Knife blades having ultra-sharp cutting edges and methods of fabrication

Abstract

Knife blades having exceptionally sharp cutting edges are formed from wafers of monocrystalline silicon using known semiconductor processing technology. In one embodiment, an elongated ridge having a flat top covered by an etchant mask is etched to undercut the mask and to shape the ridge side walls to inwardly converge towards the ridge tip. The mask is removed and a sharp ridge apex is provided by a series of oxide forming and oxide stripping processes. Individual knife blades of silicon, each comprising a ridge having a sharp cutting edge, are shaped from the wafer. In another embodiment, the silicon wafer is etched entirely through between top and bottom surfaces to form a tapered etched wall intersecting the bottom wall at a highly acute edge. The edge is sharpened by the oxide forming and oxide stripping process to form a cutting edge in the completed blade. In both embodiments, various etch masks and etching procedures are used for providing blades of various shapes.