The Dry Etching Characteristics of HfAlO3Thin Films in CF4/Cl2/Ar Inductively Coupled Plasma

In this study, the etching characteristics of HfAlO 3 thin film were investigated by varying the etch parameters such as the gas mixing ratio, the radio frequency power, the direct current bias voltage, and the process pressure in an inductively coupled plasma. The maximum etch rate of HfAlO 3 thin film and the selectivity of HfAlO 3 to SiO 2 were 20.55 nm/min and 0.38 in the CF 4 /Cl 2 /Ar (2:6:14 sccm) plasma, respectively. The plasma was analyzed by using optical emission spectroscopy. The chemical states on the surfaces of the etched HfAlO 3 thin film were investigated with X-ray photoelectron spectroscopy. The etching of HfAlO 3 thin films is performed by the interaction of Hf and Al atoms with the Cl and F radical in the CF 4 /Cl 2 /Ar plasma. However, their byproducts were remained at the surface because Hf-F and Al-F were non-volatile. Therefore, the plasma etching of the HfAlO 3 films follows the ion assisted chemical reaction.