Investigation of etch profiles in etching of PZT and Pt thin films

Reactive ion etching of PbZrxTi1-xO3 (PZT) and Pt thin films was studied by using chlorine and fluorine gas chemistry in an Inductively Coupled Plasma (ICP). PZT films were etched by varying the etching parameters including coil RF power, de-bias voltage to substrate, and gas pressure. Etching characteristics of PZT films were investigated in terms of etch rare, etch selectivity, etch profile. Etch profile along with etch anisotropy was observed as a function of etching parameter by field emission scanning electron microscopy (FESEM). For the understanding of etching mechanism, X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) analysis for the film composition were utilized. Platinum thin films have been etched by using Cl-2/Ar in an ICP for the development of fence-ree etching. The redeposited materials formed on the pattern sidewall by using Cl-2/Ar gas combination were analyzed by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). We found that the redeposited material was mainly PtCl2 compound. Based on this result, SiCl4/Cl-2/Ar gas chemistry has been proposed as a new etching gas and demonstrated good etching profile of Pt films without unwanted redeposition.