半導體廠測試區生產規劃模式之構建

Abstract

本文所欲探討的生產工廠為半導體製程後段(back-end)的測試區，其生產 規劃的首要目標為滿足顧客交期，有別於晶圓製造廠以最大產出為以生產 排程的目標。測試區的待測產品為前一製程階段之晶圓成品及晶粒封裝廠 的已封裝晶粒，在半導體廠的封裝作業依賴外包，而晶圓生產週期較長及 製程複雜等因素下，使得待測產品的到達為動態性方式。另外由於機台設 置時間相對於單位測試時間相當大的情形下，現場工件的測試一般皆以批 量方式進行，而測試批量的規劃則受限於工件動態性到達的情況。本研究 在規劃測試批量時係以滿足顧客交期為主要目標，降低設置時間及提高機 台利用率為次要目標。本文以階層式的方式來建立一短期的生產規劃架構 ，架構中包含短期主生產排程規劃、測試批量決定與排程規劃，以及現場 機台派工三個功能模組，以此來含蓋測試區必須考量的生產因素。一般晶 圓廠均擁有一固定時間幅度的準確輸出資料可供製程下游使用，故本文各 個模組將利用這些資料以前瞻性(lookahead )的方式，根據未來各批量到 貨時點分布資料，在滿足顧客交期的限制下，規劃出一節省機器設置時間 ，提高機器利用率的合理排程。 The semiconductor testing is the final stage of semiconductor manufacturing process. The production objective of testing differs from wafer fabrication in that the emphasis is on metting due dates rather than on maintaining high throughput. The input materials of testing are wafer products and the packaged devices which are output of wafer fabrication and assembly/packaging factory respectively. Usually, the assembly/ packaging operations are subcontracted. Whereas, wafer fabrication is the previous stage of semiconductor testing. Wafer fabrication needs complicated process steps and takes the long cycle time. The arrival pattern of jobs is thus dynamic and nongomgenous. The setup time of testing machine is very large compared to its unit processing time. Hence products flow through the testing facility in batches. The batch size is constrained by dynamic jobs arrival time. The batch size planning thus is the main work of this research. The main objective is meeting due dates while the secondary objective is reducing setup times so as to increase machine utilization rates. The production planning system for semiconductor testing is proposed. This system consists of the master production schedule module, batch size/schedule planning module, and shop floor dispatching module. All the factors which must be considered in the production planning for the testing area shall be considered in one of the three modules. Because wafer fabrication and assembly/packaging factories generally can supply confirmable production information for the coming time interval. These information will be used to plan a feasible batch size and lot release time. These informaion will be used to plan a feasible batch size and lot release time. The corresponding schedule then can be constructed. With the help of the lookahead method, the reducing machine setup time while considering the satisfication of orders' due dates can be achieved.