產品組合不確定下TFT-LCD陣列製程光罩類型與數量之決策

Abstract

TFT-LCD產業於世代交替之際，舊世代廠房的生產情境面臨轉型，由少樣多量的大尺寸庫存式生產轉型為多樣少量的中小尺寸訂單式生產。舊世代廠房的生產線上，並存多部功能相同但類型不同的機台。光罩是TFT-LCD陣列製程瓶頸機台的主要治具，各產品的光罩需配合其使用的機台，各產品的光罩組合會影響機台產能的配置。此外，光罩價格昂貴，若購買不恰當，會導致某些類型的機台產能不足，某些類型的機台卻閒置的不良狀況，進而影響產出，導致利潤下降。本文探討在現有的機台類別及其數量限制下，管理者面臨未來產品需求組合不確定的環境時，以最大化利潤為目標，構建各產品的光罩類別及其數量決策模式。本文以一案例說明該光罩組合決策模式，並進行參數敏感度分析，以供決策者參考。

The production environment in a traditional 4.5” TFT-LCD factory has changed dramatically over the last five years. Due to new generation factories arising, the traditional 4.5” TFT-LCD factories are forced to accept orders to produce various small size display products instead of make-to-stock products. A large number of products are produced concurrently in a production line. In general, the photo machine is the bottle-neck machine in TFT-LCD array manufacturing process. There are variety types of photo machines existed in a production line. Mask is the main fixture of photo machine. The price of mask is very expensive. There are five photo operations in each product routing. Each operation for each product needs a mask as fixture of the photo machine. The type of mask must match with the type of photo machine. A large numbers of mask types and numbers must be decided. The performance of this decision is the outputs. In this study, we deal with the uncertain demand problem that the uncertain demand is represented by the probability distribution of product mixed. A linear programming model is formulated to decide the type and number of mask for each product to maximize the profit under the constraints of machine capacity. A real case is given to illustrate the decision model. And we also do sensitivity analysis.