TFT阵列基板过孔电阻与耐流性能研究

Research of via hole resistance and current withstanding properties in TFT array substrate

薄膜晶体管阵列基板过孔电阻大、耐流性差易发生过孔烧毁,引起显示异常。目前针对过孔电阻与耐流性影响因素及机理尚不明确,制约着未来高耐流性过孔的制备和应用。本文实验结果表明氧化铟锡(Indium Tin Oxide,ITO)膜方块电阻减小、过孔坡度角减小、ITO膜与金属接触面积增大均可降低过孔电阻、提升过孔耐流性。结合过孔结构及机理分析指出,过孔电阻主要由ITO膜层自身电阻(R_(ITO))及过孔接触电阻(R_(contact))组成,ITO膜方块电阻及过孔坡度角减小会使R_(ITO)减小,ITO膜与金属接触面积增大会使R_(contact)减小。基板中部过孔耐流性差与中部的ITO膜方块电阻及过孔坡度角偏大有关。在满足产品光学品质标准前提下,ITO膜厚增厚、调控绝缘层膜质以及干法刻蚀参数减小坡度角、加大过孔接触面积设计是降低过孔电阻、提升过孔耐流性的有效途径。

If TFT array substrate has large via hole resistance and poor current withstanding properties,via hole is easy to burn up which will cause abnormal display.At present,the influencing factors and mechanism of the via hole resistance and current withstanding properties are not clear,which restricts the preparation and application of the via hole with good current withstanding properties.In this paper,the experimental results show that reducing block resistance of indium tin oxide film(ITO),reducing the slope angle of via hole and increasing contact area between ITO film and metal can reduce via hole resistance and improve current withstanding properties of the via hole.Combined with the analysis of via hole structure and mechanism,it is pointed out that the via hole resistance is mainly composed of ITO film resistance(R_(ITO))and the via hole contact resistance(R_(contact)).Either reducing block resistance of ITO film or the slope angle of via hole will reduce ITO film resistance(R_(ITO)),while increasing contact area between ITO film and metal will reduce the via hole contact resistance(R_(contact)).The via hole current withstanding properties is worse in middle of the substrate because the ITO film block resistance and via hole slope angle are larger.Thicken ITO film,regulating insulating layer film quality and dry etching parameters to reduce slope angle and increase via hole contact area are effective ways the via hole resistance and improve the via hole current withstanding properties under the premise of meeting product optical quality standard.