Non-uniform Covering Layer Carbon Nanotube Sheet
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Solution Overview
Problem
The thermal conduction in thermal interface materials used in electronic devices becomes non-uniform due to differences in thermal expansion coefficients between semiconductor devices and circuit boards, leading to uneven contact pressure and increased thermal resistance.
Innovation Solution
A carbon nanotube sheet with a bundle structure oriented in a predetermined direction, a covering layer with non-uniform thickness, and a filling layer is used between the carbon nanotubes, allowing for uniform contact pressure and consistent thermal conduction by adjusting the thickness of the covering layer to maintain constant stress across the sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thermal conduction sheet with uniform covering layer thickness is used, then the manufacturing process is simple, but the thermal conduction becomes non-uniform due to deformation from thermal expansion differences
Solution Approach 1:
The covering layer thickness is made non-uniform to compensate for the non-uniform deformation caused by thermal expansion differences. Specifically, the covering layer is thicker in regions that experience greater compression during deformation, ensuring that the carbon nanotubes maintain consistent contact pressure with the heat generation source across the entire surface.
2Temperature
If carbon nanotubes are used for high thermal conductivity, then heat dissipation performance is improved, but the sheet becomes sensitive to deformation from thermal expansion differences
Solution Approach 1:
The non-uniform covering layer acts as a pre-designed compensation mechanism that anticipates the deformation caused by thermal expansion differences. By building in the thickness variation beforehand, the carbon nanotubes are protected from developing non-uniform contact pressure, maintaining stable thermal resistance and reliable heat dissipation performance throughout operation.
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 ensures consistent thermal conduction and mechanical strength across the carbon nanotube sheet, maintaining low thermal resistance and effective heat dissipation even under deformation, thereby improving the thermal management in electronic devices.
Implementation Method 1
The plurality of carbon nanotubes 111 are oriented in the thickness direction of the thermal conduction sheet 110 and conduct heat of the semiconductor device 132 to the heat spreader 133
Implementation Method 2
By being heated in the reflow process, the solders 135 are melted and the circuit board 131 and the semiconductor device 132 are soldered. By the reflow process, the filling layer in the thermal conduction sheet 110 is melted to a liquid state and the thermal conduction sheet 110 is adhered to the semiconductor device 132 and the heat spreader 133
Implementation Method 3
the thermal conduction sheet 110 is adhered to the semiconductor device 132 and the heat spreader 133
Implementation Method 4
By the heating of the reflow process, the circuit board 131 and the semiconductor device 132 are thermally-expanded
Data Source
AI summary
A sheet structure has: a bundle structure including a plurality of linear structures made of carbon which are oriented in a predetermined direction; a covering layer covering the plurality of linear structures made of carbon; and a filling layer provided between the plurality of linear structures made of carbon covered with the covering layer. The thickness of the covering layer is not uniform in a direction crossing the predetermined direction.