Embodiments of three-dimensional memory device architectures and fabrication methods therefore are disclosed. In an example, the memory device includes a substrate having a first layer stack on it. The first layer stack includes alternating conductor and insulator layers. A second layer stack is disposed over the first layer stack where the second layer stack also includes alternating conductor and insulator layers. One or more vertical structures extend through the first layers stack. A conductive material is disposed on a top surface of the one or more vertical structures. One or more second vertical structures extend through the second layer stack and through a portion of the conductive material.