1 Introduction

A large number of MST/MEMS ^[1]-based products for automotive application have successfully entered the market during the past decade. Pressure, acceleration and mass-flow sensors are offered by many suppliers. Yaw-rate sensors for roll-over detection, vehicle dynamics control and navigation systems are expected to become the next big opportunity for automotive MEMS. Inkjet printers have become the biggest MEMS application in terms of unit sales. In optical networks MEMS have become a key technology and enabler for broadband optical data transmission. In contrast to these relatively mature markets the applications of MST/MEMS in the fields of mobile communications and bioMEMS are just emerging. The number of mobile phones produced in 2002 is expected to be around 400 Million units. The mobile phone manufacturers face an ongoing pressure to miniaturize and reduce costs. For these reasons they consider MST/MEMS as a possible solution. Examples include silicon microphones, RF-switches, resonators and passive RF-components. bioMEMS have attracted a lot of attention during the past years specially in the USA, and many approaches are under evaluation.

MST/MEMS components for automotive and communication applications have in common that they are usually manufactured using methods closely related to semiconductor processing. This approach has proven to be the most cost efficient in large volume production. All big MST/MEMS suppliers have a solid background in semiconductor manufacturing and many of them have converted former IC fabs into MEMS fabs.