Plasma Enhanced-Chemical Vapor Deposited Polymers: Plasma Phase Reactions, Plasma-Surface Interactions, and Film Properties

The field of plasma enhanced-chemical vapour deposition (PE-CVD) of polymers is fascinating because it succeeds in polymerizing monomer units also at low pressure (<1Torr), that is, under conditions where conventional (chain-growth) polymerization would not lead to film deposition, because of thelow ceiling temperature at that low pressure. Furthermore, the advantage of PE-CVD with respect to the traditional CVD approach is its compatibility with thermo-sensitive substrates (e.g., polymers) due to the high reactivity at low thermal budget of the plasma. This chapter presents an overview of the production routes of the active species in low-pressure plasma, highlighting the role of selected plasma diagnostics for radical (and theirsurface reactivity) detection. Furthermore, the chapter addresses the role of ions during plasma polymerization and presents a critical overview of the approaches reported in literature toward the description of plasma polymerization through a macroscopic approach. Finally, the chapter includes selected examples of plasma polymerization processes focused on precursor structure retention/fragmentation, densification via ion bombardment, and topography evolution with film thickness.