Three-dimensional memory device with high contact via density and methods of forming the same

Abstract

A three-dimensional memory device includes an alternating stack of insulating layers and electrically conductive layers, a first three-dimensional memory array located in a first memory array region, and a second three-dimensional memory array located in a second memory array region that is laterally spaced from the first memory array region along a first horizontal direction by an inter-array region. The alternating stack is laterally bounded by two trench fill structures that are laterally spaced apart along a second horizontal direction by an inter-trench spacing. The inter-array region includes a stepped cavity having vertical steps of the alternating stack that laterally extend along different horizontal directions. Multiple rows of contact via structures may contact different electrically conductive layers in the stepped cavity. Alternatively or additionally, a top portion of the stepped cavity and a width of a bridge region of the electrically conductive layers in the inter-array region may have a variable lateral extent along the second horizontal direction.