Novel Single and Co-Ion Implantation Induced Backside Etch Stop Structures for 3D Multilayer Stacked Package

This innovative approach proposes a unique method involving single and co-implantation with nitrogen and boron for wafer thinning. Various implant resources, including different etch solutions, such as KOH and KOH-H2O-IPA (hybrid solvents), are utilized in the thinning process. Both co-ion implantation and single-ion implantation demonstrate an etch retardation effect, highlighting their effectiveness in controlling the thinning process. Tests were conducted to measure the etch rate difference between undoped silicon and heavily doped silicon to assess the etch selectivity. Notably, the highest etch selectivity 46 was achieved in the boron-doped structure when etched with the hybrid solvent solution.