Plasma etching of Ir and PZT using a hard mask and C12/N2/O2 and C12/CHF3/O2 chemistry

摘要

Processes for etching PZT and/or forming a ferroelectric capacitor with Ir/IrOx electrodes and a PZT ferroelectric layer use a titanium-containing hard mask, a chlorine/oxygen-based plasma, and a hot substrate, typically at about 350 ° C. The processes add a fluorine-containing compound such as CHF3 to the chlorine/oxygen-based plasma for etching of the PZT layer and add nitrogen to improve sidewall profiles when etching Ir layers. The chlorine/oxygen-based plasmas provide good selectivity with high etch rates for Ir and PZT layers and low etch rates for the hard mask.