Dynamic load balancing among multiple fabrication lines through estimation of minimum inter-operation time

We propose a load balancing method which balances all processing operations of products among multiple semiconductor wafer fabrication lines (fabs) by using predictive scheduling results. Through a simulation experiment we confirmed that the proposed method enabled improved load balancing (compared to conventional methods) among multiple fabrication lines each of which can independently fabricate wafers and has different wafer processing capacity. The load balancing feature effectively reduces the waiting time at each process step and the lead time of all products in multiple fabs. Another promising application of the proposed method is performance evaluation of automated material handling systems (AMHS) in terms of inter-operation time, and we have used the method to evaluate the transportation efficiency of actual fabs.