We examine a scheduling problemof cluster tools that concurrently process two wafer types in a cyclic operational sequence. Whereas the process steps for different wafer types are assigned to different processing modules (PMs), the wafer loading and unloading tasks at the PMs are performed by a single robot. For a given cycle plan, which is a mix of different wafers for each cycle, we wish to d…
Abstract—Cluster tools, each of which consists of multiple processing modules, one material handling robot, and loadlocks, are widely used for wafer fabrication processes, such as lithography, etching, and deposition. There have been many approaches and algorithms for cyclic scheduling of cluster tools in which the robot repeats a specified sequence for processing identical wafers. However, t…
Abstract Cluster tools each of which consists of processing modules (PMs), a transport robot and loadlocks perform most wafer fabrication processes in semiconductor manufacturing. Recently, the lot size has been decreasing from 25 wafers to even 7-8 wafers due to the larger wafer size and circuit width reduction especially in large scale integration (LSI) manufacturing. Hence, the lot switchin…