Failure Response Strategy For Single-Arm Cluster Tools With Purge Operation

Semiconductor manufacturing industry is the pillar of the modern information industry,which has important strategic significance for promoting the development of Chinese economic development and technological progress.As the wafer size increases and the wafer wire width decreases,the higher quality is required during the wafer fabrication in the wafer manufacturing industry,to improve the quality of wafer and the cleanliness of chamber,cluster tools need to clean chambers to remove the chemical residues in chambers.When one predetermined wafer is processed by chambers,chambers should be cleaned,which is called purge operation.When purging operation is taken into account,the conventional backward strategy for the single-arm cluster tool is no longer the optimal scheduling strategy.A modified backward strategy has been obtained by determining the optimal number of free chambers in each step.Furthermore,for some processing processes,wafers have strict residency time constraint,that is to say,wafers must have a limited residency time in processing chamber.At the same time,single-arm cluster tools with purge operation may fail.When one parallel chamber fails in a certain processing step,it is possible for cluster tool to continue to process.Therefore,in order to improve efficiency of cluster tool and ensure the quality of wafer,this paper studies the failure problem of single-arm cluster tool with purge operation under the residency time constraint.Firstly,some knowledge of single-arm cluster tools,dual-arm cluster tools,multicluster tools and Petri nets(PN)is introduced.Then,Petri net models of single-arm cluster tool with purge operation are given in two cases before and after the failure,and the control strategy to avoid deadlock is given.Next,the transitions and places in the Resource-Oriented Petri Nets(ROPN)model are associated with time.Secondly,according to the ROPN model before the failure,we analyze the operation time characteristic of single-arm cluster tool with purge operation,for example,the robot cycle time,the wafer sojourn time,and obtain the Linear Programming Models(LPM)in two cases before and after the failure,at the same time,LINGO solver is given to solve the LPM models.Finally,when the system is schedulable in the case after the failure,we give the failure response strategy in the cases that one non-idle chamber and one idle chamber respectively fails.In other words,when the system is not schedulable in the case after the failure,we give the failure response strategy,too.In other words,when cluster tools can be scheduled in the case after the failure,this paper provides corresponding failure response strategies in the cases that one non-idle chamber and one idle chamber respectively fails by disabling the failed chamber,so that cluster tool can be smoothly transferred from the steady state before failure to the steady state after failure.When cluster tool cannot be scheduled in the case after the failure,the stopping operation is carried out.Then,the corresponding Gantt charts are given through examples,which verifies the validity and correctness of the proposed LPM in the case after the failure and failure response strategies.The above research results show that the proposed failure response strategies can solve the failure problem of single-arm cluster tools with purge operation and residency time constraint under the existing modified backward strategy.