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 Pay Contract Terms
Meaning
The contractual agreements that define the payment structure and delivery conditions for silicon wafers dictate the financial relationship between a chip designer and a foundry. Under wafer pay contract terms, the buyer may pay for completed wafers regardless of the yield, or pay only for the working chips harvested. This choice determines who bears the risk of manufacturing defects.
Payment Trigger
Defining when payment is due, such as upon delivery or after testing, affects the buyer’s cash flow. Fabs often require a deposit before starting a run. This ensures they do not lose money if the buyer cancels the order.
Risk Allocation
Sharing the risk of yield drops is a major point of negotiation in these agreements. Buyers prefer to pay per good die, while foundries prefer to sell whole wafers. The final agreement depends on the bargaining power of each party.
Volume Commitment
Securing favorable terms requires the buyer to commit to minimum annual wafer volumes. Fabs offer lower prices to buyers who promise to fill their production lines. If the buyer fails to meet these volumes, the foundry can charge a penalty or raise the price for future wafers, which can significantly increase the buyer’s manufacturing costs and disrupt their financial planning.