Using microindentation technique, the indentation behavior of silicon wafers etched by a KOH water system was investigated. Surface-degradation in the etched Si wafers was observed, which was due to the formation of etch-pits. Indentation-induced radial crack was used to evaluate the indentation-fracture toughness. The indentation-fracture toughness for the etched Si wafers was found to be less than the polished silicon wafers, in agreement with the etching-induced surface degradation. Such surface degradation in the etched Si wafers makes it possible to remove surface defects and smooth the surface of Si wafers by using KOH water system. (C) 2004 The Electrochemical Society.