Overall yield is the composite yield from wafer start to shipped product — calculated by multiplying probe yield, assembly yield, and final test yield, representing the true efficiency of the entire manufacturing process and determining profitability.

What Is Overall Yield?

• Definition: Probe Yield × Assembly Yield × Final Test Yield.
• Example: 90% × 99% × 98% = 87.3% overall.
• Measurement: Good shipped units / Wafer starts.
• Impact: Directly determines manufacturing cost and profit.

Why Overall Yield Matters

• Profitability: Higher yield means lower cost per good unit.
• Competitiveness: Yield advantage translates to price or margin advantage.
• Capacity: Higher yield means more output from same fab.
• Investment: Yield improvements have huge ROI.

Calculation

overall_yield = probe_yield * assembly_yield * final_test_yield
# Example: 0.90 × 0.99 × 0.98 = 0.873 (87.3%)

Improvement Strategy: Focus on lowest yield step first for maximum overall yield improvement (Pareto principle).

Economic Impact: 1% yield improvement can add millions in annual profit for high-volume products.

Overall yield is the bottom line metric — the single number that determines whether a product is profitable or not, making yield improvement the highest-priority activity in semiconductor manufacturing.