A cathode device

Abstract

This application relates to a cathode device, which includes a cathode tube, a cathode cover, a target fixing device, a magnetic yoke, a flange assembly, and a cooling system. The cathode tube is fixedly installed inside the cathode cover. The cathode tube includes a cathode tube body, an insulation assembly, and a connector assembly. The cathode tube body includes a transition ring, a cooling sealing plate, a water inlet connector, a water outlet connector, and a base. The base has a flow channel for the cooling medium. The insulation assembly is formed by sequentially welding a Kovar alloy ring one, a ceramic insulating ring, and a Kovar alloy ring two. The target fixing device is installed at the front of the cathode tube and has a target mounting groove. The target is fixed in the target mounting groove and closely adheres to the target mounting surface. The magnetic yoke is installed behind the base. The rear of the cathode cover seals and fixes the connector assembly, which is sealed to the flange assembly. The cooling system is connected to the water inlet and water outlet connectors of the cathode tube body. This application features high cooling efficiency, reliable fixing, and is not prone to cracking.

Description

Technical Field

[0001] This application relates to a cathode device, which is mainly applicable to the design of magnetron sputtering cathode targets with efficient cooling, uniform magnetic field distribution and long life. Background Technology

[0002] Magnetron sputtering is a widely used thin film deposition technology. Its core component is the cathode target, which uses a magnetic field to confine plasma to improve sputtering efficiency. Traditional cathode targets have the following problems: 1. Insufficient cooling efficiency at high power, which can easily cause thermal deformation or cracking of the target material; 2. The fabrication of the cathode tube involves welding oxygen-free copper, stainless steel, Kovar alloy, and insulating ceramics. The technology involves welding processes between dissimilar metals, as well as welding processes between metals and non-metals. Different materials have different coefficients of thermal expansion, which can easily lead to welding cracks during the welding process. Summary of the Invention

[0003] The technical problem solved by this application is to overcome the above-mentioned deficiencies in the prior art and to provide a highly efficient and reliable cathode device.

[0004] The technical solution adopted by this application to solve the above-mentioned technical problems includes: a cathode device, comprising a cathode tube, a cathode cover, a target fixing device, a magnetic yoke, a flange assembly, and a cooling system. The cathode tube is fixedly installed inside the cathode cover. The cathode tube includes a cathode tube body, an insulation assembly, and a connector assembly connected in sequence. The cathode tube body includes a transition ring, a cooling sealing plate, a water inlet connector, a water outlet connector, and a base. The transition ring, cooling sealing plate, water inlet connector, and water outlet connector are all installed on the base. The base has a flow channel for the flow of cooling medium. The insulation assembly is used to isolate the current generated by high voltage. The insulation assembly is formed by welding Kovar alloy ring one, a ceramic insulating ring, and Kovar alloy ring two in sequence. The target fixing device is installed at the front of the cathode tube. The target fixing device has a target mounting groove. The target is fixed on the target mounting groove and close to the target mounting surface. The magnetic yoke is installed at the rear of the base. The rear of the cathode cover is sealed and fixed with the connector assembly. The connector assembly is sealed and connected to the flange assembly. The cooling system is connected to the water inlet connector and the water outlet connector of the cathode tube body and is cooled by circulating cooling medium.

[0005] The cathode tube, cathode cover, and target fixing device described in this application are all annular structures, and the flow channel is cylindrical in shape.

[0006] In this application, the cathode tube and the cathode cover are fastened together by threads. The outer surface of the cathode cover is provided with an electrolytic polishing layer to ensure that the magnetic field inside the cathode cover is uniform and to shield the influence of external interference sources.

[0007] The flange assembly includes an outer flange, a cathode metal sealing ring, and a flange sealing ring. The cathode metal sealing ring is disposed between the joint assembly and the outer flange to prevent external air from entering the cathode device from the side. The flange sealing ring is disposed at the rear of the outer flange to prevent external air from entering the cathode device from the rear.

[0008] The cooling system includes a cooling inlet pipe and a cooling outlet pipe. The cooling inlet pipe is connected to an inlet connector, and the cooling outlet pipe is connected to an outlet connector. The inlet connector and the outlet connector are located at the upper and lower parts of the flow channel, respectively. The ratio of the flow channel radius to the base radius is 4~5:6, and the ratio of the front-to-back distance of the flow channel to the front-to-back distance of the base is 12~16:30, resulting in high heat dissipation efficiency.

