考量價格折扣情境下半導體後段一元化代工服務之生產規劃模式建構

Abstract

由晶圓製造業者所主導之「半導體後段一元化代工服務(Semiconductor Backend Turnkey Service; SBTS)」可提供IC 設計公司從晶圓製造、晶圓針測、晶圓封裝到最終測試的全套代工服務。為提供優質的服務並提升獲利空間，晶圓製造業者須考量後段代工廠之生產能力，妥善進行中期、短期生產規劃，期以最小成本執行一元化代工服務。 承上所述，本文建構一「半導體後段一元化代工服務之生產規劃模式」，此模式分為「產量配置模組」與「訂單分配模組」。「產量配置模組」為中期規劃，分兩階段各別建構整數規劃模式來求解，第一階段考量訂單之預測需求、代工廠商之產能限制及數量折扣資訊，求解最小總產量配置成本，第二階段以第一階段之結果為參考依據，在晶圓製造業者允許之成本變動範圍內，進一步將相鄰製程能否接續加工之製程資訊納入考量，以最大化代工廠商相鄰製程可連續代工之數量為目標，求解每月各代工廠商各製程規格之預定配置量及外包單價。「訂單分配模組」為短期規劃，承接「產量配置模組」之規劃結果，考量來到訂單之各項需求、代工廠商執行各式代工方案所需之生產週期時間，以最小訂單分配成本為目標，設計整數規劃模式求解每日各代工廠商以各式代工方案加工各訂單各製程規格之數量，使允諾之訂單皆能如期如量地達交。 經由案例分析結果指出，若晶圓製造業者在執行產量配置規劃時，即同時考量數量折扣資訊及相鄰製程能否接續加工之製程資訊，則不論在產量配置階段或訂單分配階段皆有其成本效益。

The Semicondutor Backend Turnkey Service (SBTS), implemented by wafer fabricators, provides IC designer the whole outsourcing service package, including wafer manufacturing, circuit probing testing, integrated circuit (IC) assembly, and final testing. In order to provide high quality SBTS and improve profit, wafer fabricators need to execute medium term and short term production planning with considerations of the capability of backend outsourcing firms for implementing SBTS with minimum cost. This thesis proposed a production planning system for SBTS, which includes capacity allocation module and order allocation module. The capacity allocation module completes the medium term planning through two-stage integer programming models. The first stage solves minimal capacity allocation cost with considerations of demand forecast, the capacity limit and quantity discount information of each outsourcing firm. Based on the result of fist stage, the second stage considers the availability of consecutive-processing, and solves the maximization of the consecutive-processing amount of all outsourcing firms. The result of second stage includes the outsourcing price and the corresponding amount booked from each outsourcing firm. The order allocation module is designed for short term planning. Based on the result of capacity allocation planning, order allocation module constructs the integer programming model, which considers the requests and due dates of all orders, to assign SBTS orders to appropriate outsourcing firms with minimum order allocation cost. According to the result of cases analysis, if wafer fabricators fully consider the information about quantity discount and about the availability of consecutive-processing when making capacity allocation plan, then there is undeniable cost benefit at capacity allocation and order allocation.