramic substrate.

[0041] In this embodiment, copper is added to a silicon nitride substrate. After ultrasonic cleaning, the ceramic substrate is fixed in a molding chamber. The air inside the chamber is replaced with argon gas to reduce the oxygen content to below 100 ppm.

[0042] The ceramic substrate is then heated, and the alumina plate is heated to 200°C.

[0043] Before printing, a layer of copper powder is first laid on the substrate surface. Then, a laser is used to scan the surface at a power of 300W and a scanning speed of 10 mm / s to form a silicon metalloid layer on the substrate surface. The subsequent steps are the same as in Example 1.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the technical scope of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method of additive copper material on ceramic substrate, characterized by, Includes the following steps: Step S1: Prepare the ceramic substrate; Step S2: Perform surface metallization treatment on the ceramic substrate; Step S3: Fix the ceramic substrate in the molding chamber; Step S4: Inert gas is introduced into the molding chamber to replace the air inside the chamber. Step S5: After heating the ceramic substrate, powder is spread on it. The powder spread is copper material powder. Step S6: After a layer of powder is laid, the laser is activated to melt the powder and fuse it with the ceramic substrate. Step S7: Increase laser power and begin printing copper parts; Repeat the toner application and printing steps until printing is complete.

2. The method of claim 1, wherein, The ceramic substrate is an alumina or aluminum nitride substrate.

3. The method of claim 2, wherein, In step S2, the ceramic substrate is surface-metallized using a direct copper plating method.

4. The method of claim 2, wherein the copper material is deposited on the ceramic substrate by a method selected from the group consisting of electroplating, electroless plating, and physical vapor deposition. In step S4, during the process of replacing the air inside the chamber, the oxygen content inside the chamber is reduced to less than 100 ppm. In step S5, the ceramic substrate is heated to 200°C.

5. The method of claim 2, wherein, include: In step S8, when printing reaches the 50th layer, pause the powder application and use a laser to scan the cross-section of the part to ensure that the part is heated evenly.

6. The method of claim 2, wherein, In step S7, after the powder fuses with the ceramic substrate to form an "adhesion layer", the laser power is increased to 200W and the scanning speed is 800mm / s to start printing copper material parts.

7. The method of claim 1, wherein, The ceramic substrate is a silicon carbide or silicon dioxide substrate.

8. The method of claim 7, wherein, In step S2, titanium material is sputtered onto the surface of a ceramic substrate using a PVD process to form a reaction layer.

9. The method for adding copper material onto a ceramic substrate as described in claim 1, characterized in that, The ceramic substrate is a silicon nitride substrate.

10. The method for adding copper material to a ceramic substrate as described in claim 9, characterized in that, In step S4, during the process of replacing the air inside the chamber, the oxygen content inside the chamber is reduced to less than 100 ppm. In step S7, a layer of copper powder is first laid on the surface of the ceramic substrate, and then a laser is used to scan the surface of the ceramic substrate. The laser power is 300W and the scanning speed is 10 mm / s, so that a metal-like silicon layer is formed on the surface of the ceramic substrate.

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