Composite Die-Attach Solder for High Thermal Conductivity
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Solution Overview
Problem
Current solder materials used in electronic packaging face limitations in thermal conductivity, leading to hot spots and reduced reliability in high-power applications, particularly due to void formation and the toxicity of lead-based alloys, which necessitates a lead-free solder with enhanced thermal dissipation capabilities.
Innovation Solution
A solder material comprising a solder alloy combined with a thermal conductivity modifying component, such as embedded copper wires, to achieve a bulk thermal conductivity of between 75 and 150 W/m-K, thereby improving heat dissipation and mechanical strength beyond traditional solder capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional solder materials are used, then mechanical bonding is achieved, but thermal conductivity is insufficient leading to hot spots
Solution Approach 1:
The patent uses composite materials by combining solder alloy with high thermal conductivity filler particles (such as silver, copper, or aluminum oxide) to create a die attach material that simultaneously provides mechanical bonding and enhanced thermal conductivity. This composite structure resolves the contradiction by integrating multiple functions into a single material system.
Solution Approach 2:
The patent changes the physical and chemical parameters of the solder material by adjusting the composition ratios of solder alloy and filler particles, controlling particle size distribution, and optimizing the microstructure. These parameter changes enable the material to achieve both adequate mechanical strength and high thermal conductivity, resolving the thermal conductivity-reliability contradiction.
2Temperature
If lead-based solder alloys are used, then thermal conductivity is improved, but toxicity increases
Solution Approach 1:
The patent changes the chemical composition parameters by replacing lead-based alloys with lead-free solder alloys (such as SnAgCu, SnBi, or SnZn) while adjusting the filler particle composition and distribution. This parameter change eliminates toxicity while maintaining or enhancing thermal conductivity through the composite structure, resolving the contradiction between thermal performance and environmental safety.
Solution Approach 2:
The patent uses composite materials to compensate for the lower inherent thermal conductivity of lead-free solders by incorporating high thermal conductivity filler particles. This composite approach allows the material to achieve thermal conductivity levels comparable to or exceeding lead-based solders without the associated toxicity, resolving the harmful factors-thermal conductivity contradiction.
3Ease of operation
If solder paste is used, then ease of application is improved, but solder volume and joint strength are insufficient for large devices
Solution Approach 1:
The patent segments the solder material into discrete filler particles distributed within the solder alloy matrix. This segmentation allows for controlled volume and distribution of solder material, enabling adequate joint strength for large devices while maintaining the ease of application characteristics of paste form. The segmented structure also facilitates better wetting and flow properties.
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 enhanced thermal conductivity and mechanical strength of the solder material ensure effective heat transfer and reliability, reducing the risk of hot spots and extending the service life of high-power electronic devices by allowing for efficient heat dissipation and stable performance under high temperatures.
Implementation Method 1
solder material comprising a solder alloy and a thermal conductivity modifying component, wherein the solder material has a bulk thermal conductivity of between 75 and 150 W/m-K
Data Source
AI summary
A solder material comprising a solder alloy and a thermal conductivity modifying component. The solder material has a bulk thermal conductivity of between about 75 and about 150 W/m-K and is usable in enhancing the thermal conductivity of the solder, allowing for optimal heat transfer and reliability in electronic packaging applications.