Characterizing fluorocarbon assisted atomic layer etching of Si using cyclic Ar/CF and Ar/CHF plasma.

With the increasing interest in establishing directional etching methods capable of atomic scale resolution for fabricating highly scaled electronic devices, the need for development and characterization of atomic layer etching processes, or generally etch processes with atomic layer precision, is growing. In this work, a flux-controlled cyclic plasma process is used for etching of SiO and Si at the Angstrom-level. This is based on steady-state Ar plasma, with periodic, precise injection of a fluorocarbon (FC) precursor (CF and CHF) and synchronized, plasma-based Ar ion bombardment [D.

Effect of the chamber wall on fluorocarbon-assisted atomic layer etching of SiO using cyclic Ar/CF plasma.

The authors studied the effect of the temperature and chemical state of the chamber wall on process performance for atomic layer etching of SiO using a steady-state Ar plasma, periodic injection of a defined number of CF molecules, and synchronized plasma-based Ar ion bombardment. To evaluate these effects, the authors measured the quartz coupling window temperature. The plasma gas phase chemistry was characterized using optical emission spectroscopy.