Radio frequency planar cathode

Abstract

The utility model discloses a radio frequency plane cathode, a cathode assembly is provided with a plurality of radio frequency interfaces, a radio frequency power connection terminal is respectively connected with the plurality of radio frequency interfaces, and the impedance between the radio frequency power connection terminal and any radio frequency interface is equal. According to the radio frequency planar cathode with the optimized design, the impedance from the radio frequency power connection end to the power connection point is equal, so that the radio frequency power is uniformly distributed on the cathode assembly, the power connection point can obtain the same voltage equipotential point, the utilization rate of a target material is ensured, and meanwhile, the coating uniformity is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of radio frequency planar cathodes, in particular to a radio frequency planar cathode. Background Art

[0002] RF sputtering coating is mostly used for sputtering and depositing insulating dielectric thin films. The RF sputtering cathode uses a RF power supply connected to the cathode to discharge on the cathode surface to form a plasma, and the ions in the plasma bombard the target material.

[0003] Since the electrons in the plasma formed by RF sputtering through glow discharge have a small mass, they can change their direction of movement as the direction of the electric field changes at high speed. Compared with the DC sputtering device, which emits electrons directly from the cathode to the anode, the electrons generated by RF sputtering follow the external electric field oscillations in the discharge space for many times and finally reach the anode, which prolongs the actual path of the electrons, increases the probability of collision between each electron and the working gas atom, and increases the ionization rate of the gas atoms, so that sputtering deposition can be achieved under high vacuum.

[0004] Therefore, if Figure 1 and 2 As shown in the figure, the conventional single-point connection in the middle introduces RF power. The farther away from the connection point, the smaller the RF power becomes, resulting in the coating being thin on both sides and thick in the middle, with poor uniformity. Figure 3 and 4 As shown in the figure, the industry usually adopts the method of connecting one end of the target to the RF cathode for film coating to solve the problem of film coating uniformity. However, this method has a low target material utilization rate. The method of simply increasing the connection point can improve the film coating uniformity to a certain extent. However, due to the different lengths of the RF transmission path, the uniformity of the obtained film thickness is still insufficient. Utility Model Content

[0005] In order to solve the technical problems existing in the background technology, the utility model proposes a radio frequency planar cathode.

[0006] The utility model provides a radio frequency planar cathode, comprising: a cathode assembly and a radio frequency power connection terminal;

[0007] The cathode assembly includes a cathode base, a magnetic circuit and a target material. A plurality of radio frequency interfaces are provided on one side of the cathode base. The magnetic circuit and the target material are installed on the side of the cathode base away from the radio frequency interfaces. The magnetic circuit is located between the target material and the cathode base.

[0008] The radio frequency power connection terminal is installed on the cathode base and is respectively connected to a plurality of radio frequency interfaces, and the impedance between the radio frequency power connection terminal and any radio frequency interface is equal.

[0009] Preferably, it also includes a connector, which is provided with a radio frequency input terminal and multiple radio frequency output terminals, the radio frequency connector is connected to the radio frequency input terminal, each radio frequency interface is connected to an radio frequency output terminal, the radio frequency input terminal is connected to the multiple radio frequency output terminals through lines, and the lengths of any two lines are equal.

[0010] Preferably, a branch circuit is provided on the electrical connector, and the branch circuit includes multiple levels of branches connected in sequence, each level of the branch is provided with a sub-input terminal connected to the output terminal of the previous level branch and multiple sub-output terminals connected to the sub-input terminal of the next level branch, the sub-input terminal of the first level branch serves as the RF input terminal, and the sub-output terminal of the last level branch serves as the RF output terminal.

[0011] Preferably, the radio frequency input terminal is located in the middle of the electrical connector, and the radio frequency electrical connector terminal is mounted on the electrical connector.

[0012] Preferably, the electrical connection adopts a connection board, and the branch circuit is arranged on the connection board;

[0013] Preferably, the RF input terminal is located at the top of the power board, and the plurality of RF output terminals are located at the bottom of the power board;

[0014] Preferably, a radio frequency connection pole extending upward from the radio frequency input end is provided in the middle of the connection board, and the radio frequency connection terminal is installed on the upper end of the radio frequency connection pole.

