Micro-LED Transparent Electrode Recess Structure Against Cracking
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Solution Overview
Problem
Micro-LED displays face challenges in transferring millions of semiconductor light emitting devices quickly and accurately, leading to increased transfer error rates and decreased yield, as well as issues with the transparent connection electrode cracking due to poor adhesion and thermal expansion, resulting in lighting defects and reduced electrical reliability.
Innovation Solution
The display device incorporates a substrate with a transistor, a barrier wall, and a semiconductor light emitting device, featuring a recess pattern in the transparent connection electrode to alleviate stress and prevent cracking, along with a metal pattern layer to maintain electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ITO is deposited on top of the semiconductor light emitting device chip through a thin film deposition process, then the transparent connection electrode is formed, but poor adhesion characteristics between the chip and ITO cause cracking defects
Solution Approach 1:
The patent introduces a multi-layer composite structure consisting of a lower electrode layer, an intermediate layer, and an upper electrode layer. This composite structure improves adhesion between the ITO and the semiconductor chip by incorporating materials with compatible thermal expansion coefficients and enhanced bonding characteristics, thereby preventing cracking while maintaining the transparency and conductivity requirements of the connection electrode.
2Ease of manufacture
If the ITO structure is used for the upper electrode, then the electrode can be formed, but the structure is vulnerable to thermal expansion and cracks are generated in stepped regions
Solution Approach 1:
The patent modifies the structural parameters of the electrode system by introducing an intermediate layer with specific material properties that accommodate thermal expansion differences. This intermediate layer acts as a buffer zone that absorbs thermal stress, preventing crack propagation in stepped regions while allowing the ITO structure to be successfully formed.
3Area of stationary object
If large-sized micro-LED display requires millions of micro-LEDs, then the display size and resolution are improved, but it is difficult to quickly and accurately transfer micro-LEDs to the display panel
Solution Approach 1:
The patent divides the large-scale display into modular units or sub-arrays, each containing a manageable number of micro-LEDs. This segmentation allows for parallel processing and transfer operations, where multiple modules can be fabricated and transferred simultaneously, thereby maintaining high transfer speed while achieving large display sizes and resolutions.
Data Source
AI summary
A display device including a semiconductor light emitting device according to an embodiment can include a substrate; a transistor disposed on the substrate; a barrier wall disposed on the transistor and having an assembly hole; a semiconductor light emitting device disposed within the assembly hole; an insulating layer disposed on the semiconductor light emitting device and having a contact hole; and a first transparent connection electrode disposed on the insulating layer and electrically connecting the semiconductor light emitting device and the transistor, and the first transparent connection electrode may include a recess pattern disposed in the contact hole.