晶圓製造廠黃光區派工法則之探討

Abstract

半導體晶圓製造為目前國內最具競爭力之產業，然而由於晶圓製造本 身複雜之製程特性及機台特性，以致造成其在生產管理上的困難。目前與 晶圓製造生產排程相關的文獻，較少針對派工法則做詳細的探討，然而現 場卻亟需要派工之生產決策。 根據限制理論所述， 限制資源為決定系統生產績效之主要因素。由於晶圓製造廠的黃光區可謂 整個晶圓製造的物流配送中心，且常為晶圓製造廠的瓶頸限制所在，故本 研究主要即針對黃光區，在充分考量機台加工特性、光罩管理、平衡產出 、等候時間限制、緊急批及設備當機與維修保養等因素下，發展一套通用 的派工模式－ PADR ，並配合爐管區及離子植入區具特殊加工特性機台之 適當派工法則，以有效平衡系統工作負荷，降低生產週期時間、重加工、 報廢及在製品存貨，並期能提高晶圓廠整體的產出。本研究同時利用模擬 及統計檢定，探討黃光區機台派工演算法各權重因子在不同水準下配合 FW 及 UL 兩種投片法則對黃光區及晶圓廠整體績效指標之影響，並歸納 出黃光區之基本派工通則。由模擬結果可知 PADR 相較於 FIFO 及 SPT 有較佳的績效表現， 顯示本研究利用權重與門檻值的觀念將各影響因子 在派工法則中作一整體的考量來指定加工優序為一可行且有效的方法。同 時，投片法則中以控制系統在製品量於一合理水準之 FW 投片法則在系統 各方面的績效表現皆優於 UL 投片法則。 The major objective of this research is to develop a general dispatchingmodel for the photolithography area, bottleneck area, in the wafer fabricationfactory. This research first analyzes the manufacturing process and machinecharacteristics in wafer fabrication to find out the important factors whichinfluence on the performance the most in the photolithography area as well asthe entire factory. By carefully considering these factors, a dispatchingmodel, PADR, for machines in the photolithography area is developed. In this research, an AUTOSCHED simulation model for a real world factory isconstructed and the corresponding statistical hypotheses testing is designedso that the significance of the above factors to the system performance can beanalyzed and finally different dispatching strategies under different mixed ofsystem properties for the photolithography area can be derived. The simulationresults indicate that PADR can effectively balance load, reduce average cycletime and waiting time, and increase throughput rate. Also, larger improvementscome from input contorl policy than from dispatching rule, in particular, FW(Fixed-WIP) provides improved performance over UL(Uniform-Loading) input.