[0015] Preferably, the cathode assembly is provided with a receiving groove for placing the electrical connector.

[0016] Preferably, the branch circuits are symmetrically distributed on both sides of the radio frequency power connection terminal.

[0017] Preferably, the branch circuit includes N levels of branches, the Xth level branch is located between the X-1th level branch and the X-2th level branch, X and N are both natural numbers, 2≤X≤N;

[0018] Preferably, each branch of the branch circuit is provided with two sub-output terminals.

[0019] Preferably, a positioning hole is provided at each sub-input terminal, and a positioning screw fixed to the cathode base is installed at the positioning hole.

[0020] In the utility model, the proposed radio frequency planar cathode has a plurality of radio frequency interfaces on the cathode assembly, and the radio frequency power terminals are respectively connected to the plurality of radio frequency interfaces, and the impedance between the radio frequency power terminals and any radio frequency interface is equal. Through the above-mentioned optimized radio frequency planar cathode, the impedance from the radio frequency power terminal to the power connection point is equal, so that the radio frequency power is evenly distributed on the cathode assembly, so that the power connection point can obtain the same voltage equipotential point, which ensures the utilization rate of the target material and greatly improves the uniformity of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1The utility model is a schematic diagram of a radio frequency power connection method in the prior art.

[0022] Figure 2 for Figure 1 Schematic diagram of the coating shape for RF power connection method.

[0023] Figure 3 This is a schematic diagram of another radio frequency power connection method of the prior art of the utility model.

[0024] Figure 4 for Figure 3 Schematic diagram of the coating shape for RF power connection method.

[0025] Figure 5 The present invention is a schematic structural diagram of an implementation of a radio frequency planar cathode proposed by the present invention.

[0026] Figure 6 This is a schematic diagram of the coating shape of an implementation of a radio frequency planar cathode proposed by the utility model.

[0027] Figure 7 The present invention is a schematic structural diagram of a connector for an implementation of a radio frequency planar cathode proposed by the present invention.

[0028] Figure 8 The present invention provides a schematic diagram of the branch circuit structure of a connector of an implementation mode of a radio frequency planar cathode provided by the present invention.

[0029] Fig. 9 The present invention is a schematic structural diagram of a connector for an implementation of a radio frequency planar cathode proposed by the present invention.

[0030] Fig.10 The present invention is a schematic structural diagram of a power connection board of an implementation mode of a radio frequency planar cathode proposed by the present invention.

[0031] Fig.11 This is a structural schematic diagram of an implementation mode of a radio frequency planar cathode proposed by the utility model, in which a power connection plate is installed on a cathode base.

[0032] Fig.12 The present invention is a schematic structural diagram of an implementation of a radio frequency planar cathode proposed by the present invention.

[0033] Fig.13 for Fig.12 Schematic diagram of the local structure. DETAILED DESCRIPTION

[0034] like Figures 5 to 13 As shown, Figure 5 This is a schematic structural diagram of an implementation method of a radio frequency planar cathode proposed by the utility model. Figure 6This is a schematic diagram of the coating shape of an implementation of a radio frequency planar cathode proposed in the utility model. Figure 7 This is a schematic diagram of the structure of a connector of an implementation mode of a radio frequency planar cathode proposed by the utility model. Figure 8 This is a schematic diagram of the branch circuit structure of a connector of an implementation mode of a radio frequency planar cathode proposed by the utility model. Fig. 9 This is a schematic diagram of the structure of a connector of an implementation mode of a radio frequency planar cathode proposed by the utility model. Fig.10 This is a schematic structural diagram of a power connection board of an implementation mode of a radio frequency planar cathode proposed in the utility model. Fig.11 This is a schematic structural diagram of an implementation of a radio frequency planar cathode proposed in the utility model, in which a power connection plate is installed on a cathode base. Fig.12 This is a schematic structural diagram of an implementation method of a radio frequency planar cathode proposed by the utility model. Fig.13 for Fig.12 Schematic diagram of the local structure.

