Analytic approximations for multiserver batch-service workstations with multiple process recipes in semiconductor wafer fabrication

This study extends previous results for batch-service workstations to batch-service/batch-lot workstations with multiple process recipes, e.g., diffusion operations in semiconductor manufacturing. The model considered herein explicitly considers the existence of a manufacturing operation associated with multiple process recipes in the semiconductor factory. Consequently, the revised balance equations are submitted and an improved approximation is presented for this case. Based on a comparison with simulation results, this new approximation is shown to be superior to the previously developed analytical approaches. This new approximation is especially strong in cases where the number of process recipes grows, system traffic intensity is moderate, and arrival rate of each recipe is nearly the same