Scheduling of multi-slot cluster tools with wafer delay constraints

Abstract

Cluster tools are widely used in most semiconductor manufacturing processes. As process technology advances and precise control become possible, a multi-slot cluster tool which has high productivity compared to the area by processing multiple wafers in each chamber has been developed and operated. This multi-slot cluster tool's production efficiency increases when the tool consists of resources with extended structures. As the number of slots in the chamber increases, the equipment has higher productivity, but the quality of the wafer deteriorates because the delay of the processed wafers exposed to residual heat and gas in the chamber increases. In order to develop and operate cost-effective equipment, scheduling in consideration of wafer delay while responding to various structures is essential, but studies related to this have not been conducted yet. Therefore, in this study, we proposed a methodology to determine the schedule of the robot to minimize chamber delay through modeling of the multi-slot cluster tool with wafer delay constraints. We then proposed sequences for the robot with three or more arms and developed the model for determining the structure and schedule that guarantees the best performance for the process with time constraints through modeling-based analysis. Finally, we proposed a model that determines the equipment structure and schedule which includes the operation for the chamber, for the process with the chamber cleaning operation.