Gas Distribution System for Sputtering Cathode for Optical Thin Films

Abstract

The present invention relates to the technical field of thin film preparation, in particular to a gas distribution system for a sputtering cathode for an optical thin film. The system includes at least one section of double-tube pipeline, and the double-tube pipeline is connected with a gas mass flow controller, and the mass and flow rate of the process gas conveyed by it are controlled by the gas mass flow controller. The double-tube pipeline is composed of an inner tube and an outer tube sleeved around the outer periphery of the inner tube, and air outlet holes are respectively formed in the inner tube and the outer tube. The advantages of the present invention are as follows: 1) The process gas is arranged in a multi-section layout and is independently controlled by the gas mass flow controller respectively, and the flow rate of the gas entering the cathode unit cavity can be adjusted section by section according to the process requirements; 2) The use of the double-tube can effectively reduce the pressure difference at each air outlet hole distributed on the single-section outer tube; 3) The air flow transmission and diversion baffle can make the gas reflect multiple times and guide the gas to flow out directionally towards the target surface; 4) The diffusion diversion plate can control and guide the direction of the gas entering the cavity interior.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film preparation, and in particular to a gas distribution system for a sputtering cathode for optical thin films. Background Art

[0002] With the increasing application of magnetron cathodes in the production of optical thin films, different optical film systems have higher and higher requirements for the optical constants of the produced thin films. In addition to a stable power supply system, the stable operation of a magnetron sputtering cathode also requires a good process gas distribution system to ensure.

[0003] During the production process of optical thin films, the rotational movement of the turntable or the transmission of the substrate is likely to cause the disorder of the process gas flow inside the process chamber. The disordered gas flow will cause the material sputtered from the target surface to adhere to the target surface of other workstations again, which will cause mutual contamination of the target surfaces. The turbulent flow of the reactive gas will cause changes in the gas atmosphere of the other target positions and other phenomena. This situation will cause the optical constants of the produced film layer to be unstable and the film layer thickness to be difficult to control. Sometimes it will even cause cathode poisoning, resulting in a gradual change in the working state of the cathode. Summary of the Invention

[0004] The purpose of the present invention is to provide a gas distribution system for a sputtering cathode for optical thin films according to the deficiencies of the above-mentioned prior art. The double-tube structure is used to transport gas and cooperate with the gas flow transmission guiding and gas diffusion guiding structures to improve the stability of the process gas transported by the magnetron sputtering cathode unit, ensure that the gas flow direction meets the process requirements while avoiding gas flow disorder.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A gas distribution system for a sputtering cathode for optical thin films is arranged in a magnetron sputtering cathode unit, and is characterized in that: the system includes at least one section of double-tube pipeline, the double-tube pipeline is connected with a gas mass flow controller, and the quality and flow rate of the process gas transported by it are controlled by the gas mass flow controller; the double-tube pipeline is composed of an inner tube and an outer tube sleeved outside the inner tube, and air outlet holes are respectively opened on the inner tube and the outer tube.

[0007] Two or more sections of the double-tube pipelines are arranged in the system, and the double-tube pipelines are independent of each other, and each section of the double-tube pipeline is separately connected with the gas mass flow controller.

[0008] An air flow transmission guiding structure is arranged outside the outer tube, and the air flow transmission guiding structure is used for equalizing pressure, splitting flow and guiding the process gas transported by the outer tube.

[0009] The gas flow transmission and guiding structure includes an upper plate body disposed above the direction of the air outlet holes of the outer tube, and a lower plate body disposed below the upper plate body. The process gas reaches the surface of the target in the magnetron sputtering cathode unit after being reflected and guided by the upper plate body and the lower plate body.

[0010] A gas diffusion and guiding structure is provided in the magnetron sputtering cathode unit, and the process gas can diffuse from the magnetron sputtering cathode unit to the process cavity under the guiding action of the gas diffusion and guiding structure.

[0011] The air outlet holes on the inner tube and the outer tube are arranged in an array.

[0012] The double-tube pipeline is connected to the gas mass flow controller located on the atmosphere side through a process gas inlet joint.

