Abstract
Thermally-induced voltage alteration (TIVA) is a laser-based method for localizing interconnect defects in ICs. Its main limitation is that the laser must heat the defect and change its resistance sufficiently to produce a measurable voltage alteration. Anything that interferes with laser absorption or alters defect heating makes TIVA less effective. This article presents the results of a study on the effects of local structures on TIVA imaging. The authors selected a polysilicon-metal test structure as the focal point of their study, which entailed experimental investigation along with modeling and simulation. It was found that the TIVA profiles on this structure are strongly influenced by local geometry, particularly the variation of interlevel silicon dioxide thickness and the placement of polysilicon lines with respect to aluminum lines. Understanding such relationships is essential for locating defects using TIVA techniques.
