Structure and fabrication method for electromigration immortal nanoscale interconnects

摘要

After forming a trench opening including narrow trench portions spaced apart by wide trench portions and forming a stack of a first diffusion barrier layer and a first liner layer on sidewalls and a bottom surface of the trench opening, a reflow process is performed to fill the narrow trench portions but not the wide trench portions with a first conductive material layer. A stack of a second diffusion barrier layer and a second liner layer is formed on portions of the first liner layer and ends of the first conductive material layer exposed by the wide trench portions. A second conductive material layer is deposited to fill the wide trench portions. Portions of the second diffusion barrier layer and the second liner layer located between the first conductive material layer and the second conductive material layer act as vertical blocking boundaries to prevent the electromigration of metal atoms.

主权项

1. An interconnect structure, comprising:
a trench opening located within a dielectric material layer present on a substrate, the trench opening comprising a plurality of first trench portions having a first width and at least one second trench portion having a second width greater than the first width, the at least one second trench portion separating the plurality of first trench portions from each other; a first diffusion barrier present on sidewalls and a bottom surface of the trench opening; a first liner present on the first diffusion barrier; first conductive material portions present on portions of the first liner located within the plurality of first trench portions, each first conductive material portion filling a remaining space of each of the plurality of first trench portions; and an electromigration blocking island located within the at least one second trench portion and abutting respective ends of adjacent first conductive material portions, the electromigration blocking island comprising a second diffusion barrier present on portions of the first liner located in the at least one second trench portion and the respective ends of the adjacent first conductive material portions, a second liner present on the second diffusion barrier, and a second conductive material portion present on the second liner and filling a remaining space of the at least one second trench portion.