A multi-layered integrated semiconductor device incorporates an upper and lower IC chips which are connected with each other via a first set of wiring pads of the upper IC chip to a second set of wiring pads of the lower IC chip. The device is provided with a multiplicity of pair-wise connected external monitoring terminals on the periphery of the upper IC chip, and a multiplicity of monitoring pads on the lower IC chip, in opposition to the pair-wise connected monitoring pads, so that pad-to-pad resistances between the pads of the upper and lower IC chips can be externally measured by directly connecting the monitoring pads to the external terminals.