A method for fabricating a semiconductor chip includes forming a plurality of conducting pads at a front face of a substrate, thinning a rear face of the substrate, etching openings under each conducting pad from the rear face, depositing a layer of a dielectric on walls and a bottom of the openings, forming a conducting material in the openings, and forming a conducting strip on the rear face. The conducting strip is electrically connected to the conducting material of each of the openings. The etching is stopped when the respective conducting pad is reached.