Vertical LED Manufacturing via Laser Lift-Off Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional methods for manufacturing vertical LEDs suffer from damage to the light emitting structure during the laser lift-off (LLO) process, leading to cracks and degraded reliability and characteristics due to the rigid and poorly conductive sapphire substrate.
Innovation Solution
The method involves forming a light emitting structure on a sapphire substrate, followed by a p-electrode and structure support layer, then performing LLO to separate the substrate, and subsequent isolation of unit LED elements through an ISO process, with optional buffer films and insulating/reflecting films to protect the structure from laser impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LLO process is performed to remove sapphire substrate for vertical LED manufacturing, then thermal conductivity and reliability are improved, but cracks occur at the edge of light emitting structure during the process
Solution Approach 1:
The patent applies preliminary action by performing the isolation process before the LLO process. Specifically, the light emitting structure is isolated into unit LED elements through etching or other isolation methods while still on the sapphire substrate, creating physical separation between adjacent structures. This preliminary isolation prevents crack propagation during the subsequent LLO process, as cracks are confined to individual isolated units rather than spreading across the entire light emitting structure.
Solution Approach 2:
The patent applies segmentation by dividing the continuous light emitting structure into discrete unit LED elements through the isolation process. This segmentation creates independent isolated regions that can withstand the thermal stress of LLO without causing cracks to propagate across the entire structure. The segmented approach allows each unit to be processed independently during LLO, preventing catastrophic failure of the whole structure.
2Productivity
If LLO process is performed with high laser energy to remove substrate quickly, then productivity is improved, but damage to light emitting structure and degradation of adhesion occur
Solution Approach 1:
The patent applies preliminary action by performing isolation before LLO, which enables the use of higher laser energies during substrate removal. The isolated structures act as protective barriers that prevent excessive laser energy from causing catastrophic damage to the light emitting structure. This allows the LLO process to be performed more aggressively and quickly while maintaining structure integrity.
Solution Approach 2:
The patent applies local quality by creating different structural conditions in different regions. The isolated regions between LED units have different properties (removed or modified material) compared to the protected LED structure regions. This local differentiation allows the LLO process to remove substrate efficiently in isolated areas while protecting the critical LED light emitting structures from damage through selective exposure to laser energy.
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 prevents damage to the light emitting structure during LLO, enhancing the reliability and characteristics of the vertical LED by isolating the structure after substrate removal, thereby improving production yield and chip performance.
Implementation Method 1
removing the sapphire substrate through an LLO (laser lift-off) process
Data Source
Figure 1A~1C
Figure 1D~1F
Figure 2~3C
AI summary
Provided is a method of manufacturing a vertical LED, the method including the steps of: preparing a sapphire substrate; forming a light emitting structure in which an n-type nitride semiconductor layer, an active layer, and a p-type nitride semiconductor layer are sequentially laminated on the sapphire substrate; forming a p-electrode on the p-type nitride semiconductor layer; forming a structure support layer on the p-electrode; removing the sapphire substrate through an LLO (laser lift-off) process; isolating the light emitting structure into unit LED elements through an ISO (isolation) process; and forming an n-electrode on each of the n-type nitride semiconductor layers of the isolated light emitting structures.