Axial multi-cathode vacuum coating equipment and method for composite gradient coating

Abstract

The present invention discloses an axial multi-cathode vacuum coating equipment and a method for composite gradient coating. A central electrode and a plurality of side electrodes are provided on a multi-cathode target head. The central electrode is located at the center of the multi-cathode target head, and the side electrodes are arranged around the central electrode. The central electrode is connected to a central target wire, and the side electrodes are connected to side target wires. The central target wire is arranged along the center line of the pipeline, and the side targets are arranged in a spiral around the central target. The central target and the side targets are connected by a plurality of ceramic components with holes. The central electrode is connected to a first sputtering power supply, and the side electrodes are connected to a second sputtering power supply. It not only solves the problem of the use of some alloy target wires that cannot be processed, but also can ensure the lateral and axial uniformity of the composition, film thickness and structure of the thin film during the coating process, and adjust the component ratio of the thin film.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetron sputtering, and particularly to an axial multi-cathode vacuum coating equipment and a method for composite gradient coating. Background Art

[0002] Magnetron sputtering coating on the inner wall of a tube is a surface thin film technology, and its equipment is widely used for depositing target thin films on the inner wall of tubular samples. During the magnetron sputtering coating process on the inner wall of a tube, the prepared target material (usually metal or ceramic) is first placed in the sample tube to be coated in a vacuum state, and a parallel magnetic field on the surface of the target material is provided by an external solenoid coil. Then, by applying a certain negative voltage to the target material, a plasma field is formed in the sample tube. Gas ions bombard the outer wall of the target material, and the generated particles are deposited on the inner wall of the sample tube, and finally a uniform thin film is formed on the inner wall of the tube. The magnetron sputtering coating technology on the inner wall of a tube has the following advantages: high film quality, using a magnetic field to control the movement of ions, a uniform, dense, and high-quality thin film can be formed, thereby improving the performance and reliability of the device. High production efficiency, the magnetron sputtering technology is a fast and efficient thin film preparation method, and high-quality thin film products can be produced on a large scale. Wide application range, the magnetron sputtering technology on the inner wall of a tube can be used for the preparation of thin films of various materials, including metals, ceramics, etc., so it has a wide application in the fields of electronic devices, optical elements, solar cells, etc.

[0003] However, currently, the target materials used for preparing tubular samples are mostly target wires with a diameter of 0.5 - 6 mm. Considering the preparation process of the target materials and the basic properties of the materials, single-element target materials and some alloy target wires are mainly used. Among them, the sintering preparation cost of most alloy target materials is expensive, and it is difficult to prepare long alloy target materials due to the limitation of the mold. For example: taking the Ti-Zr-V ternary alloy as the target material, using a magnetron sputtering device to deposit a non-evaporable getter film on the inner wall of a slender tube. After sintering, the toughness of this target material decreases, and it is difficult to prepare a long target wire for coating long tubes. For example: a uniform diamond-like carbon film needs to be deposited on the inner wall of some tubes. The target material commonly used for magnetron sputtering deposition of diamond-like carbon films is pure tungsten carbide (WC) / tungsten carbide-cobalt (WC-Co) target material. Tungsten carbide target material has extremely high hardness, which can reach 2500 - 2700 HV. Therefore, the preparation process of the corresponding target wire (0.5 - 6 mm in diameter) is complex and costly. In addition, it is difficult to adjust the composition ratio of the thin film while ensuring the overall uniformity of the thin film. Currently, only the Hefei Institute can prepare this type of alloy target wire.

