Workload control concepts in job shops: a critical assessment

The paper considers a (static) portfolio system that satisfies adding-up contraints and the gross substitution theorem. The paper shows the relationship of the two conditions to the weak dominant diagonal property of the matrix of interest rate elasticities. This enables to investigate the impact of simultaneous changes in interest rates on the asset demands.

Genetic Algorithm for Job Scheduling with Maintenance Consideration in Semiconductor Manufacturing Process

This paper presents wafer sequencing problems considering perceived chamber conditions and maintenance activities in a single cluster tool through the simulation-based optimization method. We develop optimization methods which would lead to the best wafer release policy in the chamber tool to maximize the overall yield of the wafers in semiconductor manufacturing system. Since chamber degradation will jeopardize wafer yields, chamber maintenance is taken into account for the wafer sequence decision-making process. Furthermore, genetic algorithm is modified for solving the scheduling problems in this paper. As results, it has been shown that job scheduling has to be managed based on the chamber degradation condition and maintenance activities to maximize overall wafer yield.open

Simulation-Based Analysis on Operational Control of Batch Processors in Wafer Fabrication

[EN] In semiconductor wafer fabrication (wafer fab), wafers go through hundreds of process steps on a variety of processing machines for electrical circuit building operations. One of the special features in the wafer fabs is that there exist batch processors (BPs) where several wafer lots are processed at the same time as a batch. The batch processors have a significant influence on system performance because the repetitive batching and de-batching activities in a reentrant product flow system lead to non-smooth product flows with high variability. Existing research on the BP control problems has mostly focused on the local performance, such as waiting time at the BP stations. This paper attempts to examine how much BP control policies affect the system-wide behavior of the wafer fabs. A simulation model is constructed with which experiments are performed to analyze the performance of BP control rules under various production environments. Some meaningful insights on BP control decisions are identified through simulation results.This work was supported by the Pukyong National University Research Abroad Fund (C-D-2016-0843).Koo, P.; Ruiz García, R. (2020). Simulation-Based Analysis on Operational Control of Batch Processors in Wafer Fabrication. Applied Sciences. 10(17):1-17. https://doi.org/10.3390/app10175936S1171017Wang, L.-C., Chu, P.-C., & Lin, S.-Y. (2019). Impact of capacity fluctuation on throughput performance for semiconductor wafer fabrication. Robotics and Computer-Integrated Manufacturing, 55, 208-216. doi:10.1016/j.rcim.2018.03.005Ham, M. (2012). Integer programming-based real-time dispatching (i-RTD) heuristic for wet-etch station at wafer fabrication. International Journal of Production Research, 50(10), 2809-2822. doi:10.1080/00207543.2011.594816Mathirajan, M., & Sivakumar, A. I. (2006). A literature review, classification and simple meta-analysis on scheduling of batch processors in semiconductor. The International Journal of Advanced Manufacturing Technology, 29(9-10), 990-1001. doi:10.1007/s00170-005-2585-1FOWLER, J. W., HOGG, G. L., & PHILLIPS, D. T. (2000). Control of multiproduct bulk server diffusion/oxidation processes. Part 2: multiple servers. IIE Transactions, 32(2), 167-176. doi:10.1080/07408170008963889Van Der Zee, D. J. (2002). Adaptive scheduling of batch servers in flow shops. International Journal of Production Research, 40(12), 2811-2833. doi:10.1080/00207540210136559Wang, J., Zheng, P., & Zhang, J. (2020). Big data analytics for cycle time related feature selection in the semiconductor wafer fabrication system. Computers & Industrial Engineering, 143, 106362. doi:10.1016/j.cie.2020.106362Neuts, M. F. (1967). A General Class of Bulk Queues with Poisson Input. The Annals of Mathematical Statistics, 38(3), 759-770. doi:10.1214/aoms/1177698869Deb, R. K., & Serfozo, R. F. (1973). Optimal control of batch service queues. Advances in Applied Probability, 5(2), 340-361. doi:10.2307/1426040Gurnani, H., Anupindi, R., & Akella, R. (1992). Control of batch processing systems in semiconductor wafer fabrication facilities. IEEE Transactions on Semiconductor Manufacturing, 5(4), 319-328. doi:10.1109/66.175364Avramidis, A. N., Healy, K. J., & Uzsoy, R. (1998). Control of a batch-processing machine: A computational approach. International Journal of Production Research, 36(11), 3167-3181. doi:10.1080/002075498192355Fowler, J. W., Phojanamongkolkij, N., Cochran, J. K., & Montgomery, D. C. (2002). Optimal batching in a wafer fabrication facility using a multiproduct G/G/c model with batch processing. International Journal of Production Research, 40(2), 275-292. doi:10.1080/00207540110081489Glassey, C. R., & Weng, W. W. (1991). Dynamic batching heuristic for simultaneous processing. IEEE Transactions on Semiconductor Manufacturing, 4(2), 77-82. doi:10.1109/66.79719Fowler, J. W., Phillips, D. T., & Hogg, G. L. (1992). Real-time control of multiproduct bulk-service semiconductor manufacturing processes. IEEE Transactions on Semiconductor Manufacturing, 5(2), 158-163. doi:10.1109/66.136278Sarin, S. C., Varadarajan, A., & Wang, L. (2010). A survey of dispatching rules for operational control in wafer fabrication. Production Planning & Control, 22(1), 4-24. doi:10.1080/09537287.2010.490014Koo, P.