晶圓製造廠目標導向型生產活動控制系統之設計

Abstract

因應晶圓製造市場競爭激烈之情況，本文立處於"客戶導向型"生產製造環境下，進行一目標導向型生產活動控制系統之設計。該系統除需面臨原有製造現場既存之不確定因素外，尚需克服因客戶臨時性下單、換單與工單停滯所帶來之衝擊；另外，為確保"客戶導向"之落實與維持產出、週期時間與達交績效之穩健性，於設計系統控制機制的同時，亦針對各項目標加以監控，以確保目標之達成。除前述問題外，本文並突破工作站暫存區無容量限制之傳統假設，使其立論基礎更切合實務。 目標導向型生產活動控制系統，包括：投料反應機制、派工決策機制與目標監控系統。其中，投料與派工機制以負荷型雙界法(load-oriented two-boundary)為主軸，此法係由修正雙界法(TB+)結合負荷導向工單製造法(LOMC)之理念，以實際負荷觀取代原始TB+實體在製品觀之作法後所衍生；而目標監控系統則是以促使目標之達成為標的，其子機制與個別目標如下：交期達成度監控係以掌控工單交期為目的；關鍵工作站現況監控則以監控關鍵工作站之負荷狀況與防止瓶頸缺料為使命；產線平衡監控期能促使監控單位之實際負荷愈趨近於規劃負荷；暫存區容量監控則著眼於防止工作站擁塞上。 經實例驗証顯示：負荷型雙界法確實能彌補TB+以實體在製品量設定門檻之缺失，其成效反應於降低週期時間標準差與全距之績效上；而目標監控系統亦能於產出達規劃目標之前提下，有效避免暫存區擁塞情況，並持續改善週期時間績效與達交績效，此情況實能說明本文所設計之目標導向型生產活動控制系統具備完整應用性。

In the highly competitive environment, this thesis proceeds to design the target-oriented production activity control system (TOPAC) for the customer-oriented wafer fabrication. On the assumption that each stocker has limited capacity, differing from tradition, this system not only has to handle the uncertain events (machine down, PM), but also carries the impact from customer's casual demands (order trade-off, lot hold). Besides, in order to success in customer-oriented production, TOPAC also focuses on achieving such performance targets as throughput, cycle time, and delivery. The TOPAC consists of order release mechanism, dispatching mechanism, and target monitor system. Order release mechanism and dispatching mechanism are executed basing on the developing of the load-oriented two-boundary control (LOTB). The LOTB applies the idea of the revised two-boundary (TB+) and load-oriented manufacturing control (LOMC)；however, the physical WIP threshold of TB+ is replaced with load threshold. Target monitor system, designed for achieving targets, has four subsystems with individual goal as follows: due-date monitor for order delivery, critical-resource monitor for checking critical resource's load state and avoiding bottleneck starvation, line-balance monitor for keeping each layer load close to the corresponding target, stocker-space monitor for preventing stockers from burst. The case study shows that LOTB can reduce standard deviation and the range of product cycle time, which results from the WIP measuring in load so as to offset the weakness of using physical WIP level in TB+. Additionally, target monitor system also achieves the throughput targets with less blocks, shorter cycle time and better delivery performance. Thus, the designed TOPAC is applicable in customer-oriented wafer fabrication.