[0004] Patent CN 112680706 B discloses a magnetron sputtering device for coating the inner wall of a tube with a large length-diameter ratio. In a large-diameter tubular sample, multiple magnetron targets are placed inside the tube. By independently controlling the power supply of the magnetron targets, the control of the film composition ratio is achieved. However, a single magnetron target cannot deposit a film on the entire inner wall of the sample tube simultaneously, and each magnetron target has a divergent film coating, making it impossible to ensure the uniformity of the inner wall film. For the multi-layer films with different components deposited using multiple magnetron targets, it is difficult to ensure the film thickness in the axial direction of the inner wall film and the uniformity of each layer of film components. Summary of the Invention

[0005] In view of the above-mentioned prior art, the object of the present invention is to provide an axial multi-cathode vacuum coating equipment and its composite gradient functional film process, which can achieve the adjustable film composition ratio at any time during the deposition process while ensuring the overall uniformity of the film on the inner wall of the tube. By changing the placement method of the axial multi-cathodes during the deposition of the film and proposing a special target design and placement method, different component ratio films can be deposited in the magnetron sputtering coating equipment on the inner wall of the tube.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] In the first aspect of the present invention, an axial multi-cathode vacuum coating equipment is provided, which includes a sample pipeline. An electromagnet is provided outside the sample pipeline, and a multi-cathode target head is provided at the top of the sample pipeline. A central electrode and several side electrodes are provided on the multi-cathode target head. The central electrode is located at the center of the multi-cathode target head, and the side electrodes are arranged around the central electrode; the central electrode is connected to the central target wire, and the side electrodes are connected to the side target wires. The central target wire is arranged along the center line of the pipeline, and the side targets are spirally arranged around the central target; the central target and the side targets are connected by several perforated ceramic components; the central electrode is connected to the first sputtering power supply, the side electrodes are connected to the second sputtering power supply, and the top of the sample pipeline is connected to the bias power supply; the bottom of the sample pipeline is connected to a vacuum transition chamber. A gas pipeline, an air extraction pipeline, and a vacuum pipeline are provided on the vacuum transition chamber. The vacuum transition chamber is also respectively connected to the first sputtering power supply, the second sputtering power supply, and the bias power supply.

[0008] Preferably, the central target is vertically placed, the central target and the side targets penetrate the sample pipeline, and the central target and the side targets are electrically insulated from each other.

[0009] Preferably, the diameters of the central target and the side targets are 1-4 mm, the diameter of the sample pipeline is 2-3 cm, and the length of the sample pipeline is 0.1-20 m.

[0010] Preferably, the ceramic component is triangular. A first connection hole for the central target to pass through is provided at the center of the ceramic component, and second connection holes for the side targets to pass through are provided at the three corners of the ceramic component.

[0011] More preferably, the number of the ceramic components is greater than or equal to 2.

[0012] The second aspect of the present invention provides a method for composite gradient coating using the above-mentioned axial multi-cathode vacuum coating equipment, including the following steps:

[0013] (1) Placing the target: Connect the central target to the central electrode of the multi-cathode target head, and connect the side target to the side electrode. The central target passes through the first connection hole of the ceramic component, and the side target passes through the second connection hole of the ceramic component. Then place the central target and the side target into the sample pipeline.

[0014] (2) Connecting the sample pipeline: Place the sample pipeline at the uniform magnetic field in the middle of the electromagnet. Connect the bottom of the sample pipeline to the vacuum transition chamber. Connect the central electrode to the first sputtering power supply, connect the side electrode to the second sputtering power supply, and connect the top of the sample pipeline to the bias power supply. The first sputtering power supply, the second sputtering power supply, and the bias power supply are all connected to the vacuum transition chamber.

[0015] (3) Coating: Adjust the vacuum degree inside the sample pipeline, then introduce inert gas, adjust the air pressure, start the electromagnet, the first sputtering power supply, the second sputtering power supply, and the bias power supply, and adjust the magnetic field strength and voltage inside the sample pipeline to perform coating.

[0016] Preferably, the vacuum degree inside the sample pipeline is greater than 1×10 -3 Pa, the magnetic field strength is 80 - 1000 Gauss, the air pressure is 0.1 - 10 Pa, the voltage is 450 - 500 V, the current is 0.1 - 0.3 A, the frequency is 3 - 8 kHz. The inert gas inside the sample pipeline is one of Ar and Kr. The first sputtering power supply and the second sputtering power supply are one of DC power supply, pulsed power supply, medium-frequency power supply, and radio-frequency power supply. The bias power supply is a DC power supply, and the sputtering time is 1 - 5 h.

