Network risk-adaptive abnormality response policy for oht vehicle in semiconductor fab

Abstract

This dissertation examines the effects of errors occurring in the Overhead Hoist Transport (OHT) vehicles, used for logistics transportation within semiconductor manufacturing processes, and suggests operational policies to address these issues. OHT vehicle errors are common problems in various manufacturing processes such as semiconductor fabrication, leading to decreased vehicle utilization due to inspection and repair downtimes. Furthermore, when a vehicle halts at a specific location due to an error, it can adversely impact the logistics transportation of other OHT vehicles. Therefore, there is a need for error response operational policies that consider these implications. In this study, we analyze the impact of vehicle errors at specific locations on logistics transportation, considering the layout structure of the OHT system in semiconductor processes, the traffic volume on each track, and the vehicle’s path planning algorithm. Additionally, using a simulation testbed, we propose error response operational policies that consider the impact of error occurrence locations on logistics transportation.