An integrated circuit (IC) includes multiple embedded test circuits that
all include a ring oscillator coupled to a test load. The test load
either is a direct short in the ring oscillator or else is a interconnect
load that is representative of one of the interconnect layers in the IC.
A model equation is defined for each embedded test circuit, with each
model equation specifying the output delay of its associated embedded
test circuit as a function of Front End OF the Line (FEOL) and Back End
Of the Line (BEOL) parameters. The model equations are then solved for
the various FEOL and BEOL parameters as functions of the test circuit
output delays. Finally, measured output delay values are substituted in
to these parameter equations to generate actual values for the various
FEOL and BEOL parameters, thereby allowing any areas of concern to be
quickly and accurately identified.