[0009] A metal transition layer is provided at the interface of the ceramic insulating ring to enhance the strength of the welded joint between Kovar alloy ring 1, Kovar alloy ring 2, and the ceramic insulating ring.

[0010] The contact surfaces of Kovar alloy ring 1, Kovar alloy ring 2 and ceramic insulating ring in this application are provided with nickel plating layers, and the connection surfaces of transition ring and base and cooling sealing plate are provided with nickel plating layers, which further enhances the strength of the welded joints between Kovar alloy ring 1, Kovar alloy ring 2 and ceramic insulating ring.

[0011] The nickel plating thickness on the contact surfaces of the Kovar alloy ring one, Kovar alloy ring two and the ceramic insulating ring is between 5 micrometers and 15 micrometers, and the nickel plating thickness on the connection surfaces of the transition ring and the base and cooling sealing plate is between 5 micrometers and 15 micrometers.

[0012] The transition ring, water inlet connector, water outlet connector, exhaust connector, connector flange, and external flange are all made of stainless steel, while the base, cooling sealing plate, cathode metal sealing ring, and flange sealing ring are all made of oxygen-free copper.

[0013] The distance from the weld between Kovar alloy ring one and the transition ring to the middle of Kovar alloy ring one, and the distance from the weld between Kovar alloy ring two and the joint flange to the middle of Kovar alloy ring two, are both no less than 10 mm. Increasing these distances reduces the adverse effects of heat generated during welding Kovar alloy ring one to the cathode tube body and during welding Kovar alloy ring two to the joint flange on the ceramic insulating ring, preventing the risk of cracking. As a special case, the distance from the weld between Kovar alloy ring one and the transition ring to the middle of Kovar alloy ring one, and the distance from the weld between Kovar alloy ring two and the joint flange to the middle of Kovar alloy ring two, are between 12 mm and 15 mm.

[0014] Compared with the prior art, this application has the following advantages and effects: high cooling efficiency, reliable fixation, and less prone to cracking. Attached Figure Description

[0015] Figure 1This is a structural schematic diagram of an embodiment of this application.

[0016] Figure 2 This is a schematic diagram of the main structure of the cathode tube according to an embodiment of this application.

[0017] Figure 3 This is a schematic diagram of the insulation component structure according to an embodiment of this application.

[0018] Figure 4 This is a schematic diagram of the connector assembly structure according to an embodiment of this application.

[0019] Figure 5 This is a schematic diagram of the connection between the cooling component and the insulating component after welding according to an embodiment of this application.

[0020] Figure 6 yes Figure 5 The diagram shows the connection of the cooling component and insulation component assembly after welding with the joint assembly.

[0021] In the diagram: Cathode tube 1, (stainless steel) transition ring 11, connecting surface between transition ring and base 111, (oxygen-free copper) cooling sealing plate 12, water inlet connector 13, water outlet connector 14, (oxygen-free copper) base 15, flow channel 151, magnetic yoke mounting groove 152, target mounting surface 153, insulating assembly 16, Kovar alloy ring one 161, nickel plating position of Kovar alloy one 1611, welding point between Kovar alloy ring one and transition ring 1612, ceramic insulating ring 162, metallization position of ceramic insulating ring 1621, Kovar alloy ring two 163, nickel plating position of Kovar alloy two 1631, welding point between Kovar alloy ring two and joint flange 1 632, Connector assembly 17, (stainless steel) connector flange 171, vent connector 172, cathode cover 2, target fixing device 3, target mounting groove 31, magnetic yoke 4, flange assembly 5, external flange 51, cathode metal (oxygen-free copper) sealing ring 52, (oxygen-free copper) flange sealing ring 53, cooling system 6, cooling water inlet pipe 61, cooling water outlet pipe 62, flow channel radius L1, flow channel front-to-back distance L2, base front-to-back distance L3, front-to-back distance from the weld between Kovar alloy ring one and transition ring to the middle of Kovar alloy ring one L4, front-to-back distance from the weld between Kovar alloy ring two and connector flange to the middle of Kovar alloy ring two L5. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present application, but the present application is not limited to the following embodiments. In the figures, left represents the front and right represents the rear.

