Effects of hydrogen on plasma etching for silicon and silicon nitride

For more precise control of plasma etching processes, a better understanding of interaction of ions and radicals contained in plasmas with Si, SiO2 and SiN surfaces is desirable. In this study, mass-analyzed ion beam experiments were employed to clarify hydrogen effects during plasmas etching process containing hydrogen such as HBr and hydrofulorocarbon. It has been shown that H + ion injection damages Si surfaces and also enhances oxygen radical diffusion in Si if oxygen radicals are simultaneously supplied. As to SiN etching by hydrofluorocarbon ions, it has been found that the presence of hydrogen in the CHxFy + ion beam increases the sputtering yield of SiN, which is consistent with the observation of SiN etching by hydrofluorocarbon plasmas.