Pad Electrode Encapsulation Layout Without Mask Etching Damage
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Solution Overview
Problem
The existing manufacturing processes for display devices require the use of mask structures to deposit encapsulation layers without overlapping pad electrodes, leading to increased process costs and potential damage to the pad electrodes and protective insulating layers during etching, which can result in contact failures and reduced reliability.
Innovation Solution
A method involving the formation of a conductive layer with specific etching rates for dry and wet etching processes, allowing for the deposition of inorganic encapsulation layers over the entire display and pad areas without masks, and selectively removing overlapping parts using atmospheric-pressure plasma, while protecting the pad electrodes and insulating layers by ensuring the conductive layer is not etched during the initial process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a mask structure is used to deposit the encapsulation layer without overlapping the pad electrode, then the encapsulation layer can be deposited precisely, but the process cost increases
Solution Approach 1:
A conductive layer is introduced as an intermediary between the pad electrode and the encapsulation layer. This conductive layer serves as a sacrificial mask that can be selectively removed, allowing the encapsulation layer to be deposited over the entire area without requiring a permanent mask structure, thus reducing process cost while maintaining deposition precision
Solution Approach 2:
The conductive layer is designed as a temporary, disposable structure that is removed after serving its purpose as a deposition mask. This disposable approach eliminates the need for expensive, reusable mask structures while achieving precise encapsulation layer deposition
2Manufacturing precision
If etching is performed to remove overlapping encapsulation layer, then the encapsulation layer can be corrected, but the pad electrode and protective insulating layer may be damaged
Solution Approach 1:
The conductive layer is formed beforehand to cushion and protect the pad electrode and protective insulating layer during the etching process. It acts as a protective barrier that prevents etching damage to underlying structures while allowing precise removal of overlapping encapsulation layer
Solution Approach 2:
The conductive layer serves as an intermediary protective layer during etching. It absorbs the etching action intended for the encapsulation layer, preventing the etchant from reaching and damaging the pad electrode and protective insulating layer beneath
3Manufacturing precision
If the conductive layer is etched during the initial process, then the overlapping encapsulation layer can be removed, but the pad electrode reliability decreases
Solution Approach 1:
The etching selectivity parameters are changed by choosing materials with different etching rates. The conductive layer is selected to have high resistance to the initial etching process, while the encapsulation layer has high etching rate, enabling selective removal of encapsulation layer without affecting the conductive layer or pad electrode
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
This approach reduces the number of mask structures needed, lowers manufacturing costs, and enhances the reliability of the display device by preventing damage to the pad electrodes and insulating layers, ensuring reliable electrical connections.
Implementation Method 1
removing a part of the inorganic encapsulation layer overlapping at least a part of the pad electrode through a first etching process
Implementation Method 2
The conductive layer may have a first etching rate for a first etching process. The inorganic encapsulation layer may have a second etching rate, which is higher than the first etching rate, for the first etching process
Implementation Method 3
The second etching process may include a wet etching process
Implementation Method 4
The conductive layer may have a third etching rate for a second etching process. The pad electrode may have a fourth etching rate, which is lower than the third etching rate, for the second etching process
Implementation Method 5
forming an inorganic encapsulation layer on the protective insulating layer
Implementation Method 6
forming an inorganic encapsulation layer on the protective insulating layer
Data Source
AI summary
A display device according to an embodiment of the present invention may include a substrate including a display area and a pad area located on one side of the display area, a pad electrode disposed in the pad area on the substrate, a protective insulating layer disposed on the substrate and the pad electrode to expose at least a part of a top surface of the pad electrode, an inorganic encapsulation layer disposed on the protective insulating layer, and a conductive layer disposed in the pad area between an end of the inorganic encapsulation layer adjacent to the pad electrode and the protective insulating layer.