[0023] See Figures 1-6The embodiments of this application mainly include a cathode tube 1, a cathode cover 2, a target fixing device 3, a magnetic yoke 4, a flange assembly 5, and a cooling system 6. The cathode tube 1 is fixedly installed inside the cathode cover 2, and the cathode tube 1 includes a cathode tube body fixed as one piece (see Figure 2 The cathode tube 1 consists of an insulating component 16 and a connector component 17, all assembled using a composite welding method. The cathode tube body includes a transition ring 11, a cooling sealing plate 12, a water inlet connector 13, a water outlet connector 14, and a base 15. The base 15 has a flow channel 151 for the cooling medium to flow through. The insulating component 16 is used to isolate the current generated by high voltage. The insulating component 16 is formed by sequentially welding Kovar alloy ring 161, ceramic insulating ring 162, and Kovar alloy ring 163. The target fixing device 3 is installed at the front of the cathode tube 1. The target fixing device 3 has a target mounting groove 31. The target is fixed on the target mounting groove 31 and closely attached to the target mounting surface 153. The magnetic yoke 4 is installed at the rear of the base 15. The rear of the cathode cover 2 seals and fixes the connector component 17. The connector component 17 is sealed and connected to the flange component 5. The cooling system 6 is installed on the water inlet connector 13 and the water outlet connector 14 of the cathode tube body and cools the tube by circulating the cooling medium.

[0024] The cathode tube 1, cathode cover 2, and target fixing device 3 described in this application are all annular structures (all with circular cross-sections), and the flow channel 151 is cylindrical in shape (with a circular cross-section).

[0025] The cathode cover 2 of this application is used to shield the magnetic field inside the cathode tube 1 so that it is not affected. The cathode tube 1 is fixed inside the cathode cover 2. The cathode tube 1 and the cathode cover 2 are connected by threads. The surface of the cathode cover 2 is electrolytically polished (layered) to reduce the impact of use in a vacuum environment, ensure the uniformity of the magnetic field inside the cover, and shield the influence of external interference sources.

[0026] The flange assembly 5 includes an outer flange 51, a cathode metal sealing ring 52, and a flange sealing ring 53. The cathode metal sealing ring 52 is disposed between the joint assembly 17 and the outer flange 51 to prevent external air from entering the cathode device through the side. The flange sealing ring 53 is disposed at the rear of the outer flange 51 to prevent external air from entering the cathode device through the rear.

[0027] The cathode tube body carries away the heat generated by the target head (referring to the cathode tube body) during operation through two stainless steel connectors (inlet connector 13 and outlet connector 14). Inlet connector 13 and outlet connector 14 are connected to cooling water inlet pipe 61 and cooling water outlet pipe 62, respectively. Inlet connector 13 and outlet connector 14 are located at the upper and lower parts of flow channel 151, respectively. Flow channel 151 is made as large as possible while ensuring the strength of base 15 to increase the contact area between cooling water and base 15, thereby increasing heat exchange efficiency. As a special case, the ratio of the radius L1 of flow channel 151 to the radius of base 15 is 5:6, and the ratio of the front-to-back distance L2 of flow channel 151 to the front-to-back distance L3 of base 15 is 13:30, resulting in high heat dissipation efficiency. Because the target material is in close contact with the oxygen-free copper base 15, the heat generated by high-speed particle bombardment of the target material is transferred to base 15 and then cooled by the cooling system 6, ensuring a stable working environment. The target material and the target material fixing device 3 are fastened with threads, facilitating quick replacement and maintenance of the target material and improving production efficiency. The magnetic yoke 4 is bolted to the cooling sealing plate 12 for easy replacement. The cathode tube body is vacuum brazed to form a target cooling structure, which is cooled by cooling water introduced through the cooling water inlet pipe 61 and cooling water outlet pipe 62 of the cooling system 6.

[0028] In this application, the components of the cathode tube body are fixed together by vacuum brazing, the components of the insulation assembly 16 are fixed together by vacuum brazing, the components of the connector assembly 17 are fixed together by argon arc welding or laser welding, the cathode metal sealing ring 51 and the flange sealing ring 52 of the sealing assembly 5 are fixed together by argon arc welding or laser welding, the cathode tube body is fixedly connected to the front of the insulation assembly 16 by argon arc welding or laser welding, the rear of the insulation assembly 16 is fixedly connected to the connector assembly 17 by argon arc welding, and the rear of the connector assembly 17 is sealed to the flange assembly 5.

