Microelectronic devices including stair step structures, and related electronic systems and methods

1 . A microelectronic device, comprising:

a stack structure comprising a vertically alternating sequence of conductive structures and insulating structures arranged in tiers, the stack structure further comprising:

a first block comprising first stadium structures having steps comprising horizontal ends of the tiers,

an arrangement of the first stadium structures ascending from a lowermost first stadium structure having a lowermost step of the first stadium structures to an uppermost first stadium structure having an uppermost step of the first stadium structures in a first horizontal direction; and

a second block neighboring the first block in a second horizontal direction orthogonal to the first horizontal direction and comprising second stadium structures having additional steps comprising additional horizontal ends of the tiers,

an arrangement of second stadium structures descending from an uppermost second stadium structure having an uppermost additional step of the second stadium structures to a lowermost second stadium structure having a lowermost additional step of the second stadium structures in the first horizontal direction,

the lowermost second stadium structure of the second block horizontally aligned with the uppermost first stadium structure of the first block,

first crest regions between pairs of the first stadium structures neighboring one another within the first block, wherein an uppermost surface of at least one crest region of the first crest regions is disposed at a height of an uppermost surface of the first block; and

second crest regions between pairs of the second stadium structures neighboring one another within the second block, wherein an uppermost surface of at least one crest region of the second crest regions is disposed at a height of an uppermost surface of the second block.

2 . The microelectronic device of claim 1 , further comprising a dielectric slot structure interposed between the first block and the second block in the second horizontal direction.

3 . The microelectronic device of claim 2 , wherein:

the first block of the stack structure further comprises first bridge structures interposed between the first stadium structures and the dielectric slot structure in the second horizontal direction; and

the second block of the stack structure further comprises second bridge structures interposed between the second stadium structures and the dielectric slot structure the second horizontal direction.

4 . The microelectronic device of claim 1 , wherein horizontal centers of the uppermost first stadium structure of the first block and the lowermost second stadium structure of the second block are substantially horizontally aligned within one another in the second horizontal direction.

5 . The microelectronic device of claim 1 , wherein the first crest regions incrementally decrease in width in the first horizontal direction from the uppermost first stadium structure to the lowermost first stadium structure of the first block.

6 . The microelectronic device of claim 5 , wherein the lowermost first stadium structure of the first stadium structures and another of the first stadium structures neighboring the lowermost first stadium structure do not include one of the first crest regions interposed therebetween.

7 . A microelectronic device, comprising:

a stack structure comprising tiers of conductive structures vertically interleaved with insulative structure, the stack structure further comprising:

a first block comprising:

upper first stadium structures vertically above a center plane of the stack structure;

lower first stadium structures vertically below the center plane of the stack structure; and

first crest regions disposed between at least two of the upper first stadium structures, wherein an uppermost surface of at least one crest region of the first crest regions is disposed at a height of an uppermost surface of the first block;

a second block laterally neighboring the first block and comprising:

upper second stadium structures vertically above the center plane of the stack structure;

lower second stadium structures vertically below the center plane of the stack structure, and

second crest regions disposed between at least two of the upper second stadium structures, wherein an uppermost surface of at least one crest region of the second crest regions is disposed at a height of an uppermost surface of the second block; and

wherein an uppermost one of the upper first stadium structures having an uppermost step of the first stadium structures of the first block is horizontally aligned with a lowermost one of the lower second stadium structures having a lowermost additional step of the second stadium structures of the second block.

8 . The microelectronic device of claim 7 , wherein the upper first stadium structures and the lower first stadium structures of the first block are oriented along a first axis oblique to the center plane of the stack structure.

9 . The microelectronic device of claim 8 , wherein vertical centers of the upper second stadium structures of the second block and vertical centers of the lower second stadium structures of the second block are aligned along a second axis oblique to the center plane of the stack structure.

10 . The microelectronic device of claim 7 , wherein an uppermost one of the upper second stadium structures of the second block is horizontally aligned with a lowermost one of the lower first stadium structures of the first block.

11 . The microelectronic device of claim 7 , wherein each of the tiers individually comprises one of the conductive structures and one of the insulating structures.

12 . The microelectronic device of claim 7 , further comprising:

a dielectric slot structure horizontally interposed between the first block and the second block;

first bridge structures horizontally interposed between the dielectric slot structure and each of the upper first stadium structures and the lower first stadium structures, the first bridge structures comprising relatively elevated portions of the stack structure; and

second bridge structures horizontally interposed between the dielectric slot structure and each of the upper second stadium structures and the lower second stadium structures, the second bridge structures comprising additional relatively elevated portions of the stack structure.

13 . The microelectronic device of claim 7 , wherein each of the first block and the second block comprises a respective center stadium structure intersecting the center plane.

14 . A memory device, comprising:

a stack structure comprising tiers each comprising a conductive material and an insulative material vertically neighboring the conductive material, the stack structure divided into blocks extending in parallel in a first direction and separated from one another in a second direction by dielectric slot structures, the blocks comprising:

a first block comprising:

first stadium structures comprising staircase structures individually having steps comprising horizontal ends of at least some the tiers of the stack structure;

first elevated regions neighboring sides of the first stadium structures in the second direction; and

first additional elevated regions neighboring opposing ends of the first stadium structures in the first direction, uppermost surfaces of the first additional elevated regions substantially coplanar with uppermost surfaces of the first elevated regions; and

a second block neighboring the first block and comprising:

second stadium structures comprising additional staircase structures individually having additional steps comprising additional horizontal ends of the at least some the tiers of the stack structure,

a vertical positioning arrangement of the second stadium structures in the first direction inverted relative to that of the first stadium structures of the first block, and

centers of the second stadium structures substantially aligned with centers of the first stadium structures in the first direction;

second elevated regions neighboring sides of the second stadium structures in the second direction;

second additional elevated regions neighboring opposing ends of the second stadium structures in the first direction,

uppermost surfaces of the second additional elevated regions substantially coplanar with uppermost surfaces of the second elevated regions, and

widths, in the second direction, of at least some of the first elevated regions of the first block different than additional widths, in the second direction, of at least some of the second elevated regions most proximate to the at least some of the first elevated regions; and

strings of memory cells vertically extending through the first block and the second block of the stack structure.

15 . The memory device of claim 14 , wherein a width, in the second direction, of one of the first elevated regions laterally adjacent an uppermost one of the first stadium structures is greater than a width, in the second direction, of one of the second elevated regions laterally adjacent a lowermost one of the second stadium structures substantially aligned with the an uppermost one of the first stadium structures in the first direction.