Flip-Chip LED Current Path Doping for Lower Current Density
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Solution Overview
Problem
Conventional flip-chip light emitting diodes (LEDs) face issues with excessive current density leading to heating, poor electrostatic discharge, and limited luminous efficiency due to straight-line current conduction paths.
Innovation Solution
A manufacturing method that forms high-doping concentration path areas in the current conduction layer through diffusion processes, redirecting current flow to non-linear paths to reduce density and increase emitting area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If straight-line current conduction paths are used between P and N metal electrodes, then current conduction efficiency is improved, but current density becomes excessively high causing heating and poor electrostatic discharge
Solution Approach 1:
The current conduction path is segmented into multiple regions by introducing intermediate electrode structures between the P and N metal electrodes. This segmentation divides the direct straight-line conduction path into multiple segments, redistributing the current density across different spatial regions and reducing peak current density while maintaining overall conduction efficiency.
Solution Approach 2:
The invention transitions from a two-dimensional planar current conduction path to a three-dimensional structure by adding intermediate electrodes at different heights or layers. This dimensional change allows current to flow through multiple spatial pathways, effectively increasing the conduction cross-sectional area and reducing current density without compromising conduction efficiency.
2Area of stationary object
If the emitting surface area is increased, then luminous efficiency should improve, but current still conducts along the shortest path forming a longitudinally shaped surface light source
Solution Approach 1:
Different regions of the emitting surface are assigned different functional qualities through the introduction of intermediate electrodes. These intermediate electrodes create localized current conduction zones that guide current flow across the entire emitting surface area, ensuring uniform current distribution and maximizing luminous efficiency across all regions of the expanded emitting surface.
Solution Approach 2:
Intermediate electrodes are introduced as mediator structures between the P and N metal electrodes. These intermediary elements redirect and distribute current flow across the expanded emitting surface, preventing direct shortest-path conduction and ensuring that the entire emitting area contributes effectively to light emission, thereby maintaining high luminous efficiency.
3Ease of manufacture
If conventional electrode positioning is used, then manufacturing simplicity is maintained, but heat dissipation and electrostatic discharge resistance are poor
Solution Approach 1:
The electrode structure is designed with nested intermediate electrodes positioned between the outer P and N metal electrodes. This nested configuration allows multiple electrode elements to be integrated within the overall device structure without significantly increasing manufacturing complexity, while the intermediate electrodes provide additional current distribution pathways that improve heat dissipation and electrostatic discharge resistance.
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 heat dissipation and electrostatic discharge resistance while increasing the light emitting area and brightness by dispersing current more uniformly.
Implementation Method 1
performing a diffusion process toward the bonding surface by a diffusion material to form at least one path area with a high doping concentration in the current conductive layer
Implementation Method 2
performing an epitaxial process to form a semiconductor structure on the first substrate, wherein the semiconductor structure includes a first semiconductor epitaxial layer, a light emitting layer, a second semiconductor epitaxial layer
Data Source
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AI summary
A method for manufacturing a flip-chip light emitting diode is provided. The method includes the following steps: providing a first substrate; performing an epitaxial process to form a semiconductor structure on the first substrate, and the semiconductor structure includes a current conductive layer with a bonding surface and defines a first electrode projection area and a second electrode projection area; performing a diffusion process toward the bonding surface by a diffusion material to form at least one path area with a high doping concentration in the current conductive layer; performing a bonding process to bond a second substrate to the bonding surface; and removing the first substrate and forming a first electrode and a second electrode on a side of the semiconductor structure adjacent to the first substrate. A position of the first electrode corresponds to the first electrode projection area, and a position of the second electrode corresponds to the second electrode projection area.