ManufacturingMVP
Wafer yield
Estimate the fraction of good dies from defect density (Poisson or Murphy model).
Inputs
Result
Enter values and calculate to see the result.
Interpretation
Enter defect density and die size, then pick a model. Yield depends on the product D·A (defect density × die area).
Formula
Poisson: Y = e^(−D·A)
Murphy: Y = ((1 − e^(−D·A)) / (D·A))²
Variables
| Symbol | Variable | Unit |
|---|---|---|
| Y | Die yield | fraction |
| D | Defect density | m⁻² |
| A | Die area (w × h) | m² |
Assumptions & validity
This tool assumes:
- A single fatal defect within the die area kills the die.
- Poisson: defects are random, independent, and uniformly distributed.
- Murphy: accounts for non-uniform defect distribution across the wafer.
- Only random defect limited yield — no systematic/parametric loss.
Worked example
D = 0.5 defects/cm², die 10 mm × 10 mm (A = 1 cm²) → D·A = 0.5.
Poisson: Y = e^(−0.5) ≈ 0.607 → 60.7%