PLASMA-ENHANCED IN-SITU CHAMBER CLEANING EVALUATED BY EXTRACTED-PLASMA-PARAMETER ANALYSIS

We have demonstrated that high-efficiency in situ chamber cleaning wit h short gas residence time is possible for SiO2 etching chambers by us e of NF3 plasma, and that the endpoint determination of the cleaning i s possible by monitoring the optical emission intensities of CO or H. Nitrogen trifluoride (NF3), which has a low N-F bond energy, can gener ate a plasma with a high density of ions and radicals featuring low ki netic energy, The cleaning efficiency of several halogenated-gas plasm as has been evaluated based on extracted-plasma-parameter analysis. In this analysis important plasma parameters, such as ion energy and ion flux density, can be extracted through a simple rf waveform measureme nt at the plasma excitation electrode. The accuracy of this technique has been confirmed with a newly developed rf-plasma direct probing met hod and by ion current measurements.