Array Substrate Fabrication via Inverted Electrode Sequence
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Solution Overview
Problem
The surface oxidation of copper (Cu) electrodes in liquid crystal display (LCD) devices leads to increased contact resistance, preventing the connection of pixel electrodes to source or drain electrodes, which compromises the yield rate of products due to the active nature of low-resistance metals like Cu.
Innovation Solution
A method for fabricating an array substrate where a pixel electrode is formed first, followed by source and drain electrodes, with an etch stop layer containing via holes that connect these electrodes to the metal oxide semiconductor active layer, preventing surface oxidation issues during the etching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If low-resistance metals such as Cu are used to fabricate gate lines, data lines, and TFT electrodes, then resistance is reduced, but surface oxidation occurs during etching, increasing contact resistance and compromising yield rate
Solution Approach 1:
The pixel electrode is formed before the source and drain electrodes, so that when etching the source and drain electrodes, the pixel electrode is already in place to prevent oxidation of the Cu surface at the contact interface. This preliminary formation of the pixel electrode creates a protective effect that prevents the harmful oxidation reaction from occurring at critical contact points.
2Reliability
If Cu electrodes are formed and then etched to create pixel electrodes, then low-resistance connections are achieved, but contact resistance increases due to oxidation over time
Solution Approach 1:
The pixel electrode is formed in advance before the source and drain electrodes, creating a protective barrier that prevents oxidation from progressing at the contact interfaces. This preliminary action ensures that even as time passes and oxidation would normally progress, the critical contact surfaces remain protected, maintaining stable contact resistance over the product lifetime.
3Ease of manufacture
If source and drain electrodes are formed before pixel electrode, then fabrication process is simplified, but oxidation prevents connection between pixel electrode and drain electrode
Solution Approach 1:
The conventional fabrication sequence is inverted: instead of forming source and drain electrodes first and then the pixel electrode, the pixel electrode is formed first, followed by the source and drain electrodes. This inversion of the process sequence resolves the oxidation problem while maintaining manufacturing feasibility, as the pixel electrode's presence during etching prevents oxidation at the contact interfaces.
Data Source
AI summary
An array substrate, a method for fabricating the same and a display device are disclosed. The method for fabricating the array substrate includes: forming a pattern of a gate electrode, a pattern of a gate insulation layer and a pattern of a metal oxide semiconductor active layer on a base substrate; forming an etch stop layer; forming a pattern of a pixel electrode first, and then forming a pattern of a source electrode and a pattern of a drain electrode; wherein the pattern of the pixel electrode is connected to the pattern of the metal oxide semiconductor active layer through the pattern of the source electrode or the pattern of the drain electrode. The method can prevent the problem that the pattern of the pixel electrode failing to connect to the pattern of the source electrode or the pattern of the drain electrode.