A three-dimensional (3D) integrated circuit (IC) is provided. In some embodiments, a second IC die is bonded to a first IC die by a first bonding structure. A third IC die is bonded to the second IC die by a second bonding structure. The second bonding structure is arranged between back sides of the second IC die and the third IC die opposite to corresponding interconnect structures and comprises a first TSV (through substrate via) disposed through a second substrate of the second IC die and a second TSV disposed through a third substrate of the third IC die. The second bonding structure further comprises conductive features with oppositely titled sidewalls disposed between the first TSV and the second TSV.