| 摘要 |
PURPOSE: A method for forming a contact plug of a semiconductor device is provided to suppress generation of defects in the contact plug and thereby to improve reliability of a metal interconnection. CONSTITUTION: In the method, a lower interconnection line(22) is formed on a semiconductor substrate(21). An interlayer dielectric(23) is formed on the substrate(21) and the lower interconnection line(22), and then selectively etched to form a contact hole exposing the lower interconnection line(22). Next, a barrier metal layer(25) is formed on the interlayer dielectric(23) and in the contact hole, and then polished until the interlayer dielectric(23) is exposed. The barrier metal layer(25) is therefore confined within the contact hole. Thereafter, the contact plug(26) of tungsten is selectively formed only on the barrier metal layer(25) in the contact hole. After that, an upper interconnection line(27) is formed over the entire surface including the contact plug(26).
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