Idle vehicle circulation policies in a semiconductor FAB
Idle vehicle handling is addressed for the path-based automated material handling system (AMHS) in a semiconductor fabrication line. Since a typical semiconductor fabrication line has a single path in each bay and no sidetracks to park idle vehicles, a vehicle should be dispatched to somewhere if necessary even without a new assignment to prevent blocking of other vehicles. We investigate the continuous-move policy, the move-when-necessary policy and their variants. Our simulations show that the idle vehicle circulation policy significantly affects the AMHS productivity, so the policy should be carefully designed for the AMHS instance.
idle vehicle circulation parking overhead hoist transport automated guided vehicle