[0029] The method for manufacturing the cathode device in this application includes: S1: Preparation steps, including the preparation and fabrication of all required materials and parts; S11: Material preparation and part structure fabrication (completing part production according to technical requirements); S12: Kovar alloy ring 161 and Kovar alloy ring 163 are nickel-plated (the contact surfaces of Kovar alloy ring 161, Kovar alloy ring 163 and ceramic insulating ring 162 are nickel-plated); ceramic insulating ring 162 is metallized; the connection surface 111 between transition ring 11 and base 15 and cooling sealing plate 12 is nickel-plated, with a nickel plating thickness of 5~15 micrometers. S2: Fabrication of cathode tube body, insulation assembly 16, and connector assembly 17 There is no specific order in which these three components are created; the effect is the same whether any component is created first or last. The fabrication of the cathode tube body: After the five parts of the cathode tube body are assembled, they are fixed by vacuum brazing. After welding, helium testing is used to determine whether it meets the requirements. Fabrication of insulating component 16: After Kovar alloy ring 161, ceramic insulating ring 162, and Kovar alloy ring 163 are installed, they are fixed by vacuum brazing. After welding, helium testing is used to determine whether they meet the requirements. Fabrication of joint assembly 17: Joint flange 161 and venting joint 162 are fixed by argon arc welding or laser welding; S3: The cathode tube body and insulation component 16 are fixed by argon arc welding, such as Figure 5 ; S4: The assembly of the cathode tube body and the insulation component 16 is fixed to the connector assembly 17 by argon arc welding, such as Figure 6 .

[0030] The remaining installation steps of the cathode device in this application are conventional steps, such as... S5: The assembly of the cathode tube body, insulation component 16, and connector component 17 is fixedly connected to the flange component 5.

[0031] S6: The cathode cover 2 is fixedly installed on the connector assembly 17 by threads, the cooling water inlet pipe 61 is connected to the water inlet connector 13 by threads, and the cooling water outlet pipe 62 is connected to the water outlet connector 14 by threads.

[0032] In step S12 of this application, the nickel plating thickness of Kovar alloy ring 161 and Kovar alloy ring 163 is 5~15 micrometers.

[0033] The metallization step of the ceramic insulating ring 162 adopts the molybdenum-manganese sintering method, including: S121: Molybdenum powder and manganese powder are mixed in a mass ratio of 9:1, and a cotton wool solution is added to make a paste. This paste is then applied to the contact surfaces (referred to as interfaces) between the ceramic insulating ring 162 and the Kovar alloy ring 161 and Kovar alloy ring 163. Figure 3 On the contact surface (1621, the metallization position of the ceramic insulating ring) of the ceramic insulating ring, the coating thickness is controlled at 10-30 micrometers. After coating, it is sintered in a hydrogen-protected furnace at a heating rate of 5℃ / min until it reaches 1350℃, and then held at that temperature for 30 min. Manganese migrates to the interface of the ceramic insulating ring 162 (the contact surface corresponding to Kovar alloy ring 161 and Kovar alloy ring 163) to form a metal transition layer. In this application, molybdenum-manganese metal sintering is first performed, and a metal transition layer (ceramic metallization) is formed on the interface of the ceramic insulating ring 162 through interatomic diffusion. Then, it is vacuum brazed with the nickel-plated Kovar alloy ring 161 and Kovar alloy ring 163 to increase the bonding force between the Kovar alloy ring 161 and Kovar alloy ring 163 and the ceramic insulating ring.

[0034] The steps for fabricating the cathode tube body include: The five main components of the cathode tube (transition ring 11, cooling sealing plate 12, water inlet connector 13, water outlet connector 14, and base 15) are installed. The solder used is 72% (by mass) silver and 28% (by mass) copper silver-copper brazing filler metal. The shape of the solder matches the connection surface 111 of the transition ring 11, base 15, and target fixing device 12, and is placed on the connection surface 111 for vacuum brazing. After welding, helium testing is used to determine whether it meets the requirements.

[0035] The manufacturing steps for insulating component 16 are as follows: After the Kovar alloy ring 161, ceramic insulating ring 162, and Kovar alloy ring 2 163 are installed, they are fixed by vacuum brazing. The solder used is 72% (by weight) silver and 28% (by weight) copper silver-copper brazing filler metal. The shape of the solder matches the contact surface of the ceramic insulating ring 162 with the corresponding contact surfaces of the Kovar alloy ring 161 and Kovar alloy ring 2 163, and is placed on the contact surface for vacuum brazing. After welding, helium testing is used to determine whether it meets the requirements.

