晶圓廠黃光區考慮重工情況下派工法則構建

Abstract

半導體晶圓製造為我國重點產業，亦是我國最具競爭力的產業。一片晶圓製造過程常需經過300~400道的製程步驟。冗長又複雜的製程步驟，又常因現製現場的不確定因素，如緊急工單的插入、不良圓重工、機臺當機等，造成晶圓廠生管作業困難。 本研究以半導體製造廠生產活動控制的派工作業為研究主題。由於晶圓製造的物料成本昂貴，如果製造過程中有不良品產生，常以重工的方式重製不良品。然而進行不良晶圓重工作業，會增加晶圓廠內在製品數量，並增加重工晶圓批量的流程時間。晶圓製造廠瓶頸限制所在為黃光區，故針對黃光區派工作業，考慮兩種不同重工策略：(1)母批在原地等待子批，及(2)母批在後續製程等待子批，發展一考慮重工作業的派工法則。經由模擬的驗證，本研究發展之派工法則能平順晶圓廠內物流，降低重工批量對生產系統的負荷。

Semiconductor industry is one of the most leading edge industry in Taiwan. Generally, the process flow of wafer fabrication may contain 300~400 steps or operations. It is complicated and filled with uncertainties, like hot order, rework lot, machine down and so on. Therefore, the production planning and control in wafer fabrication is an tough issue. In wafer fabrication, the material cost of wafer is expensive. To reduce the cost and increase the yield of wafer fabrication, it is imperative to repair the defective wafers produced during the manufacturing process. However, repairing defected wafer will not only increase the WIP level but the flow time of rework lots as well. In wafer FAB, rework of wafer is only allowed in the photolithography area, where is the bottleneck of the entire wafer FAB. The objective of this research is to develop a dispatching rule concerned with rework for photolithography area. The dispatching rule considers two kinds of rework strategies: (1) hold the mother lot while the child lot is reworked and (2) process mother lot while the child lot is reworked, and complete the lot in latter process. We conduct experimental simulation and the results indicate that the dispatching strategy developed in this research can improve the production performance of wafer fabrication factories.