本研究提出一個信心指標的機制與方法，藉以評估虛擬量測系統的信心度。該機制與方法藉由分析生產設備的製程參數資料，計算出一個介於零與壹之間的信心值，以判斷虛擬量測系統推估結果是否可以被信賴。本研究亦提出計算信心指標門檻值的方法，若信心指標值大於此門檻時，代表該虛擬量測之推估結果可以被信賴；反之，則代表該推估結果的可信度較低，需要進一步確認。除上述信心指標外，本研究亦提出製程參數相似度指標，該指標之定義為目前輸入之製程參數與推估模型用以訓練建模之所有參數的相似程度。而參數相似度指標可分為: 整體相似度指標及個體相似性指標，此相似度指標將被用以輔助信心指標之判斷及找尋發生異常的製程參數。因此，可解決虛擬量測系統可製造性的問題。本論文應用本信心度評估機制與方法，並以300-mm半導體晶圓廠之蝕刻機台製程為例，實驗結果證明此方法適用於具有虛擬量測系統之生產設備 (如半導體與TFT-LCD廠之生產製程設備的虛擬量測系統)。

This work proposes a novel method for evaluating the reliability of a virtual metrology system (VMS). The proposed method calculates a reliance index (RI) value between 0 and 1 by analyzing the process data of production equipment to determine the reliability of the virtual metrology results. This method also defines an RI threshold. If an RI value exceeds the threshold, the conjecture result is reliable; otherwise, the conjecture result needs to be further examined. Besides the RI, the method also proposes process data similarity indexes (SIs). The SIs are defined to assess the degree of similarity between the input set of process data and those historical sets of process data used to establish the conjecture model. The proposed method includes two types of SIs: global similarity index (GSI) and individual similarity index (ISI). Both GSI and ISI are applied to assist the RI in gauging the reliance level and locating the key parameter(s) that cause major deviation, thus resolving the VMS manufacturability problem. An illustrative example involving 300-mm semiconductor foundry etching equipment in Taiwan is presented. Experimental results demonstrate that the proposed method is applicable to the VMS of production equipment (such as that for semiconductor and TFT-LCD).

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