Etching properties of Al2O3 films in inductively coupled plasma

The etch characteristics of Al 2 O 3 films was investigated by using BCl 3 /Cl 2 /Ar inductively coupled plasma. The Al 2 O 3 thin films were grown by atomic layer deposition method. The behavior of etch rate of Al 2 O 3 thin films was investigated as a function of BCl 3 ratio to Cl 2 /Ar plasma, r.f. power, d.c. bias and pressure. In order to understand the changes of radicals, volume density of Cl, B radical and BCl molecule were investigated with optical emission spectroscopy (OES). The volume density of B radical increased in all the conditions. The chemical states of Al 2 O 3 thin films were studied with X-ray photoelectron spectroscopy. The etch mechanism of ALD deposited Al 2 O 3 can be explained with the competition between chemical etching by formation volatile AlCl 3 , Al 2 Cl 6 or BOCl 3 and physical sputtering by energetic ions.