Array Substrate Transparent Electrode Adhesion in Passivation Holes
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Solution Overview
Problem
The adhesion strength between the Source/Drain metal pattern and the passivation layer is weakened in the passivation hole area, leading to delamination and foreign material peel-off phenomena, which can cause display failures such as pixel defects and hot pixels in liquid crystal display devices.
Innovation Solution
A transparent electrode pattern, typically made of ITO, is formed between the Source/Drain metal pattern and the passivation layer in the passivation hole area to enhance adhesion strength, preventing delamination and foreign material peel-off by acting as a cover layer between the S/D metal pattern and the upper passivation layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a passivation hole is formed to expose the S/D metal pattern for connection purposes, then electrical connection is enabled, but adhesion strength between the S/D metal pattern and the passivation layer is weakened leading to delamination
Solution Approach 1:
A transparent electrode pattern is introduced as an intermediary layer between the S/D metal pattern and the upper passivation layer in the passivation hole area. This intermediate transparent electrode layer serves as a mediator that maintains electrical connection while preventing direct contact between the metal pattern and passivation layer, thereby eliminating delamination issues.
Solution Approach 2:
The structure employs a composite material approach by combining the transparent electrode material with the passivation layer to form a composite passivation structure. This composite structure integrates both electrical conductivity and protective passivation functions while maintaining strong adhesion, preventing the delamination that would occur with direct metal-passivation contact.
2Object-affected harmful factors
If the passivation layer is removed in the passivation hole area, then foreign material peel-off is prevented, but delamination occurs due to weakened adhesion
Solution Approach 1:
The transparent electrode pattern acts as an intermediary that replaces the need to completely remove the passivation layer. It provides a stable interface that prevents foreign material peel-off while maintaining adhesion strength, eliminating the trade-off between preventing contamination and maintaining structural integrity.
Solution Approach 2:
The transparent electrode pattern is formed in advance as a protective cushioning layer before the upper passivation layer is applied. This pre-formed intermediate layer cushions against adhesion failures and prevents delamination from occurring in the first place, addressing the problem before it can manifest.
3Strength
If a transparent electrode pattern is formed between the S/D metal pattern and the passivation layer, then adhesion strength is improved and delamination is prevented, but device complexity increases
Solution Approach 1:
The transparent electrode pattern serves multiple functions simultaneously: it provides electrical connection, acts as an adhesion promoter to prevent delamination, and serves as a barrier layer. This multi-functionality justifies the additional structural element by consolidating multiple requirements into a single component.
Solution Approach 2:
The solution changes the material parameter by introducing a transparent electrode material with specific properties (conductivity, adhesion characteristics, transparency) that differ from conventional passivation materials. This parameter change enables the formation of a stable interface that prevents delamination without significantly complicating the overall device structure.
Data Source
AI summary
The present disclosure provides an array substrate for a display device and a manufacturing method thereof. A transparent electrode pattern (ITO) may be formed between a source/drain metal pattern and a passivation layer located above the source/drain metal pattern, which are formed in a passivation hole area of a non-active area of the array substrate. Accordingly, it may be possible to prevent display failure caused by a delamination phenomenon or peel-off of a material of the passivation layer due to the lack of adhesion strength between a metal layer and the passivation layer in the passivation hole area.