Ion flux and energy virtual sensor for measuring ion flux and energy distribution at a RF biased electrode in ICP reactor (RIE-mode)

The modern technology of micro- and nanoelectronics involves a great number of steps, such as pattern transfer, where Reactive Ion Etching (RIE) in rf plasma reactors is widely used. To control the etching process, the ion flux and ion energy distribution should be managed precisely. However, the measurements of these parameters during the process in the real-time operation are impossible. This paper is devoted to the construction of a virtual diagnostics of the Ion Energy Distribution (IED) function. This method for the determination of the ion energy spectrum on the surface of rf biased electrode is based on model calculations using in-situ measured discharge parameters. The results of IED virtual diagnostics were compared with data, obtained by Retarded Field Energy Analyzer (RFEA). This was done for Ar- and H₂-plasmas operated under low-pressure rf plasma conditions. The good agreement between the model and the experimental justifies the conclusion that the IED virtual diagnostics can be applied successfully. This enables the in-situ monitoring of the IED at the electrode surface in RIE reactors. (paper)