Patent ID: 7615819
Filing Date: 2009-11-10
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate including an upper surface; an insulating film formed above the upper surface of the semiconductor substrate, the insulating film including a contact hole penetrating the insulating film, the contact hole including an upper portion, a lower portion located below the upper portion, and a boundary portion connecting the upper portion and the lower portion, the upper portion including an upper end having a first inner width, the boundary portion having a second inner width the same as the first inner width, and the lower portion including a lower end having a third inner width smaller than the second inner width; a wiring portion formed on the insulating film; and a contact plug formed in the contact hole, including a first conductive plug formed in the lower portion of the contact hole so that the exposed upper surface of the semiconductor substrate is in contact with the first conductive plug and a second conductive plug formed on the first conductive plug so that the wiring portion is in contact with the second conductive plug, the first conductive plug comprising a polycrystalline silicon film and the second conductive plug being comprising a conductive material film which differs from the polycrystalline silicon film, wherein the first and second conductive plugs have an interface with a height that is lower than a height of the boundary portion relative to the upper surface of the semiconductor substrate.