| 摘要 |
PURPOSE: A metal plug formation method is provided to improve a step coverage of contact hole and a yield by flattening upper portion of the metal plug without convex formation. CONSTITUTION: An insulating layer(12) having contact holes is formed on a lower conductive layer(11). After depositing a barrier metal(13), a metal film(14) having low contact resistance is filled into the contact hole, wherein the line-width of the metal film(14) is wider than that of the contact hole. An ARC(anti-reflection coating) film(15) is formed on the metal film(14). Then, the resultant structure is etched in order to remain the metal film(14) only on the upper portion of the contact hole, and the exposed barrier metal(13) is removed. The protrusive metal film(14) is then polished, thereby forming a flat metal plug.
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