[0013] The advantages of the present invention are as follows: 1) The process gas has a multi-stage layout and is independently controlled by the gas mass flow controller respectively. The flow rate of the gas entering the cathode unit cavity can be adjusted in sections according to the process requirements, which is convenient for process implementation and improves the product quality; 2) The use of the double-tube can effectively reduce the pressure difference at each air outlet hole distributed on a single section of the outer tube, making the gas flow stable; 3) The gas flow transmission and guiding baffle can reflect the gas multiple times and guide the gas to flow out in a direction towards the target surface, making the gas flow towards the target surface uniform and stable, effectively ensuring the working performance of the target; 4) The diffusion and guiding plate can control and guide the direction of the gas entering the cavity, effectively improving the film formation quality, especially ensuring the optical constants and film thickness uniformity of the film layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of the present invention;

[0015] Figure 2 is a schematic longitudinal sectional structural diagram of the present invention;

[0016] Figure 3 is a schematic structural diagram of the diffusion and guiding plate in the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The features of the present invention and other related features are further described in detail below through embodiments with reference to the accompanying drawings for the understanding of those skilled in the same industry:

[0018] As Figures 1-3 shown, the labels 1-12 in the figure respectively represent: double-tube pipeline 1, outer tube 2, inner tube 3, outer tube air outlet hole 4, inner tube air outlet hole 5, gas flow transmission and guiding baffle 6, diffusion and guiding plate 7, cathode target tube 8, gas mass flow controller 9, process gas inlet joint 10, cathode cover plate 11, cathode end head 12.

[0019] Embodiment: In this embodiment, the sputtering cathode gas distribution system for optical thin films is arranged inside the magnetron sputtering cathode unit to control the gas flow stability of the process gas inside the magnetron sputtering cathode unit and the process gas it conveys to the process chamber, thereby solving problems such as unstable optical constants during the production of optical film layers by the magnetron sputtering cathode unit. As Figure 1 shown, one end of the magnetron sputtering cathode unit is its cathode tip 12, and a cathode cover plate 11 is provided below it. The inner side of the cathode cover plate 11 is the vacuum side, and its outer side is the atmosphere side. A cathode target tube 8 is arranged inside the magnetron sputtering cathode unit, and a target material is placed inside the cathode target tube 8.

[0020] As Figure 1 shown, the sputtering cathode gas distribution system for optical thin films in this embodiment includes a three - stage double - sleeve pipeline 1. Each section of the double - sleeve pipeline 1 is independently arranged, that is, the double - sleeve pipelines 1 are independent of each other. Each section of the double - sleeve pipeline 1 is respectively connected to a gas mass flow controller 9 located on the atmosphere side through a process gas inlet joint 10 to realize the introduction from the atmosphere side to the process chamber on the vacuum side.

[0021] Specifically, the gas mass flow controller 9 can be connected to the process gas supply device through its external interface. The process gas is introduced from the atmosphere side into the double - sleeve pipeline 1 inside the magnetron sputtering cathode unit on the vacuum side through the gas mass flow controller 9. At the same time, the gas flow of each section of the double - sleeve pipeline 1 can be independently controlled through the gas mass flow controller 9, and combined with the three - stage double - sleeve pipeline 1, the gas flow of the process gas flowing to the target material can be controlled, especially the local gas flow control corresponding to the position of each section of the double - sleeve pipeline 1, so as to achieve precise control of the gas flow, avoid disorder, and ensure the working performance of the target material.

[0022] As Figure 1 shown, each section of the double - sleeve pipeline 1, as the intake structure of the magnetron sputtering cathode unit, is composed of an outer tube 2 and an inner tube 3, where the outer tube 2 is sleeved around the inner tube 3. Outer tube outlet holes 4 are arranged in an array - type interval along the length direction of the outer tube 2, and inner tube outlet holes 5 are also arranged in an array - type interval along the length direction of the inner tube 3. The outlet holes 5 connect the inside of the inner tube 3 and the outside of the outer tube 2, and the outer tube outlet holes 4 connect the inside of the outer tube 2 and the inside of the magnetron sputtering cathode unit. The double - sleeve pipeline 1 composed of the nested outer tube 2 and inner tube 3 can effectively reduce the pressure difference at each of the outer tube outlet holes 4 distributed on the outer tube 2 of each section, thereby improving the gas flow uniformity.

[0023] In some embodiments, as Figure 2As shown in the figure, two rows of outer tube air outlets 4 are symmetrically arranged along the circumferential direction of the outer tube 2, and these two rows of outer tube air outlets 4 are both arranged at intervals in an array. Moreover, the two rows of outer tube air outlets 4 face two different air outlet directions to achieve the splitting of process gas, so as to meet the quantity requirements of the target materials provided in the magnetron sputtering cathode unit, and at the same time ensure the air flow uniformity.

