Dry Etching of a Pb(Zr,Ti)O3 Capacitor Module with a TiN Hard Mask in an O2/Cl2 Plasma

The etching characteristics of Ir, Pt, and Pb(Zr,Ti)O3 in an O2/Cl2 helicon wave plasma were evaluated to fabricate a PZT capacitor module by using a one-mask etch scheme. The etch rates of all the layers were significantly affected by the etch process conditions, such as the chamber pressure, the rf source power, the rf bias power, and the mixing ratio of the etching gases (O2/Cl2). A high etch selectivity and fence-free etching of a 500-nm-thick Ir/IrO2/Pb(Zr,Ti)O3/Pt/IrO2/Ir/TiAlN capacitor stack with a slope of 70 could be achieved using a 200-nm-thick TiN hard mask and optimized etch process conditions. After a recovery anneal at 600 ℃, the one-mask-etched PZT capacitor array exhibited a highly vertical hysteresis loop with a remanent polarization (2Pr) of 52 μC/cm2 and a leakage current density of 3 × 10−6 A/cm2 at an applied voltage of 3 V. KCI Citation Count: 2