Monitoring of Condition of Deposited Film Causing Particles in Plasma Etching by Using Practical Load Impedance Monitoring Method

We monitor the change in thickness of films deposited on the inner chamber wall of mass-production plasma etching equipment by using previously developed load impedance monitoring system. The film composed of etching reaction products causes generation of flaked particles and is a factor that decreases production yield and overall equipment effectiveness (OEE) in the mass production of LSI. The method that can monitor the change in film thickness and contribute to decreasing flaked particles is highly required. The results of this study indicate that mainly the imaginary part of load impedance changes when a film is deposited on the inner wall, and demonstrate that the system can detect changes in the film thickness without remodeling of the equipment. This real-time and noninvasive monitoring method is expected to improve the production yield and OEE, and it could be used to develop a predictive maintenance regime in future.