等候時間之產能規劃探討 -以P公司擴散生產區為例

Abstract

晶圓廠在建廠初期就已經決定產能規模，並依此決定產能規劃(Capacity Plan)、機台配置(LAYOUT)，根據產能規劃，可推算各產品的生產週期，並決定每一道製程的生產時間和標準等候時間，但隨著產品世代的轉變，製程的微縮，為了讓固定的晶圓裡放入更多的電路或者提高製程良率和品質，產品負責人會在主要製程間加上等候時間的限制。 但本研究發現當製程緊縮等候時間限制小於當初規劃產能的標準等待時間時，就可能會造成產能低估，無形中造成生產加工時間的拉長、生產週期及成本的增加，這些都是舊的產能公式無法考慮到的影響，因為產能並未將等候時間限制這參數考慮進產能計算，無法即時知道產能限制，所以超過等候時間限制的在製品高於常態水準。 本研究分析各時間限制參數及產能的變化關係，知道等候時間長短如何影響產能負載，並設計一個快速因應時間緊縮的產能參數，以因應產能的微小變化，即使等候限制時間改變，也能快速計算產能投資是否會有相應的影響，更能精準的預測產出目標，並且有效降低在製品的異常數量。

An appropriate scope for capacity of Wafer Factory has been defined in the beginning of factory build-up and that helps create a Layout and Capacity Plan which is used to scale each production cycle and determine the production time and standard wait time for each manufacturing process. However in order to improve the efficiency of each wafer or to have high yield rate and quality in compliance with the technology progress. The Queue Time Limit is considered in mainly manufacturing process. In this study, we investigated that capacity could be underestimated if Queue Time Limit is less than initial standards while manufacturing process is shrinking. Sometimes you will have unexpected problems that will affect the production line and cause your production rate to slow down. The Queue Time Limit was overlooked as a parameter in the formula, which therefore lead to the inability to complete the parts needed on time. As a consequence you will have an above average amount of semi-processed goods waiting to be finished. This study analyzes the correlation between the parameters of each time limit and various capability of the production line. Understanding the effects of the wait time on capability load, and then setup a capacity parameter to rapidly adapt to the limited amount of time to cope with the small changes in capacity. Moreover, the associated influence of capacity investment is able to be calculated even if the time limit changes.This study will improve forecasting accuracy within the production planning and effectively reduce the numbers of the semi-processed goods and down time in production.