Quiescent-Signal Analysis: A Multiple Supply Pad IDDQ Method

Increasing leakage current makes single-threshold IDDQ testing ineffective for differentiating defective and detect-free chips. Quiescent-signal analysis is a new detection and diagnosis technique that uses IDDQ measurement at multiple chip supply ports, reducing the leakage component in each measurement and significantly improving detection of subtle detects. In this article, we apply linear regression analysis and a new technique called ellipse analysis to the data collected from a set of 12 test chips to illustrate QSA's defect detection capabilities and limitations. The design permits control over the magnitude of the emulated-defect current and the leakage current