Failure Analysis Method by Using Different Wavelengths Lasers and Its Application

We succeeded in an accurate detection for failure locations on a silicon semiconductor device (hereafter called "IC") by applying the failure analysis method in which two kinds of laser beams having different wavelengths are simultaneously irradiated on a surface of IC. Short wavelength laser beam (lambda = l083nm) causes potential changes in an internal circuit of IC due to generating many electron-hole pairs in the semiconductor. On the other hand, long wavelength laser beam (lambda =1360 nm) causes an easy operation of parasitic bipolar elements due to increasing temperature of IC by irradiation heat. By combining these effects of two laser beams, the accurate detection of latch-up locations on internal circuits of IC (has been recognized to be difficult up to now) has come possible. © 1999 Elsevier Science Ltd. All rights reserved.