Wafer level packaging of micro-electro-mechanical systems (mems) and complementary metal-oxide-semiconductor (cmos) substrates

Abstract

The embodiments of methods and structures for forming through silicon vias a CMOS substrate bonded to a MEMS substrate and a capping substrate provide mechanisms for integrating CMOS and MEMS devices that use less real-estate and are more reliable. The through silicon vias electrically connect to metal-1 level of the CMOS devices. Copper metal may be plated on a barrier/Cu-seed layer to partially fill the through silicon vias, which saves time and cost. The formation method may involve using dual dielectric layers on the substrate surface as etching mask to eliminate a photolithographical process during the removal of oxide layer at the bottoms of through silicon vias. In some embodiments, the through silicon vias land on polysilicon gate structures to prevent notch formation during etching of the vias.