Process for removing a residue from a metal structure on a semiconductor substrate

1. A process for removing residue comprising a polymeric resist and metal oxide from a metal structure on a semiconductor substrate, the process comprising a pre-treatment of the substrate with the residue, the pre-treatment including the steps of:

(a) heating up the substrate with the metal structure and the residue in the presence of molecular nitrogen gas without the presence of a plasma;

(b) performing a stabilization step in the presence of only molecular nitrogen gas without the presence of a plasma, the pre-treatment being followed by;

(c) performing a passivation step employing a plasma containing at least one material selected from the group consisting of water, nitrogen and oxygen; and

(d) performing a stripping step containing oxygen to remove the residue, wherein step (b) is performed before steps (c) and (d).

2. The process according to claim 1 , wherein process step d) is followed by a vacuum-plasma modification of the residue and an exsitu solution clean step to remove any remaining residue.

3. The process according to claim 1 , wherein the heating up step a) is conducted in the presence of pure nitrogen gas.

4. The process according to claim 1 , wherein the heating up step a) is conducted in the presence of a mixture of nitrogen gas and oxygen gas.

5. The process according to claim 1 , wherein the stabilization step b) is conducted in the presence of pure nitrogen gas.

6. The process according to claim 1 , wherein the stabilization step b) is conducted in the presence of a mixture of nitrogen gas and oxygen gas.

7. The process according to claim 1 , wherein at least one of the process steps is conducted in a temperature range of 20 to 400° C.

8. The process according to claim 1 , wherein the heating up step a) is conducted for a time longer than 2 seconds.

9. The process according to claim 8 , wherein the heating up step a) is conducted for a time longer than 15 seconds.

10. The process according to claim 1 , wherein the stabilization step b) is conducted for a duration between 1 and 20 seconds.

11. The process according to claim 1 , wherein the heating up step a) is conducted with a volumetric flow rate of greater than 10 sccm nitrogen gas.

12. A process for removing residue comprising a polymeric resist and metal oxide from a metal structure on a semiconductor substrate, the process comprising the steps of:

(a) heating up the substrate with the metal structure in the presence of molecular nitrogen gas without the presence of a plasma, wherein the heating up step a) is conducted with a volumetric flow rate of greater than 1000 sccm nitrogen gas;

(b) performing a stabilization step in the presence of only molecular nitrogen gas without the presence of a plasma;

(c) performing a passivation step employing a plasma containing at least one material selected from the group consisting of water, nitrogen and oxygen; and

(d) performing a stripping step containing oxygen to remove the residue, wherein step (b) is performed before steps (c) and (d).

13. The process according to claim 1 , wherein the stabilization step b) is conducted with a volumetric flow rate of greater than 10 sccm nitrogen gas.

14. A process for removing residue comprising a polymeric resist and metal oxide from a metal structure on a semiconductor substrate, the process comprising the steps of:

(a) heating up the substrate with the metal structure in the presence of molecular nitrogen gas without the presence of a plasma;

(b) performing a stabilization step in the presence of only molecular nitrogen gas without the presence of a plasma, wherein the stabilization step b) is conducted with a volumetric flow rate of greater than 1000 sccm nitrogen gas;

(c) performing a passivation step employing a plasma containing at least one material selected from the group consisting of water, nitrogen and oxygen; and

(d) performing a stripping step containing oxygen to remove the residue, wherein step (b) is performed before steps (c) and (d).

15. The process according to claim 1 , wherein the total gas pressure in the heat up step a) and the stabilization step is in the range from 0.2 to 10 Torr.

16. The process according to claim 1 , wherein the stripping process comprises a plasma etch process.

17. The process according to claim 13 , wherein the plasma etching is a TCP (ICP) process operating at 13.56 MHz.

18. The process according to claim 1 , wherein the stripping step comprises a plasma process.

19. The process according to claim 18 , wherein the stripping step uses CF 4 as agent.

20. The process according to claim 1 , wherein the stripping process comprises the application of a microwave process, the microwave radiation having a frequency in the Gigahertz range.

21. The process according to claim 1 , wherein the process is used in the production of a semiconductor device using lithography technology with exposure wavelengths selected from the group of 193 and 248 nm and provides metal structures for a dimensional technology node of 170 nm or less.

22. The process according to claim 21 , wherein the dimensional technology node is less than 110 nm.

23. The process according to claim 1 , wherein the metal structure comprises aluminum or aluminum-copper alloy.

24. The process according to claim 1 , wherein the residue comprises a compound based on aluminum oxide.

25. The process according to claim 24 , wherein the residue includes at least one of Si, C, F and Br.

26. The process according to claim 1 , and further comprising performing a cleaning step using a wet solution after the stripping step.

27. The process according to claim 1 , wherein the pre-treatment is performed in the presence of pure nitrogen.