Modeling Multi Tiered Yield Variances across Alternative Semiconductor Fabrication Facilities for Industrial Processors
Industrial processor margins depend on adjusting fab allocation for parametric bin shift rather than wafer cost alone.
Wafer Edge Exclusion
Meaning
The unusable outer ring of a semiconductor wafer is ignored during electrical testing and die yields calculation due to frequent manufacturing defects near the physical margin. Applying a standard wafer edge exclusion prevents the waste of testing resources on dies that are highly likely to be defective.
Yield Calculation
Accurate wafer yield estimations must subtract the dies located in the outer exclusion zone. When wafer edge exclusion is factored into yield calculations, it provides a more realistic estimate of usable silicon dies per wafer, ensuring that the final cost of goods sold is not underestimated.
Contractual Boundary
Wafer supply contracts must define the exact width of the outer exclusion zone to avoid disputes over yield calculations. If the foundry’s processes cause defects to extend beyond the agreed wafer edge exclusion zone, the designer has the right to demand financial compensation or additional wafer runs to make up for the lost yield.
Inventory Planning
Supply chain managers rely on accurate yield predictions to plan their finished goods inventory. By using wafer edge exclusion to generate realistic yield forecasts, companies can ensure a steady supply of finished chips to their distribution networks, reducing the risk of product shortages. This reliable supply helps maintain strong relationships with global distributors and secures long-term exclusive supply agreements by minimizing the occurrence of costly delivery delays.