Study on the etch characteristics of BST thin films by using inductively coupled plasma

In this study, BST thin films were etched with inductively coupled CF4/(Cl-2+Ar) plasmas. The etch characteristics of BST thin films as a function of CF4/(Cl-2+Ar) gas mixtures were analyzed by using quadrupole mass spectrometry (QMS) and optical emission spectroscopy (OES). The maximum etch rate of the BST thin films was 53.6 nm/min, because a small addition of CF4 to the Cl-2/Ar mixture increased the chemical effect. The profile of the etched BST film is over 70, but the etch residue is not found at the sidewall. The optimum condition appears to be a 10% CF4/(Cl-2+Ar) gas mixture in the present work.