Patent ID: 7594713

Claim:
An inkjet printer having a printhead with a plurality of unit cells each comprising: a wafer substrate having a layer of micro-electromechanical drive circuitry, with a dielectric layer on the drive circuitry layer, and a passivation layer on the dielectric layer, the passivation layer defining a plurality of vias; sidewalls located on the passivation layer with a nozzle plate so that the nozzle plate and the sidewalls together form an ink chamber; and a heater element suspended from the sidewalls in said ink chamber, the heater element electrically connected to the drive circuitry layer through the vias, the unit cell having an ink channel defined through the wafer substrate ending in an ejection nozzle in the nozzle plate, wherein the vias through the passivation layer corresponds with contact electrodes defined on the heater element, the vias forming a grid of apertures through said passivation layer.