Method of patterning a low-k dielectric film
Methods of patterning low-k dielectric films are described. In an example, a method of patterning a low-k dielectric film involves forming and patterning a mask layer above a low-k dielectric layer, the low-k dielectric layer disposed above a substrate. The method also involves modifying exposed portions of the low-k dielectric layer with a nitrogen-free plasma process. The method also involves removing, with a remote plasma process, the modified portions of the low-k dielectric layer selective to the mask layer and unmodified portions of the low-k dielectric layer.
1. A method of patterning a low-k dielectric film, the method comprising:
forming and patterning a mask layer above a low-k dielectric layer, the low-k dielectric layer disposed above a substrate;
modifying exposed portions of the low-k dielectric layer with a nitrogen-free plasma process;
removing, with a remote plasma process, the modified portions of the low-k dielectric layer selective to the mask layer and unmodified portions of the low-k dielectric layer; and
repeating the modifying and the removing one or more times to form one or more trenches in the low-k dielectric layer without forming a fluorocarbon polymer on the low-k dielectric layer.
2. The method of claim 1 , wherein modifying exposed portions of the low-k dielectric layer with the nitrogen-free plasma process comprises using a plasma based on a combination of Ar, SiF 4 and O 2 .
3. The method of claim 1 , wherein removing the modified portions of the low-k dielectric layer with the remote plasma process comprises using a plasma based on a combination of gases selected from the group consisting of NF 3 /O 2 /N 2 , CF 4 /O 2 /N 2 and NF 3 /NH 3 .
4. The method of claim 1 , wherein modifying exposed portions of the low-k dielectric layer with the nitrogen-free plasma process further comprises depositing a protection layer and modifying the low-k layer in a same operation.
5. The method of claim 4 , wherein modifying exposed portions of the low-k dielectric layer and depositing the protection layer with the nitrogen-free plasma process comprises using a plasma based on a combination of Ar, SiF 4 and O 2 .
6. The method of claim 4 , wherein removing the modified portions of the low-k dielectric layer with the remote plasma process further comprises removing the protection layer with the remote plasma process.
7. The method of claim 6 , wherein removing the modified portions of the low-k dielectric layer and the protection layer with the remote plasma process comprises using a plasma based on a combination of gases selected from the group consisting of NF 3 /O 2 /N 2 , CF 4 /O 2 /N 2 and NF 3 /NH 3 .
8. The method of claim 1 , wherein the modifying the exposed portions of the low-k dielectric layer with the nitrogen-free plasma process comprises processing at a first stage of a plasma etch chamber, and wherein removing the modified portions of the low-k dielectric layer with the remote plasma process comprises processing at a second, different, stage of the plasma etch chamber.
9. The method of claim 8 , wherein a showerhead of the etch chamber is positioned between the first and second stages, the second stage above the showerhead.
10. A method of patterning a low-k dielectric film, the method comprising:
forming and patterning a mask layer above a low-k dielectric layer, the low-k dielectric layer disposed above a substrate;
modifying exposed portions of the low-k dielectric layer with a plasma process, the modifying performed by using a first protection layer deposition process and second, subsequent low-k modification plasma process;
removing, with a remote plasma process, the modified portions of the low-k dielectric layer selective to the mask layer and unmodified portions of the low-k dielectric layer; and
repeating the modifying and the removing one or more times to form one or more trenches in the low-k dielectric layer without forming a fluorocarbon polymer on the low-k dielectric layer.
11. The method of claim 10 , wherein using the first protection layer deposition process comprises flowing a combination of trimethyl silane and O 2 .
12. The method of claim 10 , wherein using the low-k modification plasma process comprises using Ar, N 2 , or both Ar and N 2 .
13. The method of claim 10 , wherein removing the modified portions of the low-k dielectric layer with the remote plasma process comprises using a plasma based on a combination of gases selected from the group consisting of NF 3 /O 2 /N 2 , CF 4 /O 2 /N 2 and NF 3 /NH 3 .
14. The method of claim 10 , wherein using the first protection layer deposition process comprises forming a protection layer, and wherein removing the modified portions of the low-k dielectric layer with the remote plasma process further comprises removing the protection layer with the remote plasma process.
15. The method of claim 14 , wherein removing the modified portions of the low-k dielectric layer and the protection layer with the remote plasma process comprises using a plasma based on a combination of gases selected from the group consisting of NF 3 /O 2 /N 2 , CF 4 /O 2 /N 2 and NF 3 /NH 3 .
16. The method of claim 10 , wherein the modifying the exposed portions of the low-k dielectric layer comprises processing at a first stage of a plasma etch chamber, and wherein removing the modified portions of the low-k dielectric layer with the remote plasma process comprises processing at a second, different, stage of the plasma etch chamber.
17. The method of claim 16 , wherein a showerhead of the etch chamber is positioned between the first and second stages, the second stage above the showerhead.