Impedance monitoring of CCP chamber contamination

Changes in the conditions inside the chamber often causes process shift in plasma process. We studied chamber impedance monitoring under off-plasma conditions. As the deposition process continues film residues are accumulated on the chamber components, and it may increase the reactance in the impedance network of the process chamber. When it is measured by a vector network analyzer (VNA), the reactance component increases significantly. Notably, a strong correlation (R² = 0.99) was observed between the occurrence of the SiF3 peak indicative of the contamination level during the in-situ dry-cleaning (ISD) step. This correlation was attributed to an increase in the capacitance component within the chamber, as verified through the equivalent circuit analysis. These results demonstrate the feasibility of monitoring chamber contamination even in chambers in the off-plasma state.