LED Substrate Deepened Concave Portions via Anisotropic Etching
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Solution Overview
Problem
Conventional LED substrates with shallow nano-patterned concave portions suffer from inadequate light extraction efficiency due to insufficient depth, limiting brightness improvement.
Innovation Solution
A method involving a nano-patterned substrate with convex and concave portions, where protection structures are formed to expose the concave portions for anisotropic etching, deepening them using inductively coupled plasma etching with a CF4, Cl2, and BCl3 gas mixture, resulting in concave portions deeper than 1 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional nanoimprint lithography is used to form nano-patterns on LED substrate, then the manufacturing process is simple and quick, but the concave portions have insufficient depth (only 300 nm)
Solution Approach 1:
The patent segments the manufacturing process into two distinct stages: first forming initial nano-patterns using conventional nanoimprint lithography, then performing a second anisotropic etching process to deepen the concave portions. This segmentation allows each process to be optimized independently - the first stage maintains simplicity while the second stage achieves the required depth precision.
Solution Approach 2:
The patent applies preliminary action by first forming the nano-patterned substrate with convex and first concave portions using nanoimprint lithography, then using these pre-formed structures as templates for the subsequent deepening etching process. The protection structures are formed based on this preliminary pattern, guiding the second etching to achieve precise depth control.
2Illumination intensity
If the concave portions are deepened to improve light extraction efficiency, then brightness increases, but the manufacturing complexity increases
Solution Approach 1:
The patent introduces protection structures as intermediary elements that selectively cover convex portions while exposing concave portions for deepening etching. These protection structures act as mediators between the initial nano-pattern and the final deep concave structure, enabling precise depth control without requiring complex mask alignment or multiple lithography steps.
Solution Approach 2:
The patent replaces complex mechanical mask alignment systems with a self-aligned chemical etching approach. The protection structures are formed through epitaxial growth that automatically conforms to the underlying nano-pattern, eliminating the need for precise mechanical positioning and reducing overall manufacturing complexity despite the additional etching step.
3Ease of manufacture
If shallow concave portions (300 nm depth) are used on the substrate, then the manufacturing is easier, but light extraction efficiency is poor
Solution Approach 1:
The patent changes the depth parameter of the concave portions from the conventional 300 nm to greater than 1 μm through a controlled second etching process. This parameter change is achieved by adjusting etching conditions (gas composition, power, time) while maintaining the self-aligned protection structure approach, thus improving light extraction without proportionally increasing manufacturing difficulty.
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
Enhances light extraction efficiency by increasing the depth of concave portions, reducing light absorption and increasing reflected front light, resulting in improved brightness compared to conventional methods.
Implementation Method 1
performing an anisotropic etching process to etch the bottom surface of each of the first concave portions
Implementation Method 2
the anisotropic etching process is performed using an inductively coupled plasma etching process
Implementation Method 3
more light of this invention can be reflected as front light
Data Source
AI summary
A method of manufacturing a light emitting diode (LED) substrate includes following steps: providing a nano-patterned substrate, which has a plurality of convex portions and a plurality of first concave portions that are spaced apart from each other, wherein each first concave portion has a depth (d1); forming a plurality of protection structures to cover each convex portion, and exposing a bottom surface of each first concave portion; performing an anisotropic etching processing to etch the bottom surface of each first concave portion which is not covered by the protection structure so as to form a plurality of second concave portions having a depth (d2), and d2 is greater than d1.