Electronic circuitry operates best and most reliably at lower temperatures. However, todays more complex and smaller device dimensions along with closer packing result in higher heat density and elevated operating temperatures.
Higher operating temperatures decrease the service life of the device or module. Any temperature sensitive materials used in a module can degrade and wear out more quickly. Other failure mechanisms, such as metal migration, can occur, particularly when both high temperature and humidity conditions are present. Here, metal whiskers or dendrites can grow from the conducting lines. With lines being spaced closer together in todays devices, shorts between lines can occur and cause device failure. Additionally, when temperatures fluctuate, device interconnections and other components can fatigue from expansion and contraction due to thermal stresses and eventually fail.
Higher temperatures also increase the electrical resistance of the conducting lines within a device or module, slowing the signal speed and reducing performance. As devices become more complex, conducting paths become longer and this performance reduction is more significant.
For all of the above reasons, its critical to minimize temperature of the electronics by designing efficient ways of carrying away their generated heat.