Liquid crystal is an efficient technique of optical analysis used to detect and localize certain integrated circuit (IC) failures. It is a non-invasive technique performed from either the front of devices. Leakage current in semiconductor devices is likely to cause local heating along the current path. By coating the device surface with a material sensitive to temperature changes, one can detect the location of the hot spot. Liquid crystals change phase at a given temperature. By bringing the device very close to this transition temperature using a hot chuck, one can detect very small local heating. Liquid crystal is a powerful early-stage failure analysis technique since it localizes failures non-invasively.
local heating due to short circuit