Patent ID: 7432582

Claim:
A fluidic ejection device, comprising: a substrate having a frontside and a backside; a circuit element formed on the frontside of the substrate from a plurality of layers of materials, wherein an intermediate layer of the plurality of layers is an electrical contact layer; a contact pad formed on the backside of the substrate, wherein the contact pad is in electrical communication with off-substrate circuitry; and an interconnect extending at least partially through the substrate to electrically connect the electrical contact layer to the contact pad, the interconnect including a trench having sides formed from the backside of the substrate to the backside of the electrical contact layer, the electrical contact layer remaining intact, the trench being filled with an electrically conductive material, and the interconnect being unexposed to the frontside of the substrate, and wherein the interconnect further includes a passivating layer atomic layer disposed on the sides of the trench prior to the trench being substantially filled with the electrically conductive material.