While the thermal conductivity properties of metals make for ideal thermal interface materials (TIMs)—in reality—their hardness can limit their effectiveness due to high interfacial resistance. However, there are a number of alloys which are liquid at or near room temperature that could provide intriguing alternatives. A liquid alloy enables you to maintain the high thermal conductivity of metals, while at the same time mitigating the interfacial resistance issues that exist with solids.
Even allowing for the large amount of published literature showing the potential high performance of liquid metals when used as a TIM, these materials have seen relatively little adoption in production environments. We’ve identified two significant limiting factors for this:
1) applying a consistent amount of liquid metal in high volume
2) containing the liquid metal under the heat sink.
Recently, we investigated methodologies and techniques that could enable the use of liquid metal in a wider array of TIM1, TIM1.5, and TIM2 applications. Several methods for applying the liquid metal were assessed, including dispensing, jetting, and spraying. Because liquid metal has an extremely high density compared to fluxes and polymers that are typically used in electronics, it creates a unique challenge for the equipment. We also explored the containment challenge, and identified an innovative solution of embedding a solid metal matrix into the liquid.
I will share the results of this assessment during my presentation, Innovative Liquid Metal Thermal Interface Technology for TIM2 Applications, at the Semi-Therm 35th Annual Symposium & Exhibit, March 18-22, in San Jose, Calif., USA. If you are planning to attend Semi-Therm, stop by my presentation on Tuesday, March 13 during Session 3!