Application of FMEA and KT Method on Fab Daily Management

失效模式效應分析與KT手法於半導體晶圓代工廠日常管理之應用

劉鐵(Tie Liu) ； 林啓良(Chi-Liang Lin) ； 劉智強(Johnson Liu)

《品質學報》 15卷6期 (2008/12) Pp. 399-407

摘要

由於現代半導體晶圓代工廠的製造過程非常複雜，加上高額的投資成本，如何透過有效的日常管理，以確保工廠順利營運，是極其重要的課題。在每天的日常管理中，工程師經常會碰到高風險的緊急日管問題。針對這類問題，本論文提出一種新的應用手法，整合失效模式效應分析(FMEA)與KT手法，來協助工程師有效而快速地處理緊急日管問題。該應用手法基本上遵循品管改善流程(QC story)的步驟。首先是定義問題，然後是進行現況掌握與現況分析，接著根據既有的FMEA資料庫，界定出針對特定失效模式的失效原因，再利用KT手法收歛到最可能的原因。我們主要是利用KT手法中的3W1H（何物、何處、何時、何量），以及IS/IS NOT（是／不是）來分析各種可能原因的可能性。並進一步透過可能性、可行性與成本需求性的討論，安排出各種可能原因的優先順序，再從中選取第一名或前三名優先進行真因驗證。驗證的方式必須以結構化的方式來進行，包括懷疑的對象、驗證的對策、收集的證據、以及得到的結論，並以失效機制分析進行綜合佐證。接著，再針對該特定的失效原因與失效模式，利用FMEA方法計算其風險優先係數(RPN)，然後再根據SOD（嚴重度、發生度、檢測度）分析，提出建議改善對策以降低其RPN。最終不僅解決該問題；同時也降低了風險。最後，我們將這個新的構想，應用在半導體晶圓代工廠一個實際的日管問題，亦即高電流離子植入製程管制監測異常問題。透過該真實案例的應用與說明，證實本文成功地整合FMEA與KT手法，並可推廣應用至半導體晶圓代工廠其他的日管問題。

關鍵字

失效模式效應分析 ； KT手法 ； 品管改善流程 ； 日常管理 ； 風險評估

並列摘要

Due to the complicated process and huge cost of a modern semiconductor wafer foundry fab, how to ensure its smooth operation through daily management is very important. In daily management, fab engineers often encounter risky and urgent issues. In this paper, we have introduced a new application to integrate FMEA (failure mode and effect analysis) and Kepner-Tregoe (KT) method to help engineers handle urgent daily management issues of a fab in an efficient and effective manner. The application basically follows the steps of QC story. After problem was defined, background and status analysis were conducted. The possible causes for the certain failure mode with respect to the problem were identified from the established FMEA database. Based on the possible causes from the given FMEA table, we used KT method to narrow down the most probable cause. The possibilities of all possible causes were analyzed by using 3W1H (What, Where, When and How Many) together with ”IS” and ”IS NOT” method. The priorities of possible causes were further discussed by considering possibility, feasibility, and cost. Then we choose the top one or three to verify first based on the final priority. The root cause verification is conducted in a structure way including suspect, action, evidence and conclusion, and further explained by failure mechanism analysis. FMEA method was then used to calculate Risk Priority Number (RPN) of the failure mode, and the recommended actions were proposed based on SOD analysis (severity, occurrence and detection) to reduce the RPN. Finally, not only the issue has been solved, but also the risk has been reduced. Furthermore, we apply such a new idea to handle an urgent daily management case in a fab, which is a PCM (Process Control Monitor) test abnormal issue caused by High Current (HI) implanter. From the real case application, it is proved that FMEA and KT method have been integrated successfully. This application has great potential to extend to other complicated and urgent fab daily management issues.

並列關鍵字

FMEA ； KT method ； QC story ； daily management ； risk assessment

參考文獻

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