Composite Thermal Interface Material With Phase-Change Metal Filler
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Solution Overview
Problem
Conventional thermal-interface materials face challenges in achieving low thermal-contact resistance across solid-solid interfaces, especially in high-power applications with limited upper-threshold temperatures, where thermal resistance remains a significant component of the overall thermal budget.
Innovation Solution
The development of composite thermal-interface materials incorporating a metallic filler dispersed within a silicone oil substrate, where the metallic filler undergoes a phase transition within an expected operating temperature range, enhancing conductive heat transfer and reducing thermal resistance through improved bulk thermal conductivity and surface wetting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional thermal-interface materials are used, then manufacturing and assembly are simpler, but thermal-contact resistance remains high
Solution Approach 1:
The patent changes the physical state parameter of the thermal-interface material from solid to liquid (or partially liquid) by incorporating metallic fillers that undergo phase transition within the operating temperature range. This parameter change enables the material to flow and wet non-uniform surfaces, achieving low thermal-contact resistance (<0.03° C.-cm2/W) while accommodating manufacturing variations without requiring precision machining.
Solution Approach 2:
The patent creates a composite thermal-interface material consisting of a liquid or partially liquid carrier medium combined with metallic fillers (such as gallium, indium, or their alloys) that have specific phase transition temperatures. This composite structure provides both the flowability needed for surface wetting and the high thermal conductivity needed for efficient heat transfer, resolving the contradiction between thermal performance and manufacturing tolerance.
2Reliability
If solid thermal-interface materials are used, then material stability is higher, but thermal resistance remains significant
Solution Approach 1:
The patent exploits phase transitions of metallic fillers (solid to liquid) within the expected operating temperature range to optimize thermal interface performance. The material transitions from a more rigid state to a flowing state, enabling it to conform to non-uniform surfaces and maintain low thermal-contact resistance while remaining stable within the operational temperature window.
Solution Approach 2:
The patent carefully selects metallic fillers whose phase transition temperatures fall within the device's operating range, allowing the material to change its physical state parameter (viscosity, flowability) in response to temperature changes. This enables the material to self-adjust to surface irregularities while maintaining overall compositional stability during normal 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
These materials provide thermal resistances of less than 0.03° C.-cm2/W, offering a 50% reduction compared to conventional high-performance materials, while being more forgiving during manufacturing and assembly, and capable of handling non-uniform interfaces.
Implementation Method 1
a metallic filler that is liquid, or begins to melt, at or near typical ambient temperatures
Implementation Method 2
the metallic filler undergoes a phase transition within an expected operating temperature range
Implementation Method 3
excess heat conducts across the interface between the heat-generating component and the cold plate or heat sink
Implementation Method 4
enhancing conductive heat transfer and reducing thermal resistance through improved bulk thermal conductivity and surface wetting
Data Source
AI summary
A heat-transfer component defines a thermal-interface surface and has a composite thermal-interface material on the thermal-interface surface. The composite thermal-interface material comprises a silicone oil substrate and a metallic filler. In some embodiments, the metallic filler undergoes a transition from solid to liquid at a temperature below a typical operating temperature of an electronic device. For example, an embodiment of a metallic filler has a solid-to-liquid transition temperature between about 25° C. and about 95° C. In some embodiments, a second thermal interface material extends around an outer periphery of the composite thermal interface material, which can inhibit or prevent seepage or other migration of metallic filler in the composite thermal-interface material out of a thermal interface region between the heat-transfer component and, e.g., a heat-generating component. Also disclosed are electrical devices having a heat generating component cooled by such a heat-transfer component.