Alternatives to reduce perfluorinated compound (PFC) emissions from semiconductor dielectric etch processes: meeting environmental commitments while minimizing costs

Perfluorinated compounds (PFCs) are widely used in semiconductor processing. These inert gases are used as a safe and efficient method to carry fluorine to etch and chemical vapor deposition (CVD) chambers. However, PFC´s have high global warming potentials (GWP) and extremely long atmospheric lifetimes. In recognition of the importance of reducing emissions of PFCs, the semiconductor industry association (SM) committed to voluntarily reduce PFC emissions. For the United States, Europe and Japan the commitment involves reducing PFC emissions 10% below 1995 levels by 2010. United States semiconductor PFC emissions have grown from 5.9 million metric tons of carbon dioxide equivalent (MMTCO₂E) in 1995 (baseline year) to 7.4 MMTCO₂E in 2000. Draft results for 2001 indicate a reduction in PFC emissions, to 5.5 MMTCO₂E but they are largely due to a drop in production. Concurrently, the industry has transitioned from 200 mm to 300 mm wafers, and from aluminum to copper interconnect technologies. Future PFC emissions could therefore be significantly different. This paper utilizes a bottom-up model to estimate PFC emissions with a focus on dielectric etch processes, since both process substitution and abatement options are available. A design for environmental (DFE) tool, the environmental value systems (EnV-S) analysis is used to compare processes and options to achieve PFC reduction targets in a cost-effective manner.