Reduced PFC emissions and gas consumption using a c-C4F8-based PECVD chamber clean chemistry

Perfluorocompounds (PFCs) used in semiconductor manufacturing are potential contributors to greenhouse gas-driven climate change. PFCs emitted from plasma enhanced chemical vapor deposition (PECVD) chamber cleans can be a significant portion of the total PFC emissions for a typical semiconductor fabrication facility. Previous work adopting octafluorocyclobutane (c-C₄F₈) clean chemistries to reduce gas consumption and PFC emissions have been reported on applied materials and novellus PECVD tools. In this study, c-C₄F₈ was evaluated as an alternative chamber clean gas on Mattson ASPEN II PECVD tools. A statistical design of experiment (DOE) methodology and tool emission analysis by Fourier transform infrared spectrometry were used to develop a low gas consumption and low PFC emission process. This c-C₄F₈ process reduced the clean gas consumption by 65% and PFC emission by 78%, compared to our current C₂F₆ clean with no impact on deposited film properties or process repeatability.