A study on the Cl2/C2H4/Ar plasma etching of ITO using inductively coupled plasma

In this study, the indium tin oxide (ITO) was etched by an inductively coupled plasma (ICP) etcher using Cl2/C2H4/Ar as the etching gases. The etch rates were studied as a function of RF power, inductively coupled plasma (ICP) source power, working pressure and gas mixing ratio. We found that the RF Power plays a dominant role in the elevation of the etch rates, which indicates that the ITO etching in this study is a physical mechanism dominated etching. The state of the photoresist (PR) was observed after each experiment. As expected, the high power, which generally leads to a high etch rate, would distort the PR mask, resulting in a bad etched profile of the sample. Through research, we got a relatively high etch rate (∼ 200nm/min) with the shape of PR mask remain undistorted. The profile, which includes the morphology of the film sidewall and surface after the etching process, was sensitive to the gas mixing ratio. We adjusted the gas mixing ratio, and observed the profile using a scanning electron microscope (SEM), then optimal morphology was get as the Cl2/C2H4/Ar at the value of 30sccm/7sccm/50sccm.