Improvement of Etch Rate and Profile by SF6, C₄F8 and O₂ gas modulation

초록

Deep trench etching of silicon was investigated as a function of RF source power, DC bias voltage, C₄F8 gas flow rate, and O₂ gas addition. On increasing the RF source power from 300 W to 700 W, the etch rate was increased from 3.52 ㎛/min to 7.07 ㎛/min. The addition of O₂ gas improved the etch rate and the selectivity. The highest etch rate is achieved at the O₂ gas addition of 12 %. The selectivity to PR was 65.75 with O₂ gas addition of 24 %. At DC bias voltage of -40 V and C4F8 gas flow rate of 30 sccm, We were able to achieve etch rate as high as 5.25 ㎛/min with good etch profile.

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