-H., & Moon, D. H. (2013). A Review on Control Strategies of Batch Processing Machines in Semiconductor Manufacturing. IFAC Proceedings Volumes, 46(9), 1690-1695. doi:10.3182/20130619-3-ru-3018.00203Leachman, R. C., Kang, J., & Lin, V. (2002). SLIM: Short Cycle Time and Low Inventory in Manufacturing at Samsung Electronics. Interfaces, 32(1), 61-77. doi:10.1287/inte.32.1.61.15ROBINSON, J. K., FOWLER, J. W., & BARD, J. F. (1995). The use of upstream and downstream information in scheduling semiconductor batch operations. International Journal of Production Research, 33(7), 1849-1869. doi:10.1080/00207549508904785NEALE, J. J., & DUENYAS, I. (2000). Control of manufacturing networks which contain a batch processing machine. IIE Transactions, 32(11), 1027-1041. doi:10.1080/07408170008967459SOLOMON, L., FOWLER, J. W., PFUND, M., & JENSEN, P. H. (2002). THE INCLUSION OF FUTURE ARRIVALS AND DOWNSTREAM SETUPS INTO WAFER FABRICATION BATCH PROCESSING DECISIONS. Journal of Electronics Manufacturing, 11(02), 149-159. doi:10.1142/s0960313102000370Çerekçi, A., & Banerjee, A. (2015). Effect of upstream re-sequencing in controlling cycle time performance of batch processors. Computers & Industrial Engineering, 88, 206-216. doi:10.1016/j.cie.2015.07.005Yeong-Dae, K., Dong-Ho, L., Jung-Ug, K., & Hwan-Kyun, R. (1998). A simulation study on lot release control, mask scheduling, and batch scheduling in semiconductor wafer fabrication facilities. Journal of Manufacturing Systems, 17(2), 107-117. doi:10.1016/s0278-6125(98)80024-1Bahaji, N., & Kuhl, M. E. (2008). A simulation study of new multi-objective composite dispatching rules, CONWIP, and push lot release in semiconductor fabrication. International Journal of Production Research, 46(14), 3801-3824. doi:10.1080/00207540600711879Li, Y., Jiang, Z., & Jia, W. (2013). An integrated release and dispatch policy for semiconductor wafer fabrication. International Journal of Production Research, 52(8), 2275-2292. doi:10.1080/00207543.2013.854938SPEARMAN, M. L., WOODRUFF, D. L., & HOPP, W. J. (1990). CONWIP: a pull alternative to kanban. International Journal of Production Research, 28(5), 879-894. doi:10.1080/00207549008942761Wein, L. M. (1988). Scheduling semiconductor wafer fabrication. IEEE Transactions on Semiconductor Manufacturing, 1(3), 115-130. doi:10.1109/66.4384Glassey, C. R., & Resende, M. G. C. (1988). Closed-loop job release control for VLSI circuit manufacturing. IEEE Transactions on Semiconductor Manufacturing, 1(1), 36-46. doi:10.1109/66.4371Qi, C., Sivakumar, A. I., & Gershwin, S. B. (2008). An efficient new job release control methodology. International Journal of Production Research, 47(3), 703-731. doi:10.1080/00207540701455335Yeong-Dae Kim, Jae-Gon Kim, Bum Choi, & Hyung-Un Kim. (2001). Production scheduling in a semiconductor wafer fabrication facility producing multiple product types with distinct due dates. IEEE Transactions on Robotics and Automation, 17(5), 589-598. doi:10.1109/70.96466

Production Scheduling

Generally speaking, scheduling is the procedure of mapping a set of tasks or jobs (studied objects) to a set of target resources efficiently. More specifically, as a part of a larger planning and scheduling process, production scheduling is essential for the proper functioning of a manufacturing enterprise. This book presents ten chapters divided into five sections. Section 1 discusses rescheduling strategies, policies, and methods for production scheduling. Section 2 presents two chapters about flow shop scheduling. Section 3 describes heuristic and metaheuristic methods for treating the scheduling problem in an efficient manner. In addition, two test cases are presented in Section 4. The first uses simulation, while the second shows a real implementation of a production scheduling system. Finally, Section 5 presents some modeling strategies for building production scheduling systems. This book will be of interest to those working in the decision-making branches of production, in various operational research areas, as well as computational methods design. People from a diverse background ranging from academia and research to those working in industry, can take advantage of this volume

