Characterization of thermoelectric devices in ICs as stimulated by a scanning laser beam

SEI (Seebeck effect imaging) generated by TLS (thermal laser stimulation) has proven to be a very powerful tool for open circuit localization in microelectronics and is a common tool in FA laboratories. Although the basic Seebeck effect (SE) is understood well, the interpretation of some results remained unsolved, especially under bias voltage or in complex structures like ICs. A parametric investigation of SE in passive devices of various resistances is presented, and information about SE in active devices is provided. The results are interpreted taking into account that SE is never the only effect which is produced by TLS. With the contribution of SE together with the conventional optical beam induced resistance change (OBIRCH) in interconnects and contacts, this systematic approach based on device simulation represents the full variety of SEI phenomena, in constant current and constant voltage conditions. Constant current is the regular SEI operation mode and should be used whenever possible as the SE signal does not depend on device resistance. In ICs though, usually constant voltage is mandatory.