Microelectronic devices with mirrored blocks of multi-set staircased stadiums, and related systems and methods

Abstract

Microelectronic devices include a stack having a vertically alternating sequence of insulative and conductive structures arranged in tiers. Slit structures extend through the stack, dividing the stack into blocks. A first series of stadiums—within the stack of a first block of a pair of the blocks—includes at least one stadium having multiple parallel sets of staircases. A second series of stadiums—within the stack of a second block of the pair of blocks—includes at least one additional stadium having additional multiple parallel sets of staircases that are mirrored, across one of the slit structures, to the multiple parallel sets of staircases of the first series. In methods of fabrication, common mask openings are used to form the mirrored staircase profiles once stadiums are already at substantially their final depths in the stack structure. Electronic systems are also disclosed.