The thermal interface material (TIM) is the layer that connects the hot components to heat sinks or other thermally conductive devices in electronic circuit boards. There are several factors to consider when selecting a TIM for your design. The primary two are TIM hardness and compliance, with the latter referring to how well a TIM can bend or deform under stress. Using a softer TIM can help prevent vibrations that could disrupt heat transfer, but it may not be as effective at filling micro-gaps or preventing misalignment of the thermal interface components.
The TIM type you select is also dependent on the specific requirements of your application. For example, if you are replacing hardware with adhesive films, you want to ensure that the film is compatible with your substrates. Additionally, if your TIM is exposed to harsh conditions, it is important that it can resist environmental effects such as salt mist, corrosive gases, and high humidity.
Other considerations for the TIM include its ability to adhere to a substrate, and its mechanical properties such as hardness and compressibility. Harder TIM materials have higher adhesion, while the flexibility of a soft TIM can allow it to conform better to uneven or rough surfaces.
Lastly, the cost of the TIM and its chemical resistance are also important to consider. For instance, certain TIMs can be damaged by the exposure to chemicals such as acetone or alcohols. This damage can result in delamination, which can increase the thermal impedance between the interfaces.Liquid metal thermal paste