Methods of forming semiconductor device structures including staircase structures

1. A method of forming a semiconductor device structure, comprising:

forming a stack structure comprising stacked tiers each comprising a conductive structure and an insulating structure vertically adjacent the conductive structure;

forming a masking structure over a portion of the stack structure;

removing portions of the stacked tiers of the stack structure not covered by the masking structure to form a secondary stack structure comprising at least one stadium structure having steps comprising lateral ends of the stacked tiers, the at least one stadium structure comprising a first staircase structure and a second staircase structure that mirrors the first staircase structure;

removing the masking structure after forming the secondary stack structure;

removing portions of the secondary stack structure to form a tertiary stack structure comprising:

opposing end sections exhibiting a first width in a first horizontal direction;

an interior section horizontally laterally intervening between the opposing end sections in a second horizontal direction orthogonal to the first horizontal direction and exhibiting a second width in the first horizontal direction smaller than the first width, the interior section comprising:

at least one additional stadium structure exhibiting a smaller width in the first horizontal direction than the at least one stadium structure of the secondary stack structure, and comprising a first additional staircase structure and a second additional staircase structure that mirrors the first staircase structure; and

an elongate middle region extending in the first horizontal direction and directly adjacent a first side of the at least one additional stadium structure in the second horizontal direction; and

an opening horizontally adjacent, in the first horizontal direction, a second side of the at least one additional stadium structure opposing the first side, the opening vertically extending completely through the tertiary stack structure and horizontally extending in the second horizontal direction continuously across an entire length of the at least one additional stadium structure, additional conductive structures of the tertiary stack structure laterally extending from additional steps of the at least one additional stadium structure and completely across the elongate middle region of the interior section;

coupling at least one contact structure to one or more of the additional conductive structures of the tertiary stack structure at one or more of the additional steps of the at least one additional stadium structure; and

forming at least one routing structure coupled to the at least one contact structure and extending from the at least one contact structure, through the opening, and to at least one string driver device.

2. The method of claim 1 , wherein removing portions of the secondary stack structure comprises removing portions of the at least one stadium structure to form the at least one additional stadium structure and the opening horizontally laterally adjacent the second side of the at least one additional stadium structure.

3. The method of claim 1 , further comprising:

coupling at least one contact structure to the conductive structure of one or more of the stacked tiers at one or more steps of the at least one additional stadium structure; and

forming at least one routing structure coupled to and extending between the at least one contact structure and at least one string driver device.

4. The method of claim 1 , wherein coupling at least one contact structure to one or more of the additional conductive structures comprises forming multiple contact structures on multiple additional steps of the at least one additional stadium structure.

5. The method of claim 4 , wherein forming the multiple contact structures on multiple additional steps of the at least one additional stadium structure comprises aligning the multiple contact structures on the multiple additional steps of the at least one additional stadium structure.

6. The method of claim 1 , wherein forming at least one routing structure comprises:

forming a first portion of the at least one routing structure to outwardly laterally extend from the at least one contact structure in a direction perpendicular to the tertiary stack structure;

forming a second portion of the at least one routing structure to longitudinally extend away from the first portion in an additional direction perpendicular to the direction of the first portion; and

forming a third portion of the at least one routing structure to outwardly laterally extend away from the second portion and to the at least one string driver device in another direction perpendicular to the additional direction of the second portion and parallel to the tertiary stack structure.

7. The method of claim 1 , wherein:

coupling at least one contact structure to one or more of the additional conductive structures of the tertiary stack structure comprises coupling multiple contact structures to multiple additional conductive structures of the tertiary stack structure; and

forming at least one routing structure comprises forming multiple routing structures each independently coupled to and extending between the multiple contact structures and the at least one string driver device.

8. The method of claim 7 , wherein forming multiple routing structures each independently coupled to and extending between the multiple contact structures and the at least one string driver device comprises coupling the multiple routing structures to switching devices of only one string driver device.

9. A method of forming a semiconductor device structure, comprising:

forming stacked tiers each comprising a conductive structure and an insulating structure vertically adjacent the conductive structure;

removing portions of the stacked tiers to form a stadium structure having steps comprising lateral ends of the stacked tiers, the stadium structure comprising a first staircase structure having a generally positive slope and a second staircase structure mirroring the first staircase structure and having a generally negative slope;

removing a portion of the stadium structure to form an opening vertically extending completely through the stacked tiers, the opening horizontally adjacent a first side of a remaining portion the stadium structure in a first horizontal direction and horizontally extending continuously across an entire length of the stadium structure in a second horizontal direction orthogonal to the first horizontal direction, conductive structures of the stacked tiers horizontally extending from the steps of the remaining portion of the stadium structure completely across a second side of the remaining portion of the stadium structure opposing the first side to form continuous conductive paths laterally extending completely across the stacked tiers in the second horizontal direction;

coupling at least one contact structure to the conductive structure of one or more of the stacked tiers at one or more of the steps of the remaining portion of the stadium structure; and

coupling at least one routing structure to the at least one contact structure, the at least one routing structure extending from the at least one contact structure, through the opening, and to at least one string driver device.

10. The method of claim 9 , wherein removing portions of the stacked tiers to form a stadium structure comprises:

forming a hard mask material over a portion of the stacked tiers;

selectively etching the stacked tiers using to the hard mask material to form the stadium structure.

11. The method of claim 9 , wherein coupling at least one contact structure to the conductive structure of one or more of the stacked tiers at one or more of the steps of the remaining portions of the stadium structure comprises coupling multiple, substantially aligned contact structures to the steps of the remaining portions of the stadium structure.

12. The method of claim 9 , wherein coupling at least one routing structure to the at least one contact structure comprises forming the at least one routing structure to comprise:

at least one first portion coupled to the at least one contact structure and outwardly laterally extending in a direction oriented perpendicular to the stacked tiers;

at least one second portion coupled to the at least one first portion and longitudinally extending through the opening in an additional direction oriented perpendicular to the direction of the at least one first portion; and

at least one third portion coupled to the at least one second portion and outwardly laterally extending in another direction oriented perpendicular to the additional direction of the at least one second portion and parallel to the stacked tiers.

13. The method of claim 9 , wherein coupling at least one routing structure to the at least one contact structure comprises coupling multiple routing structures to multiple contact structures, some of the multiple routing structures extending to a first string driver device underlying the stacked tiers, and other of the multiple routing structures extending to a second string driver device underlying the stacked tiers.

14. A method of forming a semiconductor device structure, comprising:

forming a stack structure comprising tiers each comprising a conductive structure and an insulating structure longitudinally adjacent the conductive structure;

forming an opening vertically extending completely through the stack structure;

removing remaining portions of the stack structure horizontally adjacent the opening in a first horizontal direction to form a stadium structure adjacent the opening in the first horizontal direction and comprising a first staircase structure having a generally positive slope and a second staircase structure extending in series with the first staircase structure and having a generally negative slope, conductive structures of the tiers of the stack structure terminating at steps of the stadium structure and forming continuous conductive paths horizontally extending completely across the tiers in a second horizontal direction orthogonal to the first horizontal direction;

coupling contact structures to the steps of the at least one staircase structure; and

coupling routing structures to the contact structures, the routing structures extending from contact structures, through the opening, and to one or more string driver devices.

15. The method of claim 14 , wherein:

forming an opening extending through the stack structure comprises:

forming a masking material over a portion of the stack structure; and

removing another portion of the stack structure not covered by the masking material; and

removing remaining portions of the stack structure laterally adjacent the opening comprises:

removing a portion of the masking material; and

selectively etching the stack structure using a remaining portion of the masking material.