B4C and WC as viable alternatives to SiC for plasma-facing components in semiconductor manufacturing

This study investigates the feasibility of boron carbide (B4C) and tungsten carbide (WC) as viable alternatives to silicon carbide (SiC) for plasma-facing components in plasma etching chambers. These materials were assessed for their ability to produce the volatile reaction by-products during plasma etching as a critical property for minimizing the contaminants in semiconductor manufacturing. The plasma etching experiments under various CF4/Ar/O2 gas mixtures revealed that B4C and WC exhibited the etching behavior comparable to SiC, although the etch rate and etching mechanism were dependent on the specific plasma conditions. SiC showed the highest plasma resistance under CF4-rich condition, B4C demonstrated a superior resistance in Ar-rich plasma, and WC achieved a significantly lower etch rate in O2-free environment. These variations in etch rates were closely related to the distinct surface reactions with the plasma, governed by the intrinsic material properties such as oxidation resistance, sublimation enthalpy, and sputtering resistance. By uncovering these surface etching mechanisms, this study provides the valuable insight into the material selection for different plasma conditions and lays a foundation for further exploration of volatile by-product ceramics as an advanced plasma etching chamber component.