PURPOSE: To indicate the levels of the electric potentials of a wiring and the image of the distribution of insulating matters by detecting thermal waves excited on the surface of an LSI due to the irradiation of an electron beam and combining the wiring, obtained from a thermal wave signal, with the image of the distribution of the insulating matters and the image of the distribution of electric potentials produced by a secondary electron signal.
CONSTITUTION: A sample LSI 1 is periodically driven by an LSI-driving circuit 2 according to data sent from a memory 21. An electron beam discharged from an electron gun 17 is turned into pulses synchronously with the LSI1 by means of a stroboscopic device, then irradiated upon the LSI1. Secondary electrons discharged from the LSI1 are detected by a secondary-electron detector 13, and a secondary electron signal is turned into a binary one by means of the binary circuit of a picture-treating circuit 12. On the other hand, thermal waves excited on the surface of the LSI1 are transferred to an ultrasonic detector 9 in which they are converted into a voltage signal. The thus obtained signal is sent through a sampling circuit 11 to the circuit 12 in which it is turned into a binary one. The circuit 12 treat both of the above binary signals to obtain a ternary image which corresponds to wiring patterns of a low and a high electric potential and insulating matters, thereby enabling three-colored indication for example to be realized on a displayer 14.
ISHIZUKA TOSHIHIRO
ITOU AKIO
GOTOU YOSHIAKI
FURUKAWA YASUO
Next Patent: METHOD OF PREVENTING CHANGE IN RESISTANCE OF SECONDARY- ELECTRON MULTIPLIER