晶圓製造廠生產批量設定之研究

Abstract

半導體產業競爭日益激烈，顧客服務提昇對晶圓代工廠尤其重要，如 何縮短其生產前置時間一直是重要的生產管理課題，市場不景氣時，縮減 晶圓批量應是一個好的策略，但晶圓製造廠以往受限於機台及製程因素， 無法以JIT 的理念運用批量縮減以縮小生產前置時間；然而因技術的進步 ，使得目前機台及製程因素的限制已經逐漸消失，所以晶圓批量設定成為 另一條改善生產前置時間的途徑。 不同於大部份批量設定相關文獻之 成本衡量方式，吾人所建立的架構探討晶圓批量大小與生產前置時間之關 係，期望充分利用晶圓製造廠多餘產能，並配合晶圓廠其他生產因子之限 制或影響條件下，達成下列主要成果（1）驗證晶圓批量縮減之效果，（2 ）決定一最佳晶圓批量及敏感度分析，（3）WIP及爐管派工策略對批量設 定效果之影響，以極小化生產前置時間，進而提昇顧客服務水準。 To gain the competitive advantage, cycle time reduction is one of the most critical issues in wafer fabrication (especiallyin wafer foundries). Due to the recession of semiconductorindustry in 1996, cycle time reduction to provide better customerservice becomes an even crucial issue for wafer foundries.It is commonly accepted that lot size reduction can shorten roduction cycle time. Due to constraints of conventional equipmentand technology, this concept did not widely applied in waferfabrication. However, because the progress of advanced technologies,restrictions of equipment and processes have been lessened in recent years. Wafer lot sizing policy thus becomes an alternativeand important method in reducing cycle time and deserves an extensive study. Therefore, instead of concentrating on the development of better scheduling methods or releasing and dispatching policies to reducecycle time in wafer fabrication, this research intents to achievethis goal through wafer lot sizing policies in which the bottleneckresource must be better utilized while non-bottleneck resources payallowable penalties in setup time and surplus capacity. This studyfirst analyzes the impact as well as the constraints of lot sizingpolicy on cycle time reduction for wafer fabrication. Global lot sizes at different utilization levels of critical equipment are suggested. The corresponding sensitivity analysis are made. Systemperformance influenced by batch equipment dispatching rules and the corresponding lot size policies are also studies.