Patterned Epitaxial Laser Lift-Off for Uniform UV Energy Distribution
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Solution Overview
Problem
The challenge in achieving high-quality laser lift-off of patterned substrates during the epitaxial growth of materials, such as MicroLED, lies in the differing material structures and beam energy requirements between patterned and planar structure areas, which complicates the temperature and intensity distribution conditions for effective lift-off.
Innovation Solution
A patterned epitaxial structure laser lift-off device is designed with a substrate, reshaping structures, a transmittance adjustment structure, gas transmission systems, an ultraviolet source, and a light entry window, featuring V-shaped groove structures and planar interfaces on the sapphire substrate, along with reshaping structures and a transmittance adjustment structure to modulate light energy density and reduce stress during lift-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If patterned substrates are used for epitaxial growth, then stress release during material growth is improved, but the laser lift-off process becomes more difficult due to differing material structures and beam energy requirements
Solution Approach 1:
The substrate is divided into patterned structures (e.g., V-shaped grooves, pillars, or holes) and planar structures. This segmentation allows different regions to have different material compositions and optical properties, enabling stress release during growth while creating distinct beam energy requirements for lift-off
Solution Approach 2:
Different regions of the substrate are designed with different properties: patterned areas have specific material compositions for stress management, while planar areas have different properties. This local differentiation requires the laser beam to have spatially varying intensity distribution to achieve effective lift-off across the entire substrate
2Reliability
If homogeneous epitaxial thick film substrates are used, then device performance is improved, but cost becomes prohibitively expensive
Solution Approach 1:
Instead of using expensive homogeneous thick film substrates throughout, the invention uses patterned substrates where only specific regions have the required material properties for high performance. This localized approach maintains device performance in critical areas while reducing overall material costs
Solution Approach 2:
The substrate is segmented into patterned structures that provide the necessary performance characteristics only where needed, rather than requiring the entire substrate to be expensive homogeneous material. This segmentation enables cost-effective manufacturing while preserving device performance
3Ease of manufacture
If laser lift-off is performed on patterned substrates, then cost is reduced compared to homogeneous substrates, but the temperature field distribution and beam intensity distribution requirements become more complex
Solution Approach 1:
The laser beam parameters (intensity distribution, wavelength, pulse duration) are dynamically adjusted to match the spatially varying requirements of the patterned substrate. The beam intensity is modulated to provide higher energy to patterned regions and lower energy to planar regions, enabling controlled lift-off despite the complexity
Solution Approach 2:
The invention changes multiple laser parameters simultaneously (wavelength, intensity distribution, pulse duration, focusing) to optimize the lift-off process for patterned substrates. By adjusting these parameters, the complex temperature field requirements are satisfied while maintaining cost-effectiveness
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 device enhances the yield of the laser lift-off process by optimizing light energy distribution and reducing stress, allowing for efficient lift-off of patterned substrates with improved device performance.
Implementation Method 1
laser lift-off process has essential requirements about the temperature field distribution and the intensity distribution conditions of the laser lift-off beam
Implementation Method 2
The laser lift-off process has essential requirements about the temperature field distribution
Implementation Method 3
reshaping structures... to modulate light energy density
Implementation Method 4
transmittance adjustment structure... to modulate light energy density
Data Source
AI summary
A patterned epitaxial structure laser lift-off device, including a substrate, reshaping structures, a transmittance adjustment structure, a patterned epitaxial structure, gas transmission systems, an ultraviolet source, a lift-off chamber and a light entry window. The gas transmission systems are at two sides of the lift-off chamber; the light entry window is on the lift-off chamber; the ultraviolet source is above the outside of the light entry window; the patterned epitaxial structure is inside the lift-off chamber; the substrate is on the patterned epitaxial structure. The patterned epitaxial structure includes an epitaxial structure, a sapphire substrate, patterned structures, oblique interfaces and planar interfaces, several patterned structures being uniformly designed on the epitaxial structure, each of the patterned structures being a V-shaped groove structure formed by two oblique interfaces, two adjacent patterned structures being connected by means of a planar interface.