A concurrent approach for facility layout and AMHS design in semiconductor manufacturing

This paper presents a concurrent approach to solve the design problem of facility layout and automated material handling system (AMHS) for semiconductor fabs. The layout is composed of bays which are unequal-area blocks with equal height but flexible width. In particular, the bay width and locations of a shortcut, bays, and their stockers, which are major fab design considerations, are concurrently determined in this problem. We developed a mixed integer programming (MIP) model for this problem to minimize the total travel distance (TTD) based on unidirectional interbay flow and a bidirectional shortcut. To solve large-sized problems, we developed a five-step heuristic algorithm to exploit and explore the solution space based on the MIP model. The computational results show that the proposed algorithm is able to find optimal solutions of small-sized problems and to solve large-sized problems within acceptable time.