  Micromechanical devices like accelerometers or rotation sensors form an
increasing segment beneath the devices supplying the consumer market. A hybrid
integration approach to build smart sensor clusters for the precise detection
of movements in all spatial dimensions requires a large toolbox of interconnect
technologies, each with its own constraints regarding the total process
integration. Specific challenges described in this paper are post-CMOS
feedthroughs, front-to-front die contact arrays, vacuum-compliant lateral
interconnect and fine-pitch solder balling to finally form a Chip-Scale
System-in-Package (CSSiP).
