Flexible Backplane Planarization for Metal Layer Reliability
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Solution Overview
Problem
The deposition of a metal conductive layer on a flexible substrate with organic polymer residues and air-borne particles results in protrusions, leading to disconnections and reduced yields, while cleaning equipment wastes resources and fails to completely remove protrusions, and the risk of damage during glass substrate peeling is high.
Innovation Solution
A planarization layer with a smoother surface roughness than the flexible substrate is introduced between the flexible substrate and the driving circuit layer to even the deposition and reduce protrusion impact, eliminating the need for equipment cleaning and minimizing damage during peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a flexible substrate is prepared directly on a glass substrate and a metal conductive layer is deposited on it, then the glass substrate can be peeled off, but the protrusions on the flexible substrate cause the metal conductive layer to be pierced and disconnected
Solution Approach 1:
A planarization layer is introduced as an intermediary between the flexible substrate and the metal conductive layer. This planarization layer has a smoother upper surface that prevents the metal conductive layer from being pierced by protrusions on the flexible substrate, while still allowing the metal conductive layer to be deposited on it. The planarization layer effectively mediates the interaction between the rough flexible substrate and the metal conductive layer, solving the disconnection problem.
Solution Approach 2:
The planarization layer is prepared in advance before depositing the metal conductive layer. By creating a smooth planarized surface beforehand, the subsequent metal conductive layer deposition is ensured to be uniform and free from piercing defects caused by underlying protrusions. This preliminary action prevents potential connection failures before they occur.
2Manufacturing precision
If machine equipment is cleaned to reduce dust and particles, then fewer protrusions are formed, but machine time, manpower and materials are wasted
Solution Approach 1:
Instead of trying to eliminate the harmful effect of protrusions through costly and time-consuming cleaning processes, the invention converts the harmful protrusions into a manageable condition by covering them with a planarization layer. The planarization layer's lower surface can accommodate certain程度的 roughness and protrusions, transforming the previously harmful surface irregularities into a non-critical condition that does not affect the final product quality.
3Device complexity
If only a flexible substrate is provided between the glass substrate and the driving circuit layer, then the structure is simple, but the metal conductive layer is at high risk of damage when the glass substrate is peeled off
Solution Approach 1:
The planarization layer serves as a cushioning layer that is prepared in advance before the metal conductive layer is deposited. This cushioning layer provides mechanical protection and stress distribution, reducing the risk of damage to the metal conductive layer when the glass substrate is peeled off. The planarization layer absorbs and distributes the mechanical stresses that occur during the peeling process, preventing concentrated stresses that could pierce or damage the metal conductive layer.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The planarization layer effectively reduces disconnections and improves display quality by evenly depositing the metal conductive layer, enhances reliability, and avoids resource waste and damage, while maintaining a simple process.
Implementation Method 1
When the metal conductive layer is subsequently deposited on the flexible substrate, the metal conductive layer may climb a slope at a position where there is a protrusion
Data Source
AI summary
The present disclosure provides a backplane, a backlight module, and a display panel. The backplane comprises a flexible substrate, a planarization layer, and a driving circuit layer, wherein a surface roughness of one side of the planarization layer close to the driving circuit layer is smaller than a surface roughness of one side of the flexible substrate close to the planarization layer.