A semiconductor chip stack includes a first semiconductor chip, a second semiconductor chip, and a connection via which the first electrode and the second electrode are electrically connected to each other. The connection includes a first column and a second column. The first column is constituted by a material having a higher degree of activity with respect to heat than a material that constitutes the second column and is smaller in volume than the second column. Further, the connection has an aspect ratio of 0.5 or higher in a height direction.