Micro LED Transfer via Laser-Activated Resin Release Layer
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Solution Overview
Problem
In the manufacturing of micro LED display devices, residual films often remain on the light-emitting devices after transfer from a source substrate to a driving substrate, leading to issues such as degradation of optical characteristics, contact failures, and increased manufacturing costs due to the need for residual film processing and washing.
Innovation Solution
A method involving a release layer with a resin material thickness of 0.1 μm to 0.5 μm, which is decomposed by laser light to prevent residual films on the micro LEDs, using a combination of first and second release layers with different absorption rates and thicknesses to facilitate efficient transfer and adhesion to the driving substrate without damaging the micro LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a release layer with thickness less than 0.1 μm is used, then the transfer process is simpler, but residual films remain on the light-emitting device after transfer
Solution Approach 1:
The patent applies parameter changes by optimizing the release layer thickness to a specific range (0.1 μm to 0.5 μm) and selecting materials with appropriate laser absorption rates (60%-100%). This quantitative parameter optimization enables complete decomposition of the release layer during laser transfer, eliminating residual films while maintaining process feasibility.
Solution Approach 2:
The patent utilizes phase transitions by selecting release layer materials that undergo complete decomposition or vaporization when exposed to laser light. This phase change from solid to gas/decomposed state allows the release layer to be fully removed during the transfer process, preventing residual film formation on the light-emitting device.
2Manufacturing precision
If a release layer with thickness greater than 0.5 μm is used, then residual films are eliminated, but energy consumption increases and plasma damage occurs
Solution Approach 1:
The patent optimizes the release layer thickness parameter to the range of 0.1 μm to 0.5 μm, which is sufficient to prevent residual films while minimizing laser energy requirements. This parameter optimization balances residual film elimination with energy efficiency, avoiding excessive energy consumption and plasma damage.
Solution Approach 2:
The patent uses a two-layer release layer structure where a first release layer (1 μm to 5 μm) serves as a sacrificial layer that absorbs excess laser energy, while a second release layer (0.1 μm to 0.5 μm) directly contacts the light-emitting device. This layered approach protects the device from plasma damage while eliminating residual films.
3Device complexity
If a single release layer is used, then the structure is simpler, but transfer reliability is insufficient
Solution Approach 1:
The patent divides the release layer into two distinct layers with different functions: a first release layer (1 μm to 5 μm) with lower laser absorption rate that protects the source substrate, and a second release layer (0.1 μm to 0.5 μm) with high absorption rate that ensures complete decomposition and residual film elimination. This segmentation improves transfer reliability while managing complexity.
Solution Approach 2:
The patent employs composite materials by combining two different resin materials with distinct laser absorption characteristics. The first release layer uses a material with 1%-50% absorption rate, while the second layer uses a material with 60%-100% absorption rate. This composite structure enables both source substrate protection and complete release layer decomposition.
4Productivity
If laser energy is increased to decompose the release layer, then transfer efficiency improves, but plasma damage to the light-emitting device increases
Solution Approach 1:
The patent introduces a first release layer as an intermediary sacrificial layer between the laser source and the light-emitting device. This layer absorbs excess laser energy and dissipates it harmlessly, preventing plasma formation that would damage the device. The second release layer then decomposes completely at lower energy levels, achieving efficient transfer without plasma damage.
Solution Approach 2:
The first release layer functions as a disposable sacrificial layer that is intentionally designed to absorb and dissipate excess laser energy. This short-living component protects the valuable light-emitting device from plasma damage while enabling efficient transfer of the second release layer and device.
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 eliminates the need for residual film processing, stabilizes the transfer process, reduces energy usage and plasma damage, and lowers manufacturing costs by ensuring precise positioning and efficient reuse of the source substrate.
Implementation Method 1
a release layer between the source substrate and the light-emitting element, the light-emitting element being held onto the source substrate by the release layer in which the release layer includes a resin material
Implementation Method 2
moving the light-emitting element to a surface of the adhesive layer on the driving substrate from the source substrate by irradiating laser light of the certain wavelength to the release layer through the source substrate
Data Source
AI summary
Provided are a method of manufacturing a display device and a source substrate structure. The method of manufacturing the display device includes holding a light-emitting element on a source substrate that passes laser light of a certain wavelength therethrough, the holding being performed by a release layer between the source substrate and the light-emitting element, forming an adhesive layer on a driving substrate on which a driving substrate-side electrode is formed, moving the light-emitting element to a surface of the adhesive layer on the driving substrate from the source substrate by irradiating laser light of the certain wavelength to the release layer through the source substrate, and adhering the moved light-emitting element to the driving substrate by using the adhesive layer, and the release layer comprises a resin material with a thickness that is greater than or equal to 0.1 μm and is less than or equal to 0.5 μm.