| Summary: | 碩士 === 國立交通大學 === 工業工程與管理系 === 87 === Memory and foundry are the two major product areas of Taiwan IC industry. However, owing to the overcapacity and decreasing price in DRAM business, many memory venders face the pressure to readjust their business focus. To lower the risks, some of them try to introduce the foundry business. When a wafer fabrication factory combines memory business and foundry business, it may produce products under Make-to-order (MTO) and Make-to-stock (MTS) hybrid production environment. Since MTS and MTO have many differences in production planning and control, a manufacturer in hybrid production environment must consider the differences and try their best to manage their production performance, such as the due date performance of MTO products and throughput rate of MTS products.
The objective of this research is to develop an production activity control (PAC) method for wafer fabrication factories in hybrid production environment. The primary consideration of this paper is the due date performance of MTO products, then take maximization of system throughput and smooth throughput of MTS products as secondary consideration. This study construct a PAC method based on the concept of Theory of Constraint, workload control and capacity fill-up to improve overall performance in hybrid production environment. The release method first decides the release schedule of MTO products in consideration of their due date, then apply appropriate MTS products to fill up remained capacity, to ensure on time delivery of MTO products and maximize system throughput. As for dispatch rule, this method monitors progress of MTO products to avoid tardiness, and monitor WIP of MTS products at each stage in bottleneck and capacity constraint workstation to ensure smooth production of MTS products. From the experimental results, not only a lower WIP and higher throughput was obtained, but also due date performance of MTO products was improved. Concerning MTS products, the throughput rate and its variance was controlled effectively while applied the proposed WIP monitor and control mechanism.
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