Gas utilization in remote plasma cleaning and stripping applications

The use of nitrogen trifluoride (NF3) as an alternative to perfluorocompounds (PFC) for stripping and reactor cleaning applications was evaluated. NF3 was used to etch silicon, silicon dioxide, and silicon nitride. Its performance was then compared with that of CF4, C2F6, and C3F8, focusing on the dissociation efficiency of the parent molecule in the discharge, the etch rate, and the gas utilization. The destruction efficiency of NF3 in the discharge was determined by mass spectrometry. The removal rates for NF3 and microwave power are higher than those for PFC gases. The gas utilization is also higher for NF3 than for the other gases investigated.