In an effort to reduce perfluorocarbon (PFC) usage and emissions, a Spansion thin films deposition engineer pioneered a two-phase PFC reduction project in 2003. Phase One consisted of switching dielectric deposition cleans from using C3F8 to C4F8 or C4F8O. The switch to the new gases allowed for much lower gas usage as a result of their more complete plasma dissociation. Phase Two pursued and successfully completed a gas conversion for tungsten deposition plasma cleans, switching from C2F6 to C4F8O. In both phases of the project Spansion engineers worked very closely with 3M and DuPont, the manufacturers of C4F8O and C4F8 respectively, to develop an optimized process for both chamber cleaning and PFC reductions.
The new chemistries reduce PFC emissions without the need for point-of-use abatement. Point-of-use abatement is a standard industry practice for controlling PFC emissions that requires utilities including electricity, water, natural gas, nitrogen, and oxygen. Spansion has avoided the depletion of natural resources through the completion of these projects.
Details of Reductions
Additional Information :
The emissions reductions realized as a result of the new chemistries, compared to the original C2F6 chamber clean gas, are approximately 80,000 metric tons of carbon equivalent (MTCE).