Thermally Conductive Sheet with Thickness-Oriented Fillers
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Solution Overview
Problem
Conventional thermally conductive sheets used in semiconductor elements often have high contact thermal resistance due to their anisotropic filler alignment and lack of flexibility, which hinders efficient heat dissipation and adhesion to adherends, especially when used in inclined or uneven surfaces.
Innovation Solution
A thermally conductive sheet with a binder resin and a first thermally conductive filler aligned in the thickness direction, achieving a contact thermal resistance of 0.46° C·cm2/W or less, is produced by dispersing the filler in a resin composition, forming a molded block, and slicing it into a sheet, optimizing filler orientation and adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermally conductive sheet is made by highly filling with thermally conductive filler to improve thermal conductivity, then thermal conductivity is improved, but flexibility deteriorates and contact thermal resistance increases
Solution Approach 1:
The patent uses a composite material system consisting of thermally conductive filler particles dispersed in a flexible polymer matrix. This composite structure allows the sheet to maintain high thermal conductivity through the filler while preserving flexibility through the polymer binder, resolving the contradiction between thermal performance and mechanical flexibility.
Solution Approach 2:
The patent optimizes the filler volume fraction and particle size distribution to achieve the desired balance. By controlling these parameters, the sheet achieves sufficient thermal conductivity while maintaining adequate flexibility for practical application, addressing the trade-off between thermal performance and mechanical properties.
2Temperature
If a thermally conductive sheet is made by highly filling with thermally conductive filler to improve thermal conductivity, then thermal conductivity is improved, but contact thermal resistance increases
Solution Approach 1:
The patent employs a flexible polymer matrix that allows the thermally conductive sheet to conform to the surface topology of adherends. This flexibility enables intimate contact between the sheet and irregular surfaces, reducing contact thermal resistance while maintaining high bulk thermal conductivity through the filler content.
Solution Approach 2:
The patent optimizes the filler volume fraction and particle size distribution to achieve the desired balance. By controlling these parameters, the sheet achieves sufficient thermal conductivity while maintaining adequate flexibility for practical application, addressing the trade-off between thermal performance and mechanical properties.
3Force
If the thermally conductive sheet is made thinner to reduce load on adherend, then mechanical load is reduced, but contact thermal resistance increases
Solution Approach 1:
The patent employs a flexible polymer matrix that allows the thermally conductive sheet to conform to the surface topology of adherends. This flexibility enables intimate contact between the sheet and irregular surfaces, reducing contact thermal resistance while maintaining high bulk thermal conductivity through the filler content.
4Reliability
If the thermally conductive sheet is made softer to provide low contact thermal resistance, then contact thermal resistance is reduced, but mechanical strength deteriorates
Solution Approach 1:
The patent uses a composite material system consisting of thermally conductive filler particles dispersed in a flexible polymer matrix. This composite structure allows the sheet to maintain high thermal conductivity through the filler while preserving flexibility and adequate mechanical strength through the polymer binder, resolving the contradiction between thermal performance and mechanical flexibility.
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 provides a thermally conductive sheet with low contact thermal resistance and high thermal conductivity, enabling effective heat dissipation and flexibility, suitable for use in semiconductor elements with varying surface shapes.
Implementation Method 1
a first thermally conductive filler aligned in a thickness direction of the thermally conductive sheet... carbon fibers as a thermally conductive filler are known to have a thermal conductivity of approximately 600 to 1,200 W/m·K in a fiber direction
Data Source
AI summary
A thermally conductive sheet includes: a binder resin; and a first thermally conductive filler oriented in a thickness direction of the thermally conductive sheet. The thermally conductive sheet has a contact thermal resistance with regard to an adherend of 0.46° C.·cm2/W or less. The first thermally conductive filler is preferably a fibrous thermally conductive filler and/or a flaky thermally conductive filler. The thermally conductive sheet preferably further includes a second thermally conductive filler which is at least one selected from a group consisting of alumina, aluminum, zinc oxide, boron nitride, aluminum nitride, graphite, and a magnetic powder.