Contractual Defect Density Guarantee Structures across Secondary Foundry Wafer Supply Agreements
Effective defect guarantee structures map precise inspection recipes and mathematical yield models directly to gross-to-net credit adjustment formulas.
Functional Yield Loss
Meaning
Semiconductor operational defect metrics calculate the percentage of fabricated integrated circuits that fail electrical tests prior to final assembly. Foundry supply contracts incorporate functional yield loss to evaluate process capability and determine financial adjustments for defective silicon. Agreements establish baseline parametric expectations and define financial credit formulas for excess die failures.
Quality engineers track these failure rates to separate material flaws from design flaws.
Parametric Defect Allocation
Electrical testing at the wafer level identifies functional failures caused by gate oxide breakdown or metal bridging errors. Under functional yield loss frameworks, test results dictate whether wafer costs are borne by the foundry or passed to the fabless designer. If defects stem from known process instability, the foundry issues billing credits for non-performing die.
Commercial Penalty Threshold
Contractual yield targets govern financial remedies when functional die counts fall below target expectations. When functional yield loss exceeds agreed limits across consecutive wafer lots, buyers retain the contractual right to cancel pending purchase orders. Foundries must compensate customers for wasted packaging and test materials if defective die were shipped past wafer probe checks.
Die Count Floor
Minimum acceptable functional die counts per wafer frame the financial boundary of commercial claims. Reaching this baseline threshold prevents foundries from invoicing buyers for severely compromised fabrication runs.