晶圓製造廠生產績效指標關係模式之構建

Abstract

由於系統限制資源乃為決定系統生產績效的主要因素，因此妥善利用 限制資源產能為生產規劃的主要理念；但充分利用限制資源將可能增加現 場在製品量，此與極小化在製品量及極小化生產週期之目標相互衝突，因 此如何權衡生產績效指標，如在製品量、生產流動時間與產出量乃為生產 規劃的主要重點。 目前與晶圓製造生產規劃及排程相關的文獻，大多 探討生產控制因子對生產績效指標的影響，並未對影響生產績效的因素以 及績效指標間的消長、利害關係作分析。而本研究主要的目的，在於構建 晶圓製造廠生產績效指標間的關係模式，以期使決策者能在各種不同的生 產控制策略下訂定各項的生產目標。 本論文主要在探討系統總產出、 生產週期時間、系統在製品量以及瓶頸機台利用率四個績效指標之間的關 係。藉由生產績效指標的分析、生產系統的模擬、模擬資料的迴歸分析以 及決策分析的程序，來構建生產績效指標間的關係模式。利用此關係模式 ，決策者可決定可行的生產績效值並且選擇適當的生產控制策略以利生產 目標的達成。本實例僅以三種派工法則及0%緊急批量的條件下做說明，決 策者亦可利用本論文所提之流程，針對各種不同生產規劃與控制策略的組 合，進行敏感度分析，並可藉此了解各績效指標在不同的生產規劃與控制 策略組合下的表現。 One of the primary goals of the production planning in wafer fabrication is to fully utilize the capacity of the constraint resource to maximize the throughput. However, the increase of the capacity utilization may result in high work-in-process( WIP), long cycle time, and so on. How to properly manage the trade-off among different or conflict production performance indices is a crucial issue in this industry. The major objective of this research is to develop a procedure to construct a relationship model for production performance indices so that variant production targets can be derived under different system settings. In this study, commonly used production performance indices in wafer fabrication are surveyed and analyzed first and four major production performance indices including total throughput, cycletime, WIP, and utilization of bottleneck equipment are then picked. A simulation model with real world data extruded from a wafer fab in the Science-Based Industrial Park in Taiwan is employed. A regression analysis is employed to examine the relationships among these four indices. The relationship can be applied to determine the most feasible combination of performance measures under a given environment and can be used to select the proper control strategy so that intended target performance measures can be reached in a specific system scenario. Results of illustration are presented and analyses of results are given.