Thermal modeling and simulations were used to analyze the thermal profiles of a polysilicon-metal test structure generated by localized heating with an infrared laser. Localized laser heating is the basis of a new failure analysis technique, thermally induced voltage alteration (TIVA), that can identify shorted interconnects in integrated circuits. The modeling results show that variations in thermal profiles of the test structure measured by the TIVA technique are due mainly to preferential laser absorption in various locations in the test structure. Differences in oxide thickness also affect the local heat conduction and temperature distribution. Modeling results also show that local variation in heat conduction is less important than the absorbed laser power in determining the local temperatures since our test structure has feature sizes that are small compared to the length over which the heat spreads.