[0035] Reference Figure 5 and 6 The utility model provides a radio frequency planar cathode, comprising: a cathode assembly and a radio frequency power terminal 1;

[0036] The cathode assembly includes a cathode base 11, a magnetic circuit 15 and a target material 17. A plurality of radio frequency interfaces are provided on one side of the cathode base 11. The magnetic circuit 15 and the target material 17 are installed on the side of the cathode base 11 away from the radio frequency interfaces. The magnetic circuit 15 is located between the target material 17 and the cathode base 11.

[0037] The radio frequency power terminal 1 is mounted on the cathode base 11 and is connected to a plurality of radio frequency interfaces respectively, and the impedance between the radio frequency power terminal 1 and any radio frequency interface is equal.

[0038] In the specific operation of the RF planar cathode of this embodiment, the RF current is uniformly transmitted from the RF power connection terminal to the cathode base 11 via multiple RF interfaces. A magnetic circuit 15 is provided between the cathode base 11 and the target 17. The magnetic field generated by the magnetic circuit 15 can capture secondary electrons, extend the electron movement path, and effectively suppress the bombardment of high-energy electrons on the substrate. The RF power is transmitted by equal impedance power connection to ensure uniform electric field intensity on the surface of the target 17, so that the target is uniformly consumed, thereby ensuring uniform coating thickness on the substrate, and its height difference (high coating uniformity) meets the requirements, thereby improving the utilization rate of the target.

[0039] In this embodiment, the proposed RF planar cathode has multiple RF interfaces on the cathode assembly, and the RF power terminals are respectively connected to the multiple RF interfaces, and the impedance between the RF power terminals and any RF interface is equal. Through the above-mentioned optimized design of the RF planar cathode, the impedance from the RF power terminal to the power point is equal, so that the RF power is evenly distributed on the cathode assembly, so that the power point can obtain the same voltage equipotential point, which ensures the utilization rate of the target material and greatly improves the uniformity of the coating.

[0040] In actual operation, wires of equal length may be directly used to connect the RF power terminal and the RF interface respectively to ensure that the impedance of the connection path is equal.

[0041] In a specific implementation, in order to facilitate the equal impedance connection of radio frequency, the radio frequency planar cathode of this embodiment also includes a connector, which is provided with a radio frequency input terminal 61 and a plurality of radio frequency output terminals 62, the radio frequency power terminal 1 is connected to the radio frequency input terminal 61, each radio frequency interface is connected to a radio frequency output terminal 62, the radio frequency input terminal 61 is connected to the plurality of radio frequency output terminals 62 through a line, and the lengths of any two lines are equal. The structure of the connector can be designed according to the shape of the target. For example, in order to adapt to a circular target, it can be designed as follows: Figure 7 During installation, it is only necessary to connect the RF output end of the connector to the RF interface of the cathode assembly, and connect the RF power terminal to the RF input end of the connector, so that the impedance of each RF connection path is equal.

[0042] In the specific design of the electrical switch, a one-to-many branching method or a multi-level branch circuit method can be adopted.

[0043] Reference Figure 7 and 8 In one embodiment, the branch circuit includes multiple branches connected in sequence, each branch is provided with a sub-input terminal connected to the output terminal of the previous branch and multiple sub-output terminals connected to the sub-input terminal of the next branch, the sub-input terminal of the first branch is used as the RF input terminal 61, and the sub-output terminal of the last branch is used as the RF output terminal 62. Designing the branch circuit in a multi-stage branch manner is convenient for design and ensures that the RF outputs of different output terminals are equal.

[0044] Furthermore, if Figure 7 As shown, the RF input terminal 61 is located in the middle of the switch, and the RF power terminal 1 is installed on the switch. Fig. 9 As shown, the RF input terminal can be located in the middle of the connector, and the branch circuits can be led out to both sides or up and down.

