Etch Control Layer Protects Bank Tips in Display Devices
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Solution Overview
Problem
During the etching process of inorganic layers in display devices, the tips of the second bank are prone to damage or bending, which can lead to non-uniform formation of light-emitting elements and reduced reliability of the display device.
Innovation Solution
An etch control layer, composed of materials like indium gallium zinc oxide (IGZO), indium zinc oxide (IZO), or gallium zinc oxide (GZO), is applied on the top surface of the first common electrode and the sides of the first bank, as well as the bottom surfaces of the tips of the second bank, to prevent etching and ensure uniform formation of light-emitting elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the etching process is performed to remove inorganic layers, then the inorganic layers are successfully removed, but the tips of the second bank are damaged or bent
Solution Approach 1:
An etch control layer is introduced as an intermediary protective layer between the etching environment and the bank tips. This layer has higher resistance to the etching gas than the inorganic layers, allowing it to serve as a sacrificial barrier that protects the bank tips during the etching process while being removable afterward.
Solution Approach 2:
The etch control layer is formed on the bank tips before the etching process begins. This preliminary protective coating is applied in advance to prevent damage to the bank tips during subsequent etching operations, ensuring their structural integrity is maintained throughout the manufacturing process.
2Reliability
If the etch control layer is applied to protect the bank tips, then the bank tips are protected from damage, but the device structure becomes more complex
Solution Approach 1:
The etch control layer serves multiple functions: it protects bank tips during etching, acts as an etching barrier for inorganic layers, and can be selectively removed afterward. This multi-functionality justifies the additional layer by providing several benefits within a single structural addition.
Solution Approach 2:
The etch control layer is designed with specific material parameters (higher etching resistance) that differentiate it from other layers. By controlling the vaporization temperature and etching gas resistance parameters, the layer achieves selective protection and removal characteristics that simplify the overall manufacturing process despite the added structural complexity.
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 etch control layer effectively protects the tips of the second bank from damage during etching, resulting in uniform formation of light-emitting elements and improved reliability of the display device.
Implementation Method 1
a vaporization temperature of the etch control layer for a fluorine (F)-based etching gas may be higher than a vaporization temperature of the first inorganic layer for the F-based etching gas
Data Source
AI summary
A display device includes a first pixel electrode disposed in a first emission area on a substrate, an insulating layer covering edges of the first pixel electrode, a first light-emitting layer disposed on the first pixel electrode and the insulating layer, a first common electrode disposed on the first light-emitting layer, a first bank disposed on the insulating layer, the first bank surrounding the first emission area, a second bank disposed on the first bank, around the first emission area, the second bank including tips projected from sides of the first bank, and an etch control layer disposed on a top surface of the first common electrode, on the sides of the first bank, and on bottom surfaces of the tips of the second bank.