Microelectronic circuit characterization via photothermal radiometry of scribeline recombination lifetime

Three-dimensional (3D) photothermal radiometric microscopic imaging and las er-intensity-modulation frequency scans have been used for the non-contact, non-intrusive measurement of electronic transport properties of integrated circuits in patterned 4" Si wafers. The experimental data showed that carr ier recombination lifetimes along each scribeline remain constant. However, variations in surface recombination velocities and carrier diffusion coeff icients were found. It was further found that such variations are related t o the presence of highly doped poly-Si structures adjacent to the scribelin e. The presence of poly-Si pads does not affect the value of the bulk recom bination lifetime. It only affects the surface recombination velocity and/o r the diffusion coefficient. The actual location of the scribeline on the w afer surface may affect the value of the lifetime. As a result of these mea surements, it is concluded that scribeline photothermal radiometric probing can be used effectively for monitoring local values of the carrier recombi nation lifetime and, through those, wafer contamination and damage during d evice fabrication processing.