High resolution studies of crystalline damage induced by lapping and single-point diamond machining of Si(100)

Si(100) wafers were prepared by both diamond turning and standard lapping and polishing techniques. For single-point diamond machining, characterization of subsurface damage resulting from ductile-regime machining identified a plastic-yield zone consisting of slip planes and dislocation networks extending 1 to 3 μm deep despite surface root-mean-square roughness values as low as 5 nm. For conventional lapping and polishing using alumina grit, a transition from brittle to ductile yield was observed for grit sizes less than 300 nm. Subsurface damage depth correlated to surface roughness in a more straightforward manner than for the diamond point machining. Completely damage-free material removal was obtained only when a chemical component to the polishing was present.