PLATINUM ETCHING AND PLASMA CHARACTERISTICS IN RF MAGNETRON AND ELECTRON-CYCLOTRON-RESONANCE PLASMAS

The properties of platinum etching were investigated using both rf mag netron and electron cyclotron resonance plasmas, together with measure ment of the plasma parameters. Experiments were performed over a wide pressure range from 0.4 to 50 mTorr in Cl2 plasmas. In rf magnetron pl asmas, the etch rate of Pt was constant at the substrate temperature f rom 20 to 160-degrees-C. The etch rate and the plasma electron density increased with decreasing gas pressure from 50 to 5 mTorr. In ECR pla smas for rf power of 300 W, the etch rate of Pt was almost constant (a pproximately 100 nm/min) with decreasing gas pressure from 5 to 0.4 mT orr, while the plasma electron density was gradually increased with de creasing gas pressure. These experimental results were discussed with respect to the relationship between the etch yield and ratio of neutra l Cl flux and ion flux incident on the substrate. Submicron patterning (0.5 mum lines & spaces) of platinum masked with photoresist was demo nstrated using Cl2 PlasMas in ECR discharges. High accuracy was obtain ed with no undercutting.