A semiconductor device includes: a first chip including a plurality of first device features and a plurality of first interconnect structures disposed above the first device features; a second chip including a plurality of second device features and a plurality of second interconnect structures disposed above the second device features; and an interposer bonded to the first chip and the second chip, and disposed on an opposite side from the first and second device features with respect to the first and second interconnect structures; wherein the interposer includes a plurality of power rails configured to deliver power to the first and second chips.