Patent ID: 7768126

Claim:
An apparatus comprising: a substrate defining a trench with a left side portion, a right side portion and a bottom portion, the trench formed through: 1) the substrate, and 2) an area where electrical connection is desired; a copper contact at least partially located in the trench; and a barrier disposed between the substrate and the copper contact, the barrier substantially layering the trench, wherein the barrier comprises at least two layers, the at least two layers include first and second layers, and wherein the first layer substantially covers the left and right side portions of the trench and the bottom portion of the trench and the second layer substantially covers the bottom portion of the trench and covers a larger portion of the left side portion than the right side portion of the trench, wherein the second layer does not cover a portion of the bottom portion of the trench, and wherein a first shape of the left side portion of the second layer is a different shape than a second shape of the right side portion of the second layer, and wherein the two layers comprise different materials.