| Summary: | 碩士 === 國立成功大學 === 高階管理碩士在職專班 === 91 === Semiconductor fabrication in Taiwan plays a decisive role in global market , the main reason is because suppliers in Taiwan have the competitive advantages in R&D and cost control. During the real operation of semiconductor fabrication, we often use “Control dummy/Dummy wafer (CW/DW)” to monitor and test precision machine on process and obtain the process parameter deviation as well as understand the real value of machine on process. Once the measured value exceeded the normal range, we would take action promptly to re-check and investigate the inner parameter setup of machine including software and hardware on the production line, to avoid producing NG goods resulting from exceeding process control specification or equipment malfunction.
The monthly input cost of CW/DW accounts for 3-8% among FAB monthly overall input cost, which is next to machine depreciation (around 40-60%) and input cost of product wafer (around 5-10%). All of these figures are variation values, they will grow and decline as per the FAB productivity utility rate. The unit price of control/dummy wafer in 12-inch wafer fab maintains around NT$ 7-10 thousand. If there are 30,000 pieces of CW/DW in stock, it will consume the cost value of inventory around NT$ 200-300 million. In the meantime, monthly input cost is around NT$ 20-30 million, which indeed is a huge burden for a business manager of semiconductor wafer fab.
CW/DW management is mainly to maintain sufficient CW/DW supply without shortage on production line, which is quite an important premise for wafer management. There are many variables such as the minimization of all related cost and relevant CW/DW management. Besides, there are over 200 types of CW/DW, and corresponding variables of each type will have over millions of combinations. The values of variables will change due to time passes.
A supervisor must know how to retrieve useful data from lots of information; then, he/she must know how to have good combinations to implement excellent CW/DW management. The above-mentioned key point is our major study domain for this thesis.
Rapid figure collection, through the handling of decision supporting model on decision tree, could get optimum reference value rapidly. Also, it’s our ideal goal for this thesis study. Firstly, database inquiry formula integrates summary parameter database, which combines with the characteristic of computer rapid calculation. Then, through “rapid retrieve decisive action” of database, input data will generate outcome value. Simultaneously, suitable action suggested value would be generated, this value will offer supervisor management check and input timing control.
This is an applicable thesis featuring practical management. I sincerely look forward to seeing more inspiration for my friends who also have been working for the same industry, they may discover the profundity of decision management science.
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