Patent ID: 8778737

Claim:
A method of substrate bonding involving a device substrate having a first surface and a second surface opposite to the first surface, the method comprising: forming device structures of at least one product chip using the first surface of the device substrate; forming a first wiring layer of an interconnect structure for the device structures of the at least one product chip; planarizing the first wiring layer; in response to planarizing the first wiring layer, removably bonding a temporary handle wafer to the first wiring layer; and in response to removably bonding the temporary handle wafer to the first wiring layer, bonding the second surface of the device substrate to a final handle substrate, wherein the device structures are formed for first and second product chips using the first surface of the device substrate, the first product chip is separated from the second product chip by a kerf street, and the kerf street is planarized when the first wiring layer of the interconnect structure is planarized.