A Multi-Modal Diagnostic Workflow for Marginal Scan Transition Failures in Advanced Logic Devices
A Multi-Modal Diagnostic Workflow for Marginal Scan Transition Failures in Advanced Logic Devices
Tuesday, October 6, 2026: 2:10 PM
Summary:
Marginal, temperature- and voltage-dependent transition failures observed in scan tests are becoming more common in advanced logic devices and often cannot be easily localized using conventional scan diagnosis or a single optical fault isolation technique. This paper introduces a practical, end‑to‑end workflow that integrates scan diagnosis, targeted bench tests, dynamic emission microscopy (EMMI), multiple laser‑assisted fault isolations (SDL, LADA, and TR‑LADA), and physical failure analysis (PFA) to successfully root-cause a temperature- and voltage‑sensitive slow‑to‑fall failure. Beginning with an extensive suspect list derived from preliminary diagnostics, targeted bench experiments systematically reduce uncertainty and facilitate precise optical fault isolation (OFI). OFI provides spatial confirmation near the pass/fail boundary. Nanoprobing and TEM identified a localized resistive via caused by marginal process etch. The results demonstrate that the proposed multi‑modal workflow accelerates convergence from many suspects to a defensible root cause and provides actionable guidance for continuous yield improvement and screening of scan transition failures.
Marginal, temperature- and voltage-dependent transition failures observed in scan tests are becoming more common in advanced logic devices and often cannot be easily localized using conventional scan diagnosis or a single optical fault isolation technique. This paper introduces a practical, end‑to‑end workflow that integrates scan diagnosis, targeted bench tests, dynamic emission microscopy (EMMI), multiple laser‑assisted fault isolations (SDL, LADA, and TR‑LADA), and physical failure analysis (PFA) to successfully root-cause a temperature- and voltage‑sensitive slow‑to‑fall failure. Beginning with an extensive suspect list derived from preliminary diagnostics, targeted bench experiments systematically reduce uncertainty and facilitate precise optical fault isolation (OFI). OFI provides spatial confirmation near the pass/fail boundary. Nanoprobing and TEM identified a localized resistive via caused by marginal process etch. The results demonstrate that the proposed multi‑modal workflow accelerates convergence from many suspects to a defensible root cause and provides actionable guidance for continuous yield improvement and screening of scan transition failures.