PURPOSE: To obtain a system for measuring two-dimensional voltage distribution of LSI and high rate variation thereof by taking advantage of electrooptic effect and phase conjugated wave.
CONSTITUTION: An object 1 to be measured, e.g. an integrated circuit, produces a voltage distribution upon receiving an electric signal from an electric signal source 10 thus generating an electric field around the object 1. Variation of refractive index of an electrooptic crystal 3 disposed in the vicinity of the object 1 due to the electric field is then detected in the form of phase modulation of pulse laser light synchronized with the electric signal source 10 being impinged on the electrooptic crystal 3. In order to measure voltage distribution of the object 1 with high spatial resolution, wave front of the near field pattern of laser light subjected to phase modulation is reproduced by phase conjugated wave. Voltage distribution can be detected in the form of light intensity distribution through interference of the phase conjugated wave and a reference light. Variation of voltage distribution can also be measured by delaying a trigger signal being fed from the electric signal source 10.
HASEGAWA NOBORU
UEDA KENJI
MATSUMOTO TAKAHIRO
