Methods of forming a microelectronic device including stair step structures

1. A method of forming a microelectronic device, the method comprising:

forming isolated nitride structures on steps of stair step structures formed in a stack structure comprising a vertically alternating arrangement of first insulative materials and second insulative materials arranged in tiers;

forming a photoresist material over a lowermost stair step structure of the stair step structures prior to forming the isolated nitride structures on the steps of the stair step structures; and

replacing the isolated nitride structures and the second insulative materials with an electrically conductive material to respectively form conductive pad structures and electrically conductive structures.

2. The method of claim 1 , wherein forming isolated nitride structures on steps of stair step structures comprises forming the isolated nitride structures over portions of the second insulative materials.

3. The method of claim 1 , further comprising forming conductive contact structures in electrical communication with the conductive pad structures and the electrically conductive structures.

4. The method of claim 1 , wherein replacing the isolated nitride structures and the second insulative materials with an electrically conductive material to respectively form conductive pad structures and electrically conductive structures comprises forming conductive pad structures at the steps of about one half of the stair step structures.

5. The method of claim 1 , wherein forming isolated nitride structures comprises:

forming a nitride material on the steps of the stair step structures;

exposing the nitride material to a plasma; and

exposing the nitride material to an etchant to remove vertically extending portions of the nitride material and form the isolated nitride structures.

6. A method of forming a microelectronic device, the method comprising:

forming a stack structure comprising a vertically alternating arrangement of insulative materials and additional insulative materials arranged in tiers;

forming a lowermost stair step structure in the stack structure;

forming a photoresist material over the lowermost stair step structure;

forming other stair step structures in the stack structure after forming the photoresist material;

forming nitride structures on steps of the other stair step structures;

exposing the nitride structures to a plasma;

removing portions of the nitride structures to form isolated nitride structures;

replacing the isolated nitride structures and the additional insulative materials with an electrically conductive material to respectively form conductive pad structures and electrically conductive structures.

7. The method of claim 6 , wherein forming nitride structures comprises forming the nitride structures to have a thickness in a vertical direction within a range of from about 5 nm to about 50 nm.

8. The method of claim 6 , wherein forming isolated nitride structures on steps of a stair step structure comprises forming the isolated nitride structures on the additional insulative materials of the stair step structure.

9. A method of forming a microelectronic device, the method comprising:

forming a stack structure comprising a vertically alternating arrangement of first insulative materials and second insulative materials arranged in tiers;

forming a slot structure comprising a dielectric material extending through the stack structure to form a first sub-block and a second sub-block;

forming stair step structures in the stack structure after forming the slot structure;

forming isolated nitride structures on steps of the stair step structures;

forming a photoresist material over some of the stair step structures; and

replacing the isolated nitride structures and the second insulative material with an electrically conductive material to respectively form conductive pad structures and electrically conductive structures.

10. The method of claim 9 , wherein forming the stair step structures comprises forming the stair step structures in each of the first sub-block and the second sub-block.

11. The method of claim 9 , wherein forming isolated nitride structures comprises exposing nitride structures to a plasma to densify horizontally extending portions of the nitride structures.

12. The method of claim 11 , further comprising selectively removing less dense portions of the nitride structures relative to more dense portions of the nitride structures to form the isolated nitride structures.