[0017] After the electromagnet is powered on, a uniform magnetic field is formed inside the pipeline. One end of the first sputtering power supply is connected to the central electrode, and the other end is connected to the vacuum transition chamber; the second sputtering power supply is connected to the side electrode, and the other end is connected to the vacuum transition chamber; control the first sputtering power supply and the second sputtering power supply to supply power to the target. Under the action of the magnetic field, the atoms on the surface of the target wire escape and are sputtered onto the inner wall of the sample pipeline to be coated to form a film. One end of the bias power supply is connected to the sample pipeline to be coated, and the other end is connected to the vacuum transition chamber; during the coating process, the bias power supply provides a certain positive bias voltage for the sample pipeline to be coated, so as to optimize the deposition and properties of the film. The vacuum transition chamber is provided with a gas pipeline, an air extraction pipeline, and a vacuum pipeline. Control the intake pipeline and the extraction pipeline to make the process air pressure inside the sample pipeline to be coated within the air pressure range required for glow discharge;

[0018] The present invention deposits multiple layers of thin films in a capillary tube at one time. A central target wire and a plurality of side target wires are arranged in the sample tube. By controlling the target wires separately, one or more layers of thin films with different component ratios can be plated on the inner wall of the sample tube. In the prior art, multiple target wires are placed vertically in a tube for film coating, and the components of the prepared thin film are unevenly distributed. The present invention fixes a target material at the spatial position of the central axis of the sample tube by spiral winding, and a plurality of spiral target wires are staggered and fixed with the central axis as the axis. The target materials are evenly distributed in the axial direction, thereby ensuring the consistency of multiple target materials during the deposition process and obtaining a thin film with uniform composition.

[0019] The prior art controls several target wires through the same power supply, and can only obtain a film with a single component ratio. The present invention allows the target wire to run through the entire space of the sample pipeline, and the target wires are independently insulated from each other. At the same time, through multiple independent power supplies, the coating parameters of different target wires are independently controlled to achieve precise control of the film component ratio. In the coating process provided by the present invention, in addition to the general process gas pressure, magnetic field strength, sputtering power supply and other parameter controls, the performance optimization in the tube inner wall vacuum coating technology can also be achieved by adjusting the voltage and frequency of the input bias power supply. The vacuum transition chamber, the target wire and the sample pipeline to be plated are insulated from each other. When a negative pressure is input to the target wire and a positive bias is input to the sample pipeline to be plated, it can ensure that the charge states between the sample to be plated and the target material are independent of each other, thereby achieving a more accurate surface treatment and coating process.

[0020] Beneficial effects of the present invention:

[0021] The present invention ensures the overall uniformity of the film on the inner wall of the tube, and realizes that the film component ratio can be adjusted at any time during the deposition process. The axial multi-cathode placement method during the film deposition process deposits films with different component ratios in the tube inner wall magnetron sputtering coating equipment through special target material design and placement. The present invention can not only avoid the use of expensive and complex alloy target wires, but also ensure the uniformity of the film and adjust the component ratio of the film during the coating process. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 : A schematic structural diagram of the axial multi-cathode vacuum coating device of the present invention;

[0023] Figure 2 : Schematic diagram of the multi-cathode target head of the present invention;

[0024] Figure 3 : A schematic diagram of a ceramic component of the present invention;

[0025] Figure 4 : An embodiment of the dual target placement of a graphite target and a tungsten wire target of the present invention;

[0026] Figure 5 :SEM image of the film cross-section of the second embodiment of the present invention;

[0027] As shown in the figure: 1. Multi-cathode target head; 2. Sample pipeline; 3. Electromagnet; 4. Ceramic component; 5. Gas pipeline; 6. Exhaust pipeline; 7. Vacuum pipeline; 8. Vacuum transition chamber; 9. First sputtering power supply; 10. Bias power supply; 11. Central target; 12. Side target; 13. Central electrode; 14. Side electrode; 15. Second sputtering power supply; 16. First connection hole; 17. Second connection hole. Detailed implementation manners

[0028] It should be noted that the following detailed description is exemplary and is intended to provide further illustration of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0029] As described in the background art, a single magnetron target cannot deposit a film on the inner wall of the entire sample tube simultaneously, and it is impossible to ensure the uniformity of the film on the inner wall. When using multiple magnetron targets to deposit multiple layers of films with different components, it is difficult to ensure the film thickness in the axial direction of the film on the inner wall and the uniformity of each layer of film components.

