US Patent 7683493 Intermetallic diffusion block device and method of manufacture

One embodiment of the present invention is directed to an under bump metallurgy material. The under bump metallurgy material of this embodiment includes an adhesion layer and a conduction layer formed on top of the adhesion layer. The under bump metallurgy material of this embodiment also includes a barrier layer plated on top of the conduction layer and a sacrificial layer plated on top of the barrier layer. The conduction layer of this embodiment includes a trench formed therein, the trench contacting a portion of the barrier layer and blocking a path of intermetallic formation between the conduction layer and the sacrificial layer.