Characteristics of Ru etching using ICP and helicon O2/Cl2 plasmas

We have investigated and compared the characteristics of Ru etching by employing O2/Cl2 inductively coupled plasma (ICP) and helicon plasma. We have studied the variation of Ru etch rate and the Ru to SiO2 etch selectivity with varying the gas flow ratio, the bias power, and the total gas flow rate. With optimizing the process for two different plasma sources, we have obtained higher etch rate of Ru electrode by using ICP, compared to by using helicon plasma. We demonstrated the etching slope of greater than 85° in terms of real pattern, using ICP. X-ray photoelectron spectroscopy (XPS) revealed that the Ru surface etched using ICP contained less amount of O element than using helicon plasma.