The requirements on production processes of CMOS components are fundamentally different from those of MEMS components. Therefore it is state of the art to process the different components in separate clean rooms and bring them together in a common housing afterwards. In some cases it brings decisive advantages to conduct micromechanical processes directly on a CMOS wafer. Typical examples are electrical rewiring for production of chip-size packages, the manufacture of electrical vias or the application of galvanic structures. Another example involves MEMS sensors which are bonded on an ASIC like a cover to realize compact package dimensions or very low- inductive connections.
Fraunhofer Institute for Silicon Technology