Scheduling revisited workstations in integrated-circuit fabrication

The cost of building new semiconductor wafer fabrication factories has grown rapidly, and a state-of-the-art fab may cost 250 million dollars or more. Obtaining an acceptable return on this investment requires high productivity from the fabrication facilities. This paper describes the Photo Dispatcher system which was developed to make machine-loading recommendations on a set of key fab machines. Dispatching policies that generally perform well in job shops (e.g., Shortest Remaining Processing Time) perform poorly for workstations such as photolithography which are visited several times by the same lot of silicon wafers. The Photo Dispatcher evaluates the history of workloads throughout the fab and identifies bottleneck areas. The scheduler then assigns priorities to lots depending on where they are headed after photolithography. These priorities are designed to avoid starving bottleneck workstations and to give preference to lots that are headed to areas where they can be processed with minimal waiting. Other factors considered by the scheduler to establish priorities are the nearness of a lot to the end of its process flow and the time that the lot has already been waiting in queue. Simulations that model the equipment and products in one of Texas Instrument's wafer fabs show the Photo Dispatcher can produce a 10 percent improvement in the time required to fabricate integrated circuits

Workload control in job shops with re-entrant flows:an assessment by simulation

One of the key functions of Workload Control is order release. Jobs are not released immediately onto the shop floor – they are withheld and selectively released to create a mix of jobs that keeps work-in-process within limits and meet due dates. A recent implementation of Workload Control’s release method highlighted an important issue thus far overlooked by research: How to accommodate re-entrant flows, whereby a station is visited multiple times by the same job? We present the first study to compare the performance of Workload Control both with and without re-entrant flows. Simulation results from a job shop model highlight two important aspects: (i) re-entrant flows increase variability in the work arriving at a station, leading to a direct detrimental effect on performance; (ii) re-entrant flows affect the release decision-making process since the load contribution of all visits by a job to a station has to fit within the norm. Both aspects have implications for practice and our interpretation of previous research since: (i) parameters given for work arriving may significantly differ from those realised; (ii) increased workload contributions at release mean that prior simulations may have been unstable, leading to some jobs never being released

Generic POLCA : a production and materials flow control mechanism for quick response manufacturing

A production and materials flow control mechanism for quick response manufacturing (QRM) is proposed. This is called generic paired-cell overlapping loops of cards with authorization (GPOLCA). It is an adaptation of the POLCA mechanism developed as part of the QRM strategy. GPOLCA implements an input–output control order release strategy based on an inventory of production authorization cards instead of materials. It is best suited for companies that manufacture large variety of products with variable demand. A description of GPOLCA is made together with a comparative study of its performance in relation with other mechanisms namely MRP and POLCA. The results show that GPOLCA attains better performance

Markov Process Modeling of A System Under WIPLOAD Control

This paper analyzes a proposed release controlmethodology, WIPLOAD Control (WIPLCtrl), using a transfer line case modeled by Markov process modeling methodology. The performance of WIPLCtrl is compared with that of CONWIP under 13 system configurations in terms of throughput, average inventory level, as well as average cycle time. As a supplement to the analytical model, a simulation model of the transfer line is used to observe the performance of the release control methodologies on the standard deviation of cycle time. From the analysis, we identify the system configurations in which the advantages of WIPLCtrl could be observed.Singapore-MIT Alliance (SMA

A new perspective on Workload Control by measuring operating performances through an economic valorization

Workload Control (WLC) is a production planning and control system conceived to reduce queuing times of job-shop systems, and to offer a solution to the lead time syndrome; a critical issue that often bewilders make-to-order manufacturers. Nowadays, advantages of WLC are unanimously acknowledged, but real successful stories are still limited. This paper starts from the lack of a consistent way to assess performance of WLC, an important burden for its acceptance in the industry. As researchers often put more focus on the performance measures that better confirm their hypotheses, many measures, related to different WLC features, have emerged over years. However, this excess of measures may even mislead practitioners, in the evaluation of alternative production planning and control systems. To close this gap, we propose quantifying the main benefit of WLC in economic terms, as this is the easiest, and probably only way, to compare different and even conflicting performance measures. Costs and incomes are identified and used to develop an overall economic measure that can be used to evaluate, or even to fine tune, the operating features of WLC. The quality of our approach is finally demonstrated via simulation, considering the 6-machines job-shop scenario typically adopted as benchmark in technical literature