Interconnect open defect diagnosis with minimal physical information

Abstract

We consider the problem of determining the location of open defects in interconnects of deep submicron (DSM) designs. The target defect sites for this work are the vias in interconnects which are known to be defect prone. It is known that in DSM designs below 90 nm technology the circuit parameters may vary widely from nominal or design values and process variations make them less predictable. Thus it becomes necessary to develop methods for locating defect sites without accurate knowledge of circuit parameters. Logic diagnosis which is based on gate level net lists is one such method but the resolution of defect sites obtained by logic diagnosis is considered to be unacceptably low for locating open vias. We investigate a procedure that uses minimal information beyond the net lists and give experimental results to demonstrate the defect resolution obtained using the method. The additional information used by the proposed method is a list of nodes in the neighborhoods of circuit nodes and the circuit layout. Specifically, difficult to determine circuit parameters of manufactured instances of a design such as coupling capacitances between circuit nodes and threshold voltages of gates in the circuit are not needed to use the proposed diagnosis procedure.