Carbon Nanotube Sheet Thermal Interface Material
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Solution Overview
Problem
Conventional heat radiation materials using carbon nanotubes fail to adequately utilize their high thermal conductivity, and existing thermal interface materials like PCM and indium have limitations in thermal conductivity and compatibility with semiconductor elements.
Innovation Solution
A heat radiation material comprising linear structures of carbon atoms, specifically carbon nanotubes, are arranged in a sheet structure with a thermoplastic resin filling layer to enhance thermal conductivity and electric conductivity, allowing direct contact with heat sources and spreaders, and a method of manufacturing this sheet involving substrate growth and thermoplastic resin processing to optimize thermal contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If PCM is used as thermal interface material to contact minute concavities and convexities, then contact area is improved, but thermal conductivity deteriorates (about 1-5 W/m·K)
Solution Approach 1:
The patent uses a composite structure combining carbon nanotubes (providing high thermal conductivity) with a thermoplastic resin matrix (providing conformability to surfaces). This composite approach allows the material to simultaneously achieve high thermal conductivity while maintaining good contact with minute concavities and convexities on semiconductor element surfaces.
2Area of stationary object
If indium is used as thermal interface material, then contact area is improved, but thermal conductivity deteriorates (about 50 W/m·K)
Solution Approach 1:
The patent employs a composite material system where carbon nanotubes are embedded in a thermoplastic resin. The carbon nanotubes provide exceptional thermal conductivity (approximately 1500 W/m·K), significantly outperforming indium, while the thermoplastic resin ensures conformability to surface irregularities, achieving both high thermal conductivity and good contact area.
3Reliability
If carbon nanotubes are used to achieve high thermal conductivity, then thermal conductivity is improved (about 1500 W/m·K), but contact area deteriorates due to flexibility loss
Solution Approach 1:
The patent creates a composite where rigid carbon nanotubes (providing high thermal conductivity) are embedded in a flexible thermoplastic resin matrix. The resin acts as a flexible binder that allows the carbon nanotube structure to conform to surface irregularities, maintaining good contact area while preserving the high thermal conductivity of the carbon nanotubes.
Solution Approach 2:
The patent utilizes the temperature-dependent properties of the thermoplastic resin, which becomes more flexible at elevated temperatures. This parameter change allows the material to better conform to surface irregularities during operation, improving contact area while maintaining the high thermal conductivity pathway provided by the carbon nanotubes.
4Reliability
If film thickness is reduced to improve thermal conductivity of PCM, then thermal conductivity is improved, but adaptability deteriorates (cannot absorb concavities and convexities)
Solution Approach 1:
The patent uses a composite material where the thermoplastic resin provides the necessary thickness and flexibility to absorb surface irregularities, while the embedded carbon nanotubes provide the high thermal conductivity. This composite structure eliminates the need to thin the film to achieve high thermal conductivity, as the carbon nanotubes maintain high conductivity even at greater thicknesses where the resin can conform to surface variations.
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 carbon nanotube sheet achieves significantly improved thermal conductivity and electric conductivity, effectively managing heat radiation from semiconductor elements with reduced thermal contact resistance and increased reliability in electronic devices.
Implementation Method 1
linear structures of carbon atoms represented by carbon nanotubes are noted as a material having higher thermal conductivity than PCM and indium. The carbon nanotubes not only have a very high thermal conductivity (about 1500 [W/m·K])
Implementation Method 2
The carbon nanotubes not only have a very high thermal conductivity (about 1500 [W/m·K]), but also is superior in flexibility and heat resistance
Data Source
AI summary
The electronic device includes a heat generator 54, a heat radiator 58, and a heat radiation material 56 disposed between the heat generator 54 and the heat radiator 58 and including a plurality of linear structures 12 of carbon atoms and a filling layer 14 formed of a thermoplastic resin and disposed between the plurality of linear structures 12.