Journal of Vacuum Science & Technology A, Vol.19, No.4, 1312-1314, 2001
Effect of temperature on etch rate of iridium and platinum in CF4/O-2
Iridium and platinum films were etched in the CF4/O-2 plasma in an electron cyclotron resonance etch reactor. Wafers were placed on a heated chuck during etching, with the temperature maintained in the range of 70-250 degreesC before etching. A rf power was applied to the wafer chuck to generate a self-bias potential. At temperature below 100 degreesC, the iridium etch rate was low value. The iridium etch rate increased with temperature, and reached about 1500 Angstrom /min above 200 degreesC. Platinum also showed a low etch rate value below 150 degreesC, increasing to about 1500 Angstrom /min at 250 degreesC. The increase of etch rate at higher temperature was attributed to the formation of volatile compounds, IrF6 or PtF6 .