Queue time and x-factor characteristics for semiconductor manufacturing with small lot sizes

Small lot size is widely regarded as a promising means to achieve shorter cycle times in semiconductor manufacturing. The dominant contributor to cycle time is queue time. In this paper, we quantify how the queue time changes with lot size reductions by means of queuing theory and single-operation simulation. This includes an analysis of the factors shaping this queue time change and how their influence changes for different availability characteristics. Additionally, the x-factor changes resulting from the changes in queue time and raw process time are outlined.