Methods of forming microelectronic devices, and related electronic systems
A method of forming a microelectronic device comprises forming line structures comprising conductive material and insulative material overlying the conductive material, the line structures separated from one another by trenches. An isolation material is formed on surfaces of the line structures inside and outside of the trenches, the isolation material only partially filling the trenches to form air gaps interposed between the line structures. Openings are formed to extend through the isolation material and expose portions of the insulative material of the line structures. The exposed portions of the insulative material of the line structures are removed to form extended openings extending to the conductive material of the line structures. Conductive contact structures are formed within the extended openings. Conductive pad structures are formed on the conductive contact structures. Additional methods, microelectronic devices, memory devices, and electronic systems are also described.
1. A method of forming a microelectronic device, comprising:
forming line structures comprising conductive bit lines and insulative line structures vertically adjacent the conductive bit lines, the line structures extending in a first horizontal direction and separated from one another in a second direction orthogonal to the first horizontal direction by trenches;
forming an isolation material on surfaces of the line structures inside and outside of the trenches, the isolation material only partially filling the trenches to form air gaps interposed between the line structures, the air gaps vertically overlapping the conductive bit lines;
forming openings extending through the isolation material and exposing portions of the insulative line structures of the line structures;
removing the exposed portions of the insulative line structures of the line structures to form extended openings extending to the conductive bit lines of the line structures;
forming conductive contact structures within the extended openings and directly physically contacting the conductive bit lines, the conductive contact structures partially vertically overlapping the air gaps; and
forming conductive pad structures vertically adjacent the conductive contact structures;
further comprising forming spacer structures within the openings prior to removing the exposed portions of the insulative line structures of the line structures to form the extended openings, the spacer structures partially filling the openings and comprising dielectric material; and
further comprising forming the spacer structures to at least partially horizontally intervene between remaining, unfilled portions of the openings and the air gaps.
2. The method of claim 1 , wherein forming an isolation material on surfaces of the line structures inside and outside of the trenches comprises forming the isolation material on side surfaces of each of the conductive bit lines and the insulative line structures and on upper surfaces of the insulative line structures.
3. The method of claim 1 , further comprising:
selecting the insulative line structures of the line structures to comprise a dielectric nitride material; and
selecting the isolation material to comprise a dielectric oxide material.
4. The method of claim 1 , wherein forming openings extending through the isolation material and exposing portions of the insulative line structures of the line structures comprises forming the each of the openings to be horizontally aligned with one of the line structures thereunder.
5. The method of claim 1 , wherein forming openings extending through the isolation material and exposing portions of the insulative line structures of the line structures comprises forming each of the openings to horizontally extend beyond horizontal boundaries of one of the line structures thereunder.
6. The method of claim 1 , wherein removing the exposed portions of the insulative line structures of the line structures to form extended openings comprises forming vertically lower portions of the extended openings to be horizontally wider than vertically higher portions of the extended openings.
7. The method of claim 1 , wherein forming conductive contact structures within the extended openings comprises:
forming a conductive contact material inside and outside of the extended openings, the conductive contact material substantially filling the extended openings; and
removing portions of the conductive contact material outside of boundaries of the extended openings.
8. The method of claim 1 , wherein forming conductive pad structures on the conductive contact structures comprises forming the conductive pad structures through a damascene process.
9. The method of claim 1 , wherein forming conductive pad structures on the conductive contact structures comprises forming each of the conductive pad structures to horizontally extend beyond horizontal boundaries of one of the conductive contact structures in physical contact therewith.
10. The method of claim 1 , wherein forming conductive pad structures on the conductive contact structures comprises forming the conductive pad structures to comprise copper.