Three-dimensional imaging of a silicon flip chip using the two-photon optical-beam induced current effect

Abstract
We describe two- and three-dimensional imaging of a flip-chipsiliconintegrated circuit using backside optical probing and femtosecondtwo-photon excitation at a laser wavelength of 1.275 μm. Using a ×50 microscope objective, we typically achieved micron resolutions or better in both lateral and axial directions. Using axial scanning and a peak-detection algorithm we have demonstrated optical depth profiling across components on the chip.