A monolithic three-dimensional (3D) integrated circuit (IC) device includes a lower tier including a lower tier cell and an upper tier arranged over the lower tier. The upper tier has a first upper tier cell and a second upper tier cell separated by a predetermined lateral space. A monolithic inter-tier via (MIV) extends from the lower tier through the predetermined lateral space, and the MIV has a first end electrically connected to the lower tier cell and a second end electrically connected to the first upper tier cell.