A packaged semiconductor chip is provided which includes a semiconductor
chip and a package element. The semiconductor chip includes a plurality
of semiconductor devices and a plurality of conductive features disposed
at an exterior face of the semiconductor chip. The package element has a
plurality of external features conductively connected to the plurality of
conductive features of the semiconductor chip. The semiconductor chip
includes a monitored element including a conductive interconnect that
conductively interconnects a first node of the semiconductor chip to a
second node of the semiconductor chip. A detection circuit in the
semiconductor chip is operable to compare a variable voltage drop across
the monitored element with a reference voltage drop across a reference
element on the chip at a plurality of different times during a lifetime
of the packaged semiconductor chip so as to detect when the resistance of
the monitored element is over threshold.