Abstract
An e-beam tester is widely used for the internal analysis of LSI circuits. However, its low waveform acquisition speed is a significant drawback for LSI circuits featuring high integration and high speed. We have introduced a novel optical probing system applicable to quarter-micron VLSI circuits. Based on an electro-optic sampling technique, this probing system achieved a sub-micron spatial resolution by utilizing the scanning force microscope technique. This system can measure internal signal waveforms of VLSI circuits much faster than e-beam testers, and can measure the DC voltage level, which is not possible with e-beam testers.