A Guide to Thermal Interface Materials

Why Thermal Interface Materials?

Technological advances mean devices are getting smaller and more efficient all the time. As a result, operating temperatures of components are increasing along with the demand for cooling and temperature control of electronic devices.

TIM’s (thermal interface materials) are used in almost all electronic products to remove heat, maintain device processing speed/functionality and extend the lifetime of electronic products. They play a major role in ensuring long-term performance and reliability and as such, the need for innovative high-performance thermal solutions is continually growing.

Why Use Liquid Thermal Interface Materials?

Bond lines are a hugely significant factor in thermal management, the efficiency of heat dissipation is directly affected by the bond line thickness. The thicker a layer of TIM is, the more the rate of heat dissipation becomes limited. The heat sink itself will have a higher thermal conductivity than any thermal interface material so the main aim is to transfer the heat to the heat sink as quickly as possible, primarily achieved through thin bond lines. The thinnest bond lines can only be achieved using liquids.

No two surfaces are completely smooth, liquid TIMs offer a much better surface contact than thermals pads or foils can. Choosing a material with good gap filling properties, such as a silicone paste, greatly increases the chance of interfacing surfaces mating perfectly; eliminating the chance of air gaps, which would vastly inhibit the efficient transfer of heat.

In a direct comparison against the use of thermal pads, a liquid TIM negates the requirement for pre-cut or die-cut shapes, tooling, design etc saving a lot of unnecessary costs. Liquid solutions place much less stress on the electronic components and the risk of tearing or damaging the TIM during use would be diminished.

Liquid TIMs can conform to voids with 3D designs and automated robot dispensing is available for high volume manufacturing or for intricate dispense patterns. Cure in place materials with a consistently formed bead ensure repeatability for large scale automated assembly lines. This is a major factor for the growth in the trend of choosing liquids as a solution to manage heat.

Unlike thermal foils, liquid TIMs can offer a low contact resistance with minimal pressure. With foils, a low contact resistance can only be achieved by very high pressure and they offer a much lower thermal resistance than liquid TIMs at a similar thermal conductivity level.

Silicones are a very versatile material to consider, they bond to different combinations of substrates and offer performance reliability over a wide temperature range in challenging environments. When used for potting, the cured flexibility of silicone provides excellent protection by absorbing mechanical vibration and thermal shock.

Why Techsil?

Every application and every surface is different, this is why at Techsil we like to get involved at the design stage to understand the substrates being used, the heat generated, how to eliminate the air and achieve the best possible BLT (bond line thickness) for our customers.

Ultimately this hands on approach means we can achieve a very efficient heat transfer and the best available thermal management solution.

Our experienced Technical Team understand the importance of getting things right. Why don’t you work with us to see how we can add value to your application?

View our list of Top 10 Thermal Interface Materials.

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