US Patent 7323780 Electrical interconnection structure formation

An electrical interconnection structure and method for forming. The electrical structure comprises a substrate comprising electrically conductive pads and a first dielectric layer over the substrate and the electrically conductive pads. The first dielectric layer comprises vias. A metallic layer is formed over the first dielectric layer and within the vias. A second dielectric layer is formed over the metallic layer. A ball limiting metallization layer is formed within the vias. A photoresist layer is formed over a surface of the ball limiting metallization layer. A first solder ball is formed within a first opening in the photoresist layer and a second solder ball is formed within a second opening in the photoresist layer.