This work presents for the first time an analytical study of the electrostatic coupling between bottom and top layer of 3D sequential integration devices, regarding its impact on both static and noise behavior. The effect is demonstrated experimentally through statistical measurements, and TCAD simulations are used to further examine its properties and propose ways for the limitation of inter-tier coupling. It is demonstrated that regarding digital applications, the coupling-induced fluctuations are well within the mismatch variation level.