Mechanism And MRR Research Of Lapping Single Crystal SiC Wafer

With the rapid development of the electronics industry,the demand of semiconductor materials is growing rapidly,and the requirements of various components' performance are also increasing.As an ideal semiconductor material,the Silicon carbide(SiC)single crystal is used extensively,however,the high strength,hardness and brittleness,which make it is difficult to process into high-precision,high-quality components.Lapping is an important operation for SiC single wafer processing technology,which the essence is the results of using abrasive's contour scribing and cutting parts' surface under the lapping pressure.With the effect of different parameters,the type of material removal module changed.Generally,each brittle material has the critical cutting depth,when the cutting depth of abrasive is less than the material's critical cutting depth,the material removal module will be under plastic deformation-removal mode,and get a less roughness surface;when the cutting depth is larger than the critical cutting depth,the material removal mode will be transformed into brittle fracture removal mode,and get a large surface roughness.Based on the analysis of lapping mechanism of SiC single crystal and Preston-equation,hypothetically,the contact deformation between SiC single crystal wafer and lapping pad and the abrasive is rigid body,the Material Removal Rate(MRR)is obtained.The distribution of the size of abrasive is assumed as the normal distribution during lapping process,and through the deformation of the lapping disc and SiC single crystal wafer and single abrasive's removal amount,the proposed model can predict the MRR with the number of active abrasives on lapping process calculated by statistical laws.Matlab is used to simulate the proposed model and verify its correctness.The SiC single crystal lapping experiment with different grit size,lapping pressure,speed and other parameters are conducted,and the surface roughness and material removal rate are comparatively analyzing,the results show that the MRR model with statistical laws can accurately predict the material removal rate on lapping SiC single crystal wafer and provide important reference for other single-crystalline material lapping.According to the MRR theory,Abaqus is used to simulate single abrasive cutting process which validates the transition plastic-ductile and ductile-brittle of lapping SiC single crystal.