Scheduling a dual-arm cluster tool with a cleaning operation
ZHU Qing-hua
PAN Hong-ting
Abstract：In a semiconductor manufacturing factory,a cluster tool consists of several process chambers and a robot for transporting wafers.During wafer fabrication,a process chamber must be cleaned when its processing environment reaches a contamination threshold to ensure wafer quality.This work focuses on a dual-arm cluster tool with parallel process chambers when wafer residency time constraints are imposed on processed wafers.The chamber must be cleaned when the contamination accumulates to a given threshold.This work studies the scheduling of the robot for such a scenario.Due to a cleaning operation,the cycle time of a cluster tool must be extended.To this end,this work proposes a method based on a virtual wafer,which can 1)keep the robot operation sequence the same as before the cleaning operation and 2)obtain enough time to perform a cleaning operation.When the wafer residency time constraints at the regular steps are satisfied,we analyze the workload balance of process steps for a cluster tool and propose algorithms based on closed-form calculations.The algorithms can 1)determine the variable cycle time of a cluster tool and the robot waiting time before unloading a wafer,2)switch a cluster tool from a steady state to a cleaning transient state,and 3)back to an original steady state.The computational complexity of the proposed algorithms is polynomial and can improve the productivity of a cluster tool in the case of a cleaning operation.
Keywords：semiconductor manufacturingchamber cleaningschedulingcluster tools
Publication Date：2025-09-30
Online Publishing Date：2025-10-28(First online date of this platform, not the publication date of the document)
Pages：9( 1858-1866 )