A method is disclosed for designing scan chains in an
integrated circuit chip with specific parameter sensitivities to identify fabrication process defects causing test fails and
chip yield loss. The composition of scan paths in the
integrated circuit chip is biased to allow them to also function as on-product process monitors. The method adds grouping constraints that bias scan chains to have common latch
cell usage where possible, and also biases
cell routing to constrain
scan chain routing to given restricted
metal layers for interconnects. The method assembles a
list of latch design parameters which are sensitive to
process variation or integrity, and formulates a plan for
scan chain design which determines the number and the length of scan chains. A model is formulated of
scan chain design based upon current state of yield and process integrity, wherein certain latch designs having dominant sensitivities are chosen for specific ones of the scan chains on the chip. The model is provided as input parameters to a global placement and wiring program used to lay out the scan chains.
Test data on the chip is then analyzed to determine and isolate systematic yield problems denoted by attributes of a statistically significant failing
population of a specific type of scan chain.