考慮晶圓製造廠整廠績效之整合式生產控制方法

Abstract

由於晶圓製造廠的設備投資龐大及運作成本高昂，使得追求所有設備的高利用率與其 他績效指標如交期、產出、WIP及週期時間等同受重視。然而其間存在著基本的矛盾：所 有設備的高利用率即代表著WIP及週期時間無法降低，也無助於產出率的提升；反而造成 系統的不穩定（如某機台當機即可能造成在製品的急速增加）。因此，本文認為設備的利 用率高低應該是根據需要而定的。維持瓶頸機台生產順暢與高利用率，可使產出最大化； 而非瓶頸機台則以配合瓶頸機台生產為主，以使瓶頸不缺料為首要目標，不盲目的追求機 台利用率，則有助於產出及維持低的WIP與週期時間。此外，投料方式對系統績效也有顯 著的影響。因此，本文提出以限制理論為基礎的整合式生產控制模式，此模式結合以瓶頸 資源為主的投料計畫、避免暫時性瓶頸發生的修正方法、緩衝管理及將瓶頸與非瓶頸資源 分別考慮的派工法則。經由模擬驗證顯示，本研究不僅使限制資源充分利用，同時在平均 產出水準、平均生產週期時間及平均在製品存貨上，都有良好的績效表現。

Seeing that there are a enormous amount facilities investment and a high operation capital in wafer fabrication factory. To seek fully utilized of facilities is as important as other production performance measures like due-date, out rate, WIP level, and cycle time. However, there is essential self-contradictory between them like full utilization of all facilities implies without reducing WIP level and cycle time. It is of no advantage to promote out rate and make the system unstable. Therefore, this paper thinks that the level of all facilities' utilization is decided by demands. To keep production smooth and full utilization of the bottleneck machines will make output maximum. Non-bottleneck machines focus on operating in coordination with bottleneck machines and make sure that they have enough materials to avoid them idle. It's good for out rate and keeping WIP and cycle time in low level without blindly seeking facilities fully utilized. Furthermore, it also has an outstanding influence in system performance by order releasing rule. Therefore, this paper brings up an integrated production control method that is based on Theory of Constraint. This method combines releasing plan based on bottleneck, the method of avoiding temporary bottleneck occurring, buffer management, and dispatching rule which is consideration bottleneck and non bottleneck. From the experimental results, not only the capacity constraint resource is fully utilized, but also it has high performance in following measures: average out rate, average cycle time, and average WIP level when applying the developed method.