| 摘要 |
PURPOSE: A method for etching a tungsten layer to form a bit line of a semiconductor device is provided to increase an align margin with a subsequent via by realizing a vertical profile of the tungsten layer and to increase an align margin with a subsequent buried contact by preventing a creation of a tungsten tail. CONSTITUTION: An interlayer dielectric(212), a barrier metal layer(214) and the tungsten layer(216) are deposited in sequence on a semiconductor substrate(210). The tungsten layer(216) is then etched under sulfur hexafluoride, chlorine and nitrogen atmosphere by using a plasma etching apparatus having a relatively lower power of 90 to 120 watts and a relatively lower pressure of 50 to 80 millitorr. Therefore, the etched tungsten layer(216) has a substantially vertical profile. Thereafter, the barrier metal layer(214) is etched as well, so that the bit line is obtained with a minute pattern.
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