Minimizing damage and contamination in RIE processes by extracted-plasma-parameter analysis

It is reported that important plasma parameters for reactive ion etching (RIE) processes, such as ion energy and ion flux density, can be extracted from a simple RF waveform analysis at the excitation electrode in a conventional cathode-coupled, parallel-plate plasma RIE system. This analysis does not introduce any contamination or disturbances to the process. By using the extracted plasma parameters, surface damage and contamination in Si substrates induced by reactive ion etching in a SiCl₄ plasma were investigated. Optimum RIE conditions were then confirmed by studying the relationship between these parameters and the etching performance. It is shown using the experimental data that low-energy high-flux etching is the direction for high performance RIE in future ULSI fabrication