[0030] Based on this, the present invention provides an axial multi-cathode vacuum coating device, including a sample pipeline 2, an electromagnet 3 is arranged outside the sample pipeline 2, a multi-cathode target head 1 is arranged at the top of the sample pipeline 2, a central electrode 13 and several side electrodes 14 are arranged on the multi-cathode target head 1, the central electrode 13 is located at the center of the multi-cathode target head 1, the side electrodes 14 are arranged around the central electrode 13, the central electrode 13 is connected to the central target 11, the side electrodes 14 are connected to the side target 12, the central target 11 is a graphite target, the side target 12 is a tungsten wire, the central target 11 is arranged vertically, the side target 12 is arranged helically around the central target 11, and the central target 11 and the side target 12 are connected by several ceramic components 4; the diameters of the central target 11 and the side target 12 are 1-3 mm, the diameter of the sample pipeline 2 is 2-3 cm, and the length of the sample pipeline 2 is 0.1-20 m; the central electrode 13 is connected to the first sputtering power supply 9, the side electrodes 14 are connected to the second sputtering power supply 15, and the top of the sample pipeline 2 is connected to the bias power supply 10; the bottom of the sample pipeline 2 is connected to the vacuum transition chamber 8, and the vacuum transition chamber 8 is provided with a gas pipeline 5, an exhaust pipeline 6, and a vacuum degree detection pipeline 7. The vacuum transition chamber 8 is also connected to the first sputtering power supply 9, the second sputtering power supply 15, and the bias power supply 10.

[0031] In some embodiments, the ceramic component 4 is triangular. A first connection hole 16 through which the central target 11 passes is provided at the center of the ceramic component 4, and second connection holes 17 through which the side targets 12 pass are provided at the three corners of the ceramic component 4 respectively.

[0032] A method for composite gradient coating using the above axial multi-cathode vacuum coating equipment includes the following steps:

[0033] (1) Placing the targets: Connect the central target 11 to the central electrode 13 of the multi-cathode target head 1, and connect the side targets 12 to the side electrodes 14. The central target 11 passes through the first connection hole of the ceramic component 4, and the side targets 12 pass through the second connection holes of the ceramic component 4. Place the central target 11 and the side targets 12 into the sample pipeline 2.

[0034] (2) Connecting the sample pipeline 2: Place the sample pipeline 2 at the uniform magnetic field in the middle of the electromagnet 3. The bottom of the sample pipeline 2 is connected to the vacuum transition chamber 8. Connect the central electrode 13 and the side electrodes 14 to the sputtering power supply 9, and connect the top of the sample pipeline 2 to the bias power supply 10. Both the sputtering power supply 9 and the bias power supply 10 are connected to the vacuum transition chamber 8.

[0035] (3) Coating: Adjust the vacuum degree in the sample pipeline 2 to be greater than 1×10 -3 Pa, then introduce an inert gas, adjust the gas pressure to 0.1 - 10 Pa, start the electromagnet 3, the first sputtering power supply 9, the second sputtering power supply 15 and the bias power supply 10, adjust the magnetic field strength in the sample pipeline 2 to be 80 - 1000 Gauss, the voltage to be 450 - 500 V, the current to be 0.1 - 0.3 A, and the frequency to be 3 - 8 kHz for coating. The inert gas is one of Ar and Kr. The first sputtering power supply 9 and the second sputtering power supply 15 are one of a DC power supply, a pulse power supply, an intermediate frequency power supply, and a radio frequency power supply. The bias power supply is a DC power supply, and the sputtering time is 1 - 5 h.

[0036] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the technical solutions of the present application will be described in detail below in conjunction with specific embodiments.

[0037] The test materials used in the embodiments of the present invention are all conventional test materials in the art and can be obtained through commercial channels.

