Background

The increasing miniaturisation and increasing power of electronic devices are leading to significant practical issues relating to the dissipation of heat, which has become one of the most critical problems that limit the performance, power, reliability and further miniaturization of electronic devices, with the reliability of devices being exponentially dependant on the operating temperature. As a result, a small difference in operating temperatures can result in large reductions of device lifespan.

Heat sinks are used to dissipate the heat. The efficiency of heat sinks is dependent on the thermal conductivity and interfacial thermal resistance (arising from the mismatch of non-surface flatness and surface roughness) of the thermal interface materials.

Thermal Interface Materials (TIMs) ideally have high thermal conductivity and strong deformability and are classified as: thermal greases; elastomeric thermal pads and solders.

Filler-type TIMs (pastes, epoxies, adhesives, etc) represent the majority of the global market – They are low cost, easy to apply and give reasonable performance and have become the ‘go to’ solution to mitigating excessive contact resistance in electronic packages and devices. Thermal greases are a type of thixotropic paste with high thermal conductivity that effectively fill the mating surface gaps. Thermal greases constitute two primary components: a polymer matrix and ceramic fillers. Silicone is commonly used as the base for its good thermal stability, wetting characteristics and low elastic modulus. Ceramic fillers such as alumina, aluminium nitride and boron nitride are highly thermally conductive but electrically insulative and so have been extensively used in thermal greases and other TIMs.

The average range of thermal conductance of these solutions is 1 – 4W/mK. However, high-specification silicone-based TIMs can achieve high thermal conductivities. SIGNIFICANT is differentiated from existing silicone-based solutions in being silicone-free and therefore will not “bleed” and is differentiated from existing silicone-free solutions through having greater thermal conductivity up to 15W/mK as well as being easier to process.