Effect of plasma-induced charging in interconnect metal etch on the characteristics of a ferroelectric in capacitor

Effects of plasma etching on the characteristics of a SrBi2Ta2O9 (SBT) ferr oelectric capacitor with Pt electrodes have been investigated. A TIN film w as chosen as an interconnecting metal layer and was etched in an electron c yclotron resonance (ECR) etcher with Cl-2/BCl3 plasma. The control paramete rs used for this designed experiments of the metal etch process are RF bias power, microwave source power, and pressure. The etching parameters exert little effects on the remanent polarization and coercive voltage of the fer roelectric capacitor. However, they cause a significant voltage shift in th e ferroelectric hysteresis loop. It is found that the voltage shift is indu ced by electron accumulation during the plasma etching. The electron chargi ng effect is studied using antenna structures and the voltage shift is corr elated with electron density of the plasma.