Non-Steady-State Combined Process of Etching and Imidization of Polyamidoacid Film in Nonequilibrium Oxygen Plasma

The non-steady-state process of etching of a polyamidoacid film in an nonequilibrium oxygen low-pressure inductively coupled radiofrequency-discharge plasma was studied. It was shown that an unsteady imidization process develops in the bulk of the film simultaneously with occurrence of an unsteady film etching process. The time dependence of film etching rate at varying film thickness and incident ion energy was determined. The mechanism of the unsteady etching–imidization process of the polyamidoacid film in an oxygen plasma and the role of oxygen atoms and molecules in the process are discussed.