Display Device Bonding Structure with Concave Through-Electrode Grooves
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Solution Overview
Problem
Existing display device manufacturing processes face challenges in minimizing disconnection between pixel electrodes and light emitting elements, leading to inefficiencies and reduced yield.
Innovation Solution
A display device design featuring a through electrode with a concave groove and a bottom bonding electrode with a downward convex protrusion, along with a planarized oxide layer, enhances connectivity and includes a barrier film to prevent metal ion movement, while using multiple bonding electrodes for improved bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a through electrode with concave groove and bottom bonding electrode with downward convex protrusion are used, then connection reliability between pixel electrode and light emitting element is improved, but manufacturing process complexity increases
Solution Approach 1:
The through electrode is designed with a concave groove on its upper surface, and the bottom bonding electrode has a downward convex protrusion that corresponds to this groove. This curved surface design allows the protrusion to fit into the groove, creating a mechanical interlock that significantly improves connection reliability between the pixel electrode and light emitting element, while the standardized groove-protrusion geometry keeps the manufacturing process manageable.
Solution Approach 2:
The downward convex protrusion of the bottom bonding electrode is nested within the concave groove of the through electrode. This nesting structure creates an interlocking mechanism where the protrusion fits precisely into the groove, ensuring robust mechanical and electrical connection. The nested design maximizes connection reliability through geometric interlocking while maintaining manufacturing feasibility through standardized forming processes.
2Strength
If multiple bonding electrodes with oxide layers are used, then bonding strength is improved, but manufacturing time and process steps increase
Solution Approach 1:
An oxide layer is formed on the upper surface of the through electrode before the bottom bonding electrode is attached. This preliminary oxidation creates a chemically active surface that enhances bonding strength when the bottom bonding electrode is subsequently bonded to it. By performing the oxidation step in advance as part of the electrode preparation process, the patent achieves strong bonding without significantly extending the critical path of manufacturing time.
Solution Approach 2:
The bonding structure employs composite material layers including the through electrode material, the oxide layer, and the bottom bonding electrode material. This composite construction combines the mechanical properties of the metal electrodes with the chemical bonding properties of the oxide layer, achieving superior bonding strength. The multi-material approach is integrated into the manufacturing process through sequential deposition and bonding steps that, while adding process complexity, can be performed in a streamlined fashion to minimize time loss.
3Reliability
If a barrier film is added to prevent metal ion movement, then long-term reliability is improved, but device structure complexity increases
Solution Approach 1:
A barrier film is introduced as an intermediary layer between the through electrode and the bottom bonding electrode. This barrier film prevents metal ion migration and diffusion between the two electrode layers, thereby improving long-term reliability by preventing degradation mechanisms such as electromigration and corrosion. The barrier film serves as a protective mediator that maintains the integrity of the electrical connection over time while adding only a thin functional layer to the overall device structure, minimizing the increase in structural complexity.
Data Source
AI summary
A display device including a substrate including a pixel circuit, a pixel electrode connected to the pixel circuit, an insulating layer disposed on the pixel electrode, a through electrode penetrating the insulating layer and connecting to the pixel electrode, a bottom bonding electrode and an upper bonding electrode sequentially disposed on the through electrode and the insulating layer, and a light emitting element disposed on the upper bonding electrode. The through electrode has a groove whose upper surface is concave downward. A lower surface of the bottom bonding electrode follows the surface profile of the insulating layer and the through electrode disposed below, and an upper surface is flat. The bottom bonding electrode includes an oxide layer.