Inkjet printhead with nozzle layer defining etchant holes

1. An inkjet printhead for an inkjet printer, the inkjet printhead comprising:

a wafer substrate defining an ink supply channel therethrough;

side wall portions extending away from a surface of the wafer substrate;

a nozzle layer supported on the side wall portions and extending parallel to the surface of the wafer substrate, the nozzle layer and the side wall portions defining an array of nozzle chambers, the nozzle layer defining ink ejection ports and etchant holes, the etchant holes being of sufficient diameter to retain ink in the nozzle chamber by surface tension; and

a plurality of thermal actuators cantilevered on the wafer substrate, each thermal actuator being respectively positioned in a nozzle chambers to partition the nozzle chamber, wherein

a portion of each thermal actuator facing away from a respective ink ejection port is hydrophobic to facilitate the forming of an air bubble between the thermal actuator and the wafer substrate.

2. The inkjet printhead of claim 1 , wherein the wafer substrate includes a CMOS drive circuitry layer connected to the heater layer for providing an electrical current to the heater layer.

3. The inkjet printhead of claim 2 , wherein the CMOS drive circuitry layer includes multi-level metal layers sandwiched between oxide layers.

4. The inkjet printhead of claim 1 , wherein the actuator includes a gold serpentine heater layer sandwiched between two polytetrafluoroethylene (PTFE) layers.

5. The inkjet printhead of claim 4 , wherein the PTFE layer of the actuator proximate the ink supply channel has a coefficient of thermal expansion of about 770×10 −6 .

6. The inkjet printhead of claim 4 , wherein the PTFE layer proximate the ink ejection port is configured to be hydrophilic.