Patent ID: 7041511

Claim:
A method of etching a noble metal top electrode on a ferroelectric layer while preserving the ferroelectric properties of the ferroelectric layer and removing etching residue during fabrication of a semiconductor device, comprising: preparing a substrate; depositing a barrier layer on the substrate; depositing a bottom electrode layer on the barrier layer; depositing a ferroelectric layer on the bottom electrode layer; depositing a noble metal top electrode layer on the ferroelectric layer; depositing an adhesion layer on the top electrode layer; depositing a hard mask layer on the adhesion layer; applying photoresist to the hard mask layer, and patterning and developing the photoresist; patterning the hard mask; etching the noble metal top electrode layer in an initial etching step at a predetermined RF bias power, which produces etching residue; and over etching the noble metal top electrode layer and ferroelectric layer at an RF bias power lower than that of the predetermined RF bias power to remove etching residue from the initial etching step.