Scanning 3D XRD to Map the Granular Structure in a Copper Polyheater with Subgrain Resolution

The structural degradation of metallic interconnects is one of the main failure mechanisms limiting the lifetime of High Electron Mobility Transistors. In order to observe this degradation mechanism, the evolution of the lattice strain and the morphology of the metal (Cu) grains has to be observed. Scanning 3D XRD at ID11 is the only technique that allows strain mapping in a polycrystalline bulk sample with fine (< 500 nm) spatial resolution. In this proposal, we aim to establish the suitability of this technique on Cu polyheater samples after thermal stressing. If this experiment is sucessful, it paves the way for a true in-situ experiment where we will aim to observe grain boundary sliding. Moreover, based on the 3D XRD data we will select individual grains for Dark-Field Microscopy at ID03, to correlate even finely resolved strain maps to the results from ID11.