Behaviour of a silicon spring fabricated by wire electro-discharge machining

A silicon spring/frame combination has been fabricated laterally out of a (100) silicon wafer, using wire electro-discharge machining (WEDM) in a one-dimensional measurement problem. After a thermal annealing step and an isotropic etching process the crystalline structure of the silicon wafer could be restored. Exposing the spring to over three-million working cycles yielded no detectable fatigue at all. A high-resolution X-ray diffractometer was used to measure the strain in the wafer. This is an accurate, non-destructive microscopic method newly applied in this field to obtain quantified results on the crystalline disorder. The method is applied to the microfabricated spring after annealing and etching steps.