[0036] The vacuum degree required for vacuum brazing of insulating components 16 is 5*10. -3 The welding temperature is between 820 and 850℃ and held for 15 minutes.

[0037] The distance L4 between the weld joint 1612 of Kovar alloy ring 161 and transition ring 11 and the middle of Kovar alloy ring 161, and the distance L5 between the weld joint 1632 of Kovar alloy ring 163 and joint flange 171 and the middle of Kovar alloy ring 163, are both not less than 10 mm. Increasing these two distances can reduce the adverse effects of the heat generated during the welding of Kovar alloy ring 161 to the cathode tube body and the heat generated during the welding of Kovar alloy ring 163 to joint flange 171 on the ceramic insulating ring 162, preventing the risk of cracking of the ceramic insulating ring 162. As a special case, the distance L4 between the weld joint 1612 of Kovar alloy ring 161 and transition ring 11 and the middle of Kovar alloy ring 161, and the distance L5 between the weld joint 1632 of Kovar alloy ring 163 and joint flange 171 and the middle of Kovar alloy ring 163, are between 12 mm and 15 mm.

Claims

1. A cathode device, comprising a cathode tube, a cathode shield, a target material fixing device, a magnetic yoke, a flange assembly, a cooling system, the cathode tube is fixedly installed in the cathode shield, the cathode tube comprises a cathode tube main body, an insulation assembly and a joint assembly which are fixedly connected in sequence, characterized in that: The cathode tube body includes a transition ring, a cooling sealing plate, a water inlet connector, a water outlet connector, and a base. The transition ring, cooling sealing plate, water inlet connector, and water outlet connector are all installed on the base. The base has a flow channel for the cooling medium to flow. The insulation assembly is formed by welding Kovar alloy ring one, ceramic insulation ring, and Kovar alloy ring two in sequence. The target fixing device is installed at the front of the cathode tube. The target fixing device has a target mounting groove. The target is fixed on the target mounting groove and close to the target mounting surface. The magnetic yoke is installed at the rear of the base. The rear of the cathode cover is sealed and fixed with a joint assembly. The joint assembly is sealed and connected to the flange assembly. The cooling system is connected to the water inlet connector and water outlet connector of the cathode tube body.

2. The cathode device of claim 1, wherein: The cathode tube, cathode cover, and target fixing device are all annular structures, and the flow channel is cylindrical in shape.

3. The cathode device of claim 1, wherein: The cooling system includes a cooling water inlet pipe and a cooling water outlet pipe. The cooling water inlet pipe is connected to an inlet connector, and the cooling water outlet pipe is connected to an outlet connector. The inlet connector and the outlet connector are located at the upper and lower parts of the flow channel, respectively. The ratio of the flow channel radius to the base radius is 4~5:6, and the ratio of the front-to-back distance of the flow channel to the front-to-back distance of the base is 12~16:

30.

4. The cathode device of claim 1, wherein: The cathode tube and the cathode cover are fastened together by threads, and the outer surface of the cathode cover is provided with an electrolytic polishing layer.

5. The cathode device of claim 1, wherein: The flange assembly includes an outer flange, a cathode metal seal ring, and a flange seal ring. The cathode metal seal ring is disposed between the joint assembly and the outer flange, and the flange seal ring is disposed at the rear of the outer flange.

6. The cathode device of claim 1, wherein: A metal transition layer is provided at the interface of the ceramic insulating ring.

7. The cathode device of claim 6, wherein: The contact surfaces between Kovar alloy ring 1, Kovar alloy ring 2 and the ceramic insulating ring are plated with a nickel layer.

8. The cathode device of claim 1, wherein: A nickel plating layer is provided on the connection surface between the transition ring and the base and the cooling sealing plate.

9. The cathode device of claim 1, wherein: The transition ring, inlet connector, outlet connector, and connector assembly are all made of stainless steel, while the base and cooling sealing plate are made of oxygen-free copper.

10. The cathode device of claim 1, wherein: The front-to-back distance from the weld between Kovar alloy ring one and the transition ring to the middle of Kovar alloy ring one, and the front-to-back distance from the weld between Kovar alloy ring two and the joint flange to the middle of Kovar alloy ring two, shall not be less than 10mm.

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