Optimization of double-side 3D detector technology for first productions at FBK

We report on the optimization of the technology aimed at the production of Double-Sided, Double-Column 3D detectors with full passing columns (3D-DTTC) at FBK (Trento, Italy). This R&D project is aimed at establishing a suitable technology for the production of 3D pixel sensors to be installed into the ATLAS IBL. We describe the main process modifications adopted on more recent 3D batches, to overcome the limitations affecting the first 3D batch, as arisen from its electrical characterization.