Surface characteristics and damage of monocrystalline silicon induced by wire-EDM

Wire-EDM has recently shown itself as an alternative approach for slicing silicon and other semiconductor materials without the presence of significant chipping as normally found in the traditional machining processes. However, the intensive electrical spark between a wire electrode and silicon can cause damage to the cut surface and subsurface in micro and nano-scale aspects. This paper presents the influence of major process parameters on the cut surface characteristics and damage in the wire-EDMing of silicon. An n-type monocrystalline silicon wafer was cut under different spark energy densities, duty cycles and dielectric flushing rates. Poor cut surface quality and high amount of electrode material deposition were obtained when low spark energy density, small duty cycle and low dielectric flushing rate were applied. Moreover, the amorphous and defective crystal structures of silicon were apparent under the low spark energy condition. The interactions between the wire-EDMing parameters and cut surface characteristics drawn in this study could have significances for the further development of EDM technology towards the fine-scale and damage-free processing of semiconductor materials.