• Optical beam generates photocarriers at focal point.

• Photoconductive effect in integrated circuit (IC) creates local changes in resistance.

• Constant current source supplies bias that results in voltage variation with resistance changes.

• Digital record of voltage versus scanner position produces LIVA image.

LIVA Applications

• Localization of open circuits.

• Localization of direct semiconductor damage, for example, overstress damage, crystal defects, and pinholes.

• Logic state mapping.

Backside LIVA (left) and reflected-light (right) images of an open contact defect, E.I. Cole, Jr. et al., IRPS, 388-98 (1994)