[0038] Example 1

[0039] Axial multi-cathode vacuum coating equipment, including a sample pipeline 2, an electromagnet 3 is arranged around the outside of the sample pipeline 2, a multi-cathode target head 1 is arranged at the top of the sample pipeline 2, a central electrode 13 and a side electrode 14 are arranged on the multi-cathode target head 1, the central electrode 13 is located at the center of the multi-cathode target head 1, the central electrode 13 is connected to a central target 11, the side electrode 14 is connected to a side target 12, the central target 11 is arranged vertically, the side target 12 is arranged spirally around the central target 11, the central target 11 and the side target 12 are connected by 3 ceramic components 4, the ceramic components 4 are triangular, a first connection hole for the central target 11 to pass through is arranged at the center of the ceramic component 4, and a second connection hole for the side target 12 to pass through is arranged at each of the three corners of the ceramic component 4. The central electrode 13 is connected to a first sputtering power supply 9, the side electrode 14 is connected to a second sputtering power supply 15, the top of the sample pipeline 2 is connected to a bias power supply 10; the bottom of the sample pipeline 2 is connected to a vacuum transition chamber 8, a gas pipeline 5, an air extraction pipeline 6, and a vacuum degree detection pipeline 7 are arranged on the vacuum transition chamber 8, and the vacuum transition chamber 8 is also connected to the first sputtering power supply 9, the second sputtering power supply 15, and the bias power supply 10.

[0040] A method for performing composite gradient coating using axial multi-cathode vacuum coating equipment includes the following steps:

[0041] 1. Placing the target: Use the cathode target head of a double-electrode vacuum flange with a CF35 caliber. The central electrode 13 is connected to a 2-mm diameter cylindrical graphite target that is not easily processed into a special-shaped structure, and the other electrode is connected to a 1-mm diameter metal tungsten wire in a spiral shape. One ceramic component 4 is placed every 30 cm in the middle. The carbon target passes through the first connection hole of the ceramic component 4, and the tungsten wire passes through the second connection hole of the ceramic component 4. The middle fixing piece fixes the ceramic component 4 to the graphite target. The inner diameter of the sample round tube is 30 mm and the length is 1 m. Subsequently, slowly place the central target 11 and the side target 12 into the cleaned sample pipeline 2, perform high-vacuum sealing using an oxygen-free copper gasket, and use screws to connect the cathode target head.

[0042] 2. Connecting the sample pipeline 2: Slowly and vertically place the entire sample pipeline 2 into the uniform magnetic field in the middle of the electromagnet 3, and connect the bottom of the sample pipeline 2 to the vacuum transition chamber 8. Connect the central electrode 13 to the first sputtering power supply 9, connect the side electrode 14 to the second sputtering power supply 15, connect the top of the sample pipeline 2 to the bias power supply 10, and connect the first sputtering power supply 9, the second sputtering power supply 15, and the bias power supply 10 to the vacuum transition chamber 8.

[0043] 3. Coating: Connect the vacuum pump to the vacuum pipeline 7 to make the vacuum degree inside the sample pipeline 2 greater than 1×10 -3First, introduce 5 sccm of krypton gas while maintaining the pressure in the sample tube 2 at 1 Pa. Finally, start the DC power supply of the electromagnet 3, set the rated current to 100 A, control the magnetic field strength parallel to the direction of the central target 11 at about 300 Gauss, set the voltage of the DC sputtering power supply 9 to -500 V, set the DC bias power supply 10 to -400 V, and sputter for 5 hours.

[0044] Cut the sample tube 2 along the axis and test the inner wall film. The thickness of the film along the axis is between 980 - 1050 nm, and the film uniformity is 10%. For the 200 nm thick film, W:C At% = 5:3, and for the 800 nm thick film, W:C At% = 3:2. Compared with the existing common ratio of W:C At% = 1:1, the bonding performance of the new ratio film is enhanced by 2 times, and the wear resistance is enhanced by 3 times.

