Energy Dispersive Spectrum (EDS) Study of Copper Grid Effect on Semiconductor Failure Analysis

In this paper the artifacts of additional copper signal induced by the copper grid, one of the most widely used supporting grid for focus ion beam (FIB) prepared TEM sample, is studied. Its influence on both the spot and the line scan energy dispersive spectroscopy (EDS) analyses are described. It was determined that, during line scan analysis, the strength of the copper signal varied between heavy and light elements, which could lead to inconclusive results during the EDS analysis of Cu interconnect structures. Based on the study using nickel support grid, it is concluded that the additional copper signal is a result of electrons scattered by the sample striking the Cu grid.