A Load Balancing Scheduling Approach for Dedicated Machine Constraint

The constraint of having a dedicated machine for photolithography process in semiconductor manufacturing is one of the new challenges introduced in photolithography machinery due to natural bias. With this constraint, the wafers passing through each photolithography process have to be processed on the same machine. The purpose of the limitation is to prevent the impact of natural bias. However, many scheduling polices or modeling methods proposed by previous research for the semiconductor manufacturing production have not discussed the dedicated machine constraint. In this paper, we propose the Load Balancing (LB) scheduling approach based on a Resource Schedule and Execution Matrix (RSEM) to tackle this constraint. The LB scheduling approach is to schedule each wafer lot at the first photolithography stage to a suitable machine according to the load balancing factors among machines. We describe the algorithm of the proposed LB scheduling approach and RSEM in the paper. We also present an example to demonstrate our approach and the result of the simulations to validate our approach.