Surface and subsurface damage characteristics and material removal mechanism in 6H-SiC wafer grinding

In this paper, a cross-sectional cleavages microscopy method was used for subsurface damage detecting of 6H-SiC wafer grinding. The OLS4000 laser confocal microscopy was used to observe the surface morphology and subsurface cracks. The surface and subsurface damage characteristics and material removal mechanism in different grinding conditions were analysed. The results show that the major types of surface damage in SiC grinding are chipping pits, plough scratches and smear products. Lateral and median cracks are found in the subsurface. The grinding surface quality and the depth of subsurface crack can be altered by changing the maximum undeformed chip thickness that can be adjusted with different diamond grit sizes, feed rates and wheel speeds. With the decreasing the maximum undeformed chip thickness, the grinding surface roughness decreased and a trend of a brittle–ductile transition was observed.