Patent ID: 7098142

Claim:
A method of etching a ferroelectric device having a ferroelectric layer between a top electrode layer and a bottom electrode layer, the method comprising the steps of: depositing a plurality of hardmask elements over the top electrode layer, two or more of said hardmask elements being spaced apart pairwise by first regions and spaced apart from other hardmask elements by second regions, the first regions being narrower than the second regions; etching the device using, during at least the etching of the bottom electrode layer, a two-step etching technique having a first etching step in which the bottom electrode is etched but a protective deposit is formed which protects the bottom electrode in the first regions from further etching, followed by a second step in which the deposits are removed, said technique being more effective in the second regions than the first regions, the bottom electrode layer being completely removed only in the second regions; and forming a protection layer on the hardmask, sidewalls of the top electrode and the ferroelectric layer, and on the bottom electrode, prior to the patterning of the bottom electrode.