A test chip performs measurements to evaluate the performances of
interconnects. In particular, the statistical failure distribution, the
electromigration and the leakage current are measured. An algorithm
detects a via failure at any of the available n metal layers. The test
chip includes a ROM memory array. The vias to be measured are formed in
the columns of the array. Via or contact failures are detected by forcing
a predetermined current through both an array column and a reference
column. The failure analysis is obtained by comparing the resulting
voltage drops.