Micro LED Transfer via Silicon Oxide Release Layer
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Solution Overview
Problem
Conventional methods for fabricating micro light emitting diode (micro LED) apparatuses, such as the laser lift off technique, often damage the GaN layer due to high energy consumption and are time-consuming.
Innovation Solution
A method involving the formation of a substrate with a silicon oxide layer sandwiched between silicon layers, where micro LEDs are formed on one silicon layer, bonded to a second substrate, and the silicon oxide and first silicon layers are etched for transfer, reducing energy consumption and potential damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser lift off technique is used to transfer micro LEDs, then transfer efficiency is improved, but the GaN layer is damaged due to high energy consumption
Solution Approach 1:
The patent introduces an intermediary release layer between the micro LED structure and the substrate. This release layer acts as a mediator that enables easy separation without requiring high-energy laser treatment. The release layer is specifically designed to be etchable by hydrogen fluoride, allowing non-destructive transfer of the micro LEDs to the target substrate.
Solution Approach 2:
The patent replaces the laser-based mechanical/thermal separation system with a chemical etching system. Instead of using high-energy laser beams to lift off the micro LEDs, the invention uses selective chemical etching of the release layer, which is more gentle and does not damage the sensitive GaN layer.
2Speed
If laser lift off technique is used to transfer micro LEDs, then transfer speed is improved, but energy consumption increases
Solution Approach 1:
The patent replaces the high-energy laser system with a chemical etching process using hydrogen fluoride. This substitution dramatically reduces energy consumption while maintaining transfer speed, as the chemical etching can be performed continuously and selectively on the release layer without requiring intense energy input.
Solution Approach 2:
The patent changes the physical-chemical parameters of the system by introducing a release layer with specific etchability properties. The release layer is designed to have high selectivity to hydrogen fluoride etching, allowing rapid and efficient separation at low energy consumption compared to the high-energy laser process.
3Device complexity
If conventional fabrication methods are used, then manufacturing process is simple, but manufacturing precision is reduced due to GaN layer damage
Solution Approach 1:
The release layer serves as a protective intermediary that enables precise transfer of micro LEDs without damaging the GaN layer. This intermediary layer allows for high manufacturing precision by facilitating clean separation and transfer, while the overall process remains relatively simple and can be integrated into existing fabrication workflows.
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 method effectively transfers micro LEDs without damaging the GaN layer and reduces energy consumption, providing a more efficient fabrication process.
Implementation Method 1
implanting oxygen ions through a surface of the silicon wafer into the silicon wafer to a depth greater than zero
Implementation Method 2
etching the silicon oxide layer by a dry etching process using hydrogen fluoride as a dry etchant
Data Source
AI summary
A method of fabricating a micro light emitting diode (micro LED) apparatus includes forming a first substrate including a first silicon layer, a second silicon layer, and a silicon oxide layer sandwiched between the first silicon layer and the second silicon layer; forming a plurality of micro LEDs on a side of the second silicon layer distal to the silicon oxide layer; bonding the first substrate having the plurality of micro LEDs with a second substrate; and removing the silicon oxide layer and the first silicon layer.