Study On The Influence Of The Anisotropy Of 4H-SiC Material On The Dicing Process Of The Material

As a third-generation semiconductor material,4H-SiC has the characteristics of high critical breakdown electric field,large forbidden band width,and high electron mobility.However,silicon carbide materials have high hardness and brittleness,which brings great difficulties to ultra-precision machining.Moreover,due to its hexagonal lattice structure,it has significant anisotropy,which also brings greater challenges to the machinability of SiC.At present,the influence mechanism of the anisotropy of silicon carbide materials on the processing process is still very unclear,which seriously restricts the development and application of silicon carbide materials.Therefore,it is of great significance to study the effect of the anisotropy of silicon carbide materials on the material removal mechanism during processing,which is of great significance to improve the surface quality and reduce the material damage during processing.This paper takes 4H-SiC as the research object,starts from the nanoindentation test of 4H-SiC,and systematically studies the anisotropy of the material mechanical property parameters(elastic modulus,hardness,friction coefficient,etc.)of 4H-SiC;On this basis,based on the Smoothed Particle Hydrodynamics(SPH)simulation method,the influence of the anisotropy of 4H-SiC on the material removal mechanism during nano-scratching was analyzed;Finally,the material removal mechanism of the4H-SiC material and the effect of the anisotropy of 4H-SiC on the scribing process were analyzed through the multi-grain scribing experiment.The main work includes the following four parts:(1)Through the nanoindentation test,the mechanical parameters such as elastic modulus and hardness on different crystal planes and different crystal orientation groups of 4H-SiC were obtained.Combined with the indentation morphology,the fracture toughness of different crystal orientations was obtained.The experimental results show that the mechanical properties,fracture toughness and indentation morphology of 4H-SiC exhibit obvious anisotropy.(2)Through the nano-scratch test of different crystal planes and crystal orientations of 4H-SiC,the material removal mechanism and crack evolution process of 4H-SiC when scratched along different crystal orientations were analyzed from the perspective of tangential force and crack morphology.The results show that the tangential force,crack propagation mode and scratch depth of 4H-SiC all show obvious periodicity when scratched on different crystal planes and different grain directions.(3)According to the mechanical properties parameters obtained by nanoindentation,JHC is used as the material constitutive model of 4H-SiC,and the simulation model of scratching process of single crystal 4H-SiC with different crystal orientations is established based on the SPH method.Combined with the results of experiment and simulation,the material removal mechanism and damage mechanism of different crystal planes and crystal orientations are clarified.(4)Slitting experiments under different process parameters were carried out,and the surface quality of the grooves with different crystal planes and orientations was analyzed.Combined with the material removal mechanism of the single particle scratching process,the removal mechanism of 4H-SiC material under multiple abrasive particles was analyzed,and the influence mechanism of the anisotropy of 4H-SiC on the scratching process was clarified,and the 4H-SiC material was determined.the optimal cutting direction.