特殊應用積體電路設計公司之晶圓存貨管理研究

A Study of Wafer Inventory Management in Application-specific Integrated Circuit Design House

黃慶良(Ching-Liang Huang)

指導教授 ： 饒忻

中原大學/電機資訊學院/工業與系統工程研究所/碩士(2013年)

https://doi.org/10.6840/cycu201300676

摘要

目前特殊應用積體電路(ASIC)設計市場為一零和式的競爭模式，僅有前幾名可以獲利，市場競爭非常激烈。其生產週期長達3個月，不適當的庫存管理可能導致需求旺盛時無足夠的庫存供給客戶，造成商機的損失；而當需求下滑時，無法掌握其趨勢，造成庫存跌價的損失，反而侵蝕獲利水準。
本研究提出兩種投料改善策略：(1)以原預測計算值再輔以目標庫存差額補償投料(2)依原預測計算值再加上訂單量與到貨量差額補償值計算投料量；另考量以不同時間長短之檢查點與混合前兩項改善策略進行投料，共衍生六種不同之晶圓庫存管理改善方案，以期找出ASIC設計個案公司較佳之晶圓庫存方案。本研究步驟分為三大部分：首先找出ASIC整個供應鏈之特性及個案公司現行生產規劃之情形，接下來以個案公司歷史生產數據及經驗找出影響晶圓庫存成本之問題點並提出相關的改善方向。最後提出具體之改善方案，並將各改善方案試行應用於實例當中。經由推導及實證結果，在同樣之期初庫存、預測值及客戶訂單基準下，特定改善方案對於缺貨量、缺貨頻率及生產管理成本較個案公司原執行方式皆有顯著改善，並能以最小之晶圓庫存管理成本有效提升客戶服務水準。

關鍵字

特殊應用積體電路 ； 晶圓存貨管理

並列摘要

Application-specific Integrated Circuit (ASIC) design houses have an intensive competition. Only the top one or two ASIC design houses can earn profit and possess the most of market in their specific applications. However, as a “fabless” IC design house, most of the production works have to be outsourced to the subcontractors. The lead time of production of the whole semiconductor is 3 months long. An improper wafer inventory management may provide fewer products as the market demand is going up, which results in losing many business opportunities. On the other hand, once the market trend is turning down, the higher inventory has to face a loss of lower price, which can significantly affect profit margin.
This study proposes two improvement strategies for releasing wafer, namely, (1) use the difference between target inventory and current inventory to adjust the value of forecast calculation to release wafers, and (2) use the difference between orders received and wafers received to adjust the value of forecast calculation to release wafers. In addition, we adjust the time of the check point for calculating the compensatory quantity. In total, we propose six improvement methods in order to find a better inventory management method for the case study ASIC design house. This research procedure consists of three phases. First, we explore the distinctive features of the ASIC supply chain and the current planning methods of case company. Then we find out the problems of current planning methods and propose improvement methods based on the company’s history data. Finally, we select the best method for each kind of products, in which the performance indices of inventory shortage quantity, shortage frequency, and production management cost are evaluated. Compared with the original methods used in the case study company, the proposed methods can significantly reduce the company’s wafer inventory loss and increase customer service level.

並列關鍵字

Wafer Inventory Management ； ASIC

參考文獻

1. 金新恩、梁佑任、蔡志弘、李榮貴(2010)，應用限制理論需求拉式庫存管理機制於啤酒遊戲 之研究，元培學報 ，第十七期， 65 ～ 80頁

1. Timm Gudehus,Herbert Kotzab 2007, “Comprehensive Logistics” pp. 290-303.

2. Dellaert, Nico, and Jeunet, Jully, 2003, “Controlling multi-level production in a rolling-schedule environment”. International Journal of Production Economics, Volume: 85, Issue: 1, pp. 113-121.

3. Ryu, S. W. and Lee, K. K., 2003, “A stochastic inventory model of dual sourced supply chain with lead-time reduction”. International Journal of Production Economics, Volume: 81-82, pp. 513-524.

4. Tang, Ou and Robert W. Grubbström , 2003, “The detailed coordination problem in a two-level assembly system with stochastic lead times”. International Journal of Production Economics, Volume: 81-82, pp. 415-429.