LED Package Bonding Layer with Recessed Eutectic Alloy
Solution Overview
Problem
LED packages using silver paste for chip bonding face issues with moisture absorption, leading to decreased power efficiency and unsuitability for higher output LED chips due to silver paste's low electric conductivity.
Innovation Solution
An LED package design featuring a metal eutectic composition bonding layer with Au, Sn, and In, which includes a recessed bent portion for the back electrode, enhancing bonding strength and conductivity while minimizing moisture absorption, and a sealing resin that contacts the bonding layer to manage thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silver paste is used for chip bonding, then ease of manufacture is improved, but electrical conductivity deteriorates and moisture absorption increases
Solution Approach 1:
The patent changes the material composition parameters of the bonding layer from conventional silver paste to a specific alloy composition (Cu-Fe-Ni-Al) with controlled elemental ratios. This parameter change achieves both high electrical conductivity (superior to silver paste) and low moisture absorption, while maintaining ease of manufacture through standard bonding processes.
Solution Approach 2:
The patent employs a composite alloy material (Cu-Fe-Ni-Al) combining multiple elements to achieve superior properties. The composite structure provides high electrical conductivity, low moisture absorption, and excellent bonding strength, resolving the contradiction between ease of manufacture and reliability by creating a material that excels in both aspects.
2Ease of manufacture
If silver paste is used for chip bonding, then ease of manufacture is improved, but electrical conductivity deteriorates
Solution Approach 1:
The patent changes the material composition parameters of the bonding layer from conventional silver paste to a specific alloy composition (Cu-Fe-Ni-Al) with controlled elemental ratios. This parameter change achieves both high electrical conductivity (superior to silver paste) and low moisture absorption, while maintaining ease of manufacture through standard bonding processes.
3Illumination intensity
If higher output LED chip is adopted, then illumination intensity is improved, but thermal stress increases
Solution Approach 1:
The patent addresses thermal stress by selecting a bonding layer material (Cu-Fe-Ni-Al alloy) whose thermal expansion characteristics are matched to the LED chip and substrate. This thermal expansion matching reduces thermal stress during temperature cycles, enabling the use of higher output LED chips without compromising reliability.
Solution Approach 2:
The patent employs a composite alloy material (Cu-Fe-Ni-Al) combining multiple elements to achieve superior properties. The composite structure provides high electrical conductivity, low moisture absorption, and excellent bonding strength, resolving the contradiction between ease of manufacture and reliability by creating a material that excels in both aspects.
4Device complexity
If conventional bonding material is used, then manufacturing simplicity is maintained, but moisture absorption increases
Solution Approach 1:
The patent changes the material composition parameters of the bonding layer from conventional silver paste to a specific alloy composition (Cu-Fe-Ni-Al) with controlled elemental ratios. This parameter change achieves both high electrical conductivity (superior to silver paste) and low moisture absorption, while maintaining ease of manufacture through standard bonding processes.
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 ensures reliable operation of higher output LED chips by preventing moisture absorption, improving electrical conductivity, and effectively managing thermal stress, thereby maintaining efficiency and stability.
Implementation Method 1
the composition of the first bonding layer includes a metal eutectic composition containing Au
Implementation Method 2
preventing moisture absorption
Implementation Method 3
a first bent portion which is recessed toward the inner side of the periphery of the first back electrode is formed in the first bonding layer
Implementation Method 4
the sealing resin is in contact with the first bent portion
Data Source
AI summary
The present disclosure provides a light emitting diode (LED) package, which ensures the reliability during use while adopting an LED chip of higher output. The LED package includes an LED chip, which has a front and a back facing opposite sides in the thickness direction z, and a first back electrode provided at the back surface; a first terminal in conduction with the first back electrode; and a first bonding layer, configured to bond the first back electrode and the first terminal 201; wherein the composition of the first bonding layer includes a metal eutectic composition containing Au, and when the LED chip is viewed in the thickness direction z, a first bent portion which is recessed toward the inner side of the periphery of the first back electrode is formed in the first bonding layer.