A combined fabrication methodology of the through wafer via for wl-package of GaAs image sensors

As an image sensor material, Gallium Arsenide (GaAs) has its advantages over Silicon, such as high speed and high sensitivity, and can be applied in many areas. However, little work has been reported about the packaging of GaAs image sensors, especially at wafer level. The fabrication of the through wafer interconnection structure in GaAs wafer is a key process. In this paper a new combined fabrication method of preparing the through wafer via was proposed and investigated. The fabrication method includes the optimal combination of mechanical cutting by dicing blades and wet chemical etch. The prepared via or trench was 100um in depth, and had smooth surface by which a metal layer served as through wafer interconnection could be realized.