以晶圓再生之供應商決策分析對擋控片的成本改善方案-以甲公司為例

Abstract

在半導體業中，擋控片的成本管理一直是管理階層所關注的項目。擋控片的成本由二個項目所構成- 全新擋控片和晶圓再生片，全新擋控片和晶圓再生片的成本有相關性，通常晶圓再生片的使用量愈多，會造成全新擋控片的使用量變少，因此晶圓再生之供應商的選擇對於擋控片的成本影響就很重要了。鑑於有些半導體公司並未對晶圓再生過程中所衍生的相關成本做全面性的分析，導致擋控片的成本上升，本文想利用對於晶圓再生供應商做全面性的成本分析，並對成本分析的結果做供應商的選擇，因此對擋控片的成本做改善。 本研究提出一套方法估算晶圓再生片的成本，藉以選擇適合之晶圓再生供應商。本研究利用個案公司內部之企業資源規劃系統(ERP, Enterprise Resource Planning system)所儲存的歷史資料，來估算晶圓再生供應商在處理該公司擋控片的相關成本，經由估算結果選擇成本較低的二個供應商來處理個案公司的晶圓再生片。本研究中的個案公司在以本研究之建議方法選擇晶圓再生供應商後，在整體擋控片方面的成本有顯著下降，結果證明對評估晶圓再生廠的成本不應只考慮表面成本-晶圓再生的處理價，應考慮各家廠商在晶圓再生過程會衍生的各項成本，以期獲得較佳的供應商決策。

Non-productive wafer expenditure plays an important role for material cost in semi-conductor plant . It is composed of 2 sources - brand new dummy wafer and reclaim wafer . brand new dummy wafer is raw wafer which is not used ever by production line . When brand new dummy wafer is used in production line for several times , the condition for it will become worse and can not conform with criterion for re-use . Then , it will be sent to reclaiming process for wafer surface treatment ,called reclaim process .Most of semi-conductor plants outsource this process to third party called reclaim house .After reclaiming of non-productive wafer , it will be able to reuse in production line with the same quality as brand new dummy wafer . More non-productive wafers successfully reclaimed from reclaim house will reduce usage cost of brand new dummy wafer . Hence,performance for reclaim house will be key factor to influence the expenditure of whole non-productive wafer expenditure ,because good performance reclaim house will create cost benefit to whole non-productive wafer cost and reduce cost of non-productive wafer . In light of lack of an effective cost estimation model for a specific reclaim house of the surveyed semi-conductor plant to determine whether this reclaim house provides a lower cost reclaim operation than others, this study intends to develop a simple and effective method to estimate the whole cost incurred by operations of a reclaim house instead of only using purchase cost to judge a reclaim house's cost performance .This model includes purchase cost , shortage cost ,inventory-holding cost and transportation cost to estimate how much a reclaim house costs for its reclaim procedure. The basis for this model is historical data collected from ERP system, Enterprise resource planning system .The result of this study shows this cost estimation model effective to reduce the whole non-productive cost. Thus ,it can serve a method for a purchaser or material supply planner to estimate a reclaim house with a real lower cost for its reclaiming operations.