Liner-free conductive structures with anchor points

1. A method, comprising:

depositing an etch stop layer on a cobalt contact disposed on a substrate;

depositing a dielectric layer on the etch stop layer;

etching the dielectric layer and the etch stop layer to form an opening to expose a top surface of the cobalt contact;

etching the exposed top surface of the cobalt contact to form a recess in the cobalt contact, wherein the recess extends laterally under the etch stop layer;

depositing a ruthenium metal to substantially fill the recess and the opening; and

annealing the ruthenium metal to convert a portion of the ruthenium metal that is in physical contact with the dielectric layer into a conductive ruthenium oxide layer along interfaces between the ruthenium metal and the dielectric layer and to limit cobalt concentration to less than about 6 atomic percent along grain boundaries in the ruthenium metal.

2. The method of claim 1 , further comprising:

planarizing the ruthenium metal to substantially coplanarize surfaces of the ruthenium metal and the dielectric layer; and

depositing a metal oxide on the planarized ruthenium metal.

3. The method of claim 1 , wherein annealing the ruthenium metal comprises annealing the ruthenium metal in a non-oxidizing ambient.

4. The method of claim 1 , wherein annealing the ruthenium metal comprises annealing the ruthenium metal in nitrogen (N 2 ), argon (Ar), helium (He), hydrogen (H 2 ), a forming gas, or a combination thereof.

5. The method of claim 1 , wherein annealing the ruthenium metal comprises performing an annealing process in a non-oxidizing ambient at an annealing temperature between about 200° C. and about 360° C.

6. The method of claim 1 , wherein annealing the ruthenium metal comprises performing an annealing process for a duration between about 1 min and 10 min.

7. The method of claim 1 , wherein depositing the ruthenium metal comprises depositing the ruthenium metal in physical contact with the cobalt contact.

8. The method of claim 1 , wherein depositing the ruthenium metal comprises depositing the ruthenium metal in physical contact with the etch stop layer and the dielectric layer.

9. The method of claim 1 , wherein etching the exposed top surface of the cobalt contact comprises etching the cobalt contact with a wet etching chemistry comprising an aqueous solution.

10. A method, comprising:

forming a first conductive structure on a substrate, the first conductive structure comprising a first non-alloy metal;

forming a second conductive structure on the first conductive structure, the second conductive structure comprising a second non-alloy metal different from the first non-alloy metal;

wherein forming the second conductive structure comprises:

depositing an etch stop layer on the first conductive structure;

depositing a dielectric layer on the etch stop layer;

performing a first etch to form a via opening in the dielectric layer and the etch stop layer that exposes the first non-alloy metal;

performing a second etch through the via opening to form a recess in the first conductive structure;

depositing the second non-alloy metal to substantially fill both the recess and the via opening, wherein the second non-alloy metal is deposited in physical contact with the first non-alloy metal, the etch stop layer, and the dielectric layer; and

annealing the second non-alloy metal to convert a portion of the second non-alloy metal into a conductive non-alloy metal oxide along interfaces between the second non-alloy metal and the dielectric layer and to limit cobalt concentration diffused from the first non-alloy metal to less than about 6 atomic percent along grain boundaries in the second non-alloy metal.

11. The method of claim 10 , wherein forming the first conductive structure comprises forming the first conductive structure with cobalt.

12. The method of claim 10 , wherein depositing the second non-alloy metal comprises depositing ruthenium metal.

13. The method of claim 10 , wherein performing the first etch comprises etching with a dry etching process and performing the second etch comprises etching with a wet etching process.

14. The method of claim 10 , wherein annealing the second non-alloy metal comprises annealing the second non-alloy metal between about 200° C. and about 360° C. for a duration of about 5 min.

15. The method of claim 10 , wherein annealing the second non-alloy metal comprises growing the conductive non-alloy metal oxide on sidewall surfaces of the second conductive structure between the second non-alloy metal and the dielectric layer.

16. The method of claim 10 , wherein annealing the second non-alloy metal comprises growing conductive ruthenium oxide on sidewall surfaces of the second conductive structure between the second non-alloy metal and the dielectric layer.

17. The method of claim 10 , wherein annealing the second non-alloy metal comprises reducing a number of grain boundaries in the second non-alloy metal.

18. A method, comprising:

depositing an etch stop layer on a metal contact;

etching the etch stop layer to form an opening, wherein the opening exposes a top surface of the metal contact;

etching the exposed top surface of the metal contact to form a recess in the metal contact with a ratio between a width of the recess and a height of the recess of about 3, wherein the recess exposes a portion of a bottom surface of the etch stop layer;

depositing a ruthenium metal layer to substantially fill the recess and the opening; and

annealing the ruthenium metal layer to convert a portion of the ruthenium metal layer into a conductive ruthenium oxide layer along sidewalls of the ruthenium metal layer and to limit cobalt concentration diffused from the metal contact to less than about 6 atomic percent along grain boundaries in the ruthenium metal layer.

19. The method of claim 18 , further comprising:

depositing a dielectric layer on the etch stop layer;

planarizing the ruthenium metal layer to substantially coplanarize surfaces of the ruthenium metal layer and the dielectric layer; and

depositing a metal oxide on the planarized ruthenium metal.

20. The method of claim 19 , wherein the conductive ruthenium oxide layer is formed between the ruthenium metal layer and the dielectric layer.