A stacked semiconductor memory device is provided which includes a first memory chip including a first transmission line, a second transmission line, and a logic circuit configured to execute a logic operation on a first signal of the first transmission line and a second signal of the second transmission line. The stacked semiconductor memory device further includes a second memory chip stacked over the first memory chip, an inter-chip connection unit electrically coupled between the second memory chip and the first transmission line of the first memory chip, and a dummy inter-chip connection unit electrically coupled to the second transmission line of the first memory chip and electrically isolated from the second memory chip.