Magnetic force microscopy measurement of current on integrated circuits

In IC failure analysis, current is often used to indicate the presence of a defective device. By imaging the magnetic field produced by current flowing in an IC, the defective devices can be located. In this paper, we present experimental results on imaging current-carrying lines on integrated circuits using MFM. We have experimentally determined that MFM is capable of measuring currents as small as 1 μA-10 μA on ICs. We have also carried out simulations comparing MFM imaging with experimental results. Using these simulations we have devised a method to locate accurately the position of the internal current carrying faults from MFM images. This technique has significant potential for IC fault location and other IC failure analysis applications.