A method of fabricating a metal line using a dual damascene process which enhances reliability of the semiconductor device. The method includes forming a lower metal line in a first inter metal dielectric layer; and then sequentially forming a first anti-etch layer, a second inter metal dielectric layer and a second anti-etch layer over the first inter metal dielectric layer and the lower metal line, wherein the second inter metal dielectric includes a first trench formed therein; and then forming an oxide film on the second anti-etch layer and in the first trench; and then forming a first via hole by performing a first etching process on the oxide film, the second anti-etch layer and the second inter metal dielectric layer; and then forming a second trench and a second via hole by performing a second etching process using the second anti-etch layer as a mask; and then removing a portion of the first anti-etch layer exposed in the second via hole and the second anti-etch layer; and then forming an upper metal line in the second via hole and the second trench.