A method of manufacturing a semiconductor device includes mounting at least one of a first semiconductor chip and a second semiconductor chip over a die pad of a leadframe, and inspecting a mounting position of at least one of the first semiconductor chip and the second semiconductor chip, wherein the leadframe includes first mark formed to the die pad, for indicating a first mounting region for the first semiconductor chip, and second mark formed to the die pad, for indicating a second mounting region for the second semiconductor chip, the first mark is different from the second mark, in at least either one of size and geometry, wherein, in the inspecting a mounting position of at least one of the first semiconductor chip and the second semiconductor chip, a mounting position of the first semiconductor chip is inspected when the first semiconductor chip is mounted.