Methods of fabricating semiconductor devices are provided. The method includes providing a substrate and forming an interconnect structure on the substrate. The interconnect structure includes a top metal layer. The method also includes forming a first barrier film on the top metal layer using a first deposition process with a first level of power, and forming a second barrier film on the first barrier film using a second deposition process with a second level of power that is lower than the first level of power. The method further includes forming an aluminum-containing layer on the second barrier film. In addition, the method includes patterning the first barrier film, the second barrier film and the aluminum-containing layer to form a conductive pad structure.