A dynamic system regulation measure for increasing effective capacity: the X-factor theory

Abstract

Due to the complex nature of semiconductor manufacturing it is evident that a single scheduling or regulation technique cannot best optimize the system dynamics for reducing cycle time and increasing throughput. The throughput of the system can increase to the effective capacity level of the system. When the throughput of the system approaches the effective capacity the product cycle time can dramatically increase. The "knee" of the performance curve indicates an operating point for fabs to maximize throughput while keeping the product cycle time relatively low. By increasing the effective capacity, i.e. adding a machine or improving a process, the product cycle time can be lowered or the system throughput increased by producing a shift in the "knee" of the performance curve. The bottleneck, typically defined as the most heavily utilized machine group, is often the target for increasing the system effective capacity. We will analyze the bottleneck along with other system capacity regulation measures to systematically study the relationship between bottleneck, X-factor, cycle time, and throughput measurements.