Semiconductor Light-Emitting Device Connection Metal Layer Heat Conductivity
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Solution Overview
Problem
Semiconductor light-emitting devices face reliability issues due to the high reactivity of gold with solder materials, leading to volume expansion and potential electrical shorts during the reflow process, which can cause cracks in the connection metal layer and adjacent layers.
Innovation Solution
The use of a connection metal layer with a higher heat conductivity than gold, such as copper, and a barrier layer to prevent diffusion of solder materials, along with a protective insulating layer and UBM pattern design to inhibit reaction and maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gold is used as the connection metal layer, then electrical conductivity is improved, but reactivity with solder materials increases causing volume expansion and cracks
Solution Approach 1:
A barrier layer is introduced as an intermediary between the connection metal layer and the UBM pattern/solder materials. This barrier layer prevents direct contact and reaction between the connection metal (whether gold or alternative material) and solder materials, eliminating the harmful reactivity and volume expansion effects while preserving electrical conductivity.
Solution Approach 2:
The patent changes the material parameter of the connection metal layer from exclusively gold to alternative materials with higher heat conductivity such as copper or aluminum. This parameter change improves heat dissipation while the barrier layer compensates for any reactivity concerns, achieving a better overall performance balance.
2Temperature
If copper is used as the connection metal layer, then heat conductivity is improved, but reactivity with solder materials may increase
Solution Approach 1:
The barrier layer serves as a protective intermediary that allows copper or other high heat-conductivity materials to be used in the connection metal layer without suffering from their reactivity with solder. The barrier layer blocks direct chemical interaction while permitting thermal energy transfer, thus achieving high heat conductivity without the harmful reactivity effects.
3Reliability
If a barrier layer is added to prevent diffusion, then reliability is improved, but device complexity increases
Solution Approach 1:
The connection structure is segmented into distinct functional layers: the connection metal layer for electrical connectivity, the barrier layer for diffusion prevention, and the UBM pattern for solder attachment. This segmentation allows each layer to perform its specific function optimally, improving overall reliability while maintaining a manageable and systematic structure that is easier to manufacture with standard semiconductor 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
This configuration enhances the reliability of semiconductor light-emitting devices by reducing the occurrence of cracks and electrical shorts, ensuring stable electrical connections and improved device performance.
Implementation Method 1
The connection metal layer includes a first metal element of which a heat conductivity is higher than that of gold (Au)
Implementation Method 2
A barrier layer is disposed between the connection metal layer and the UBM pattern and extends between the UBM pattern and the protective insulating layer
Implementation Method 3
electrons and holes of a junction-type semiconductor may be recombined with each other to generate energy, and the generated energy may be converted into light
Data Source
AI summary
A semiconductor light-emitting device includes a light-emitting structure including a first semiconductor layer, an active layer and a second semiconductor layer sequentially stacked. A connection electrode is positioned above the light-emitting structure. The connection electrode includes a connection metal layer electrically connected to at least one of the first and second semiconductor layers. A UBM pattern is on the connection electrode. A connection terminal is on the UBM pattern. The connection metal layer includes a first metal element. A heat conductivity of the first metal element is higher than that of gold (Au). The connection terminal includes a second metal element. A first reactivity of the first metal element with the second metal element is lower than a second reactivity of gold (Au) with the second metal element.