Thermal Interface Material System With Porous Matrix
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Solution Overview
Problem
Current thermal interface materials (TIMs) face reliability issues due to premature failure from 'pump-out' and 'dry-out' caused by relative motion and high temperatures, which compromises thermal resistance and the reliability of power module systems.
Innovation Solution
A thermally conductive porous matrix with interstitial voids and a high-temperature resistant colloidal suspension applied on both sides, forming a porous thermal pad that inhibits thermal migration and maintains low thermal resistance, using sintered particles or metal foils with strategically sized voids and colloidal suspension layers for enhanced thermal communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal grease is used to fill the interface gap between heat spreader and heat sink, then thermal resistance is reduced, but reliability deteriorates due to pump-out and dry-out
Solution Approach 1:
The patent uses a composite TIM structure combining solid porous metal particles (forming a matrix) with liquid colloidal suspension (filling voids). This composite approach allows the solid framework to provide structural stability and prevent pump-out, while the liquid suspension maintains low thermal resistance through high thermal conductivity fillers, thus resolving the contradiction between reliability and thermal performance
Solution Approach 2:
The patent employs a porous matrix formed by sintered metal particles with controlled void spaces. The porous structure allows the liquid colloidal suspension to infiltrate and occupy the voids, creating a hybrid structure where the solid framework prevents material ejection during thermal cycling while the liquid-filled pores maintain excellent thermal contact, solving both the pump-out and thermal resistance issues
2Reliability
If solid thermal pads are used to avoid pump-out and dry-out, then reliability is improved, but thermal resistance increases due to thicker bond line and lower contact area
Solution Approach 1:
The patent changes the physical state parameters of the TIM by combining solid and liquid phases. The solid porous matrix provides structural integrity like solid pads, while the liquid colloidal suspension infiltrating the pores provides low thermal resistance characteristics. This parameter change allows achieving both high reliability and low thermal resistance simultaneously
Solution Approach 2:
The patent applies different material properties to different regions: the solid porous matrix provides structural support and pump-out prevention, while the liquid colloidal suspension in the voids provides thermal conduction pathways. This local differentiation of material qualities allows the TIM to simultaneously achieve reliability and low thermal resistance
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 increases the reliability and power cycling capability of TIMs by preventing colloidal suspension migration and maintaining effective thermal contact, reducing the risk of system failure while maintaining low thermal resistance.
Implementation Method 1
thermally coupled between a heat sink and a heat source
Implementation Method 2
a thermally conductive colloidal suspension disposed on each side of the thermally conductive porous matrix to inhibit thermal pump-out
Data Source
AI summary
A thermal interface material system includes a thermally conductive porous matrix, the thermally conductive porous matrix having a plurality of interstitial voids, and a thermally conductive colloidal suspension disposed on each side of the thermally conductive porous matrix to inhibit thermal pump-out of the thermally conductive colloidal suspension so that the thermally conductive porous matrix and thermally conductive colloidal suspension collectively form a thermally conductive porous pad.