THERMAL MANAGEMENT

The thermal interface material (TIM) plays a crucial role in any thermal management solution. Despite its small physical size in most applications, it is often overlooked. However, the effectiveness of a device and its associated product heavily relies on the thermal interface material.
While many engineers prioritize heat sink design, they tend to neglect the importance of considering how heat travels from the heat source to the heat sink. Even surfaces that appear smooth have inherent surface roughness, leading to the formation of air pockets when in contact. These air pockets, due to air’s thermal insulating properties, hinder efficient heat transfer between surfaces.
In the provided image, heat originating from the blue surface can only conduct through the highlighted red points to reach the green heat sink. The arrows visually demonstrate that heat is emitted by the entire blue surface but is limited to these contact points. The yellow areas represent the air pockets. Although heat can pass through these air pockets, the transfer is highly inefficient and significantly less compared to the conduction through the red contact points.
This concept is applicable to any electrical device, typically enclosed in a case, that dissipates heat to a metal heat sink in the absence of a thermal interface material.