A novel wet etch for patterning lead zirconate-titanate (PZT) thin-films

Little is reported in the literature on the wet etching of PZT and all wet etch recipes described use high concentrations of hydrofluoric acid (HF). Here, a novel recipe which operates in a new regime of extremely low HF concentration is used to wet etch thin film PZT. The recipe provides excellent etch control, minimizes undercut and does not attack photoresist. Unlike most wet PZT etchants it does not leave a lead-rich residue, and the etchant is selective over SiO2 and ZrO2. The recipe and preliminary etching results for 5 micron-thick sol-gel deposited PZT films are described in this paper.