Study On Electrochemical Mechanical Polishing Process Of Silicon Carbide Crystal

Semiconductor industry is the key development field of national industrial upgrading and transformation.As a typical representative of the third generation of semiconductor materials,Si C has many advantages such as wide band gap,high thermal conductivity and high saturation electron mobility.It is the ideal material for high-frequency,high temperature,high efficiency and high power electronic components.It has broad application prospects in aerospace,new energy vehicles and 5G base station.The processing quality and precision of silicon carbide crystal directly affect the performance of the device,silicon carbide crystal as the substrate material,the processing surface is required to be super smooth,no defect,no damage.However,due to the characteristics of high hardness,high brittleness and high stability of silicon carbide crystal,the polishing of silicon carbide has great difficulties,mainly reflected in low polishing efficiency and difficult to ensure the quality of polishing.Therefore,this paper combines the existing polishing technology,from the perspective of improving the rate of electrochemical oxidation of silicon carbide crystals,by using diamond-alumina mixed abrasive grains for electrochemical mechanical rough polishing of silicon carbide crystals and soft abrasive grains for electromechanical fine polishing of silicon carbide crystals to improves the polishing efficiency and polishing quality.The specific research content mainly includes the following aspects:(1)By using different electrolytes for electrochemical oxidation experiments of silicon carbide crystals,combined with potentiodynamic anodic polarization curve,microscopic morphology of silicon carbide crystals after potentiostatic polarization,EDS analysis and XPS analysis,the electrolyte that can quickly oxidize silicon carbide crystals is optimized.(2)Electrochemical mechanical polishing of silicon carbide crystal was carried out by using diamond-alumina mixed abrasive grains.Through orthogonal experimental range analysis and comprehensive score analysis,the influence of experimental factors on the material removal rate MRR and surface roughness Sa of silicon carbide crystal polishing was explored.The experimental parameters of the rough polishing process and semi-fine polishing process of silicon carbide crystal were optimized to improve the polishing efficiency and polishing quality.(3)Different soft abrasive grains are used for electrochemical mechanical polishing of silicon carbide crystals.The influence of abrasive grain types,load and voltage on the polishing effect of silicon carbide crystals was analyzed through single-factor experiments,and the grain that can improve the polishing quality of silicon carbide crystals and ensure the polishing efficiency was selected.,and analyzed the effect of the balance of chemical and mechanical effects on the polishing results of silicon carbide crystals.