Abstract: An interposer for converting pitches includes an interconnect structure over the semiconductor substrate, an active circuit formed on the semiconductor substrate, wherein the active circuit is electrically connected to the interconnect structure, a first plurality of pads with a first pitch over the interconnect structure, a second plurality of pads underlying the semiconductor substrate, and a plurality of through-substrate vias in the semiconductor substrate, wherein the first and the second plurality of pads are interconnected through the plurality of through-substrate vias.