Two-photon optical beam induced current (TOBIC) images were acquired through the polished backsides of integrated circuits. An excitation beam with a photon energy below the band gap can traverse even thick substrates virtually unattenuated. At the focus—and only there—two-photon absorption generates electron-hole pairs very efficiently when using a sub-picosecond light source. An additional advantage of TOBIC is a significant increase in spatial resolution. With high numerical aperture objective lense features smaller than 1 &mgr;m are easily discernible. ©1997 American Institute of Physics.