LED Flip-Chip Substrate Using Ceramic and Aluminum for Thermal Management
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Solution Overview
Problem
Conventional LED flip-chip packaging materials face a contradiction between properties such as heat conductivity, electrical insulation, stability, and reflectivity, with no material excelling in all aspects, especially in the ultraviolet wave band.
Innovation Solution
A LED flip-chip package substrate is designed with a ceramic base, a conductive wire layer, an insulating protective layer, and a metallic reflective layer, along with an optical anti-reflective film, utilizing materials like bismaleimide-triazine, low-temperature glass glaze, and magnesium fluoride to achieve high heat conductivity, reflectivity, and insulation while maintaining stability across various wave bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mirror aluminum material is used, then heat conductivity and reflectivity are improved, but electrical insulation deteriorates
Solution Approach 1:
The patent uses a composite structure combining aluminum nitride ceramic substrate with mirror aluminum reflective layer and epoxy molding compound encapsulation. The aluminum nitride ceramic provides both high heat conductivity (200-250 W/mK) and electrical insulation, while the mirror aluminum layer adds reflectivity. This composite approach resolves the contradiction by integrating multiple materials with complementary properties rather than relying on a single material.
2Temperature
If ceramic material is used, then heat conductivity, stability and electrical insulation are improved, but reflectivity deteriorates
Solution Approach 1:
The patent combines aluminum nitride ceramic substrate with a mirror aluminum reflective layer deposited on the packaging surface. The ceramic provides thermal and electrical properties, while the aluminum layer provides high reflectivity (95%+ across UV-IR spectrum). This composite structure allows simultaneous achievement of high heat conductivity, electrical insulation, and superior reflectivity.
3Illumination intensity
If polymer material such as EMC/SMC is used, then reflectivity is improved, but heat conductivity, electrical insulation and stability deteriorate
Solution Approach 1:
The patent uses aluminum nitride ceramic substrate with high heat conductivity (200-250 W/mK) and superior electrical insulation properties, combined with mirror aluminum reflective layer for high reflectivity. The epoxy molding compound encapsulation provides additional protection. This composite approach overcomes the limitations of polymer materials by using ceramic as the base substrate, which provides the thermal and electrical properties that polymers lack.
4Ease of manufacture
If conventional materials are used, then manufacturing simplicity is maintained, but comprehensive performance (heat conductivity, reflectivity, insulation, stability) deteriorates
Solution Approach 1:
The patent employs a multi-layer composite structure including aluminum nitride ceramic substrate, mirror aluminum reflective layer, and epoxy molding compound encapsulation. While this increases material complexity, the manufacturing process follows conventional LED packaging steps: substrate preparation, chip mounting, encapsulation, and curing. The composite materials enable simultaneous achievement of high heat conductivity, electrical insulation, UV stability, and reflectivity, resolving the performance limitations of single materials.
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 solution provides an LED package structure with high heat conductivity, reflectivity, stability, and superior insulation, enhancing light extraction efficiency and reliability, particularly effective for ultraviolet LEDs by comprehensively utilizing the advantages of different materials.
Implementation Method 1
the reflectivity of the metallic reflective layer in a wave band from deep ultraviolet to infrared is more than 95%
Implementation Method 2
an optical anti-reflective film disposed on a side of the metallic reflective layer facing away from the insulating protective layer
Implementation Method 3
a ceramic base, a conductive wire layer
Data Source
AI summary
A LED flip-chip package substrate includes a ceramic base (e.g., aluminum nitride base), a conductive wire layer disposed on the ceramic base and having pads in pairs, an insulating protective layer (e.g., low-temperature glass glaze layer) disposed on a same side of the ceramic base as the conductive wire layer and exposing the pads, and a metallic reflective layer (e.g., aluminum layer) disposed on a side of the insulating protective layer facing away from the ceramic base and exposing the pads. Moreover, a LED package structure adopting the LED flip-chip package substrate and other LED package structures with similar material layers such as a chip-level packaged LED package structure are provided. By comprehensively utilizing advantages of various materials, the LED flip-chip package substrate with high heat conductivity, high reflectivity, high stability and superior insulation and the LED package structure with high reliability and even high light extraction efficiency are obtained.