LCD配向製程聚醯亞胺塗佈膜之肥邊瑕疵改善研究

Abstract

本研究的目的為改善Cell製程TFT側與CF側配向膜coating配向Polyimide(PI)膜塗佈，再經由預烤爐(hot plate)pre-bake後在印刷邊緣不均勻區域收縮範圍與段差所產生之肥邊(fat edge)瑕疵改善研究，以改善顯示器可視區域邊緣與角落視覺異常。 本論文實驗了PI配向膜塗佈之後須進行pre-bake受熱，設計hot plate兩種實驗受熱接觸方式，一種為直接接觸受熱，另一種採用有間距接觸受熱方式，兩者方式發現設定70℃溫度下直接接觸受熱升溫曲線優於近接接觸而且能大幅降低PI配向膜coating後邊緣與角落不均勻區域，使面板內可視範圍區域能增加，也探討實驗中所受到的熱通量與機台熱能散失的差異性。 實驗研究結果實際導入在LCD面板中TFT與CF的PI配向膜塗佈改善效益確實達到預期中的效果，由光學顯微鏡驗證、FIB膜厚分析、預傾角量測、官能基紅外線光譜分析結果顯示改善後之PI配向膜信賴性驗證能保持正常規格，實驗中亦發現polyimide經由瞬間昇溫過高則會產生突沸破開之小點。此研究成果可減少LCD配向膜coating製程瑕疵及降低設備所需能源與製造成本，提升液晶面板的產品競爭力。

The purpose of this research is for the improvement of fat edge defects of Polyimide (PI) membrane after pre-bake heating in the LCD alignment process. The objective is to study the heating procedure to reduce the PI membrane edge non-uniform region and the sectional difference, which are the key issues of the active area and the corner visual abnormality. Two heating modes (heating plate made contact or non-contact with PI membrane) in pre-baking process are discussed in this thesis. In the contact mode with 70ºC 10 second heating period, the experimental results showed that the "temperature increasing curve" and "un-uniform region reducing" are better than in non-contact mode. This can solve the active area issue. Besides the two heating modes operation, the heat flux between glass substrate and pre-baking furnace is also discussed. After final baking process, the alignment film is analyzed by several instruments such as optical microscope, pre-tilt angle confirmation, focus ion beam analyzer, and Fourier transformation infrared rays analyzer. The results showed that the alignment film corresponded with engineering specifications. The experiment also discovered that heating the polyimide by way of instantaneous elevates temperature increment will have the broken bumping hole on the film. This research can be a strategy for reducing defect during alignment film production, decreasing the energy needs, and saving cost to enhance the competitiveness of a company in the TFT-LCD industry.