This paper presents two different case studies that highlight the use of reflected light imaging in laser scanning microscopy. In the first case study, the exact location of defects in metal comb test structures were much easier to detect with reflected light imaging than with thermally-induced voltage alteration (TIVA). This case study also shows visible-wavelength TIVA defect localization using a 532-nm laser. A comparison between 532-nm TIVA and conventional 1320-nm TIVA is made to show the resolution improvement with the visible laser. In the second case study, the cause of a linear string of bit failures was localized easily with backside reflected light imaging. It is observed that the indicated sites matched the light-induced voltage alteration signals and the failing cells in the bit map. In both of the case studies, the reflected light images have proved very helpful in the localization and characterization of failing devices or test structures.

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