NF3/He as Replacement for C2F6 in Plasma Enhanced Chemical Vapor Deposition Cleans

NF3/He as Replacement for C2F6 in Plasma Enhanced Chemical Vapor
Deposition Cleans

      Due to the global warming potential of PerFluorinated Compounds
(PFC), the Environmental Protection Agency (EPA) is calling for a
substantial reduction in PFC emissions.  Hexafluorethane (C2F6) is a
PFC used extensively throughout the Semiconductor Industry to clean
Chemical Vapor Deposition (CVD) chambers.  Depending on the clean
process, up to 80% of the C2F6 can be unreacted and exhausted into
the atmosphere.  Currently the industry is investigating ways to
reduce, replace, recycle or abate C2F6 as a means of addressing this
emissions problem.

      On-going process improvements to the two-step C2F6 clean are
helping to reduce PFC emissions on the Applied MATerials (AMAT)
P-5000 Plasma Enhanced Chemical Vapor Deposition (PECVD)
TEtraethOxySilane (TEOS) toolset.  Based on the current EPA emission
guidelines, however,  further reduction is needed.  Alternative
chemistry evaluations indicate  that the use of Nitrogen triFluoride
:AB (NF3) has the potential to significantly reduce PFC emissions
without adversely affecting manufacturability.

      Using production qualified hardware, emission data and a RF
metrology system for endpoint detection, two two-step NF3/He
processes were developed (noted as Recipe A & B, Fig. 1).  Recipe B
is currently  being qualified for production.  Use of the NF3/He
process means that no recycling "add-ons" are needed to reduce
emissi...