TFT-LCD中驅動IC壓合製程之改善

Abstract

本文主要在探討TFT-LCD 模組製程中，驅動IC壓合過程導致的缺陷，在驅動IC利用異方性導電膠(ACF)與玻璃壓合，藉由ACF 中的導電粒子使驅動IC上的金凸塊與玻璃上的ITO導電金屬層達成電氣導通之目的。由於玻璃和驅動IC在壓合製程中，溫度梯度的差異及熱膨脹系數的不同，使得面板產生局部翹曲，內部液晶排列不一造成漏光現象因此而形成。 漏光長久以來為影響對比的一項顯著因素，而且現在為了滿足顯示器輕薄短小的需求，玻璃基板厚度一再薄化，使得漏光缺陷更加嚴重。本實驗材料選擇使用對角線長13.3吋、玻璃厚度0.3mm的面板半成品，經由驅動IC 壓合的製程，利用田口實驗設計找出最佳的條件，並以顯示畫面暗態下的漏光值作漏光率的最終判定，找尋出符合暗態畫面及對比度最佳表現，且不影響生產的其餘品質及良率水準。 以本實驗最終結果顯示，當利用田口式實驗設計法，將驅動IC 壓合製程中的最佳條件引出，再利用最佳條件進行重覆性實驗確認最佳因子及水準形成的漏光值水準比對，最後實際生產狀態下Base line 穩定性亦使漏光的程度達到有效的控管。

In this thesis the defects of the TFT-LCD module process were investigated. Applying the anisotropic conductive adhesive (ACF) and glass bonding in the driver IC bonding process utilizes the conductive particles of the ACF driver IC through the gold bumps and the conductive metal layer of ITO on glass to achieve the purpose of electrical conduction. After Chip on glass (COG) process ,the light-leakage was occurred at a specific local area. Mainly because during the glass and the driver IC in COG process, the difference of the temperature gradient resulting in the different thermal expansion coefficient, which causes a partially panel warping leading the light leakage phenomenon. Light leak has been a significant factor to affect the contras ratio, in order to produce the shorter and lighter displays, the thickness of the foundational glass substrate have been reduced rapidly, which signifies defects of more serious light leakage. Diagonal length of 13.3-inch and 0.3mm thick glass with a driver IC bonding semi-process displays were employed in the experiments, design of experiment was applied to identify the best conditions. The contrast in real display situation and light leakage value in dark screen were used to calculate the final ratio of light leakage for generate the best performance in dark screen also does not affect the quality and yields of production. The results show that the Taguchi experimental design method narrows down the operational conditions for the driver IC bonding process and the optimum condition is determined by the factor of minimizing light leakage level. In addition, base line also keeping light leakage stably.