Silicon Carbide Composite Heat Sink for Power Modules
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Solution Overview
Problem
Conventional heat dissipating components face challenges with heavy weight, insufficient heat dissipation, and high production costs due to thermal expansion differences between ceramic substrates and heat sinks, and metal-ceramic composites require complex joint structures and high processing costs to achieve desired thermal conductivity and expansion matching.
Innovation Solution
A silicon carbide composite with a plate thickness of 2-6 mm, specific warpage, and aluminum metal layers is formed by pressure impregnation, allowing for controlled thermal expansion and high thermal conductivity, enabling efficient heat dissipation with reduced processing costs and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heavy metal materials such as Mo or W are used as heat sinks, then reliability is improved, but weight increases and heat dissipation ability becomes insufficient
Solution Approach 1:
The invention uses a metal-ceramic composite material (aluminum matrix with silicon carbide particles) that combines the low density of aluminum (2.7 g/cm³) with the low thermal expansion coefficient of silicon carbide (4.5×10⁻⁶/℃). This composite achieves both lightweight properties and thermal expansion matching with ceramic substrates, eliminating the need for heavy metals like Mo or W while maintaining joint structure reliability.
Solution Approach 2:
The invention changes the material parameters by selecting aluminum as the base metal and silicon carbide as the reinforcing particle, specifically tuning the composite's thermal expansion coefficient to match ceramic substrates (6-10×10⁻⁶/℃). This parameter optimization allows the use of lightweight aluminum-based materials instead of heavy metals, while achieving reliable joint structures through thermal expansion compatibility.
2Loss of energy
If Cu or Al are used as heat sinks, then heat dissipation ability and lightweight properties are improved, but thermal expansion difference with ceramic substrate increases, requiring complicated joint structures
Solution Approach 1:
The invention employs a metal-ceramic composite (aluminum matrix with silicon carbide particles) that maintains the excellent heat dissipation properties of aluminum while reducing thermal expansion through the incorporation of low-expansion silicon carbide particles. This composite material directly matches the thermal expansion coefficient of ceramic substrates (6-10×10⁻⁶/℃), eliminating the need for complicated compensation joint structures.
Solution Approach 2:
The invention modifies the thermal expansion parameter of aluminum by incorporating silicon carbide particles, transforming the material from having high thermal expansion (23.6×10⁻⁶/℃ for pure Al) to having matched thermal expansion (6-10×10⁻⁶/℃ for the composite). This parameter change enables direct bonding to ceramic substrates without complex joint structures, while preserving aluminum's superior heat dissipation capability.
3Reliability
If metal-ceramic composites are used to match thermal expansion, then reliability is improved, but production cost increases due to complex processing
Solution Approach 1:
The invention utilizes a porous preform structure made of silicon carbide particles arranged in a space network, which allows molten aluminum to easily infiltrate and form the composite material. This porous preform approach simplifies the manufacturing process compared to traditional dense composite methods, reducing production complexity and cost while achieving reliable thermal expansion matching.
Solution Approach 2:
The invention extracts the silicon carbide particle framework as a separate porous preform before metal infiltration, allowing independent optimization of the ceramic network structure. This separation enables simpler processing where the preform is formed first, then infiltrated with molten aluminum, reducing overall manufacturing complexity compared to attempting to create dense metal-ceramic composites in a single step.
4Loss of energy
If silicon carbide-aluminum alloy composites are used to raise thermal conductivity, then heat dissipation is improved, but coefficient of thermal expansion becomes difficult to control
Solution Approach 1:
The invention precisely controls the composition parameters of the composite, specifying 70-90 vol% silicon carbide particles and 10-30 vol% aluminum matrix. By optimizing this composition ratio and the particle size distribution (0.1-2.0 mm), the invention achieves both high thermal conductivity (100-200 W/mK) and controlled thermal expansion coefficient (6-10×10⁻⁶/℃) that matches ceramic substrates.
Solution Approach 2:
The invention creates local quality variations by using silicon carbide particles with specific size ranges (0.1-2.0 mm) and distributing them throughout the aluminum matrix. The particle size distribution and local arrangement are optimized to simultaneously achieve high thermal conductivity pathways while controlling overall thermal expansion, allowing precise control of both thermal properties through localized microstructure design.
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 composite provides a lightweight, reliable heat dissipating component with improved thermal conductivity and expansion matching, suitable for mobile equipment, reducing production costs and enhancing heat dissipation performance.
Implementation Method 1
a silicon carbide composite which is a plate-shaped porous body of silicon carbide impregnated with a metal containing aluminum as a main component
Implementation Method 2
the thermal conductivity of the silicon carbide composite is 100 W/mK or more at room temperature
Implementation Method 3
efficient heat dissipation with reduced processing costs
Implementation Method 4
dissipating heat generated by semiconductor devices to the outside
Data Source
Figure 1~3
AI summary
[Problem] To inexpensively provide a heat dissipating component that has thermal conductivity, as well as a low specific gravity, and a coefficient of thermal expansion close to that of a ceramic substrate, and furthermore having warpage so as to be able to be joined with good closeness of contact to a heat dissipating component or the like. [Solution] A silicon carbide composite which is a plate-shaped composite formed by impregnation of a porous silicon carbide molded article by a metal having aluminum as a main component, wherein the amount of warpage with respect to 10 cm of length of the main surface of the composite is 250 µm or less, and the amount of warpage of a power module using the plate-shaped composite is 250 µm or less; and a heat dissipating component using the same.