Methodology for defect impact studies under conditions of low electrical testing coverage

Abstract

A methodology is outlined to establish the prioritization of defects under conditions of low sampling statistics based on the deliberate introduction of defects at specific process points. Probe results from electrical test structures are correlated with optical defect inspection data to determine the kill rates of various defects. The methodology generalizes from a standard approach that typically relies on a high statistical sampling plan with significant wafer area coverage. In this case, the probed area coverage is reduced to 1-3% of the wafer surface but still provides defect impact prioritization for targeted defect reduction and optimized inspection strategies for optical capture and SEM review.