Contamination Considerations For Perfluoroelastomer Seals Used In Deposition Processes

Deposition processes i.e., HDPCVD, PECVD, SACVD, ALD, etc., primarily operate at elevated temperatures and involve reactive gases and plasmas for both deposition and/or chamber cleaning. The trend towards larger semiconductor wafers, smaller feature sizes and decreasing thickness of deposited layers has placed increased emphasis on the need to minimize or eliminate unwanted sources of process contamination that could result in chip defects. Precise control of film composition and morphology is critical as deposition layers approach the atomic level. Furthermore, since surface integrity at the interface level is at least as relevant as the intrinsic bulk properties of the film, minimal perturbations of surface properties can result in integration problems at both the front- end and interconnect levels. Since purity is critical to high wafer yield, reducing potential contamination from particles, metallic contaminants and outgassing caused by premature seal deterioration are major goals of semiconductor fabricators. Perfluoroelastomer parts (e.g., Kalrez
^reg
, etc.) are the preferred sealing material in deposition processes due to their extraordinary chemical resistance and thermal stability. Despite these qualities, perfluoroelastomer (FFKM) performance can vary widely depending upon chemical composition. Specially formulated FFKM products are designed to reduce contamination while maintaining sealing functionality in aggressive plasma environments.