Silicon Dioxide to Polysilicon Selectivity of a C2F6/CHF3 Dry Etch Process

The etch rates and selectivity of thermally grown silicon dioxide and polysilicon were characterized on a 2406 PLASMATRAC with a C2F6/CHF3 gas mixture. At a gas flow, CHF3 concentration, chamber pressure, and power of 60 sccm, 65%, 150mtorr, and 255 watts, respectively a 6.3:1 silicon dioxide to polysilicon selectivity occurred with an oxide etch rate 612 A/mm