Semiconductor device having reduced electromigration in copper lines with calcium-doped copper surfaces formed by using a chemical solution

Abstract

A method of fabricating a semiconductor device having copper (Cu) interconnect lines, formed in vias, whose surfaces are selectively doped with calcium (Ca) ions for preventing electromigration and a device thereby formed. The present invention method reduces electromigration in Cu interconnect lines by restricting Cu diffusion pathways along the interconnect surface. This diffusion restriction is achieved by selectively doping the Cu interconnect surfaces with Ca ions from a chemical solution. The present invention also provides a method of fabricating a semiconductor device, having a contaminant-reduced Cu-Ca/Cu interconnect line structure for reducing electromigration, improving interconnect reliability, and preventing corrosion, the method comprising: (a) providing a semiconductor substrate; (b) depositing a Cu interconnect line on the semiconductor substrate; (c) treating the Cu interconnect line in a chemical solution for facilitating selective doping of the Cu interconnect line with copper and calcium, thereby selectively forming a Cu-Ca-X film on the Cu interconnect line, wherein X denotes at least one contaminant; (d) processing the Cu-Ca-X film by sputtering under an argon (Ar) atmosphere, thereby removing the at least one contaminant, and thereby effecting a thin Cu-Ca film on the Cu interconnect line; (e) annealing the thin Cu-Ca film, whereby the thin Cu-Ca film is alloyed, thereby forming a contaminant-reduced Cu-Ca alloy surface on the Cu interconnect line, and thereby forming a contaminant-reduced Cu-Ca/Cu interconnect line structure, comprising the contaminant-reduced Cu-Ca alloy surface, on the semiconductor substrate; and (f) completing formation of the semiconductor device.

Dependencies are inferred from the claim text.