Flip-Chip LED Flat Pads Uniform Current Diffusion
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Solution Overview
Problem
Current flip-chip light-emitting diodes suffer from uneven current diffusion and low stress resistance due to eutectic surface issues, resulting in low luminous brightness and efficiency.
Innovation Solution
A light-emitting element design featuring a semiconductor structure with a reflective structure, insulating structures, and conductive structures, including a Bragg reflector, that ensures uniform current distribution and stress resistance through a eutectic phase and planarization design, with flat-type bonding pads and an electrode ring configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional flip-chip LED structure is used, then luminous efficiency is improved, but current diffusion becomes uneven resulting in low luminous brightness
Solution Approach 1:
The patent applies local quality by creating different surface structures in different regions: the first pad has a protrusion structure while the second pad has a recession structure. These localized structural variations optimize current diffusion patterns in different areas, ensuring uniform current distribution across the eutectic junction while maintaining high luminous efficiency. This resolves the contradiction by locally modifying pad structures rather than using a uniform design.
Solution Approach 2:
The patent employs asymmetry by designing the first pad with a protrusion and the second pad with a recession, creating an asymmetric configuration. This asymmetric design enables differential current diffusion paths that collectively achieve uniform overall current distribution. The asymmetric structures allow electrons and holes to diffuse more evenly across the active region, increasing luminous brightness without sacrificing efficiency.
2Loss of energy
If traditional flip-chip LED structure is used, then luminous efficiency is improved, but eutectic surface uniformity deteriorates resulting in low stress resistance
Solution Approach 1:
The patent applies local quality by creating different surface structures in different regions: the first pad has a protrusion structure while the second pad has a recession structure. These localized structural variations optimize current diffusion patterns in different areas, ensuring uniform current distribution across the eutectic junction while maintaining high luminous efficiency. This resolves the contradiction by locally modifying pad structures rather than using a uniform design.
Solution Approach 2:
The patent employs asymmetry by designing the first pad with a protrusion and the second pad with a recession, creating an asymmetric configuration. This asymmetric design enables differential current diffusion paths that collectively achieve uniform overall current distribution. The asymmetric structures allow electrons and holes to diffuse more evenly across the active region, increasing luminous brightness without sacrificing efficiency.
3Illumination intensity
If protrusion or recession design is added to bonding pads, then current diffusion uniformity is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by creating different surface structures in different regions: the first pad has a protrusion structure while the second pad has a recession structure. These localized structural variations optimize current diffusion patterns in different areas, ensuring uniform current distribution across the eutectic junction while maintaining high luminous efficiency. This resolves the contradiction by locally modifying pad structures rather than using a uniform design.
Solution Approach 2:
The patent employs asymmetry by designing the first pad with a protrusion and the second pad with a recession, creating an asymmetric configuration. This asymmetric design enables differential current diffusion paths that collectively achieve uniform overall current distribution. The asymmetric structures allow electrons and holes to diffuse more evenly across the active region, increasing luminous brightness without sacrificing efficiency.
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
The design enhances luminous brightness and stress resistance by ensuring uniform current diffusion and improved light emission, addressing the limitations of existing flip-chip light-emitting diodes.
Implementation Method 1
a Bragg reflector formed on an upper surface of the reflective structure and a side wall of the semiconductor structure, in which the Bragg reflector comprises a plurality of pairs of sub-layers, and each of the sub-layers has a refractive index different from that of the adjacent sub-layers
Implementation Method 2
Light-Emitting Diode (LED) is a light-emitting element made of semiconductor material, which can convert the electrical energy to light
Data Source
AI summary
A light-emitting element is provided, including a semiconductor structure, a reflective structure, first insulating structures, a conductive structure, and first and second pads. The reflective structure is disposed on the semiconductor structure. The first insulating structure includes first and second insulating portions covering first and second portions respectively, and a gap exposes a third portion between the first and second portions. The conductive structure includes first and second conductive portion. The first conductive portion is disposed on the first insulating portion to contact the semiconductor structure. The second conductive portion is disposed on the second insulating portion to contact the third portion through the gap. The first and second pads are respectively disposed on the first and second conductive portions. Each of the structures below the first and second pads are in flat-type bonding to enhance stress resistance.