To improve the assemblability of a semiconductor device.When a memory chip is mounted over a logic chip, a recognition range including a recognition mark formed at a back surface of the logic chip is imaged and a shape of the recognition range is recognized, alignment of a plurality of bumps of the logic chip and a plurality of projection electrodes of the above-described memory chip is performed based on a result of the recognition, and the above-described memory chip is mounted over the logic chip. At this time, the shape of the recognition range is different from any portion of an array shape of the bumps, as a result, the recognition mark in the shape of the recognition range can be reliably recognized, and alignment of the bumps of the logic chip and the projection electrodes of the above-described memory chip is performed with high accuracy.