IN-SITU STRAIN ANALYSIS WITH HIGH-SPATIAL-RESOLUTION - A NEW FAILURE INSPECTION TOOL FOR INTEGRATED-CIRCUIT APPLICATIONS

A new non-destructive technique to measure strain over small areas of specimens in the scanning electron microscope (SEM) is described. By i ntegrating new advances in secondary electron detection, imaging of in sulating oxide layers and a methodology of generating an optical moire fringe effect in the SEM, a strain analysis technique has been develo ped. Using classical methodologies of strain analysis of moire fringes established in experimental elasticity studies, we demonstrate that o ne can quantitatively estimate localized strains due to mechanically i nduced damage with very high strain and spatial resolution sensitiviti es in a non-destructive fashion. The imaging of the moire fringes is a ccomplished by voltage contrast methods. The usefulness of this techni que in rapid assessment of localized strains, especially as an in-situ measurement tool in semiconductor failure analysis, is discussed. Cop yright (C) 1996 Elsevier Science Ltd.