[0045] In order to facilitate the production of branch circuits, refer to Fig.10The electrical connection adopts a connection board 6, and the branch circuit is arranged on the connection board 6, which reduces the space occupation rate during installation. Specifically, the RF input terminal 61 is located at the top of the connection board 6, and multiple RF output terminals 62 are located at the bottom of the connection board 6. A RF connection pole 2 extending upward from the RF input terminal 61 is provided in the middle of the connection board 6, and the RF connection terminal 1 is installed at the upper end of the RF connection pole 2.

[0046] Reference Fig.11 In the specific installation method of the power board, a receiving groove for placing the power board is provided on the cathode assembly. On the one hand, the space occupied by the power board can be reduced. On the other hand, during installation, the power board can be placed in the receiving groove first, the power board can be positioned, and then the RF output end can be connected to the RF interface respectively.

[0047] In addition, a radio frequency connection pole 2 extending upward is provided in the middle of the connection board 6 , and the radio frequency connection terminal 1 is installed on the upper end of the radio frequency connection pole 2 .

[0048] In the specific arrangement of the branch circuits, the branch circuits are symmetrically distributed on both sides of the radio frequency power connection terminal 1 .

[0049] Specifically, the branch circuit includes N levels of branches, the Xth level branch is located between the X-1th level and the X-2th level branch, and X and N are both natural numbers, 2≤X≤N. Fig.10 and 11 As shown, the branch circuit forms a meandering structure, thereby improving the space utilization rate on the power board.

[0050] In the preferred design, each branch of the branch circuit is provided with two sub-output terminals, thereby forming a one-to-two and two-to-four branch, further improving the design convenience and radio frequency uniformity.

[0051] Reference Fig.12 and 13 When installing the power board, a positioning hole can be provided at each sub-input terminal, and a positioning screw 8 fixed to the cathode base 11 is installed at the positioning hole. The power board is positioned at multiple points by the positioning screws to ensure the connection reliability between the RF output terminal on the power board and the RF interface on the cathode base.

[0052] The following describes in detail a radio frequency planar cathode of this embodiment through an example.

[0053] The utility model provides a radio frequency power connection terminal 1 and a water cooling interface for the power connection terminal to provide cooling circulating water for the radio frequency power connection pole 2. The power connection base 4 is at the bottom of the radio frequency power connection pole 2 to provide contact pre-tightening force for the power connection plate 6 and the radio frequency power connection pole 2, and also serves as a water channel sealing baffle for the radio frequency power connection pole 2.

[0054] The RF power connection rod 2 transmits the RF power to the power connection board 6. Since the power connection board 6 adopts an equal impedance structure, the impedance of each power connection point is equal, and the power connection point can obtain an equipotential point with the same voltage. The RF power is transmitted to the surface of the target material 17 through the conductive ring 7. The RF current transmission parts such as the RF power connection rod 2, the power connection base 4, the power connection board 6, the conductive ring 7, etc., all adopt oxygen-free high-conductivity copper, which can effectively improve the RF current transmission efficiency. There are 99 alumina ceramic ring gaskets above and below the evenly distributed node positions to maintain the operating stability of the power connection board 6, and their function is support and electrical insulation.

[0055] The RF power is transmitted by equal impedance connection, and the RF power can be evenly transmitted to the cathode base 11 on the back of the target 17. The cathode base 11 is made of 304 stainless steel, which is used to install the magnetic circuit and provide a channel and a closed space for magnetic circuit cooling. There is a copper back plate 16 at the bottom of the cathode base 11, which is used for magnetic circuit water cooling sealing and RF power transmission. A fluororubber O-ring is used to seal between the copper back plate 16 and the cathode base 11, and the target 17 is at the bottom of the copper back plate 16.

[0056] Two annular magnetic circuits are arranged in the cathode base 11. The magnetic circuits are located on the back of the target 17. The magnetic field generated by the magnetic circuits can capture secondary electrons, extend the electron movement path, increase the collision probability between electrons and ionized gas, and thus increase the gas ionization rate, improve the deposition rate and coating quality, and effectively suppress the bombardment of high-energy electrons on the substrate. A water cooling channel is arranged in the middle of the magnetic circuit, and an external circulating water cooling system is connected through the magnetic circuit water cooling pipe and the magnetic circuit water cooling inlet and outlet.

