Multi-wafer stacking structure and fabrication method thereof

Abstract

A multi-wafer stacking structure is disclosed. In which a first interconnection layer is electrically connected to a second metal layer and a first metal layer via a first opening, a second interconnection layer is electrically connected to the first interconnection layer via a second opening, a third interconnection layer is electrically connected to a third metal layer via a third opening, and the second interconnection layer is electrically connected to the third interconnection layer. It is unnecessary to reserve a bonding lead space between wafers, a silicon substrate is eliminated, and the multi-wafer stacking thickness is reduced while multi-wafer interconnection is realized, so that the overall device thickness is reduced after multi-wafer stacked package. Moreover, there is no need of leads, so as to eliminate design processing of a silicon substrate and a plurality of shared bonding pads on the silicon substrate.