HEXAFLUOROPROPYLENE PLASMAS - POLYMERIZATION RATE-REACTION PARAMETER RELATIONSHIPS

Plasma polymerization generates thin, pinhole-free, and highly adherin g films and is often described by the ratio of power to mass flow rate (energy per mass). This research explores the relationships between p lasma reactor parameters such as monomer flow rate, plasma power, and reactor pressure and the rates of polymerization, etching, and deposit ion. The chemical structure of the amorphous, crosslinked plasma polym erized hexafluorapropylene consists largely of similar amounts of C-C F, CF, CF2, and CF3 groups and some C-C groups. A dimensionless plasma parameter (E) proportional to power and inversely proportional to flo w rate cubed was derived. E, reflecting both plasma energy and residen ce time, was used to describe various aspects of the plasma reactions. A dimensionless exponential expression successfully described the dep endence of pressure on E with a master curve. An expression for polyme rization efficiency (polymer conversion) derived in part through a mas s balance was also successfully related to E using an exponential mast er curve. The rate of deposition was described as the difference betwe en the rates of polymerization and etching. The deposition efficiency maximum and plateau were successfully described by the difference betw een polymerization and etching efficiencies, each related exponentiall y to E. The technique used to derive parameters to describe the depend ence of plasma reactions on plasma operating conditions can be applied to any monomer/reactor system.