An interconnect apparatus and a method of forming the interconnect apparatus is provided. Two substrates, such as wafers, dies, or a wafer and a die, are bonded together. A first mask is used to form a first opening extending partially to an interconnect formed on the first wafer. A dielectric liner is formed, and then another etch process is performed using the same mask. The etch process continues to expose interconnects formed on the first substrate and the second substrate. The opening is filled with a conductive material to form a conductive plug.