Stacked semiconductor device and lower module of stacked semiconductor device

A lower module of a stacked semiconductor device includes a first substrate and a first semiconductor chip held above the first substrate. The top surface of the first substrate is provided with a plurality of first chip connection terminals electrically connected to the first chip terminals, respectively, and a plurality of upper module connection terminals electrically connectable to an upper module provided with a second semiconductor chip. The back surface of the first substrate is provided with a plurality of external substrate connection terminals. Each of the first chip connection terminals is electrically connected to a corresponding one of the external substrate connection terminals, and each of the upper module connection terminals is electrically connected between a corresponding one of the chip connection terminals and a corresponding one of the external substrate connection terminals.