Vertical LED Current Blocking via Anisotropic Conductive Film
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Solution Overview
Problem
Traditional vertical LED structures face issues with heat dissipation, uneven current distribution, and poor reliability due to horizontal electrode distribution and side injection of current, which are not effectively addressed by existing technologies.
Innovation Solution
A vertical LED with a current blocking function is achieved by using a conductive substrate with a concave-convex structure and an anisotropic conductive material layer that forms a bonding layer with vertical conduction and horizontal insulation, allowing for efficient current blocking between the substrate and the light-emitting epitaxial layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wafer bonding with high pressure and high temperature is used to bond metal layers, then electrical connection is achieved, but heat dissipation performance deteriorates and manufacturing complexity increases
Solution Approach 1:
The patent introduces an anisotropic conductive adhesive film as an intermediary bonding layer between the LED chip and substrate. This film contains conductive particles that provide electrical connection while its adhesive matrix enables thermal contact, serving as a mediator that simultaneously addresses both electrical and thermal requirements without requiring high-pressure wafer bonding
Solution Approach 2:
The patent changes the bonding parameters from high pressure and high temperature (traditional wafer bonding) to low pressure and low temperature (adhesive film bonding). The anisotropic conductive adhesive film enables reliable bonding at significantly reduced temperature and pressure parameters, improving heat dissipation while maintaining electrical connection
2Reliability
If traditional wafer bonding with metal coating is used, then electrical connection is achieved, but manufacturing process complexity and cost increase
Solution Approach 1:
The patent replaces expensive precious metal bonding layers (Au, Au-Sn) with a cost-effective anisotropic conductive adhesive film. This disposable adhesive film provides the necessary electrical and thermal functions without requiring costly metal coating processes, significantly reducing material costs and simplifying manufacturing
Solution Approach 2:
The patent extracts and eliminates the complex metal coating and high-pressure bonding steps from the manufacturing process. By using the anisotropic conductive adhesive film, the process removes the need for sputtering, evaporation, or electroplating of metal layers, and eliminates the requirement for high-pressure wafer bonding equipment
3Ease of manufacture
If horizontal electrode distribution is used in standard and flip-chip structures, then fabrication is simplified, but current distribution becomes uneven and reliability decreases
Solution Approach 1:
The patent transitions from horizontal electrode distribution (standard and flip-chip structures) to vertical electrode distribution. The anisotropic conductive adhesive film enables vertical current injection through the bonding layer, changing the dimension of current flow from horizontal to vertical, which improves current distribution uniformity and reduces edge effects
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 solution enhances heat dissipation, ensures even current distribution, and improves reliability by creating a current blocking structure that simplifies fabrication and increases stability, while reducing production costs by replacing precious metal bonding with anisotropic conductive adhesive film.
Implementation Method 1
the anisotropic conductive material layer is conductive at vertical direction and insulated at horizontal direction
Implementation Method 2
the anisotropic conductive material forms a bonding layer with vertical conduction and horizontal insulation between the concave-convex substrate and the light-emitting epitaxial layer
Data Source
AI summary
A vertical LED with current blocking structure and its associated fabrication method involve an anisotropic conductive material and a conductive substrate with concave-convex structure. The anisotropic conductive material forms a bonding layer with vertical conduction and horizontal insulation between the concave-convex substrate and the light-emitting epitaxial layer, thereby forming a vertical LED with current blocking function.