Study of cycle time caused by lot arrival distribution in a semiconductor manufacturing line

Recently, competitive semiconductor manufacturing has been indispensable to satisfy market requirements for cycle time, throughput, and cost. Specially, in a large size fab like a mega-fab, precise cycle time control of individual lots is necessary. We studied the mechanism of cycle time caused by lot arrival distribution in a large size fab and found that the lot arrival is approximated to be a Poisson distribution in some conditions because of multi functional inspections. We also found that a factor of excess tool capacity over production capacity is dominant for cycle time by using simulation. As a result, meaningful parameters are obtained to maintain a targeted cycle time