5.1 研究的結論
對半導體晶圓廠來說,傳輸整合步進機是單價最昂貴的機台,因此成為工廠之瓶 頸機台,故傳輸整合步進機之排程之議題相當重要,然而在過去的研究上,多在滿批 量之情境作探討,因此往往將其視為一個機台,而未了解該機台之內部結構,可視為 一種流程式生產型態;隨著新製程和新產品之導入,晶圓廠出現小批量之情境,使得 傳輸整合步進機會因為機台結構之設計,造成產能之損失,若一間晶圓廠綜合了新製 程和新產品之情況,小批量之情境將漸趨增加,也就意謂著產能損失之發生頻率將隨 之增加,而過去對於小批量情境之傳輸整合步進機的排程研究僅有Wu & Chiou(2009)
和Wu , Lu , & Chiou (2009)作探討。
Wu & Chiou(2009)所探討的情境為單機和多機,皆未考慮 Job-family 之情況,
即未將光罩之限制納入考量,其透過七種演算法搭配單獨式派工法則進行求解; Wu , Lu , & Chiou (2009)為研究單機且考慮 Job-family 之情境,運用基因演算法搭配家族式 派工法則進行求解。然而實際的半導體晶圓廠存在著多機和 Job-family 之情境,故本 研究所提出之啟發式演算法搭配家族式派工法則可以在短時間內,得到一組近似最佳 解(工件加工順序),使得平均產出最大。而在經過大量的實驗後,可以將本研究的結 論歸納如下:
z 當欲排序的工件數目越多及排序工件的良率越低,應使用演算法結合家族式 派工法則。
z 在處理多個步進機的排序問題,本研究提出新的染色體設計,可在不增加染 色體的大小情況下,減少解題空間,使得解題品質及求解的速度獲得改善。
z mGA-Tabu-F 演算法的運算品質績效在大部份的情境下,比其他演算法結合 家族式派工法則有更優異的績效表現。
5.2 未來研究方向
本研究的未來研究方向,整理如下列數項:
1. 本研究以啟發示演算法 (meta-heuristic algorithm)找出近似解,因此未來可以 嘗試運用其他的方法求解,如:混合整數規劃、動態規劃或分枝界限法等。
2. 本研究主要考慮以最大產出為主,但對於部分代工晶圓廠之生產目標則主要 以客戶達交率為目標,故可以遲交為目標式作為探討。
3. 由於在小批量情境下,發生產能閒置問題的主要原因為 Port 數量不足,故未 來可針對Port 數量作研究,如:探討 Port 數量應設定多少,方可使傳輸整合 步進機不會發生產能損失的問題。
4. 發展新的演算法。
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