Feasibility Study of Monitoring of Particle Generation in Plasma Etching Process by Plasma Impedance Measurement

In plasma etching process at LSI mass -production line, the particles cause the decrease in the production yield and the overall equipment effectiveness (OEE). In this study, the particles, which originate from etching reaction product, are investigated under the condition that a gas shower type electrode made from the developed MgO-based ceramics is used and a Si wafer is etched by using SF6 gas. We have demonstrated that plasma impedance monitoring method can monitor the tendency of particle generation caused by the flaking off of the film deposited on chamber inner walls. This non-invasive measurement method can be easily applied to the process equipment at mass-production line therefore the results can contribute to improvement of the production yield and the OEE.