Copper interconnecting structure and preparation method thereof

Abstract

The invention belongs to the technical field of microelectronic technology, and particularly provides a copper interconnecting structure with Ru-Al-O served as a diffusing and adhering resisting layer, and a preparation method. According to the copper interconnecting structure, the conventional copper interconnecting structure is served as the basis, and conventional TaN / Ta double-layer structure is replaced by the Ru-Al-O, and the Ru-Al-O is served as the new copper diffusing resisting layer of the copper interconnecting structure. According to the preparation method, an atomic layer deposition (ALD) method is carried out to deposit a Ru-Al-O layer with thickness of 3 to 5nm on the upper layer of a thermally oxidized silica film to be served as an adhering layer, and a Ru layer with thickness of 5 to 10nm is formed on the adhering layer to be served as the diffusing resisting layer as well as a seed crystal layer of electroplating copper. The ratio of Ru to Al to O in the Ru-Al-O can be adjusted, so as to obtain higher resistance to copper diffusion and adhering property. By adopting the copper interconnecting structure, the adhering strength of the diffusing resisting layer and the silica layer at the lower layer can be improved, and the tightness under connection with the seed crystal layer can be kept; and an improved feasible program is provided for conventional copper interconnecting technology to improve the adhering capacity.

Description

technical field [0001] The invention belongs to the technical field of microelectronic technology, and specifically relates to a novel copper interconnection structure and a preparation method using a Ru-Al-O\Ru laminated structure as a diffusion and adhesion barrier layer. Background technique [0002] In the copper interconnection process, in order to prevent Cu from diffusing into Si devices and causing damage to device performance, it is necessary to wrap a diffusion barrier layer outside the copper interconnection to isolate Cu and SiO. 2 , Si, and the effect of improving the adhesion between Cu and them. The double-layer structure of TaN / Ta in the traditional process has been widely used. However, with the reduction of the device size, when the feature size is less than 45nm, in order to ensure that the copper interconnection can still have a good filling effect, the diffusion barrier layer The challenge is to have a thinner thickness and still have a strong barrier e...

AI Technical Summary

Problems solved by technology

However, a single layer of Ru is not suitable as a diffusion barrier, because experiments have shown that the Ru monolayer diffusion barrier will fail after annealing.

Images