THROUGH VIA STRUCTURE AND METHOD OF FABRICATION THEREOF

Through via structures and methods of fabrication thereof are disclosed herein. An exemplary method includes forming a trench that extends through an insulation layer and into a substrate. The substrate has a first side (e.g., frontside) and a second side (e.g., backside). The insulation layer is disposed over the first side of the substrate. The method includes filling the trench with a dielectric material and performing a thinning process on the second side of the substrate that exposes the dielectric material. After the thinning process and removing the dielectric material from the trench, the method includes forming an electrically conductive structure (e.g., a barrier liner that wraps an electrically conductive plug) in the trench that extends through the substrate from the first side to the second side. A portion of the barrier liner that forms a top of the electrically conductive structure is disposed in the insulation layer.