Tungsten plug formation

摘要

In a preferred embodiment, there is disclosed a method of forming a tungsten plug at the via level. A metal line is formed in a top portion of a first insulating layer. A second insulating layer is formed on the first insulating layer and over an exposed surface of the metal line. An etching process is applied to a region of the second insulating layer formed over the exposed surface of the metal line to create a contact hole within the region. The metal line is exposed at the region. A tungsten nitride thin film is deposited over the second insulating layer and the exposed metal line. A blanket tungsten thin film is deposited to fill the contact hole and to form a planar layer successively to the depositing of the tungsten nitride thin film. The tungsten nitride thin film and the blanket tungsten thin film are chemically mechanically polished until the upper surface of the second insulating layer is exposed.