Composite Electroplated Substrate for LED Thermal Stress Management
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Solution Overview
Problem
Vertical type light-emitting diodes (LEDs) often crack during manufacturing due to differences in thermal expansion coefficients of materials, affecting their lifetime, and high temperature processes for composite electroplating are not suitable for light-emitting diode chip production.
Innovation Solution
A light-emitting diode structure incorporating a composite electroplated substrate with a reflective layer, seed layer, interfacial layer, intermediate layer, and protection layer, utilizing materials like copper-diamond, nickel-silicon carbide, and multiple-film layers to manage thermal expansion and stress, including materials such as copper, gold, nickel, and titanium for enhanced thermal conductivity and toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal matrix composite material is produced by fusing materials in a high temperature process, then high thermal conductivity and low thermal expansion coefficient are achieved, but the process is not suitable for light-emitting diode chip manufacturing
Solution Approach 1:
The patent changes the processing parameters from high temperature fusion to low temperature electroplating process. The electroplating process operates at temperatures suitable for LED chip manufacturing while still achieving composite material formation with desired thermal properties.
Solution Approach 2:
The patent replaces the thermal fusion process with an electrochemical deposition process. Instead of using high temperature to fuse materials, electroplating is used to deposit composite material layers onto the substrate, achieving the same functional result through a different physical mechanism.
2Temperature
If conventional bonding or electroplating technology is used to attach light-emitting diodes to metal substrate, then heat dispersion is optimized, but the light-emitting diode wafer often cracks due to difference in thermal expansion coefficients
Solution Approach 1:
The patent uses composite electroplating material consisting of metal matrix with dispersed particles (such as diamond, silicon carbide, or aluminum oxide). This composite structure provides both high thermal conductivity for heat dispersion and tailored thermal expansion coefficient to match the LED wafer, preventing cracks.
Solution Approach 2:
The patent applies different material compositions at different locations or layers. The electroplated substrate has a composite structure with specific local properties - the metal matrix provides thermal conductivity while the dispersed particles adjust the thermal expansion coefficient, creating a gradient or layered structure that accommodates thermal stress.
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 effectively reduces stress and enhances the thermal management of light-emitting diodes, improving their reliability and longevity by optimizing the material selection and layer configuration for the composite electroplated substrate.
Implementation Method 1
the principle is to precipitate and co-coat nickel and silicon carbide on the substrate by the electroplating solution containing the nickel ions with the inert silicon carbide particles suspended therein
Data Source
AI summary
The application is related to a method of forming a substrate of a light-emitting diode by composite electroplating. The application illustrates a light-emitting diode comprising the following elements: a light-emitting epitaxy structure, a reflective layer disposed on the light-emitting epitaxy structure, a seed layer disposed on the reflective layer, a composite electroplating substrate disposed on the seed layer by composite electroplating, and a protection layer disposed on the composite electroplating substrate.