A method of routing electrical connections in a wafer-on-wafer structure comprises, bonding a metal bonding pad of a first wafer to a metal bonding pad of a second wafer; bonding first wafer to the second wafer with a material different from the metal bonding pads; forming metal interconnect structures connecting the metal bonding pad of the first wafer to a first device disposed within a first and second side of the first wafer; and forming metal interconnect structures connecting the metal bonding pad of the second wafer to a second and third devices disposed within the second wafer, to connect the first device to the second and third devices through the metal bonding pads, wherein the electrical connections of the devices between the first and second wafers do not have a through-via that passes completely through the first or the second wafer.