Load Balancing Among Photolithography Machines in the Semiconductor Manufacturing System

We propose a Load Balancing (LB) scheduling approach to tackle the load balancing issue in the semiconductor manufacturing system. This issue is derived from the dedicated photolithography machine constraint. The constraint of having a dedicated machine for the photolithography process in semiconductor manufacturing is one of the new challenges introduced in photolithography machinery due to natural bias. To prevent the impact of natural bias, the wafer lots passing through each photolithography process have to be processed on the same machine. However, the previous research for the semiconductor manufacturing production has not addressed the load balancing issue and dedicated photolithography machine constraint. In this paper, along with providing the LB approach to the issue, we also present a novel model, Resource Schedule and Execution Matrix (RSEM) – the representation and manipulation methods for the task process patterns. The advantage of the proposed approach is to easily schedule the wafer lots by using a simple two-dimensional matrix. We also present the simulation results to validate our approach.