Patent ID: 7008821

Claim:
A method of forming a wafer backside interconnecting wire, the wafer comprising a front surface, a back surface, at least a circuit element positioned on the front surface, and at least a bonding pad positioned on the front surface and electrically connected to the circuit element, the method comprising: forming a mask layer on the back surface, the mask layer comprising at least an opening corresponding to the bonding pad; performing a first etching process from the back surface to remove the wafer unprotected by the mask layer to form a recess, the first etching process being isotropic, wherein after the first etching process is performed, the recess has a round shape and the bonding pad is kept unexposed; removing the mask layer; performing a second etching process from the back surface to etch the wafer until exposing the bonding pad after removing the mask layer; and forming an interconnecting wire on the back surface.