Technical Paper: Winter Simulation Conference 2021

Multi-objective Parallel Batch Scheduling in Wafer Fabs with Job Timelink Constraints

Authors of this publication:

Semya Elaoud, Ruaridh Williamson, Begun Efeoglu Sanli, and Dennis Xenos.

Abstract:

We consider multi-objective batch scheduling in the complex flexible job shop problem applied to semiconductor wafer fabs. Batches have different operating costs and consecutive steps of a job are constrained with timelinks. We also consider several other process aspects that arise in semiconductor wafer fabrication facilities such as flexible machine downtime, incompatible job families, different job sizes and parallel machines. The aim is to minimize the total weighted batching cost, queuing time, and the number of violations to timelink constraints. We present a hybrid two-stage solution strategy, combining Mixed IntegerLinear Programming (MILP) models and heuristics. At a high level, the proposed approach can be broken down into “constructive” and “improvement” steps. The comparison of Flexciton schedules evaluated under uncertainty against the actual factory schedules when solving large industrial instances shows the significant improvements that our solution can bring.

More resources

Stay up to date with our latest publications.
Technical Paper: ASMC 2023

This technical publication from ASMC 2023 focuses on the practical aspects of deploying a novel solution in a critical production environment.

Technical Paper: Winter Simulation Conference 2022

The first published case study of a successful fab-wide scheduling deployment in a large-scale semiconductor wafer fab.

Technical Paper: Journal of Manufacturing Systems 2022

This journal publication delves into the complex problem of batch scheduling with varying batch costs and job timelink constraints at Renesas Electronics.

Efficient Batching Case Study

Discover how Renesas harnessed autonomous scheduling to tackle the complex challenge of efficient batching.

Renesas Electronics Case Study

Learn how we applied multi-objective optimization to the diffusion area at Renesas Electronics to manage three conflicting KPIs.

Fab Management Forum 2022

Recap on the first of two presentations from SEMICON Europa 2022 – featuring case study results from three different wafer fabs, including Renesas and Seagate.

Technical Paper: Winter Simulation Conference 2020

This technical paper provides a comprehensive overview of results from benchmark studies performed for Seagate Technology, where our solution was applied to metrology toolset scheduling.

White Paper

Our white paper details a new approach to wafer fab scheduling. A novel hybrid model that delivers optimized schedules in a matter of minutes to help fabs cut costs and increase efficiency.

Seagate Case Study 1.0

Discover how we helped a highly-utilised Seagate Technology wafer fab reduce cycle time and boost efficiency by applying our next-generation production scheduling solution.

Seagate Case Study 2.0

Learn how applying multi-objective optimization helped to increase throughput whilst reducing reticle moves and queue time.

An Introduction to Flexciton

Gain a comprehensive understanding of where we came from, what we do, and why we’re different with our company introduction.