Modeling And Experiments Of Material Remove Rate Research For 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 component performances 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.Because of the high hardness and brittleness,and the high demand of surface quality of wafer,the lapping process of SiC monocrystal wafer can only be accomplished by grinding and polishing.In the most ordinary grinding processes,abrasive model was assumed as rigid;however,the practical material removal rate(MRR)process is quite different than that was supposed.Based on the theory,we analyze the motion track of polishing abrasive and try to modify the dynamic polishing process.The motion tracks of polishing are theoretically analyzed in this thesis.It is founded that the paths of any point in the polishing pad relative to the workpiece are a group of cycloids.The results show that increasing the eccentricity is beneficial to the enlargement of the size range of polishing process.With the increasing of the speed ratio between the polishing pad and the workpiece,the abrasive at higher speed can leave longer tracks on the workpiece than that at lower speed at the same time.The more the abrasives,the more uniform the mark density under the influence of more abrasives.Abrasive in the abrasi-ve disk and the distortion of the workpiece under the action of situation ancd active abrasive assumed to be the normal distribution Lapping Process of SiC wafer are investigated which are used to determine the activities in the process of grinding particle number.The abrasive deformation under the impression of abrasive disk and workpiece was investigated and active abrasive was assumed to be normal distribution during the lapping process of SiC wafer to determine the grinding particle number in the process.Basecd on the contact condition of SiC wafers,abrasives,and grinding disk,the SiC material removal rate considering the particle deformation was established and contrast experiment was performed at the same time.All kinds of device and experiment plans have been introduced.Compared with the theoretical model,the experiment results show that the model considering the particle deformation can predict the MRR more accurate than others in the lapping process of SiC monocrystal wafers,which provides a theoretical basis and foundation for predicting and controlling MRR in the lapping process of other monocrystal materials.