Fabrication method of tft substrate structure

Abstract

The invention provides a manufacturing method of a TFT (thin film transistor) substrate structure. According to the method, an semi-exposure photomask is utilized to expose and develop an organic coating; when a via hole is formed in the organic coating, a plurality of blind holes are formed in the hole wall of the via hole, and therefore, the superficial area of the hole wall of the via hole can be increased; the blind holes are utilized to partially accommodate photoresist; and therefore, the thickness of the photoresist on the hole wall of the via hole of the organic coating can be thinned, the amount of photoresist which flows to the bottom of the via hole of the organic coating when the photoresist is heated can be decreased, and the photoresist can be prevented from being collected at the bottom of the via hole of the organic coating, and thus, electrode material residuals can be avoided, and the display effect of the display panel can be improved.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a method for manufacturing a TFT substrate structure. Background technique [0002] In the field of display technology, flat-panel displays such as Liquid Crystal Display (LCD) and Organic Light Emitting Diode (OLED) have gradually replaced CRT displays, and are widely used in LCD TVs, mobile phones, personal digital assistants, digital Cameras, computer or laptop screens, etc. [0003] Thin Film Transistor (TFT for short) is the main driving element in current liquid crystal display devices and active matrix driven organic electroluminescent display devices (Active Matrix / Organic Light-Emitting Diode, AMOLED for short), directly related to high The development direction of performance flat panel display devices. Thin film transistors have various structures, and there are also various materials for preparing thin film transistors with corresponding structures. Low Temperature...

AI Technical Summary

Problems solved by technology

[0004] In the production process of liquid crystal display panel, such as figure 1 As shown, the substrate 100 on which the thin film transistors have been formed needs to be covered with an organic film as a planarization layer (planarization, PLN) 200, so as to change the flatness of the surface of the underlying film and prevent electric fields from interfering with each other. The planarization layer is usually a photosensitive material. The photomask can form a via hole 210 on the planar layer through the exposure and development process. Afterwards, an indium tin oxide (ITO) film 300 needs to be deposited on the planar layer 200 to be used as a common electrode (COM). Since the common electrode and the TFT electrode Therefore, it is necessary to coat the photoresist 400 (photoresist, PR) on the ITO film 300. After exposing and developing the photoresist 400, the ITO at the bottom of the flat layer via hole 210 not covered by the photoresist 400 is etched away. However, in order to enhance the adhesion between the photoresist 400 and the lower ITO film 300, the process of coating the photoresist itself needs to be heated and baked, and the flow phenomenon may occur when the photoresist 400 is heated. It is about 2.5 μm, and the slope of the via hole 210 on the flat layer 200 is relatively gentle. The photoresist coated on the wall of the via hole 210 of the flat layer 200 will accumulate at the bottom of the via hole 210 due to heat, and exposure cannot remove it. Falling off, resulting in photoresist residue, and eventually resulting in ITO residue under the accumulated photoresist

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