OBSERVATION OF AL-LINES IN LSI DEVICES BY ULTRA-HIGH VOLTAGE ELECTRON-MICROSCOPE

To clarify the mechanism caused by multi-layer effect, the ultra-HVEM at 2MeV is powerful because it has an excellent penetration power for specimens. By thinning the Si-substrate of LSI devices, we can carry o ut in-situ observations of phenomena arising in the process layers; in particular, we can observe the specimens without removing the passiva tion layers that strongly affect the generation of these phenomena. We show how the orientation of Al-lines depends on the step of process a nd how it relates to the incidence of stressmigration voids. From in-s itu observation of electromigration in Al-lines with bamboo structure, it is seen that the main route of electromigration is the interface b etween the line and the passivation layer, and the migration is enhanc ed when a small gap exits in the interface.