Analysis of the quality of contacts and vias in multi-metal fabrication processes of semiconductor devices, method and test chip architecture

Abstract

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.