[0045] Example 2

[0046] The axial multi-cathode vacuum coating equipment includes a sample tube 2. An electromagnet 3 is disposed around the outside of the sample tube 2. A multi-cathode target head 1 is provided at the top of the sample tube 2. A central electrode 13 and a side electrode 14 are provided on the multi-cathode target head 1. The central electrode 13 is located at the center of the multi-cathode target head 1. The central electrode 13 is connected to the central target 11. The side electrode 14 is connected to the side target 12. The central target 11 is vertically arranged, and the side target 12 is spirally arranged around the central target 11. The central target 11 and the side target 12 are connected by 3 ceramic components 4. The ceramic component 4 is triangular. A first connection hole for the central target 11 to pass through is provided at the center of the ceramic component 4. Second connection holes for the side target 12 to pass through are provided at the three corners of the ceramic component 4. The central electrode 13 is connected to the first sputtering power supply 9, the side electrode 14 is connected to the second sputtering power supply 15, and the top of the sample tube 2 is connected to the bias power supply 10; the bottom of the sample tube 2 is connected to the vacuum transition chamber 8. A gas pipe 5, an air extraction pipe 6, and a vacuum degree detection pipe 7 are provided on the vacuum transition chamber 8. The vacuum transition chamber 8 is also connected to the first sputtering power supply 9, the second sputtering power supply 15, and the bias power supply 10.

[0047] A method for performing composite gradient coating using the axial multi-cathode vacuum coating equipment includes the following steps:

[0048] 1. Placing the target: Use the cathode target head of a double - electrode vacuum flange with a CF35 caliber. The central electrode 13 is connected to a 2 - mm - diameter cylindrical graphite target that is not easily processed into a special - shaped structure. The other electrode is connected to a 1 - mm - diameter metal tungsten wire in a spiral shape. One ceramic component 4 is placed every 30 cm in the middle. The carbon target passes through the first connection hole of the ceramic component 4, and the tungsten wire passes through the second connection hole of the ceramic component 4. The middle fixing piece fixes the ceramic component 4 to the graphite target. The inner diameter of the sample round tube is 30 mm and the length is 1 m. Subsequently, slowly place the central target 11 and the side target 12 into the cleaned sample pipe 2, use an oxygen - free copper gasket for high - vacuum sealing of the components, and use small screws to connect the cathode target head.

[0049] 2. Connecting the sample pipe 2: Slowly and vertically place the entire sample pipe 2 into the uniform magnetic field in the middle of the electromagnet 3. The bottom of the sample pipe 2 is connected to the vacuum transition chamber 8. Connect the central electrode 13 to the first sputtering power supply 9, the side electrode 14 to the second sputtering power supply 15, the top of the sample pipe 2 to the bias power supply 10. The first sputtering power supply 9, the second sputtering power supply 15, and the bias power supply 10 are all connected to the vacuum transition chamber 8.

[0050] 3. Coating: Connect the vacuum pump to the vacuum pipe 7 to make the vacuum degree inside the sample pipe 2 greater than 1×10 -3 Pa. Subsequently, introduce 5 sccm of krypton gas, maintain the gas pressure inside the sample pipe 2 at 1 Pa, start the DC power supply of the electromagnet 3 and set it to 100 A, so that the magnetic field intensity in the parallel direction on the surface of the central target 11 is 300 Gauss. Set the voltage of the DC sputtering power supply 9 to - 100 V, set the DC bias power supply 10 to - 500 V, and the sputtering time is 2 h.

[0051] Cut the sample pipe 2 along the axis, test the inner - wall film. The thickness of the film in the axial direction is between 900 - 960 nm, and the film uniformity is 10%. By changing the voltage on the target wire respectively, the ratio of W and C in the film can be changed. When the voltage increases, the number of sputtered ions increases, causing the proportion of this element in the film to increase. For example, Figure 5 For the cross - section of the film, conduct microstructure and energy - spectrum tests. It can be observed that there is an obvious interface in the film about 200 nm from the substrate. For the 150 - nm - thick film, W:C At% = 5:2, and for the 750 - nm - thick film, W:C At% = 3:1. Compared with the existing common ratio of W:C At% = 1:1, the bonding of this ratio of film is improved, and the wear - resistance performance is enhanced by 2 times.

