Micro-LED Assembly Substrate Structure for Warpage-Free Self-Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The self-assembly method for micro-LED displays faces challenges such as low self-assembly rates due to non-uniform DEP force, increased transfer error rates, and substrate warpage leading to adhesion issues and misalignment of semiconductor light emitting devices during the assembly process.
Innovation Solution
The proposed assembly substrate structure includes a substrate with spaced assembly electrodes, a magnetic structure underneath, and an insulating layer, along with an outer magnetic structure and assembly barrier walls, which generates controlled magnetic forces to stabilize the substrate and maintain precise positioning of semiconductor light emitting devices during self-assembly, enhancing the transfer rate and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If DEP force is used for self-assembly, then assembly automation is improved, but manufacturing precision deteriorates due to non-uniform force distribution causing device tilting
Solution Approach 1:
A magnetic layer is introduced as an intermediary between the semiconductor light emitting device and the DEP assembly system. The magnetic layer interacts with both the DEP force and the magnetic field, enabling dual-force control that overcomes the non-uniformity limitation of DEP alone, thereby maintaining both high automation and precision
Solution Approach 2:
The invention changes the physical parameters of the assembly system by introducing magnetic field parameters (magnetic permeability, field strength distribution) alongside the electrical parameters of DEP. This allows tuning of force distribution uniformity through magnetic field optimization, resolving the precision issue while preserving automated assembly
2Area of stationary object
If assembly substrate size is increased for large displays, then display area is improved, but stability deteriorates due to substrate warpage
Solution Approach 1:
The magnetic attraction force between the magnetic layer and the external magnet serves as a counterweight to the gravitational and stress-induced warpage forces. By adjusting magnetic field strength, the substrate is held flat against the large area, preventing warpage while enabling large display sizes
Solution Approach 2:
The invention changes the mechanical stability parameters by introducing magnetic interaction parameters. The magnetic force distribution can be optimized to compensate for stress variations across large substrates, maintaining flatness and stability even as display area increases to large dimensions
3Productivity
If transfer speed is increased for efficient assembly, then productivity is improved, but manufacturing precision deteriorates due to increased transfer errors
Solution Approach 1:
The magnetic layer acts as an intermediary that enables precise positioning during high-speed transfer. The magnetic attraction provides a holding force that maintains positioning accuracy even during rapid movement, allowing high transfer speeds without sacrificing precision
Solution Approach 2:
The magnetic field is activated before and during the transfer process to pre-position and hold the device in place. This preliminary magnetic securing action ensures that even at high transfer speeds, the device maintains accurate positioning throughout the transfer operation
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 configuration improves the self-assembly rate, reduces transfer errors, and ensures accurate positioning of LED chips, maintaining high electrical contact quality and preventing substrate warpage, thereby enhancing the overall efficiency and reliability of the micro-LED display assembly process.
Implementation Method 1
a magnetic structure disposed under the first assembly electrode and the second assembly electrode... the magnetic force generated between the magnetic structure and the assembly device... prevents warpage of the assembly substrate
Implementation Method 2
a self-assembly method using dielectrophoresis (DEP)... DEP force is required for self-assembly
Data Source
AI summary
Discussed is an assembly substrate structure of a display device including a semiconductor light emitting device and a display device having the same. The assembly substrate structure of the display device including a semiconductor light emitting device can include an assembly substrate, a first assembly electrode and a second assembly electrode disposed spaced apart from each other on the assembly substrate, a magnetic structure disposed under the first assembly electrode and the second assembly electrode and an insulating layer disposed between the first and second assembly electrodes and the magnetic structure.