Provided is a method for fabricating an interconnection line in a semiconductor device. The method includes forming a dielectric layer pattern including a region for forming the interconnection line on a semiconductor substrate, forming a diffusion barrier layer on the dielectric layer pattern, forming a first adhesion layer on the diffusion barrier layer, forming a seed layer on the first adhesion layer, forming a conductive layer to fill the region for forming the interconnection line, performing grain growth of the conductive layer by performing a first annealing process, planarizing the conductive layer to expose the top surface of the dielectric layer pattern, and forming an interface layer through reaction between the first adhesion layer and the conductive layer by performing a second annealing process at a temperature higher than that of the first annealing process.