US Patent 7259466 Low temperature bonding of multilayer substrates

Exemplary embodiments of the present invention are drawn to improved systems and process for anodically bonding multiple substrate wafers to each other at low temperatures. At least one circuit wafer having printed circuits thereon is bonded to an interposer wafer by applying an amorphous thin film between the wafers. A low voltage is applied across the wafers to heat the wafers and to cause bonding of the wafers. Multiple circuit and interposer wafers can be used. The bonding temperature is low enough that soldered connections on the circuit wafers will not flow or otherwise distort, thus maintaining electrical integrity.