Stuck-at fault is a structural fault model where a signal line is assumed permanently fixed at logic zero or logic one - Test vectors are generated to activate and propagate the assumed stuck condition to observable outputs.

What Is Stuck-at fault?

• Definition: A structural fault model where a signal line is assumed permanently fixed at logic zero or logic one.
• Core Mechanism: Test vectors are generated to activate and propagate the assumed stuck condition to observable outputs.
• Operational Scope: It is used in semiconductor test and failure-analysis engineering to improve defect detection, localization quality, and production reliability.
• Failure Modes: Exclusive reliance on stuck-at modeling can miss delay and analog-sensitive defects.

Why Stuck-at fault Matters

• Test Quality: Better DFT and analysis methods improve true defect detection and reduce escapes.
• Operational Efficiency: Effective workflows shorten debug cycles and reduce costly retest loops.
• Risk Control: Structured diagnostics lower false fails and improve root-cause confidence.
• Manufacturing Reliability: Robust methods increase repeatability across tools, lots, and operating corners.
• Scalable Execution: Well-calibrated techniques support high-volume deployment with stable outcomes.

How It Is Used in Practice

• Method Selection: Choose methods based on defect type, access constraints, and throughput requirements.
• Calibration: Use stuck-at coverage with complementary fault models such as transition and bridging.
• Validation: Track coverage, localization precision, repeatability, and field-correlation metrics across releases.

Stuck-at fault is a high-impact practice for dependable semiconductor test and failure-analysis operations - It provides a simple and widely used baseline for digital structural testing.