Micro-drilling of monocrystalline silicon using a cutting tool

The micro-chilling of monocrystalline silicon using a cutting tool was tested with the aim of fabricating three-dimensional and high aspect ratio micro-shapes. Micro-tools with a D-shaped cross-section and cutting edge radius of 0.5 mum were fabricated by wire electrodischarge grinding (WEDG). The results showed that, with a depth of cut of 0.1 mum, ductile-regime cutting was realized, and that a tool clearance angle larger than 0degrees was necessary to prevent fractures at the hole entrance. The smallest machinable hole was of 6.7 mum diameter, which is the smallest not just in the present study, but of all holes drilled using a cutting tool so far. Furthermore, an aspect ratio of more than four was obtained in the drilling of a 22 mum. diameter and 90 mum deep hole. (C) 2002 Elsevier Science Inc. All rights reserved.