According to one embodiment, a semiconductor device includes the following structure. The semiconductor chip is provided between first and second conductors. A joint component is provided between the chip and the second conductor. The thin film is provided on the second conductor and contains a material different from a material of the joint component. The second conductor includes first, second and third plates. The first plate extends in a first direction along a first surface of the chip and is connected to the chip via the joint component. The second plate extends from the first plate obliquely with respect to the first direction. The third plate extends from the second plate in the first direction. The thin film is arranged on a surface of the second plate continuous from a surface on which the joint component is provided.