Andrea Urban (nee Schilp) and Franz Laermer
Bosch researchers Franz Laermer and Andrea Schilp are the names on the earliest patents from back in 1992 that describe a highly anisotropic plasma etching process that became known as the Bosch process. The process, also known as deep reactive ion etching (DRIE), is now an indespensible part of all MEMS technology. The Bosch process allows the creation of deep structures with vertical walls in silicon, suitable for cantilever beams, moving structures for inertial sensors and cavities and channels for microfluidic MEMS. Importantly the process allows these highly complex structures to be made at high speed making MEMS production comparatively simple and cost-effective.
The process alternates between standard plasma etch that preferentially attacks the wafer from a vertical direction and a second process that deposits a chemically inert passivation layer. This passivation layer protects the entire wafer but during the etch phase the vertical ions tend to sputter off the layer at the bottom of the etched region rather than at the sides, thereby exposing the substrate to another round of etching.
Related links and articles: