Etching characteristics of fine Ta patterns with electron cyclotron resonance chlorine plasma

In this research, the etching characteristics of a Ta thin film with chlorine plasma was studied using an electron cyclotron resonance plasma etching system. The native Ta oxide on the surface was removed by a sputtering mechanism, and then ion-assisted Ta etching, desorption of Ta chloride assisted by ion bombardment, proceeded. The atomic chlorine, which is believed to be the most active species responsible for etching, could be used as an indicator of the Ta etching process. By double step etching, an accelerated formation of Ta chloride by a chemical-reaction-dominant process in the second step, following the sputtering-dominant process step, successfully protected side walls, resulting in the suppression of the microloading effect.