Methods of forming at least one conductive element and methods of forming a semiconductor structure
View Patent ↗Methods of forming conductive elements, such as interconnects and electrodes, for semiconductor structures and memory cells. The methods include forming a first conductive material and a second conductive material comprising silver in a portion of at least one opening and performing a polishing process to fill the at least one opening with at least one of the first and second conductive materials. An annealing process may be performed to form a mixture or an alloy of the silver and the first conductive material. The methods enable formation of silver containing conductive elements having reduced dimensions (e.g., less than about 20 nm). The resulting conductive elements have a desirable resistivity. The methods may be used, for example, to form interconnects for electrically connecting active devices and to form electrodes for memory cells. A semiconductor structure and a memory cell including such a conductive structure are also disclosed.
1. A method of forming at least one conductive element, comprising:
forming a first conductive material over a structure comprising at least one opening defined by sidewalls of a dielectric material, wherein the first conductive material comprises metal;
forming a second conductive material comprising silver over the first conductive material;
annealing the structure to form an annealed material comprising at least a portion of the first conductive material and the second conductive material; and
redistributing at least one of the first conductive material, the second conductive material, and the annealed material into an unfilled region of the at least one opening.
2. The method of claim 1 , further comprising forming a liner material comprising at least one of platinum, tantalum, aluminum, tin, copper, iridium, and titanium over the structure comprising the at least one opening defined by sidewalls of the dielectric material.
3. The method of claim 1 , wherein forming a first conductive material over a structure comprising at least one opening defined by sidewalls of a dielectric material comprises forming the first conductive material over the sidewalls of the dielectric material and a surface of an electrode therebetween.
4. The method of claim 1 , wherein forming a first conductive material over a structure comprising at least one opening defined by sidewalls of a dielectric material comprises forming the first conductive material over the at least one opening having at least one dimension of less than about 20 nm.
5. The method of claim 1 , wherein forming a second conductive material comprising silver over the first conductive material comprises forming silver over the first conductive material without substantially filling the at least one opening.
6. The method of claim 1 , wherein annealing the structure to form an annealed material comprising at least a portion of the first conductive material and the second conductive material comprises annealing the structure to form an annealed material comprising a mixture of silver and tantalum.
7. The method of claim 1 , wherein annealing the structure to form an annealed material comprising at least a portion of the first conductive material and the second conductive material comprises annealing the structure to form an alloy consisting of silver and at least one of platinum, aluminum, tin, copper, iridium, and titanium.
8. The method of claim 1 , wherein redistributing at least one of the first conductive material, the second conductive material, and the annealed material into an unfilled region of the at least one opening comprises performing a polishing process to redistribute the at least one of the first conductive material, the second conductive material, and the annealed material into the unfilled region of the at least one opening.
9. The method of claim 1 , wherein redistributing at least one of the first conductive material, the second conductive material, and the annealed material into an unfilled region of the at least one opening comprises substantially filling the at least one opening with at least one of the first conductive material, the second conductive material, and the annealed material.
10. The method of claim 1 , wherein forming a first conductive material comprises forming at least one of platinum, tantalum, aluminum, tin, copper, iridium, titanium, nickel, cobalt, ruthenium, and rhodium.
11. The method of claim 10 , wherein annealing the structure comprises exposing the structure to a temperature of between about 200° C. and about 600° C. to form at least one of a mixture of the second conductive material and tantalum and an alloy of the second conductive material and the at least one of platinum, aluminum, tin, copper, iridium, titanium, nickel, cobalt, ruthenium, and rhodium.
12. The method of claim 8 , wherein performing a polishing process to redistribute the at least one of the first conductive material, the second conductive material, and the annealed material into the unfilled region of the at least one opening comprises removing material from surfaces of the dielectric material adjacent to the at least one opening.
13. The method of claim 8 , wherein performing a polishing process to redistribute the at least one of the first conductive material, the second conductive material, and the annealed material into the unfilled region of the at least one opening comprises performing the polishing process using a liquid component consisting of deionized water.
14. A method of forming a semiconductor structure, comprising:
removing a portion of a dielectric material overlying a substrate to form at least one opening therein;
forming a first conductive material over the dielectric material and exposed surfaces of the at least one opening wherein the first conductive material comprises metal;
forming a second conductive material comprising silver over the first conductive material, a portion of the at least one opening remaining unfilled; and
performing a polishing process to substantially fill the unfilled portion of the at least one opening.
15. The method of claim 14 , wherein removing a portion of a dielectric material overlying a substrate to form at least one opening therein comprises forming the at least one opening having at least one dimension of less than about 20 nm.
16. The method of claim 14 , wherein forming a first conductive material comprises forming at least one of platinum, tantalum, aluminum, tin, copper, iridium, titanium, nickel, cobalt, ruthenium, and rhodium.
17. The method of claim 16 :
wherein forming at least one of platinum, tantalum, aluminum, tin, copper, iridium, titanium, nickel, cobalt, ruthenium, and rhodium comprises forming platinum; and
further comprising performing an annealing process to form an alloy of the platinum and the second conductive material.
18. The method of claim 14 , wherein performing a polishing process to substantially fill the unfilled portion of the at least one opening comprises performing the polishing process using a liquid component consisting of water to redistribute the first conductive material and the second conductive material into the unfilled portion of the at least one opening.
19. The method of claim 14 , wherein removing a portion of a dielectric material overlying a substrate to form at least one opening therein comprises removing the portion of the dielectric material overlying the substrate to form at least one opening having an aspect ratio of between about 1:1 and about 20:1.
20. The method of claim 14 , wherein performing a polishing process to substantially fill the unfilled portion of the at least one opening comprises performing a polishing process using a liquid component consisting of water to redistribute at least one of the first conductive material and the second conductive material from surfaces adjacent to the at least one opening into the at least one opening.
21. The method of claim 16 , further comprising performing an annealing process to form an alloy of the silver and at least one of the platinum, aluminum, tin, copper, iridium, titanium, nickel, cobalt, ruthenium, and rhodium.
22. The method of claim 2 , wherein forming a liner material comprising at least one of platinum, tantalum, aluminum, tin, copper, iridium, and titanium over the structure comprises forming the liner material over the sidewalls of the dielectric material and a surface of an electrode therebetween.