Void-free copper filling of recessed features using a smooth non-agglomerated copper seed layer
A method is provided for controlling copper agglomeration on a substrate and for forming void-free bulk copper metal filling of recessed features in integrated circuits. In one embodiment, the method includes providing a substrate having a topography including a top surface and at least one recessed feature comprising at least a sidewall surface and a bottom surface, depositing a barrier film on the substrate topography, and depositing a metal-containing wetting film on the barrier film. The method further includes physical vapor depositing copper metal on the metal-containing wetting film, where the substrate temperature is sufficiently high to form a smooth copper metal seed layer on the metal-containing wetting film. Void-free bulk copper metal may be plated in the at least one recessed feature.
1. A method for controlling copper agglomeration on a substrate, the method comprising:
providing a substrate having a topography including a top surface and at least one recessed feature comprising at least a sidewall surface and a bottom surface;
depositing a barrier film on the substrate topography;
depositing a metal-containing wetting film on the barrier film;
sputtering copper metal from a copper metal target; and
exposing the metal-containing wetting film to the sputtered copper metal at a substrate temperature between greater than 0° C. and 200° C., wherein the exposing deposits a continuous copper metal seed layer with no overhang on the metal-containing wetting film at an inlet of the recessed feature.
2. The method of claim 1 , wherein the metal-containing wetting film comprises palladium metal (Pd), rhodium metal (Rh), or silver metal (Ag), or compounds of ruthenium metal (Ru), Pd, Rh, or Ag that further comprise nitrogen, oxygen, carbon, boron, or phosphorus.
3. The method of claim 1 , further comprising:
heat treating the metal-containing wetting film at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
4. The method of claim 1 , further comprising:
heat treating the copper metal seed layer at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
5. The method of claim 1 , wherein the barrier film comprises tantalum nitride, titanium nitride, tungsten nitride, tantalum silicon nitride, titanium silicon nitride, or tungsten silicon nitride, or a combination thereof.
6. The method of claim 1 , wherein the at least one recessed feature is formed in a dielectric material.
7. The method of claim 1 , wherein the metal-containing wetting film comprises ruthenium metal (Ru).
8. The method of claim 1 , wherein the substrate temperature is between 10° C. and 100° C.
9. A method for processing a substrate, the method comprising:
providing a substrate having a topography including a top surface and at least one recessed feature comprising at least a sidewall surface and a bottom surface;
depositing a barrier film on the substrate topography, the barrier film having a thickness between about 1nm and about 10nm in the at least one recessed features;
depositing a metal-containing wetting film on the barrier film, the metal-containing wetting film comprising ruthenium metal (Ru), palladium metal (Pd), rhodium metal (Rh), silver metal (Ag), or compounds of Ru, Pd, Rh, or Ag that further comprise nitrogen, oxygen, carbon, boron, or phosphorus;
sputtering copper metal from a copper metal target;
exposing the metal-containing wetting film to the sputtered copper metal at a substrate temperature between greater than 0° C. and 200° C., wherein the exposing to the sputtered copper metal deposits a continuous copper metal seed layer with no overhang on the metal-containing wetting film at an inlet of the at least one recessed feature; and
plating void-free bulk copper metal in the at least one recessed feature.
10. The method of claim 9 , wherein the plating fills or overfills the at least one recessed feature.
11. The method of claim 9 , further comprising:
heat treating the metal-containing wetting film at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
12. The method of claim 9 , further comprising:
heat treating the copper metal seed layer at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
13. The method of claim 9 , wherein the barrier film comprises tantalum nitride, titanium nitride, tungsten nitride, tantalum silicon nitride, titanium silicon nitride, or tungsten silicon nitride, or a combination thereof.
14. A method for processing a substrate, the method comprising:
providing a substrate having a topography including a top surface and at least one recessed feature comprising at least a sidewall surface and a bottom surface, the least one recessed feature comprising a via, a trench, or a combination thereof;
depositing a barrier film on the substrate topography including in the at least one recessed feature, the barrier film having a thickness between about 1nm and about 10nm in the one or more recessed features;
depositing a ruthenium metal wetting film on the barrier film in a chemical vapor deposition process using Ru 3 (CO) 12 precursor and CO carrier gas, the ruthenium metal film having a thickness between about 0.1 nm and about 5 nm in the one or more recessed features;
sputtering copper metal from a copper metal target;
exposing the metal-containing wetting film to the sputtered copper metal at a substrate temperature between greater than 0° C. and 200° C., wherein the exposing to the sputtered copper metal deposits a continuous copper metal seed layer with no overhang on the metal-containing wetting film in the at least one recessed feature; and
plating void-free bulk copper metal in the at least one recessed feature, wherein the plating fills or overfills the at least one recessed feature.
15. The method of claim 14 , further comprising:
heat treating the metal wetting film at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
16. The method of claim 14 , further comprising:
heat treating the copper metal seed layer at a temperature between about 100° C. and about 400° C. in the presence of an inert gas, H 2 gas, or a combination of H 2 gas and an inert gas.
17. The method of claim 14 , wherein the barrier film comprises tantalum nitride, titanium nitride, tungsten nitride, tantalum silicon nitride, titanium silicon nitride, or tungsten silicon nitride, or a combination thereof
18. The method of claim 14 , wherein the recessed feature has a width of about 100 nm or less and an aspect ratio greater than 2:1.
19. The method of claim 14 , wherein the substrate temperature is between 10° C. and 100° C.