Reactive ion etching of TiN, TiAlN, CrN and TiCN Films in CF4/O2 and CHF3/O2 Plasmas

Abstract

AbstractThe reactive ion etching of a range of hard coatings (TiN, TiCN, CrN and TiAlN) has been examined as a function of rf power, flow rate and pressure. The films were deposited by filtered arc deposition (TiN, TiAlN and CrN) or low energy electron beam (TiCN) on polished disc substrates of M2 tool steel. The flat surfaces were lithographically patterned with a grating structure (∼1 μm pitch). The TiN and TiCN layers have shown significantly higher etch rates (100-250 nm/min) than the CrN and TiAlN (∼5 nm/min) coatings. These regimes of higher and low etch rate were identified as ion-enhanced chemical etching and physical sputtering, respectively. In CF4/O2 plasma, the etch rate of the TiN and TiCN layers increased with rf power, flow rate and pressure which were parameters known to enhance the density of active fluorine species. The etch rates of TiN and TiCN layers were higher in CF4/O2 plasma than in CHF3/O2 gases in which polymer deposition was produced at pressure ≥ 35 mTorr.