Semiconductor LED Transfer Bonding With Thermosetting Adhesive Layers
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Solution Overview
Problem
Current display technologies using semiconductor light-emitting elements face challenges in high-temperature and high-pressure bonding processes, leading to defects and difficulties in selective transfer, which affects the cost and efficiency of manufacturing flexible displays.
Innovation Solution
A method involving the use of a temporary substrate with a thermosetting adhesive and a release layer that can be separated using laser or ultraviolet light, allowing for precise bonding and transfer of semiconductor light-emitting elements to a wiring substrate while maintaining thermal stability and reducing defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stamp is used for selective transfer of semiconductor light-emitting elements, then transfer selectivity is improved, but thermal stability and adhesive force are insufficient during high-temperature and high-pressure bonding process
Solution Approach 1:
The patent applies preliminary action by pre-coating the temporary substrate with a thermosetting adhesive layer before the bonding process. This adhesive layer is specifically designed to withstand high temperatures and pressures, ensuring that the semiconductor light-emitting elements remain securely attached during the bonding process. The adhesive layer is cured in advance or during the bonding process, providing robust thermal stability and adhesive force that the stamp alone cannot provide.
2Reliability
If anisotropic conductive film is used for bonding with wiring substrate, then bonding is achieved, but selective transfer is difficult and cost reduction is limited
Solution Approach 1:
The patent applies segmentation by dividing the bonding process into distinct stages: first, semiconductor light-emitting elements are transferred to a temporary substrate using a stamp; then, the temporary substrate with attached elements is bonded to the wiring substrate using anisotropic conductive film. This segmentation allows selective transfer to be achieved in the first stage, while reliable bonding is achieved in the second stage, combining the advantages of both approaches.
3Strength
If high-temperature and high-pressure bonding process is used, then bonding strength is improved, but defects occur due to lack of thermal stability of stamp
Solution Approach 1:
The patent applies the intermediary principle by introducing a temporary substrate with a thermosetting adhesive layer as a mediator between the stamp and the wiring substrate. The temporary substrate with its heat-resistant adhesive can withstand the high-temperature and high-pressure bonding process without deforming or losing adhesion, thereby preventing defects. After bonding, the temporary substrate is removed, leaving the securely bonded semiconductor light-emitting elements on the wiring substrate.
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 enables stable and accurate transfer of semiconductor light-emitting elements during high-temperature and high-pressure bonding, reducing defect rates and enabling the production of flexible displays with improved manufacturing efficiency and cost-effectiveness.
Implementation Method 1
a release layer provided on one surface of the base portion and made of a material separable from the base portion by absorbing laser or ultraviolet light
Implementation Method 2
The adhesive layer may have a thermosetting adhesive that is cured by heat or ultraviolet light
Data Source
AI summary
A display device can include a wiring substrate including a first electrode, a plurality of semiconductor light-emitting elements electrically connected to the first electrode, a conductive adhesive layer on the wiring substrate and around the plurality of semiconductor light-emitting elements, an upper layer on one surface of the conductive adhesive layer and including a plurality of through holes corresponding to the plurality of semiconductor light-emitting elements, respectively, and a second electrode on the upper layer and electrically connected to the plurality of semiconductor light-emitting elements. The upper layer can include a thermosetting adhesive.