Fabrication of complicated three dimensional structures utilizing multi-stack bonding

Hybrid multi-wafer bonding that combines both anodic bonding and silicon direct bonding is one of the most promising manufacturing techniques for creating complex three-dimensional (3D) structures. However, the results of some key micro-fabrication processes will significantly influence the performance of 3D multilayered devices. These problems include: (1) electrical conduction property across the interface of hydrophilic direct bonded wafers; (2) the fabrication of silicon wire. Some key techniques are developed to solve these problems. These solutions are also applicable to fabricate other Microelectromechanical System devices with complex 3D structures.