Silicon Etching and Etch Techniques for NEMs and MEMs

Fabrication of precision micro- and nanoscale structures in silicon demands exacting control over pattern transfer during etching. The most utilized method to enable this pattern transfer anisotropically is plasma etching with an inductively couple plasma reactive ion etcher. When properly used, these machines can etch high-aspect-ratio structures in silicon that are hundreds of microns in height to tens of nanometers in width. The work presented here will detail how to tune parameters associated with a plasma etcher and manipulate the gas chemistry to achieve and control anisotropic silicon etches at both micro- and nanoscale. Etch masks that ensure a high pattern transfer fidelity and complement the gas chemistries employed here will also be detailed. Finally several etching techniques that use the principles detailed to fabricate extraordinary structures in silicon will be described.