Nitrogen-Vacancy Centers in Diamond for Current Imaging at the Redistributive Layer Level of Integrated Circuits

We present a novel technique based on an ensemble of Nitrogen-Vacancy (NV) centers of diamond to perform Magnetic Current Imaging (MCI) on an Integrated Circuit (IC). NV centers of diamond permit to measure the three components of the magnetic fields generated by mA range current in an IC structure over a field of 50×200μm with sub-micrometric resolution. Vector measurements allow the use of a more robust algorithm than those used for MCI using GMR or SQUID sensors and it is opening new current reconstruction prospects. Calculated MCI from these measurements shows a very good agreement with theoretical current path. Acquisition time is around 10s, which is much faster than scanning measurements using Superconducting Quantum Interference Device (SQUID) or Giant Magneto Resistance (GMR). The experimental set-up relies on a standard optical microscope, and the measurements can be performed at room temperature and atmospheric pressure. These early experiences, not optimized for IC, show that NV centers in diamond could become a real alternative for MCI in IC.