[0057] There is a back insulating plate 27 on the cathode base 11, which is made of polytetrafluoroethylene material. There is an anode back plate on the back insulating plate 27. There is a PEEK material insulating cover between the anode back plate and the RF power connection pole 2. There are anode side plates and anode baffles under the anode back plate. The anode top plate is located below the anode side plates. In order to reduce weight, the anode is made of aluminum alloy material, and the surface facing the target material 17 is sandblasted.

[0058] The cathode base 11 of the utility model is designed to be located inside the vacuum chamber, and adopts a water cooling structure, but it is not limited to this. The back of the cathode base 11 can be arranged outside the vacuum, and the magnetic circuit and the electrical components are arranged outside the vacuum. The magnet can be cooled by a cooling method other than water cooling outside the vacuum.

[0059] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A radio frequency planar cathode, characterized in that: include: Cathode assembly and radio frequency power terminal (1); The cathode assembly comprises a cathode base (11), a magnetic circuit (15) and a target material (17); a plurality of radio frequency interfaces are provided on one side of the cathode base (11); the magnetic circuit (15) and the target material (17) are installed on a side of the cathode base (11) away from the radio frequency interfaces; and the magnetic circuit (15) is located between the target material (17) and the cathode base (11); The radio frequency power connection terminal (1) is mounted on the cathode base (11) and is respectively connected to a plurality of radio frequency interfaces, and the impedance between the radio frequency power connection terminal (1) and any radio frequency interface is equal.

2. The radio frequency planar cathode according to claim 1, characterized in that: The device also comprises a connector, which is provided with a radio frequency input terminal (61) and a plurality of radio frequency output terminals (62), the radio frequency connector terminal (1) is connected to the radio frequency input terminal (61), each radio frequency interface is connected to a radio frequency output terminal (62), the radio frequency input terminal (61) and the plurality of radio frequency output terminals (62) are connected via lines, and any two lines are of equal length.

3. The radio frequency planar cathode according to claim 2, characterized in that: The electrical connector is provided with a branch circuit, which includes multiple branches connected in sequence, each branch having a sub-input end connected to the output end of the previous branch and multiple sub-output ends connected to the sub-input end of the next branch, the sub-input end of the first branch serving as a radio frequency input end (61), and the sub-output end of the last branch serving as a radio frequency output end (62).

4. The radio frequency planar cathode according to claim 3, characterized in that: The radio frequency input terminal (61) is located in the middle of the electrical connector, and the radio frequency electrical connector terminal (1) is mounted on the electrical connector.

5. The radio frequency planar cathode according to claim 4, characterized in that: The electrical connection adopts a connection board (6), and the branch circuit is arranged on the connection board (6).

6. The radio frequency planar cathode according to claim 5, characterized in that: The radio frequency input terminal (61) is located at the top of the power connection board (6), and the plurality of radio frequency output terminals (62) are located at the bottom of the power connection board (6).

7. The radio frequency planar cathode according to claim 6, characterized in that: A radio frequency connection pole (2) extending upward from a radio frequency input end (61) is provided in the middle of the connection board (6), and a radio frequency connection terminal (1) is mounted on the upper end of the radio frequency connection pole (2).

8. The radio frequency planar cathode according to claim 6, characterized in that: The cathode assembly is provided with a receiving groove for placing the electrical connector.

9. The radio frequency planar cathode according to any one of claims 4 to 6, characterized in that: The branch circuits are symmetrically distributed on both sides of the radio frequency power connection terminal (1).

10. The radio frequency planar cathode according to claim 8, characterized in that: The branch circuit includes N levels of branches, the Xth level branch is located between the X-1th level branch and the X-2th level branch, and X and N are both natural numbers, 2≤X≤N.

11. The radio frequency planar cathode according to claim 10, characterized in that: Each branch of the branch circuit is provided with two sub-output terminals.

12. The radio frequency planar cathode according to claim 3, characterized in that: A positioning hole is provided at each sub-input end, and a positioning screw (8) fixed to the cathode assembly is installed at the positioning hole.

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