高PPI ADS产品白Mura不良产生原理及改善研究

现有传统TFT-LCD 生产工艺中,Rubbing工艺在生产高PPI ADS产品的过程中,在改善Rubbing Mura不良时会使用H Cloth,但使用H Cloth Glass在经过Rubbing后ODF Rubbing Cleaner清洗时会出现白Mura不良。经过对白Mura不良Panel的微观解析,并结合H Cloth性质分析出白Mura不良是由于H Cloth自身的聚醋酸脂颗粒经过Rubbing Cleaner聚集造成的。从Rubbing Cleaner清洗时改变Glass表面性质(醇类可以有效改变界面性质)入手,通过使用IPA对Glass进行清洗以改变聚醋酸脂疏水性,使得聚醋酸脂颗粒更易被Rubbing Cleaner清洗掉来改善白Mura不良,并结合生产实际定期对IPA进行更换以保持IPA浓度处于一个稳定的区间,使得高PPI ADS产品白Mura不良发生率由改善前的3.42%降低至改善后的0.11%,白Mura不良得到非常有效的改善。

Principle and improving research of white mura defect in high PPI ADS product

In the traditional Process of TFT-LCD, H Cloth is always used to improve Rubbing Mura in the production of High PPI ADS Products,but when H Cloth is used, the White Mura Defect will appear after Rubbing Cleaner. By analyzing of White Mura Defect micro appearance and the nature of H Cloth, the White Mura Defect is caused by the gathering effect of Acetate Polymer after Rubbing Cleaner. In this paper, we change Acetate from Hydrophobic to Hydrophilic by changing the surface property of glass in the Rubbing Cleaner (alcohol can effectively change the interface property) and the Acetate Polymer particle is easily to be cleaned. In actual production, we replace IPA at regular period to keep the IPA concentration in stable range. As a result, the White Mura is effectively improved and controlled and the defect ratio is greatly decreased from 3.42% to 0.11%.