Method for integrating selective low-temperature ruthenium deposition into copper metallization of a semiconductor device
A method for integrating low-temperature selective Ru metal deposition into manufacturing of semiconductor devices to improve electromigration and stress migration in bulk Cu metal. The method includes providing a patterned substrate containing a recessed feature in a dielectric layer, where the recessed feature is at least substantially filled with planarized bulk Cu metal, heat-treating the bulk Cu metal and the dielectric layer in the presence of H 2 , N 2 , or NH 3 , or a combination thereof, and selectively depositing a Ru metal film on the heat-treated planarized bulk Cu metal.
1. A method of forming a semiconductor device, comprising:
providing a patterned substrate containing a recessed feature in a dielectric layer, the recessed feature at least substantially filled with planarized bulk Cu metal;
heat-treating the planarized bulk Cu metal and the dielectric layer in the presence of H 2 , N 2 , or NH 3 , or a combination thereof; and
selectively depositing a Ru metal film on the heat-treated planarized bulk Cu metal, wherein surface coverage of the Ru metal film on the planarized bulk Cu metal is incomplete with gaps that expose the planarized bulk Cu metal.
2. The method of claim 1 , wherein the heat-treating and depositing are performed at a substrate temperature below 200° C.
3. The method of claim 1 , wherein the depositing is performed at a substrate temperature between 100° C. and 300° C.
4. The method of claim 1 , wherein the heat-treating is performed at a substrate temperature below 200° C.
5. The method of claim 1 , wherein the heat-treating is performed at a substrate temperature between 200° C. and 400° C.
6. The method of claim 1 , wherein a thickness of the Ru metal film is between 1 Angstrom and 30 Angstrom.
7. The method of claim 1 , wherein a thickness of the Ru metal film is less than 10 Angstrom.
8. The method of claim 1 , wherein selectively depositing the Ru metal film comprises:
forming a process gas containing Ru 3 (CO) 12 precursor vapor and a CO gas, the form comprising:
heating a solid Ru 3 (CO) 12 precursor in a precursor evaporation system to a temperature between about 40° C. and about 150° C. and maintaining the solid Ru 3 (CO) 12 precursor at the temperature to form the Ru 3 (CO) 12 precursor vapor, and
flowing the CO gas in contact with the solid Ru 3 (CO) 12 precursor in the precursor evaporation system during the heating to capture the Ru 3 (CO) 12 precursor vapor in the CO gas as the vapor is being formed; and
transporting the process gas from the precursor evaporation system to a process chamber containing the patterned substrate; and
exposing the patterned substrate to the process gas in a thermal chemical vapor deposition process.
9. The method of claim 1 , wherein the recessed feature comprises one or more trenches and one or more vias.
10. The method of claim 1 , wherein the patterned substrate further comprises a barrier layer in the recessed feature.
11. The method of claim 1 , further comprising:
depositing a conformal cap layer on the Ru metal film and the dielectric layer.
12. The method of claim 11 , further comprising:
prior to depositing the cap layer, heat-treating the Ru metal film and the dielectric layer at a substrate temperature between 150° C. and 400° C. in the presence of H 2 , N 2 , or NH 3 , or a combination thereof.
13. A method of forming a semiconductor device, comprising:
providing a patterned substrate containing a recessed feature in a dielectric layer, the recessed feature at least substantially filled with planarized bulk Cu metal;
heat-treating the planarized bulk Cu metal and the dielectric layer at a substrate temperature below 200° C. in the presence of H 2 ; and
selectively depositing a Ru metal film on the heat-treated planarized bulk Cu metal by exposing the patterned substrate to the process gas containing Ru 3 (CO) 12 precursor vapor and a CO gas in a thermal chemical vapor deposition process, wherein surface coverage of the Ru metal film on the planarized bulk Cu metal is incomplete with gaps that expose the planarized bulk Cu metal.
14. The method of claim 13 , further comprising:
depositing a conformal cap layer on the Ru metal film and the dielectric layer.
15. The method of claim 13 , wherein a thickness of the Ru metal film is between 2 and 30 Angstrom.
16. The method of claim 14 , further comprising:
prior to depositing the cap layer, heat-treating the Ru metal film and the dielectric layer at a temperature between about 150° C. and about 400° C. in the presence of H 2 , N 2 , or NH 3 , or a combination thereof.
17. A method of forming a semiconductor device, comprising:
providing a patterned substrate containing a recessed feature in a dielectric layer, the recessed feature at least substantially filled with planarized bulk Cu metal;
heat-treating the planarized bulk Cu metal and the dielectric layer in the presence of N 2 or NH 3 , or combination thereof; and
selectively depositing a Ru metal film on the heat-treated planarized bulk Cu metal by exposing the patterned substrate to the process gas containing Ru 3 (CO) 12 precursor vapor and a CO gas in a thermal chemical vapor deposition process, wherein surface coverage of the Ru metal film on the planarized bulk Cu metal is incomplete with gaps that expose the planarized bulk Cu metal.
18. The method of claim 17 , further comprising depositing a conformal cap layer on the Ru metal film and the dielectric layer.
19. The method of claim 18 , further comprising:
prior to depositing the cap layer, heat-treating the Ru metal film and the dielectric layer at a substrate temperature between 150° C. and 400° C. in the presence of H 2 , N 2 , or NH 3 , or a combination thereof.