A TSV structure, method of making the TSV structure and methods of testing the TSV structure. The structure including: a trench extending from a top surface of a semiconductor substrate to a bottom surface of the semiconductor substrate, the trench surrounding a core region of the semiconductor substrate; a dielectric liner on all sidewalls of the trench; and an electrical conductor filling all remaining space in the trench, the dielectric liner electrically isolating the electrical conductor from the semiconductor substrate and from the core region.