Printhead fabrication method

1. A method of fabricating a plurality of nozzle arrangements for an inkjet printhead chip, the method comprising the steps of:

fabricating drive circuitry layers on a substrate with a CMOS fabrication process;

depositing a first sacrificial layer on the substrate;

depositing a heater layer for forming one or more heating circuits on the first sacrificial layer and etching the heater layer to form the heating circuits;

depositing a resiliently flexible layer of dielectric material on the substrate to cover the heater layer and etching the dielectric layer to form one or more actuators and one or more ink ejection members;

depositing a second sacrificial layer on the substrate to cover the actuators and the ink ejection members and etching the sacrificial layer to define deposition zones for one or more nozzle chamber walls and one or more roof walls;

depositing a layer of a structural material on the second sacrificial layer to form the nozzle chamber walls and the roof walls; and

etching away the sacrificial layers.

2. A method as claimed in claim 1 , which includes the step of depositing a bend compensation layer on the dielectric layer such that the deposition characteristics of the bend compensation layer are substantially the same as those of the heater layer, the bend compensation layer being of the same material as the heater layer.

3. A method as claimed in claim 1 , in which the step of etching the second sacrificial layer includes the step of etching a deposition zone for a nozzle that projects from each roof wall and defines one or more ink ejection ports, the step of depositing the structural material layer being carried out to define sidewalls of the nozzles and to close the nozzles.

4. A method as claimed in claim 3 , in which includes the step of planarizing the structural material layer to open the nozzles, thereby defining the ink ejection ports.

5. A method as claimed in claim 1 , in which the step of etching the second sacrificial layer and depositing the structural layer is carried out such that the nozzle chamber walls and the roof walls define nozzle chambers in which respective actuators are positioned.

6. A method as claimed in claim 5 , which includes the steps of depositing an ink passivation layer on the drive circuitry layers and etching the passivation layer to define vias for the heating circuits.