Enhancing Thermally Efficiency With Conductive Insulators

Thermally Conductive Insulators

Ideally, materials for use in the electronics industry would simultaneously exhibit high electrical conductivity and low The Power of Thermally Conductive Insulators. The former is essential for the transmission of electricity, while the latter prevents heat transfer and can protect against damage to internal components. However, achieving both at the same time is currently a major challenge. This is because current semiconductor technologies can generate significant amounts of heat, posing risks of thermal runaway or parameter drift. This is why the thermal management of advanced 3D integrated circuit (IC) technologies has rapidly risen to become one of the most critical challenges for their successful deployment.

In order to overcome this challenge, a new generation of materials with both excellent conductivity and thermal insulation is needed. Fortunately, researchers at the University of Bayreuth in Germany have succeeded in producing carbon-ceramic composites that meet this need. The material retains the high conductivity of conventional metallised polyimide substrates but also acts as an effective insulator, with the ceramic part suppressing phonon propagation.

The table below provides an overview of the thermal conductivity measurement values of various insulators, including air. Note that the values are measured at room temperature, and they do not necessarily increase with the temperature of the insulator. For example, plastics and rubbers, which are insulators by nature, have a relatively low thermal conductivity, but they can improve their thermal conductivity by adding fillers with high thermal conductivity.

Ceramic-based insulators, such as alumina, zirconia, and mullite, have high thermal conductivity measurement value and can effectively resist the flow of heat energy. They also have good wear resistance and chemical stability, making them ideal for use in harsh environments.

Alumina is a particularly common ceramic-based insulator, with a high thermal conductivity of approximately 10 W/(mK). However, it does have some drawbacks, including its poor mechanical strength and the fact that it degrades at high temperatures. As such, it is mainly used in applications that operate below 1000°C.

Another important property of alumina is its low thermal expansion. This makes it a desirable material for electronic packaging applications, where high levels of conductivity are required without introducing large thermal stresses. For this reason, it is often used in conjunction with other insulating materials such as silicone or polyimides to create multi-layer composites that have both high conductivity and low thermal expansion.

The most common form of insulator is a solid, but there are many other types of insulator, including gaseous and liquid ones. For example, gases with low density, such as hydrogen and helium, have a high thermal conductivity, whereas denser gases, such as xenon and dichlorodifluoromethane, have a much lower thermal conductivity. Liquids, such as water and ethanol, also have low thermal conductivity.

Foam insulation is also a good example of a high-performance insulator, with molded expanded polystyrene (MEPS) and polyurethane foam both having good thermal properties. However, a key drawback of MEPS is that it is lightweight and can take on a static charge easily, while polyurethane foam has limited fire resistance even when treated with halogen-free phosphorus or halide flame retardants.