A microelectronic device comprises a stack structure comprising alternating conductive structures and insulative structures. Memory cells vertically extend through the stack structure, and comprise a channel material vertically extending through the stack structure. An additional stack structure vertically overlies the stack structure and comprises additional conductive structures and additional insulative structures. First pillar structures extend through the additional stack structure and vertically overlie a portion of the memory cells. Second pillar structures are adjacent to the first pillar structures and extend through the additional stack structure and vertically overlie another portion of the memory cells. Slot structures are laterally adjacent to the first pillar structures and to the second pillar structures and extend through at least a portion of the additional stack structure. A distance between the first pillar structures and the slot structures is substantially equal to a distance between the second pillar structures and the slot structures.