TFT Array Panel Drain Electrode Segmentation for Uniform Etching
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Solution Overview
Problem
Conventional thin film transistor (TFT) array panels face issues with non-uniform organic layer thickness during etching, leading to over-etching and damage to the TFT structure, particularly when the drain electrode is under the color filter, resulting in inadequate planarization and exposure of the drain electrode.
Innovation Solution
The TFT array panel design includes a drain electrode with a first part overlapping the color filter and a second part facing the source electrode, allowing for a uniform organic layer thickness of approximately 2-3 μm, which is etched uniformly to prevent over-etching and ensure proper exposure of the drain electrode, thereby maintaining the planarization function and structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the drain electrode is positioned under the color filter, then the color filter can be formed continuously, but the organic layer thickness becomes non-uniform causing over-etching
Solution Approach 1:
The drain electrode is segmented into two parts: a first part positioned under the color filter and a second part exposed on the color filter. This segmentation allows the color filter to be formed continuously while providing an exposed region for proper organic layer etching control, resolving the contradiction between ease of manufacture and manufacturing precision.
2Manufacturing precision
If the organic layer is etched to expose the drain electrode, then proper contact is achieved, but over-etching damages the TFT structure
Solution Approach 1:
The drain electrode is preliminarily positioned with a portion exposed on the color filter before organic layer etching. This preliminary configuration ensures that the etching process can be precisely controlled to expose the drain electrode without over-etching, thereby maintaining TFT structure integrity while achieving proper contact.
3Manufacturing precision
If the organic layer thickness is reduced for uniform etching, then over-etching is prevented, but planarization function is compromised
Solution Approach 1:
The organic layer is configured with different thickness characteristics in different regions: a first organic layer over the drain electrode's first part and a second organic layer over the drain electrode's second part. This local quality differentiation allows uniform etching in the exposed region while maintaining adequate thickness for planarization function in other regions.
Data Source
AI summary
The present invention relates to a thin film transistor array panel that includes an organic layer formed on a data line and a drain electrode disposed on a color filter. A thickness of a portion of the organic layer around a contact hole exposing a portion of the drain electrode is similar to a thickness of a portion of the organic layer around a contact hole exposing a portion of the data line. Having approximately the same thickness can prevent non-uniform etching of the organic layer around contact holes and deterioration of the thin film transistor array panel.