Multi-layer Thermal Interface Material with Rupture Barrier
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Solution Overview
Problem
Current thermal interface materials (TIMs) face challenges in thermal conductivity due to low melting temperatures and mechanical compliance issues, leading to thermal fatigue and degradation in integrated circuits, and often require complex and costly packaging processes.
Innovation Solution
A multi-layer composite TIM is developed, comprising a first and second polymer layer, a liquid metal in direct contact with the first polymer layer, and a solid solute in direct contact with the second polymer layer, separated by a barrier that ruptures under compression to form a mixture, enhancing thermal conductivity and mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low melting temperature metals (In, Sn-Bi) are used as TIMs, then thermal conductivity is improved, but mechanical compliance deteriorates leading to thermal fatigue
Solution Approach 1:
The patent uses a composite material system consisting of a polymer matrix combined with liquid metal particles and solid solute particles. This composite structure allows the material to achieve both high thermal conductivity (from the liquid metal) and good mechanical compliance (from the polymer matrix), resolving the contradiction between thermal performance and mechanical reliability.
Solution Approach 2:
The patent changes the physical state of the metal component from solid (low melting point metals like In and Sn-Bi) to liquid (gallium-based liquid metal) at operating temperatures. This parameter change allows the metal to better conform to surface irregularities, improving both thermal contact and mechanical compliance while reducing thermal fatigue.
2Reliability
If gallium-based liquid metals are used as TIMs, then mechanical compliance is improved, but degradation of metal packaging and pump-out effects occur
Solution Approach 1:
The patent introduces a polymer matrix as an intermediary material that encapsulates the gallium-based liquid metal particles. This polymer barrier prevents direct contact between the liquid metal and metal packaging components, eliminating degradation and pump-out effects while still allowing the liquid metal to provide mechanical compliance through the composite structure.
Solution Approach 2:
The patent utilizes a porous or particulate structure where liquid metal particles are dispersed within the polymer matrix. This structure allows the liquid metal to maintain contact with the interface surfaces for thermal and mechanical benefits while the polymer matrix contains the liquid metal, preventing it from migrating out (pump-out) and degrading surrounding metals.
3Temperature
If ceramic or metal additives are used in TIMs, then thermal conductivity is improved, but interfacial resistance limits effective thermal conductivity
Solution Approach 1:
The patent changes the physical state of the metal component from solid to liquid, creating a liquid metal particle composite. The liquid state allows the metal particles to better conform to and wet the polymer matrix and interface surfaces, significantly reducing interfacial thermal resistance compared to solid ceramic or metal additives, thereby improving effective thermal conductivity.
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 effectively increases thermal conductivity and reduces mechanical stress on integrated circuits, minimizing leakage and corrosion, while simplifying the packaging process by eliminating the need for mixing powdered ingredients, thus providing improved thermal management and reliability.
Implementation Method 1
a barrier between the liquid metal and the solid solute. The barrier prevents contact of the liquid metal and the solid solute at normal temperature and pressure, and is configured to rupture under compression of the layered composite
Implementation Method 2
The barrier prevents contact of the liquid metal and the solid solute at normal temperature and pressure, and is configured to rupture under compression of the layered composite
Implementation Method 3
the liquid metal and the solid solute to form a mixture between the first polymer layer and the second polymer layer
Implementation Method 4
The liquid metal includes at least one of Ga, GaIn, GaInSn, BiSn, BiIn, and BiInSn. The solid solute is selected to react with the liquid metal
Implementation Method 5
TIMs dissipate heat away from ICs by reducing the thermal contact resistance between electronic packaging components
Implementation Method 6
even these relatively low melting temperatures have low mechanical compliance, leading to thermal fatigue
Data Source
AI summary
A layered composite configured to form an interface between a heat exchanger and an integrated circuit includes a first polymer layer, a second polymer layer, a liquid metal in direct contact with the first polymer layer, a solid solute in direct contact with the second polymer layer, and a barrier between the liquid metal and the solid solute. The liquid metal is liquid at normal temperature and pressure. The solid solute includes microparticles, nanoparticles, or both and is solid at normal temperature and pressure. The barrier prevents contact of the liquid metal and the solid solute at normal temperature and pressure, and is configured to rupture under compression of the layered composite, thereby allowing the liquid metal and the solid solute to form a mixture between the first polymer layer and the second polymer layer.