An X-ray Photoelectron Spectroscopy Investigation of Redeposition from Fluorine-based Plasma Etch on Magnetic Recording Slider Head Substrate

Abstract

Re-deposition is an etched by-product in the Reactive Ion Etching (RIE) process well known the causing dirty on etching work piece. In this work, we aim to investigate the re-deposition of fluorine-based plasma etch on the Al2O3-TiC substrate. To select the suitable chemical solution for cleaning, it's necessary to know that the chemical bonding of the re-deposition material. Thermodynamic theory is used to predict the potential of re-deposition compounds which should be found in our experiment. The real re-deposition is prepared by the RIE etching system. The morphology of the re-deposition is investigated by scanning electron microscope (SEM). The elemental composition and chemical bonding are characterized by X-ray photoelectron spectroscopy (XPS).Thermodynamic predicts that the re-deposition presented in our experiment should be composed of AlF3(s), TiF4(s), TiF3(s) and TiF2(s). The result showed XPS could detect the prepared re-deposition contained fluorine 31.2 At%, oxygen 23.7 At%, carbon 23.7 At%, aluminium 16.0 At% and titanium 5.4 At%. The chemical bonding; AlF3, AlF6, CF, CO, C2 and TiO2 are formed to be the re-deposition material. The in-coincidence between thermodynamic prediction of forming Ti-F compounds versus Ti-O compound as found in the experiment was able to explain via the oxidation state of atoms; the oxidation state of the sputtered Ti atoms is +4 is suitable to have the reaction with sputtered oxygen atoms (from the substrate) that have an oxidation number +2, forming the TiO2 compound.