Micro LED Etching Sequence for Sidewall Bond and Size Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micro light-emitting diode structures face issues with dry etching damaging molecular structures and causing dangling bonds, leading to reduced external quantum efficiency, and wet etching lacks stability and control over plane size due to isotropic etching.
Innovation Solution
A micro light-emitting diode structure is formed by first dividing the base layer using dry etching, followed by sequential formation of the second-type semiconductor layer and light-emitting layer using wet etching, allowing for reduced dangling bonds and improved size control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is used to divide the epitaxial wafer, then the size of micro light-emitting diode structures can be precisely controlled, but dangling bonds are generated on sidewalls causing reduced light-emitting efficiency
Solution Approach 1:
The patent segments the etching process into two distinct stages: first dry etching to achieve precise size control and pattern definition, then wet etching to remove dangling bonds and smooth sidewalls. This segmentation allows each etching method to perform its optimal function without the drawbacks of using either method alone for the complete process.
Solution Approach 2:
The patent introduces an intermediary treatment step between dry and wet etching that involves surface reconstruction and chemical treatment. This intermediary process allows the transition from the dry-etched state with dangling bonds to a final state with reduced harmful factors, effectively mediating between the precision requirement and the quality requirement.
2Object-generated harmful factors
If wet etching is used to divide the epitaxial wafer, then dangling bonds are reduced, but the plane size is reduced too much due to over-etching
Solution Approach 1:
The patent performs preliminary dry etching to establish the precise pattern and size before applying wet etching. This preliminary action defines the boundaries that protect against over-etching, as the dry-etched structures serve as masks or protective elements during the subsequent wet etching process that removes dangling bonds.
Solution Approach 2:
The patent applies partial wet etching selectively to specific regions or surfaces where dangling bonds need to be removed, rather than applying excessive wet etching uniformly throughout the structure. This controlled partial application maintains precision while achieving the benefit of reduced dangling bonds.
3Object-generated harmful factors
If long-time wet etching is applied to all layers, then dangling bonds are reduced, but the stability of manufacturing process decreases and other layers are damaged
Solution Approach 1:
The patent segments the etching process by layer type and timing, applying wet etching selectively after dry etching has established protective structures. This segmentation prevents long-time continuous wet etching that would damage multiple layers, while still achieving dangling bond reduction in the light-emitting layer through controlled, shorter wet etching exposure.
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 enhances external quantum efficiency by minimizing the adverse effects of wet etching on the micro light-emitting diode structure and improves light-emitting efficiency while maintaining stability and control over the structure's size.
Implementation Method 1
The dry etching process is to use plasma of reactive ions to etch the epitaxial wafer
Implementation Method 2
which is an anisotropic etching
Implementation Method 3
The wet etching is to etch the epitaxial wafer via chemical etching solution
Implementation Method 4
which is an isotropic etching
Data Source
AI summary
A micro light-emitting diode structure includes a first-type semiconductor layer, a light-emitting layer, a second-type semiconductor layer, and a base layer stacked with each other. A width of the light-emitting layer is greater than that of the first-type semiconductor layer and that of the second-type semiconductor layer. A width of the base layer is at least greater than that of the second-type semiconductor layer. A manufacturing method of the micro light-emitting diode structure by mixing dry etching and wet etching. The manufacturing method not only reduces the time that the semiconductor layers are in contact with the etching solution in the wet etching process to increase the etching stability, but avoids the dangling bond effect on the sidewall caused by the dry etching. Therefore, a combination of the advantages of the two etchings further increases the external quantum efficiency.