In this paper, the surface and subsurface of silicon wafers ground by different wheels have been studied. In the conventional grinding with diamond wheels, it is shown from the top that the subsurface of wafer consists of amorphous Si, followed by a thin damaged layer, strained crystal with a large compressive residue stress, and then the bulk material in single crystal. In a severe condition which causes grinding burn, part of amorphous Si is re-crystallized to form a poly-crystal Si, and part of amorphous Si possibly reacts with oxygen to form SiO2. This phenomenon becomes more pronounced in the backgrinding process with a fine grit diamond wheel when the conditions are improperly selected. In order to obtain a defect-free crystal Si structure in grinding, authors have proposed a new chemo-mechanical grinding (CMG) process which enables to remove Si from wafer but with no structure transformation induced to its surface.