Transparent Protective Layer in LTPO Array Substrates for Via Etching
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Solution Overview
Problem
The conventional low-temperature polycrystalline silicon oxide (LTPO) array substrate manufacturing process is complex and prone to errors, particularly in the etching of source and drain electrodes, leading to broken circuits and increased contact resistance, which affects the performance and reliability of the display panel.
Innovation Solution
The array substrate incorporates a transparent protective layer made of indium tin oxide or indium gallium zinc oxide, which is used to protect the active layer during the formation of via holes, improving the yield rate and transmittance by reducing over-etching and enhancing the reliability of the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple etching processes are used to form via holes to source and drain electrodes, then the via holes can be formed, but over-etching occurs causing broken circuits and increased contact resistance
Solution Approach 1:
A protective layer is formed over the active layer before the via hole etching process. This protective layer serves as a pre-established barrier that prevents etchant from reaching and damaging the source and drain electrodes, thereby avoiding over-etching and broken circuits while maintaining manufacturing precision
Solution Approach 2:
The protective layer acts as an intermediary element between the etchant and the active layer. It allows the etching process to proceed through the insulation layers while blocking the etchant from reaching the sensitive source and drain electrodes, thus mediating the etching process to achieve precise via hole formation without damage
2Reliability
If the protective layer is made opaque, then it provides good protection during etching, but transmittance of the display panel decreases
Solution Approach 1:
The protective layer is formed using transparent conductive oxide materials (such as ITO, IZO, or IGZO) instead of traditional opaque materials. This parameter change in material composition allows the protective layer to maintain its protective function while being transparent, thus preserving display panel transmittance and brightness
Solution Approach 2:
The protective layer is made from transparent conductive oxide materials that combine the properties of transparency and electrical conductivity. This composite material approach allows the protective layer to serve multiple functions: protecting during etching, maintaining transmittance, and providing electrical connectivity, thereby resolving the contradiction between protection and transparency
Data Source
AI summary
An array substrate, a manufacturing method thereof, and a display panel thereof are disclosed. The array substrate includes: an underlay; a first insulation layer; a first active layer; a protective layer; a first gate electrode disposed on the first active layer at an interval from the protective layer; a second insulation layer; and a first source electrode and a first drain electrode, wherein the first source electrode and the first drain electrode are connected to the protective layer through first via holes in the second insulation layer; wherein a material of the protective layer includes indium tin oxide or indium gallium zinc oxide.