Micro-LED Transfer Using Sacrificial Layers and Wet Etching
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Solution Overview
Problem
Current methods for manufacturing micro-LED devices are costly and time-consuming, and there is a need for more efficient transfer techniques to reduce manufacturing costs and time.
Innovation Solution
A method involving the formation of a membrane with a cavity on a substrate, followed by the deposition of undoped semiconductor layers and a sacrificial layer, which is selectively removed using wet etching, allowing for the separation and transfer of micro-LEDs using a fluid self-assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional methods are used to manufacture micro-LED devices, then manufacturing process is established, but manufacturing cost is high and manufacturing time is long
Solution Approach 1:
The substrate is divided into multiple membranes, each capable of supporting micro-LED formation. This segmentation allows parallel processing of multiple micro-LEDs simultaneously, reducing overall manufacturing time while maintaining cost efficiency through reusable substrate structures.
Solution Approach 2:
A sacrificial layer is formed in advance on the substrate before micro-LED fabrication. This preliminary action enables subsequent easy separation and transfer of micro-LEDs to target substrates, streamlining the manufacturing process and reducing total production time.
2Manufacturing precision
If micro-LEDs are transferred using conventional methods, then transfer is achieved, but surface roughness increases and transfer efficiency decreases
Solution Approach 1:
A sacrificial layer acts as an intermediary between the substrate and micro-LEDs. This layer facilitates clean separation and transfer of micro-LEDs to target substrates, maintaining surface smoothness while enabling efficient transfer through controlled wet etching processes.
Solution Approach 2:
The mechanical transfer process is replaced with a chemical separation method using wet etching of the sacrificial layer. This substitution allows micro-LEDs to be released and transferred without mechanical contact that would damage surfaces, achieving both high precision and efficiency.
3Ease of manufacture
If substrate materials are not reused, then manufacturing process is simple, but manufacturing cost increases
Solution Approach 1:
The sacrificial layer is designed to be selectively removed through wet etching, allowing the underlying substrate and membranes to be recovered and reused for subsequent micro-LED fabrication cycles. This recovery process reduces material costs while the added etching step is a simple, scalable process.
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 reduces manufacturing costs and time by enabling effective transfer of micro-LEDs with improved surface smoothness and reduced surface roughness, facilitating more efficient LED assembly and reuse of substrate materials.
Implementation Method 1
forming a sacrificial layer that may be selectively removed by wet etching on the first undoped semiconductor layer
Implementation Method 2
transferring the formed LED to a pixel region of a display panel. The LED may be transferred by using a fluid self-assembly method
Data Source
AI summary
Provided are a method of manufacturing a micro-LED and a method of manufacturing a display apparatus to which the method is applied. In the method of manufacturing a micro-LED, a membrane formed to include a cavity is formed on a substrate, and then, a sacrificial layer that may be selectively removed by wet etching is formed on the membrane. Next, a light-emitting device is formed on the sacrificial layer, and the light-emitting device is separated from the membrane by the wet etching. In an example, an undoped semiconductor layer may further be formed between the membrane and the sacrificial layer. The sacrificial layer may include an oxide layer having the same crystal lattice structure as that of the undoped semiconductor layer. In an example, another undoped semiconductor layer may further be formed between the sacrificial layer and the light-emitting device.