A semiconductor device includes an electrode pad provided on a semiconductor chip, in which the electrode pad includes aluminum (Al) as a major constituent and further including copper (Cu), a coupling ball primarily including Cu, the coupling ball is coupled to the electrode pad such that a plurality of layers of Cu and Al alloys are formed at a junction between the electrode pad and the coupling ball, and an encapsulating resin including a halogen of less than or equal to 1000 ppm, the encapsulating resin covering at least the electrode pad and the junction between the electrode pad and the coupling ball. A dimensional area of the plurality of layers of Cu and Al alloys is equal to or larger than 50% of a dimensional area of the junction between the electrode pad and the coupling ball. The plurality of layers of Cu and Al alloys includes a CuAl2 layer, a CuAl layer formed on the CuAl2 layer, and a layer including one of Cu9Al4 and Cu3Al2 formed on the CuAl layer.