摘要 本研究主要是利用薄膜電晶體液晶顯示器(TFT-LCD)前端陣列(Array)製程中,電漿化學氣相沉積機台的參數與沉膜厚度建立類神經網路模型,再以模糊規則萃取的方法從神經網路中擷取輸入與輸出間的定量模糊規則。分析的資料係由LCD廠中array部門之PECVD機台取得,參數包括沉膜製程中機台內的各種氣體流量、溫度、壓力、傳遞功率等。資料在整理過後,以機台參數與沉膜厚度分別當作輸入與輸出,共蒐集700筆資料,取其中500筆資料做為訓練樣本,再利用倒傳遞(Back-Propagation)類神經網路進行500次訓練,訓練完畢後的類神經網路模型在以200筆資料作為測試樣本檢測,其平均誤差為9.09 %,證實能夠有效模擬與預測PECVD製程中之沉膜狀況。由訓練完成的神經網路模型,再利用模糊規則萃取演算法,自類神經網路中擷取出輸入(氣體等參數)與輸出(膜厚等)間的定量模糊規則(fuzzy rules),將這些定量規則予以檢查、解釋後,建立出一套模糊專家系統,做為工程師更改配方時的參考依據。
ABSTRACT The principal object of this research is to develop a neural network model by using the parameters of the plasma enhanced chemical vapor deposition(PECVD)and the membrane thickness, then extracting the ration fuzzy rules between input and output from neural network with fuzzy rule extraction algorithm. The data of analysis was collected from the PECVD machines in the TFT-Array department, the machine parameters including the rate of all gases, temperature, pressure and bias of the chamber in membrane deposition process, etc. After arraying the data, use the parameters of the machine as input, and membrane thickness as output, the neural network model was established with back-propagation network(BPN) 500 times with 500 training data. The model was tested with 200 test data and the error rate was % in average, that prove this model can simulate and predict the situation of membrane deposition. The extraction rules were created from the trained neural network with the fuzzy rule extraction algorithm to describe the knowledge with fuzzy logic rules. After checking ,explaining and integration the rules into the knowledge base, then construct a fuzzy expert system enable to provide a reference to the engineers for the work of recipe adjustment.