[0052] Comparative example

[0053] Using the magnetron sputtering device for coating the inner wall of a tube with a large length-diameter ratio in Patent CN 112680706 B, the same target material as in Example 1 is used, with W:C At% = 1:1. Using the same coating parameters as in Example 1, the obtained inner wall thin film is tested. The thickness of the thin film in the axial direction is between 940 - 1030 nm, and the film uniformity is 12%.

[0054] The above are only the preferred embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application.

Claims

1. Axial multi-cathode vacuum coating equipment, characterized in that, It includes a sample pipeline, an electromagnet is provided outside the sample pipeline, a multi-cathode target head is provided at the top of the sample pipeline, a central electrode and several side electrodes are provided on the multi-cathode target head, the central electrode is located at the center of the multi-cathode target head, and the side electrodes are arranged around the central electrode; the central electrode is connected to the central target wire, the side electrode is connected to the side target wire, the central target wire is arranged along the pipeline center line, and the side targets are spirally arranged around the central target; the central target and the side targets are connected by several perforated ceramic components; the central electrode is connected to the first sputtering power supply, the side electrode is connected to the second sputtering power supply, and the top of the sample pipeline is connected to the bias power supply; the bottom of the sample pipeline is connected to the vacuum transition chamber, and a gas pipeline, an exhaust pipeline, and a vacuum pipeline are provided on the vacuum transition chamber. The vacuum transition chamber is also connected to the first sputtering power supply, the second sputtering power supply, and the bias power supply respectively.

2. The axial multi-cathode vacuum coating equipment according to claim 1, wherein The central target is placed vertically, the central target and the side targets penetrate the sample pipeline, and the central target and the side targets are electrically insulated from each other.

3. The axial multi-cathode vacuum coating equipment according to claim 1, characterized in that The diameters of the central target and the side targets are 1-4 mm, the diameter of the sample pipeline is 2-3 cm, and the length of the sample pipeline is 0.1-20 m.

4. The axial multi-cathode vacuum coating equipment according to claim 1, characterized in that, The ceramic component is triangular, a first connection hole for the central target to pass through is provided at the center of the ceramic component, and second connection holes for the side targets to pass through are provided at the three corners of the ceramic component respectively.

5. The axial multi-cathode vacuum coating equipment according to claim 4, characterized in that, The number of the ceramic components is greater than or equal to 2.

6. A method for composite gradient coating using the axial multi-cathode vacuum coating equipment according to any one of claims 1-5, characterized in that, It includes the following steps: (1) Placing the targets: Connect the central target to the central electrode of the multi-cathode target head, connect the side targets to the side electrodes, pass the central target through the first connection hole of the ceramic component, pass the side targets through the second connection holes of the ceramic component, and place the central target and the side targets into the sample pipeline. (2) Connecting the sample pipeline: Place the sample pipeline at the uniform magnetic field in the middle of the electromagnet, connect the bottom of the sample pipeline to the vacuum transition chamber, connect the bottom of the sample pipeline to the vacuum transition chamber, connect the central electrode to the first sputtering power supply, connect the side electrode to the second sputtering power supply, connect the top of the sample pipeline to the bias power supply, and connect the first sputtering power supply, the second sputtering power supply, and the bias power supply to the vacuum transition chamber. (3) Coating: Adjust the vacuum degree inside the sample pipeline, then introduce inert gas, adjust the air pressure, start the electromagnet, the first sputtering power supply, the second sputtering power supply, and the bias power supply, adjust the magnetic field strength and voltage inside the sample pipeline, and perform coating.

7. The method for composite gradient coating according to claim 6, wherein The vacuum degree in the sample pipeline is greater than 1×10 -3 Pa, the magnetic field strength is 80 - 1000 Gauss, the air pressure is 0.1 - 10 Pa, the voltage is 450 - 500 V, the current is 0.1 - 0.3 A, the frequency is 3 - 8 kHz, the inert gas in the sample pipeline is one of Ar and Kr, the first sputtering power supply and the second sputtering power supply are one of DC power supply, pulse power supply, medium-frequency power supply, and radio-frequency power supply, the bias power supply is a DC power supply, and the sputtering time is 1 - 5 h.

Images