Patent ID: 7378030

Claim:
A method of forming an opening through a substrate having a first side and a second side opposite the first side, the method comprising: forming a trench in the first side of the substrate; forming a mask layer within the trench; completely filling in the trench with a fill material; forming a first portion of the opening in the substrate from the second side of the substrate toward the mask layer; and forming a second portion of the opening in the substrate through the mask layer and the fill material, including communicating the second portion of the opening with the first portion of the opening and the first side of the substrate; and further comprising: before filling the trench, forming at least one hole in the mask layer, wherein filling the trench further includes filling the at least one hole in the mask layer with the fill material, and wherein forming the second portion of the opening in the substrate includes removing the fill material within the at least one hole and forming the second portion of the opening through the at least one hole in the mask layer.