Structure for connecting interconnect lines with interposed layer including metal layers and metallic compound layer

Abstract

A metal layer (7), a metallic compound layer (8) and a metal layer (9) are stacked in this order when viewed from the side of a first copper interconnect line (2) and an interlayer insulating film (5) to constitute a second conductive barrier layer (20). As the material for the metal layers (7) and (9), an element having an atomic weight higher than that of copper such as tungsten (W) or tantalum (Ta) is applicable. A second copper interconnect line (6) is conductively connected to the first copper interconnect line (2) at a contact hole (12) through the second conductive barrier layer (20). As the ratio of the volume of the second copper interconnect line (6) at the region for filling a trench (11) to the volume of the second copper interconnect line (6) at the region for filling the contact hole (12) increases, tensile stress to be concentrated at the contact hole (12) becomes greater. As a result, a void is likely to be generated in the contact hole (12). In view of this, in order to improve the adhesion especially between the second copper interconnect line (6) at the region for filling the contact hole (12) and the second conductive barrier layer (20), the metal layer (9) is provided.

Dependencies are inferred from the claim text.