In electronics, a key reliability factor is semiconductor junction temperature. The higher this temperature, the shorter the time to failure. When operating, a semiconductor is dissipating power and generating heat. As long as the device is generating heat, the temperature of the junction will rise until the heat finds a path to flow from the device. At that point, heat flow from the device will be equal to the heat being generated and thermal equilibrium will be reached.
Thermal images can provide measurements of semiconductor case temperatures.
A second and less well recognized thermal problem occurs in manufacturing when circuit boards are reflow soldered. As a result of the high temperatures to which they are subjected and their complex structure, some boards become misshapen or warped. Others exhibit mechanical problems with components or solder connections due to thermal stresses. IR reflow ovens assume a fairly homogeneous object is being heated while in fact the temperatures across the board are frequently non- uniform. Ideally, one would expect this board to look fairly uniform since it had just come from the oven.