限制理論緩衝管理應用於半導體封裝訂單管理之研究

Abstract

半導體產業中，IC設計產業算是比較特別的一環，由於大部分IC設計公司本身並不從事製造工作，而將製造工作以外包代工方式完成。也因為此種外包代工特性，所以在供應商關係及訂單管理上更顯重要。本研究是利用限制理論(TOC)裡的簡化型限制驅導排程模型(Simplified Drum-Buffer-Rope, S-DBR)及關鍵鏈專案管理(Critical Chain Project Management, CCPM) 方法，加以運用到IC設計公司封裝訂單的交期管理，透過有效的緩衝管理(Buffer Management, BM)方式，成功地提高封裝訂單的達交率(Due Date Performance, DDP)。透過文獻探討與實作分析，類似封裝訂單的High touch time加工(Touch time占Lead time比例大於20%) 在利用TOC S-DBR及緩衝管理(Buffer Management)保護交期的作法應該更靈敏地反應訂單可能的延誤，提早採取行動以避免延誤。本研究也結合了訂單與封裝廠即時的在途資訊(WIP Report)站點回報，取代了CCPM完工回報(check point) 的作法。再透過緩衝使用狀況的設定，提供了管理者對於訂單狀態較明確的行動建議(如：趕貨區、監控區、忽略區)，從而有效地提升了管理績效。以實施緩衝管理前後之達交率作比較，訂單達交率從平均約65.3%，大幅改善到實施後的平均90.7%。也證實了改良式的緩衝管理對High touch-time封裝訂單提升達交率有相當大的幫助。

IC design house is a special part of semiconductor industry. Most of IC design house don’t involve in manufacturing, they finish their products via outsourcing. Because of this outsourcing characteristics, supply chain and order management become very important to design houses. We take advantage of S-DBR (Simplified Drum-Buffer-Rope) and CCPM (Critical Chain Project Management) methods of TOC (Theory of Constraint) in this study to improve DDP (Due Date Performance) of assembly order. Trough literature review and case study, we introduce new method to assembly order management (touch-time is more than 20% of lead-time) to response potential delay quickly and sensitively. We also replace the checking point feedback by real-time WIP report to get the latest status of assembly orders. By use of the real-time WIP report and buffer consumption setup, we can provide a clear action suggestion (ex. Expediting, Monitor, Ignore) to order manager to enhance the DDP. After the adoption of new method, the DDP raise up from 65.3% to 90.7% significantly. This conclusion also proves the new buffer management method is beneficial in High touch-time environment (such as semiconductor assembly).