Thermal Interface Materials

Thermal Interface Materials are used for heat transfer from critical components in electronics.

The main driver for developing superior thermal interface materials is the need for greater heat flow away from crucial heat generating processors and other components. Some examples are LED applications, automotive electronics, power supplies, mobile phones and PCs. Good heat management leads to better performance, longer lifetime and better reliability (IDTechEx, 2016).

Thermal Interface Materials

 

A thermal interface material (TIM) is typically a paste, gel or flexible film. It’s used to enhance heat transport from one surface to another, for instance from a hot processor surface to a heat sink. A TIM should be soft as it is required to fill insulating air gaps created by the micro-scale roughness of the two hard surfaces.

Air pockets are large thermal barriers for even modest heat transfer. The degree of heat transfer you achieve depends on the performance of the specific TIM material applied, together with the interfacial resistances of the surrounding materials.

Performance

The performance of TIMs matters most in the through plane, or z-direction, of the material. Heat should be transferred out and away to the opposite surface – not sideways.

The bulk conductivity of the material (heat transfer through a given material) and thermal contact resistance of the system (thermal resistance over an interface between two materials) are the main elements of overall thermal performance when comparing TIMs.

The TIM’s ability to wet the surface influences the thermal contact resistance of the system. Therefore, a TIM with modest bulk thermal conductivity but a low interfacial resistance may exhibit a lower thermal resistance at system level than a high conductivity TIM with a large interfacial thermal resistance.

Benefits of improved TIMs:

  • Extended life time and improved reliability of electronic devices.
  • Thinner, more compact electronics.
  • Elimination of the need for more costly thermal management methods.

Advantages of CondAlign’s Materials

  • The anisotropic character of the material enables transporting heat in only one direction.
  • Better wetting of the surfaces, leading to better overall heat transfer.
  • Efficient use of the conductive particles, achieving similar heat conductivity with less particles, or better conductivity with the same loading

The CondAlign technology enables soft, flexible films with conductive pathways in the z-direction of the material with a lower particle loading than traditional thermal interface materials.

An advantage of the lower particle loading is that the polymer matrix can retain most of its original properties, such as softness and wetting capabilities. The alignment and efficient use of particles also saves costs compared to stochastic particle distribution.

CondAlign has demonstrated up to 100% improvement in thermal conductivity by aligning the particles, compared to other films of equal particle type and loading. The magnitude of this enhancement of conductivity is higher when the particle loading is lower.