| abstract |
On a first Cu interconnect line formed in a first interlayer dielectric film, a second interlayer dielectric film is formed with a barrier dielectric film interposed therebetween. A second Cu interconnect line and a contact plug are formed in the second interlayer dielectric film. A Cu alloy layer is formed only in an upper portion of the first Cu interconnect line connected to the contact plug. Consequently, in an interconnection structure having the Cu interconnect lines and contact plug, the formation of voids due to stress migration is suppressed while an increase in resistance in the Cu interconnect lines and contact plug is prevented. |