Sense and sensibility: the scaleable minifab

The objective of the scaleable minifab is cost competitive, low risk IC manufacturing to satisfy a business need. This paper analyzes the capital and operating costs of a fab, and shows how the data can be used to improve the cost structures of modular IC manufacturing while containing capital risk. A modular fab can limit capital risk by allowing capacity to be added in an incremental way when needed. The paper shows that the cost per wafer is higher for the smaller fab as predicted by economics of scale. In addition, the lower wafer cost benefit of economies of scale is overshadowed by the cost penalty of under-utilization of fab capacity. This suggests that a fab should be designed in a modular way, starting small in size and growing in modules when needed. Keeping utilization high will result in a lower average wafer cost than a larger fab with economies of scale and lower utilization.