Final test yield is the percentage of packaged devices passing comprehensive electrical and functional testing — the last quality gate before shipment, typically 95-99%, with failures indicating assembly defects, latent manufacturing issues, or marginal devices caught by thorough testing.

What Is Final Test Yield?

• Definition: (Passing devices / Total tested) × 100% at final test.
• Timing: After packaging, before shipment.
• Typical: 95-99% for mature products.
• Purpose: Last chance to catch defects before customer.

Why Final Test Matters

• Quality Gate: Prevents defective products from shipping.
• Assembly Defects: Catches packaging-induced failures.
• Comprehensive: Most thorough test in manufacturing flow.
• Customer Protection: Last defense against escapes.

Test Coverage

• Functional: All operating modes and features.
• Parametric: Speed, voltage, current, power.
• AC/DC: Timing and electrical characteristics.
• Burn-in: Extended stress for high-reliability products.

Failure Analysis: Final test failures analyzed to improve wafer probe, assembly, or test coverage.

Final test yield is the last quality checkpoint — comprehensive testing that protects customers while providing feedback to improve upstream processes.