Key Technology Research And Optimization Of Rotatable Cathode System For Magnetron Sputtering In Plasma Applications

Plasma science and technology is at the forefront of today’s scientific and technological research, the application related to national defense, aerospace, energy, chemicals, electronics and other related fields. Rotatable cathode for magnetron sputtering has been widely used in large-area thin film preparation equipments and related industrial fields.However, due to blockade of the core technologies of foreign countries, the domestic cathode exposed many issues related to low-temperature plasma technology in production.It show that there is a big gap between the independent design level of domestic and foreign,cathode high-end market are a long-term monopoly of foreign products.Therefore, to carry out the low-temperature plasma-related key technology research and optimization research on related technologies and optimization of rotatable cathode has important significance.Aiming at the main problems existing in the production of domestic cathode,based on research and technology of low-temperature plasma, this paper analyzed characteristics of plasma in the rotatable cathode for magnetron sputtering and influences to the cathode system, carried out research of key technologies which include cooling heat transfer and uniform gas distribution,optimized the cathode system in the aspects of cooling, gas distribution, magnetic field testing and adjusting, sealing, stable electrical loading.The main work is as follows:1) Carried out analysis of cathode heat transfer and design of cooling circuit; established mathematical model,numerically calculated steady-state heat transfer,obtained the total heat loading,water flow and related heat transfer parameters;applied the finite element method of a fluid, solid, thermal coupling,simulated transient heat transfer process under actual working conditions, obtained the rules of temperature, heat transfer coefficient changing with time and the distribution of flow field, temperature field on steady state of heat transfer, then the simulation results and the calculation results were compared,proved that the numerical calculation method can be used for reference of engineering design; optimized the cathode cooling system by adjusting the water flow, changing target speed, installation of water-cooled baffles,and through the simulation and comparison,explored the rules of these parameters changing to affect the heat transfer ability,achieved the requirements of the heat transfer performance of cathode.2) Analyzed the structures of gas distribution and problems of uniform gas distribution, selected single gas distribution pipeline with nozzles as the object of study, deduced the aperture changing mathematical expression having the equal hole outflow on the gas flowing direction of the pipeline, and carried out finite element modeling and fluid simulation to verify the aperture changing mathematical expression; simulated the flow distribution situation on the cathode surface of variable aperture pipeline, analyzed the factors affecting the gas distribution uniformity on the cathode surface,then by optimization design of structure such as installing outer concentric tube and external reflection plate,finally realized the uniform gas distribution on the cathode surface.3) Proposed optimization methods of cathode cooling circuit structure and gas distribution structure, discussed the methods such as gas distribution feedback control, cathode magnetic field testing and adjusting, sealing and anti leakage alarm, stability improvement of electrical loading, then completed the optimization design of rotatable cathode system.This research can provide theoretical support and technical reference for further design and optimization of rotatable cathode system,and has important practical application value.