  Depending on the type of Micro-Electro-Mechanical System (MEMS), packaging
costs are contributing up to 80% of the total device cost. Each MEMS device
category, its function and operational environment will individually dictate
the packaging requirement. Due to the lack of standardized testing procedures,
the reliability of those MEMS packages sometimes can only be proven by taking
into consideration its functionality over lifetime. Innovation with regards to
cost reduction and standardization in the field of packaging is therefore of
utmost importance to the speed of commercialisation of MEMS devices. Nowadays
heavily driven by consumer applications the MEMS device market is forecasted to
enjoy a compound annual growth rate (CAGR) above 13%, which is when compared to
the IC device market, an outstanding growth rate. Nevertheless this forecasted
value can drift upwards or downwards depending on the rate of innovation in the
field of packaging. MEMS devices typically require a specific fabrication
process where the device wafer is bonded to a second wafer which effectively
encapsulates the MEMS structure. This method leaves the device free to move
within a vacuum or an inert gas atmosphere.
