Effect of Sodium Periodate in Alumina-Based Slurry on Ru CMP for Metal–Insulator–Metal Capacitor

Abstract

In this study, a ruthenium (Ru) chemical mechanical planarization (CMP) slurry was developed and characterized to fabricate Ru bottom electrodes in capacitor structures. Sodium periodate was chosen as both the oxidant and etchant due to its strong oxidizing power. The effect of on Ru etching and polishing behaviors was investigated as a function of its concentration and polishing condition. The largest removal rate of 70 nm/min was obtained in a slurry of 0.1 M and 2 wt % alumina particles at pH 9 and a polishing pressure of 4 psi. Planarization and isolation of each capacitor was successfully performed with the developed Ru slurry.