Barrier-metal-free copper damascene technology using atomic hydrogen enhanced reflow
View Patent ↗A method for forming conductive contacts and interconnects in a semiconductor structure, and the resulting conductive components are provided. In particular, the method is used to fabricate single or dual damascene copper contacts and interconnects in integrated circuits such as memory devices and microprocessor.
1. A method of forming a contact in an opening in an insulative material, comprising:
forming a non-metal barrier material over the insulative material within the opening;
depositing a conductive material over the non-metal barrier material by ionized sputtering or metal evaporation to fill the opening; and
reflowing the conductive material in an atmosphere of atomic hydrogen at a temperature of less than about 400° C.
2. The method of claim 1 , wherein the non-metal barrier material is formed over the exposed surface of the insulative material within the opening.
3. The method of claim 1 , wherein the non-metal barrier material is formed by exposing the surface of the insulative material within the opening to a nitrogen-containing plasma.
4. The method of claim 3 , wherein the nitrogen-containing plasma is ammonia (NH 3 ).
5. The method of claim 3 , wherein the nitrogen-containing plasma is molecular nitrogen (N 2 ).
6. The method of claim 3 , wherein the nitrogen-containing plasma is a mixture of ammonia (NH 3 ) and molecular nitrogen (N 2 ).
7. The method of claim 1 , wherein the non-metal barrier material is formed to a thickness of about 5 nm to about 10 nm.
8. The method of claim 1 , wherein the non-metal barrier material comprises silicon oxynitride (SiON).
9. The method of claim 1 , wherein the insulative material comprises silicon oxyfluoride (SiOF).
10. The method of claim 1 , wherein the conductive material is deposited over the non-metal barrier material by ionized sputtering.
11. The method of claim 10 , wherein the ionized sputtering is ionized magnetron sputtering.
12. The method of claim 1 , wherein the conductive material is deposited over the non-metal barrier material by metal evaporation.
13. The method of claim 12 , wherein the metal evaporation is copper evaporation.
14. The method of claim 1 , wherein the conductive material is copper.
15. The method of claim 14 , wherein the copper conductive material is reflowed in an atmosphere of atomic hydrogen at a temperature in the range of about 300° C. to about 350° C. to ensure filling of the copper conductive material in the opening to form a substantially voidless contact.
16. The method of claim 14 , wherein the copper conductive material is reflowed in an atmosphere of atomic hydrogen at a temperature of about 320° C.
17. The method of claim 1 , wherein the conductive material is reflowed in an atmosphere of atomic hydrogen at a temperature in the range of about 300° C. to about 350° C. to ensure filling of the conductive material in the opening to form a substantially voidless contact.
18. The method of claim 1 , wherein the atmosphere of atomic hydrogen is generated from a mixed high density krypton/hydrogen (Kr/H 2 ) plasma.
19. The method of claim 18 , wherein the mixing ratio of hydrogen to inert gas in the mixed high density krypton/hydrogen (Kr/H 2 ) plasma is about 3% to about 5% H 2 /Kr.
20. The method of claim 1 , wherein the atmosphere of atomic hydrogen is generated by using a microwave-excitation high density plasma system.
21. The method of claim 1 , further comprising removing excess conductive material after the step of depositing the conductive material over the non-metal barrier material.
22. The method of claim 21 , wherein excess conductive material is removed by chemical-mechanical polishing.
23. The method of claim 1 , wherein the opening to form the contact is 0.25 μm or smaller.
24. The method of claim 1 , wherein the opening has a high aspect ratio of 3:1 or greater.
25. A method of forming an interconnect, comprising:
forming a non-metal barrier material over an insulative layer comprising a trench by exposing a surface of the insulative layer to ammonia (NH 3 ) plasma or to a plasma containing a mixture of ammonia and molecular nitrogen;
depositing a conductive material over the non-metal barrier material; and
reflowing the conductive material in an atmosphere of atomic hydrogen at a temperature of less than about 400° C.
26. The method of claim 25 , wherein the conductive material is reflowed in an atmosphere of atomic hydrogen at a temperature in the range of about 300° C. to about 350° C. to form a substantially voidless fill of conductive material within the trench.
27. The method of claim 26 , wherein the conductive material is reflowed in an atmosphere of atomic hydrogen at a temperature of about 320° C.
28. The method of claim 25 , wherein the atmosphere of atomic hydrogen is generated from a mixed high density krypton/hydrogen (Kr/H 2 ) plasma with a mixing ratio of hydrogen to inert gas of about 3% to about 5% H 2 /Kr.
29. The method of claim 25 , further comprising removing excess conductive material after the step of depositing the conductive material over the non-metal barrier material.
30. The method of claim 29 , wherein excess conductive material is removed by chemical-mechanical polishing.
31. The method of claim 25 , wherein the non-metal barrier material is formed to a thickness of about 5 nm to about 10 nm.
32. The method of claim 25 , wherein the non-metal barrier material comprises silicon oxynitride (SiON).
33. The method of claim 25 , wherein the insulative layer comprises silicon oxyfluoride (SiOF).
34. The method of claim 25 , wherein the conductive material is deposited over the non-metal barrier material by ionized sputtering.
35. The method of claim 34 , wherein the ionized sputtering is ionized magnetron sputtering.
36. The method of claim 25 , wherein the conductive material is deposited over the non-metal barrier material by metal evaporation.
37. The method of claim 36 , wherein the metal evaporation is copper evaporation.
38. The method of claim 25 , wherein the conductive material is copper.