Heterogeneous Integration Technique of Optoelectronic Dies to CMOS Circuits Via Metallic Bonding

The integration of complete optoelectronic dies, consisting of optical sources and detectors connected by waveguides for the employment of a photonic layer above CMOS integrated circuits has been proposed. Photonic dies are integrated to CMOS circuits through a novel metallic bonding technique that utilizes a thin multilayer structure of the Au-20Sn eutectic alloy along with a starting layer of a rare earth element (Gd). Its main advantage is the accomplishment of mechanical bonding and electrical connectivity of the heterogeneous devices in a single step. In this paper results on bonding quality and electrical characterization are presented