Increase of cleaning rate and reduction in global warming effect during C4F8O/O2 remote plasma cleaning of silicon nitride by adding NO and N2O

During the chemical vapor deposition chamber cleaning and oxide etching processes using perfluorocompounds (PFCs), recombined and non-reacted PFCs are emitted. The emission of PFCs needs to be controlled in the near future to reduce the effect on global warming. In this study, an optimum condition of C4F8O/O-2 cleaning chemistry for silicon nitride by using a remote inductively coupled plasma source was determined as a function of process parameters. Under the optimum condition, the net emission of PFCs during cleaning was quantified using a Fourier transform-infrared spectroscopy and then the effects of additive nitrogen-containing NO and N2O gases on the cleaning rate, the destruction removal efficiency and the million metric tons of carbon equivalent (MMTCE) were investigated. The addition of N2O and NO gases to C4F8O/O-2 cleaning chemistry dramatically increased the cleaning rate by the factor of congruent to9 and decreased the volume of emitted CF4 slightly. The increase in the cleaning rate and the decrease in the emitted volume of CF4 by the addition of N2O and NO contribute to the large decrease in the MMTCE values by 93 and 95%, respectively, compared to the case of cleaning without the additive gases. (C) 2003 Elsevier Science B.V. All rights reserved.