Carbon Nanotube Thermal Interface Material with Metallic Fill
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Solution Overview
Problem
Conventional thermal interface materials, particularly those using metallic and polymer-carbon nanotube composites, face limitations in heat conduction coefficient and mechanical stress due to high thermal expansion mismatch with semiconductor devices, necessitating a material with improved thermal conductivity and reduced mechanical stress.
Innovation Solution
A thermal interface material comprising an array of carbon nanotubes with interspaces filled with a low melting point metallic material, formed by depositing the metallic material onto the carbon nanotubes using physical vapor deposition, creating a metallic layer embedded within the carbon nanotube array.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metallic materials are used as thermal interface material, then heat conduction is improved, but thermal expansion mismatch causes mechanical stress and reliability deterioration
Solution Approach 1:
The patent uses a composite structure consisting of carbon nanotubes embedded in a polymer matrix. This composite combines the high thermal conductivity of carbon nanotubes with the low thermal expansion and flexibility of the polymer, achieving both improved heat conduction and reduced mechanical stress during temperature cycling.
Solution Approach 2:
The patent changes the material parameters by selecting a polymer with specific thermal expansion properties that match semiconductor devices, and incorporating carbon nanotubes to enhance thermal conductivity. This parameter optimization resolves the contradiction between heat conduction and thermal expansion mismatch.
2Reliability
If polymer-carbon nanotube composite is used, then thermal expansion mismatch is reduced, but heat conduction coefficient is restricted by the polymer
Solution Approach 1:
The patent creates a composite material where carbon nanotubes are dispersed in the polymer matrix. The carbon nanotubes form high-conductivity pathways for heat transfer, overcoming the limitation of the polymer's low thermal conductivity while maintaining the polymer's favorable thermal expansion properties.
Solution Approach 2:
The patent segments the thermal conduction pathway into multiple carbon nanotube-filled channels within the polymer matrix. This segmentation creates numerous parallel heat conduction paths, significantly enhancing the overall thermal conductivity of the composite material.
3Reliability
If carbon nanotubes protrude from polymer to contact components, then thermal contact is improved, but the polymer's low heat conduction restricts overall performance
Solution Approach 1:
The patent uses a composite structure where carbon nanotubes protrude from the polymer surface to ensure good thermal contact with electronic components, while the embedded carbon nanotubes within the polymer create internal heat conduction pathways, overcoming the polymer's inherent low thermal conductivity.
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 enhances thermal conductivity and reduces mechanical stress during temperature cycling, offering a higher performance thermal interface material suitable for modern electronic components with improved reliability and manufacturability.
Implementation Method 1
depositing the metallic material onto the carbon nanotubes using physical vapor deposition, creating a metallic layer embedded within the carbon nanotube array
Implementation Method 2
The particles can be made of graphite, boron nitride, silicon oxide, alumina, silver, or specially be made of carbon nanotubes. The carbon nanotubes are distributed orderly and provide a heat conduction path in the polymer
Data Source
AI summary
A thermal interface material includes an array of carbon nanotubes with interspaces defined therebetween; and a low melting point metallic material filled in the interspaces. A method for fabricating a thermal interface material, the method includes (a) providing an array of carbon nanotubes with interspaces defined therebetween; and (b) depositing a low melting point metallic material on the carbon nanotubes in the interspaces therebetween to form a metallic layer with the array of carbon nanotubes embedded therein, and thereby, achieving the thermal interface material.