無晶圓廠IC設計公司之存貨料帳準確性改善─以A公司為例

Abstract

台灣半導體業發展已近40年，獨特的專業垂直分工體系為全球罕見，包括IC設計公司、光罩製造廠、晶圓代工廠、晶圓測試廠、IC封裝與IC測試廠，其中無晶圓廠(Fabless) IC設計公司的規模僅次於美國。本論文探討某Fabless IC設計公司的存貨不準確問題，該類公司通常外包所有製造生產活動，僅依據市場預測提早2~4個月投單，並同時委外儲存原物料、半成品及成品等。面對消費性市場需求劇烈變動及產品生命週期愈來愈短的特性，企業應透過加強存貨控制與規劃，以減少存貨相關的成本侵蝕企業的獲利水準。 本研究的個案公司每年均會對每家代工廠進行完整的盤點，以確保雙方的料帳一致性，但存貨料帳準確性仍然無法維持。分析影響其存貨不準確的可能原因，包括盤點週期頻率、人工處理、物料領用、退貨、重工、存貨品項數、報表及系統等。考慮改善效益後，針對盤點週期頻率、物料領用及報表問題等提出全面性的改善方案。藉由調整該公司的存貨盤點策略、加強控管內部物料領用程序及運用盤點輔助工具自動化部分工作，以達成研究目標。研究結果發現，本研究所提之方法確實可以有效解決個案公司存貨料帳不準確的問題，同時可促使A公司及其代工廠定期檢視存貨狀況，且透過系統及工具將繁複的工作自動化，有效率地完成存貨管理工作。本研究的成果亦可作為同樣欲提升其料帳準確性的公司，於規劃與評估階段的決策參考。

The semiconductor industry has been growing for 40 years in Taiwan with unique professional vertical disintegrated engineering systems, including IC design, photomask manufacture, foundries, wafer fabrication, wafer probe, IC packaging, and final test. Taiwan’s market domination of the global semiconductor in foundry, assembly and testing sectors is assured. Taiwan has become the second largest base for the Fabless IC design houses in the world. This study explores the inventory management issue between a Fabless IC design house in Taiwan and its subcontractors. Since Fabless IC design houses outsource most of their production and inventory to subcontractors, and the production plan can only be made according to the forecast for the next 2 to 4 months. Facing the drastic changes in digital consumer market and shorter product life cycle, Fabless IC design houses have to pay attention to their inventory might to prevent from stock related loss. In this study, each subcontractor is expected to have a complete physical stock accounting annually for inventory consistency. However, the inventory account usually does not agree with the physical count. To analyse the possible causes of the inventory inaccuracy, the causes might include the frequency of cycle counting, manual processing, the process of material application, return material application, reworking, number of items, cycle count reports and system issues etc. The frequency of cycle counting, the process of material application and cycle count reports are selected for improving considering the benefit of improvement. It aims to solve the inventory inaccuracy issues by improving the strategy of inventory cycle counting, the process of material application and building a tool for the inventory data analysis. The result showed that the proposed method can solve the issues of inventory inaccuracy for the company. Furthermore, both the company and its subcontractors can review the inventory regularly and efficiently. The results of this study may also serve as the company also wants to improve the accuracy of the material posted in the planning and evaluation stage of the decision-making reference. Finally, the suggestions based on the research results and findings are served as a reference for the company that wants to improve the inventory accuracy in the planning phase.