In order to solve the aforementioned problems, the present-invention provides a semiconductor device having a multilayer interconnection structure, wherein an upper interconnection comprises a first metal layer composed of an aluminum alloy, which is formed over a lower interconnection, and a second metal layer formed over the first metal layer and composed of an aluminum alloy formed as a film at a temperature higher than that for the first metal layer. Another invention provides a semiconductor device having a multilayer interconnection structure, wherein a metal region composed of a metal different from an aluminum alloy is formed in a portion spaced by a predetermined distance in an extending direction of an upper interconnection from an end of a via hole defined in the upper interconnection composed of the aluminum alloy, which is electrically connected to a lower interconnection through the via hole.