[0024] As Figure 2 shown in the figure, an air flow transmission and diversion baffle 6 serving as an air flow transmission and guiding structure is arranged on the periphery of the outer tube 2. The air flow transmission and diversion baffle 6 includes two part plates. One is the upper plate body placed above the outer tube 2, and the other is the lower plate body located below the upper plate body. Bent structures are provided at the corresponding side ends of the upper and lower plate bodies, so that the air flow can be reflected between the upper and lower plate bodies, thereby realizing the pressure equalization, splitting and guiding of the gas.

[0025] As Figure 2 shown in the figure, since there are two rows of outer tube air outlets 4 in this embodiment, the air flow transmission and diversion baffle 6 is correspondingly and symmetrically arranged on the periphery of the two rows of outer tube air outlets 4.

[0026] Combined with Figure 2 and Figure 3 shown in the figure, a diffusion diversion plate 7 serving as a gas diffusion guiding structure is arranged at the upper end of the magnetron sputtering cathode unit; before the process gas flows out of the magnetron sputtering cathode unit, the process gas flows into the interior of the process cavity along the gas outlet direction of the diffusion diversion plate 7.

[0027] When this embodiment is in use: The process gas is controlled by the gas mass flow controller 9 to enter the inner tube 3 of the double-tube pipeline 1, and enters the outer tube 2 through the inner tube air outlet 5. At this time, a relatively uniform air pressure will exist in the outer tube 2. The process gas then flows into the interior of the magnetron sputtering cathode unit through the outer tube air outlet 4. After that, the process gas flows towards the cathode target tube 8 through multiple reflections and diffusions of the air flow transmission and diversion baffle 6. Finally, the gas flows into the interior of the process cavity under the guidance of the diffusion diversion plate 7.

[0028] When this embodiment is specifically implemented: Figure 1 The double-tube pipeline 1 shown in the figure adopts a three-section structure. However, in actual use, the number of double-tube pipelines 1 can be appropriately increased or decreased according to process requirements, such as the length of the target material in the cathode target tube 8. It should be additionally noted here that the double-tube pipeline 1 serving as the intake pipeline can also adopt a single-pipeline layout and the corresponding single-pipeline intake structure.

[0029] Although the above embodiments have described in detail the concept and embodiments of the object of the present invention with reference to the accompanying drawings, those of ordinary skill in the art can recognize that various improvements and transformations can still be made to the present invention without departing from the scope defined by the claims. Therefore, they are not elaborated one by one here.

Claims

1. A gas distribution system for a sputtering cathode used in an optical thin film, which is arranged inside a magnetron sputtering cathode unit, and is characterized in that: The system includes at least one section of double-tube pipeline. The double-tube pipeline is connected with a gas mass flow controller, and the quality and flow rate of the process gas conveyed by it are controlled by the gas mass flow controller. The double-tube pipeline is composed of an inner tube and an outer tube sleeved around the outer periphery of the inner tube. Air outlet holes are respectively formed in the inner tube and the outer tube, and the air outlet holes on the inner tube and the outer tube are both arranged in an array. An air flow transmission and guiding structure is arranged around the outer tube, and the air flow transmission and guiding structure is used for equalizing pressure, splitting flow and guiding the process gas conveyed by the outer tube. The air flow transmission and guiding structure includes an air flow transmission and guiding baffle. The air flow transmission and guiding baffle includes two parts of plate bodies. One is an upper plate body placed above the direction of the air outlet holes of the outer tube, and the other is a lower plate body located below the upper plate body. Bent structures are arranged at the corresponding side ends of the upper and lower plate bodies, so that the air flow can be reflected between the upper and lower plate bodies, thereby realizing equalizing pressure, splitting flow and guiding of the gas. The process gas reaches the surface of the target in the magnetron sputtering cathode unit after being reflected and guided by the upper plate body and the lower plate body.

2. The gas distribution system for a sputtering cathode used in an optical thin film according to claim 1, and is characterized in that: Two or more sections of the double-tube pipelines are arranged in the system, and the double-tube pipelines are independent of each other. Each section of the double-tube pipeline is respectively and independently connected with the gas mass flow controller.

3. The gas distribution system for a sputtering cathode used in an optical thin film according to claim 1, and is characterized in that: A gas diffusion and guiding structure is arranged in the magnetron sputtering cathode unit. The process gas can diffuse from the magnetron sputtering cathode unit to the process cavity under the guiding action of the gas diffusion and guiding structure. The gas diffusion and guiding structure is a diffusion guiding plate.

4. The gas distribution system for a sputtering cathode used in an optical thin film according to claim 1, and is characterized in that: The double-tube pipeline is connected with the gas mass flow controller located on the atmosphere side through a process gas inlet joint.

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