| Magnetron sputtering technology is one of the vacuum coating methods with significant advantages,compared with other conventional coating methods,this technology can effectively improve the deposition speed and reduce the low working temperature while ensuring the quality of the film,which has been widely concerned in academic research and production practice.The cathode target,playing a key role in the process parameters and film quality,which is the core of the equipment.Limited by the processing technology of target,the size of vacuum chamber and the supporting structure of equipment,the traditional magnetron sputtering target source is difficult to adapt to the surface coating of long straight workpiece.In this paper,in order to apply to the coating the outer surface of tubular workpiece,a cathode target device was designed.Based on the research of electric field,magnetic field and target source structure,the development of cylindrical magnetron sputtering target was studied,and the concentric sputtering mode of "inside target to outside target" was determined and the initial principle structure was extended for analysis and design.The specific research contents are as follows:(1)Simulation of discharge process in cylindrical magnetron sputtering target:Based on the initial principle,the DC glow discharge environment inside the target was constructed using COMSOL Multiphysic,and the DC glow discharge under low pressure Ar atmosphere was analyzed.The variation of electric field caused by the distance of different target distance is calculated,and the radial distance of the cavity of the device is obtained according to the actual situation.Based on the simulation results,the dynamic spatial distribution of the particles involved in the reaction in the cavity and the distribution of electric field and potential in the discharge steady state were determined,and the model electric field was tested based on the glow discharge theory.(2)Simulation and design of magnetic field in cylindrical magnetron sputtering target The magnetic circuit layout and structure parameters with uniform magnetic field distribution and stable intensity were simulated and calculated by COMSOL Multiphysics.The effects of the size of magnet,yoke shape and arrangement structure on the magnetic field distribution of the target surface were studied by single factor analysis,which optimizing the magnetic field.Considering the utilization rate of the target material,the uniformity of the etching and the overall sputtering rate,the double magnetic ring arrangement structure is proposed,and the magnetic circuit structure with uniform magnetic field distribution,magnetic induction intensity that meets the sputtering requirements,and the uniform magnetic field area parallel to the target surface reaches more than 40%is given.(3)Structural design of sputtering target:The parts and assembly structure of cylindrical magnetron sputtering target were designed by mechanical design.Combined with the parameters of electrical and magnetic field simulation,the whole structure of sputtering target source is designed with water cooling system and other functional devices.A light and simple sputtering target assembly structure is presented to ensure the integrity of magnetron sputtering equipment.The cylindrical magnetron sputtering target studied in this paper not only combines the characteristics of simple structure,strong versatility and high quality of coating film of planar target,but also draws on the advantages of compact structure of cylindrical target and high utilization rate of target material,which has important application value to solve the coating on the outer surface of tubular workpiece. |
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