Semiconductor packages (100) that prevent the leaching of gold from back
metal layers (118) into the solder (164) and methods for fabricating the
same are provided. An exemplary method comprises providing a
semiconductor wafer stack (110) including metal pads (112) and a
substrate (116). An adhesion/plating layer (115) is formed on the
substrate (116). A layer of gold (118) is plated on the adhesion/plating
layer (115). The layer of gold is etched in a street area (124) to expose
edge portions (128) of the layer of gold (118) and the adhesion/plating
layer (115). A layer of barrier metal (130) is deposited to form an edge
seal (129) about the exposed edge portions (128). The edge seal (129)
prevents the leaching of gold from back metal layers (118) into the
solder (162) when the wafer stack (110) is soldered to a leadframe (162).