Semiconductor wafer bonding incorporating electrical and optical interconnects

TLDR: In this paper, the formation of both electrical and optical interconnect vias within the wafer bonding interface to transfer electrical and optic signals between the bonded wafers is discussed. But the authors do not consider the transfer of optical signals across the bonding interface.

Abstract: Methods for bonding semiconductor wafers requiring the transfer of electrical and optical signals between the bonded wafers and across the bonding interface. The methods for bonding of semiconductor wafers incorporate the formation of both electrical and optical interconnect vias within the wafer bonding interface to transfer electrical and optical signals between the bonded wafers. The electrical vias are formed across the bonding surface using multiplicity of metal posts each comprised of multiple layers of metal that are interfused across the bonding surface. The optical vias are formed across the bonding surface using multiplicity of optical waveguides each comprised of a dielectric material that interfuses across the bonding interface and having an index of refraction that is higher than the index of refraction of the dielectric intermediary bonding layer between the bonded wafers. The electrical and optical vias are interspersed across the bonding surface between the bonded wafers to enable uniform transfer of both electrical and optical signals between the bonded wafers.