Parametric Yield Loss is yield loss caused by devices failing to meet electrical performance specifications — die that are physically intact (no killer defects) but whose transistors, resistors, or other components fall outside parametric limits (speed, power, leakage, voltage margins).

Parametric Yield Loss Sources

• Vth Variation: Threshold voltage outside specification — too much variation across the die.
• Leakage: Excessive off-state leakage current — die fails power consumption specification.
• Speed: Logic path delay exceeds timing target — die fails to meet target frequency (speed binning).
• Analog: Amplifier gain, offset, or matching outside specification — critical for analog/mixed-signal products.

Why It Matters

• Binning: Parametric yield determines the distribution across speed/power bins — higher bins command premium pricing.
• Process Variability: Driven by process variation (CD, implant dose, film thickness) — tighter variation improves parametric yield.
• Design Centering: Optimizing the process center point to maximize the fraction of die in target bins.

Parametric Yield Loss is working but not good enough — die that are defect-free but fail to meet performance specifications due to process variability.