An inkjet printhead integrated circuit comprises a silicon substrate having a layer of drive circuitry and a passivation layer over the drive circuitry layer. The passivation layer defines a plurality of vias exposing a plurality of contacts in the underlying drive circuitry. Sidewalls extend from the passivation layer and meet with a nozzle plate spaced apart from the passivation layer. The nozzle plate and the sidewalls together form a plurality of ink chambers, each ink chamber having a nozzle opening defined in the nozzle plate and an ink inlet. A heater element is suspended in each of the ink chambers. Each heater element is electrically connected to a respective pair of contacts in the drive circuitry layer through a respective pair of the vias.