A method of forming a semiconductor structure includes introducing, at selected conditions, hydrogen and helium species (e.g., ions) in a temporary support to form a plane of weakness at a predetermined depth therein, and to define a superficial layer and a residual part of the temporary support; forming on the temporary support an interconnection layer; placing at least one semiconductor chip on the interconnection layer; assembling a stiffener on a back side of the at least one semiconductor chip; and providing thermal energy to the temporary support to detach the residual part and provide the semiconductor structure. The interconnection layer forms an interposer free from any through via.