1. A method for manufacturing a semiconductor device, comprising the steps of: (a) mounting a first semiconductor chip over a second semiconductor chip such that a first surface of the first semiconductor chip faces to a second surface of the second semiconductor chip, wherein a first electrode pad group and a second electrode pad group are arranged over the second surface of the second semiconductor chip, wherein the first electrode pad group includes a plurality of first electrode pads arranged in a matrix of n rows and m columns (n<m), wherein n is greater than 1; wherein the second electrode pad group includes a plurality of second electrode pads, wherein a plurality of projection electrodes is arranged over the first surface of the first semiconductor chip, the (a) step including the steps of: (a1) recognizing the second electrode pad group as a recognition mark; (a2) performing alignment of the first semiconductor chip and the second semiconductor chip based on a result of having recognized the recognition mark; and (a3) mounting the first semiconductor chip over the second semiconductor chip, and electrically coupling with the plurality of first electrode pads of the second semiconductor hip and the projection electrodes of the first semiconductor chip respectively, and wherein the number of a sum of the second electrode pads is smaller than the number of a value of n times n.