Method of forming an ink supply channel

A method of forming an ink supply channel for an inkjet printhead, said method comprising the steps of:

• (i) providing a wafer having a frontside and a backside;
• (ii) etching a plurality of frontside trenches into said frontside;
• (iii) filling each of the trenches with a photoresist plug;
• (iv) forming nozzle structures on the frontside using MEMS fabrication processes;
• (v) etching at least one backside trench from said backside, each backside trench meeting with one or more of said plugs;
• (vi) removing a portion of each photoresist plug via each backside trench by subjecting said backside to a biased oxygen plasma etch, thereby exposing sidewall features in the backside trench;
• (vii) modifying the exposed sidewall features;
• and
• (viii) removing the photoresist plugs to form at least one ink supply channel, said ink supply channel connecting said backside to said frontside,
• wherein the exposed sidewall features are modified by argon ion milling.