Abstract: | Perfluorocarbon gas is widely used in the semiconductor industry. However, perfluorocarbon has anegative effect on the global environment owing to its high global warming potential (GWP) value.An alternative solution is essential. Therefore, we evaluated the possibility of replacing conventionalperfluorocarbon etching gases such as CHF3 with C6F12O, which has a low GWP and is in a liquidstate at room temperature. In this study, silicon oxynitride (SiON) films were plasma-etched usinginductively coupled CF4 +C6F12O+O2 mixed plasmas. Subsequently, the etching characteristicsof the film, such as etching rate, etching profile, selectivity over Si, and photoresist, were investigated.A double Langmuir probe was used and optical emission spectroscopy was performed for plasmadiagnostics. In addition, a contact angle goniometer and x-ray photoelectron spectroscope were usedto confirm the change in the surface properties of the etched SiON film surface. Consequently, theetching characteristics of the C6F12O mixed plasma exhibited a lower etching rate, higher SiON/Siselectivity, lower plasma damage, and more vertical etched profiles than the conventional CHF3 mixed plasma. In addition, the C6F12O gas can be recovered in the liquid state, thereby decreasingglobal warming. These results confirmed that the C6F12O precursor can sufficiently replace theconventional etching gas. |