Multi-product lot merging/splitting algorithms for a semiconductor wafer fabrication

This paper focuses on a lot merging/splitting problem in a semiconductor wafer fabrication facility. In the fab, two or more lots can be merged into a single lot if routes and all the processing conditions of the lots are the same for a number of subsequent operations, and the merged lot is split into the original lots at the point where the routes or processing conditions become different. We suggest lot merging/splitting algorithms to reduce the total tardiness of orders and the cycle times of the lots. The suggested algorithms are evaluated through a series of simulation experiments and the result shows that the algorithms work better than a method used in a real fab.