Electrical and morphological assessment of via middle and backside process technology for 3D integration

This study focuses on the prototype of a 3D circuit in 65nm CMOS node, in which digital and analog functions have been partitioned on two different layers, assembled in a face-to-face integration and reported on a BGA. The paper more specifically presents the process technology carried out for the realization of the bottom die. Major process steps are described and evaluated from an electrical performance point of view.