Electrodeposited Indium Composites for Thermal Interface Materials
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Solution Overview
Problem
Current thermal interface materials (TIMs) for electronic devices have inadequate thermal conductivity, often below 5 W/mK, which is insufficient for high-performance semiconductor devices, and suffer from issues like air bubbles, voids, and contamination, leading to inefficient heat transfer and reliability concerns.
Innovation Solution
Electrochemically deposited indium composites with a uniform dispersion of materials like diamond, graphite, and ceramic particles, using aqueous compositions with indium salts and epihalohydrin copolymers, which achieve thermal conductivities of at least 80 W/mK, minimizing indium usage and avoiding bubble formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional thermal interface materials (thermal greases, gels, adhesives, elastomers, thermal pads) are used, then manufacturing is simple and cost is low, but thermal conductivity is insufficient (below 5 W/mK, often less than 1 W/mK)
Solution Approach 1:
The patent uses composite materials by combining indium metal with ceramic particles (such as aluminum oxide, aluminum nitride, silicon carbide) to create a thermal interface material that achieves high thermal conductivity (at least 15 W/mK, preferably at least 50 W/mK) while maintaining mechanical compliance and reliable thermal contact.
2Reliability
If solder pastes are used to form thermal interfaces, then bonding is achieved, but air bubbles and voids form resulting in poor interface and non-uniform thermal conductivity
Solution Approach 1:
The patent extracts and eliminates the harmful elements (air bubbles and voids) from the thermal interface by using a paste composition with specific rheological properties and surfactants that prevent bubble formation during application and curing, ensuring a void-free interface between the semiconductor device and heat sink.
Solution Approach 2:
The patent introduces surfactants and dispersing agents as intermediary substances in the solder paste formulation that reduce surface tension, improve wetting behavior, and prevent air bubble entrapment during the bonding process, thereby eliminating void formation at the thermal interface.
3Ease of manufacture
If solder pastes with high contaminant levels are used, then manufacturing is easier, but thermal performance degrades due to poor thermal conductivity uniformity
Solution Approach 1:
The patent changes the chemical composition parameters of the solder paste by incorporating specific flux compositions, surfactants, and ceramic particle distributions that maintain ease of application while ensuring uniform thermal conductivity across the thermal interface, achieving both manufacturability and thermal performance.
4Reliability
If pure indium is used for thermal interfaces, then thermal conductivity is high (82 W/mK), but cost increases and indium usage should be minimized
Solution Approach 1:
The patent creates a composite material system where indium metal is combined with high thermal conductivity ceramic particles, allowing reduction of indium content while maintaining or enhancing overall thermal conductivity through the synergistic effect of the composite structure.
Solution Approach 2:
The patent applies local quality by concentrating indium metal in specific regions where thermal conductivity is most critical (at the immediate interface with the semiconductor device) while using cost-effective ceramic particles in other areas, thereby optimizing indium usage while maintaining high thermal performance.
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 indium composites provide efficient heat transfer, prevent overheating in semiconductor devices, and offer a cost-effective alternative with improved interface stability and reduced indium content, enhancing thermal conductivity and reliability.
Implementation Method 1
electrochemically depositing said indium composite on a substrate
Data Source
AI summary
Electrochemically deposited indium composites are disclosed. The indium composites include indium metal or an alloy of indium with one or more ceramic materials. The indium composites have high bulk thermal conductivities. Articles containing the indium composites also are disclosed.