When the laser beam strikes a location which does not contain a void, good thermal transmission exists and the change in electrical resistance is small.
[5] Thermally induced voltage alteration (TIVA) is an imaging technique which uses a laser beam to pinpoint the location of electrical shorts on a device.
The device is biased using a constant current source, and the power supply pin voltage is monitored for changes.
[7] Seebeck effect imaging (SEI) uses a laser to generate thermal gradients in conductors.
These changes are mapped to a visual image of the device in order to physically locate the floating conductors.
[8] A proof-of-concept experiment was conducted at the University of Florida which demonstrated the possibility of using thermal laser stimulation to peer into SRAM chips and extract sensitive information.