Study On The Damage Mechanism Of SiC Single Wafer Based On Indenter/scratch Technique

As the third-generation semiconductor material,SiC single crystal is widely used as the substrate material of various components due to its excellent characteristics.However,due to its extremely high hardness and typical hard and brittle materials,it is of great significance to study the mechanism of ultra-precision machining and damage of SiC single chip.Therefore,in order to reveal the damage and deformation mechanism of SiC single wafer,the micro-nano indentation /scratch technology was used to study the SiC single wafer's indentation and scratch morphological characteristics and residual stress changes,so as to provide theoretical support for the damage mechanism of SiC single wafer's precision ultra-precision grinding processing.In this paper,the surface roughness and residual stress distribution of SiC wafer under different grinding conditions were studied by using 3D surface measurement system and laser Raman spectrometer.The surface roughness of bonded abrasive is better than that of free abrasive under the same processing condition.The amplitude of residual tensile and compressive stress on the surface of consolidated abrasive after grinding is uniform,while that of surface residual tensile and compressive stress after free abrasive grinding is disorderly.When the particle size is small,the residual compressive and tensile stress of consolidated abrasive grinding SiC wafer is small,and a better wafer surface can be obtained.The indentation test was carried out on the crystal surface of 6H-SiC single chip(0001)by using the micro-nano mechanics test system.The load-displacement curve,load-hardness curve and load-elastic modulus curve were obtained according to the indentation test results.The reasons for the size effect of indentation were analyzed,and the residual stress distribution around the indentation was analyzed according to the morphology of the indentation.The hardness and elastic modulus of SiC chip decrease with the increase of loading force,and finally reach a stable state.Residual tensile and compressive stress exists in the area around the indentation with loading force of 150 mN,and the distribution of tensile and compressive stress is not uniform.The SiC single chip is obtained by scratch test results of the friction coefficient curve of different crystallographic orientation,and combining with the scratch appearance characteristics analysis of the scratch in the brittle ductile transition mechanism of load under the action of dynamic load and static load under the action of the [1?21?0] crystal to the residual stress distribution of scratches.The 6H-SiC single chip after delimit along different crystalline to wipe the SiC single chip basically stable friction coefficient in 0.185 ~ 0.240,the [1?21?0] to with the increase of the load of single crystal silicon wafer from the plastic to remove gradually transformed into brittle,scratches the center of the sag and on both sides of the accumulation phenomenon gradually increased;When the scratch loading force is less than 10.7N,the material is in the plastic removal mode,and the residual stress mainly presents the residual compressive stress,and there is a small residual tensile stress locally.When the loading force of scratches was greater than 10.7N,the material changed from plastic removal to brittle removal,and then to brittle removal mode at 14.8N.The residual tensile stress at the bottom of the scratches gradually increased,with the residual tensile stress as the main one,but the residual compressive stress was relatively large at the accumulations on both sides of the scratches.