Selective titanium nitride etching
Methods of etching exposed titanium nitride with respect to other materials on patterned heterogeneous structures are described, and may include a remote plasma etch formed from a fluorine-containing precursor. Precursor combinations including plasma effluents from the remote plasma are flowed into a substrate processing region to etch the patterned structures with high titanium nitride selectivity under a variety of operating conditions. The methods may be used to remove titanium nitride at faster rates than a variety of metal, nitride, and oxide compounds.
1. A method of etching a patterned substrate in a substrate processing region of a substrate processing chamber, wherein the patterned substrate includes an exposed titanium nitride region and a region comprising an exposed second material, the method comprising:
flowing a fluorine-containing precursor into a remote plasma region fluidly coupled with the substrate processing region while forming a plasma in the remote plasma region to produce plasma effluents, wherein the substrate processing region is at least partially separated from the remote plasma region by a showerhead or chamber wall;
flowing at least one additional precursor into the substrate processing region; and
etching the exposed titanium nitride region with the precursor combination including the plasma effluents, wherein the titanium nitride is etched at a faster rate than the exposed second material, and wherein the exposed second material comprises at least one of silicon oxide, silicon nitride, and tungsten.
2. The method of claim 1 , wherein the at least one additional precursor is selected from the group consisting of helium, argon, and molecular hydrogen (H 2 ).
3. The method of claim 1 , wherein the fluorine-containing precursor comprises a precursor selected from the group consisting of atomic fluorine, diatomic fluorine, nitrogen trifluoride, carbon tetrafluoride, hydrogen fluoride, and xenon difluoride.
4. The method of claim 1 , wherein the plasma in the remote plasma region is a capacitively-coupled plasma.
5. The method of claim 1 , wherein the substrate processing region is plasma-free during the etching process.
6. The method of claim 1 , wherein the at least one additional precursor consists of either or both of helium and argon.
7. The method of claim 6 , wherein the precursor combination including plasma effluents is substantially devoid of hydrogen.
8. The method of claim 6 , wherein the exposed second material comprises silicon oxide and the selectivity of the etching operation (exposed titanium nitride region: exposed silicon oxide region) is greater than or about 5:1.
9. The method of claim 8 , wherein the selectivity of the etching operation (exposed titanium nitride region: exposed silicon oxide region) is greater than or about 10:1.
10. The method of claim 6 , wherein the substrate temperature is maintained at or below about 50° C. during the etch process.
11. The method of claim 10 , wherein the substrate temperature is maintained at or below about 10° C. during the etch process.
12. The method of claim 1 , wherein the at least one additional precursor comprises hydrogen.
13. The method of claim 12 , wherein the exposed second material comprises tungsten and the selectivity of the etching operation (exposed titanium nitride region: exposed tungsten region) is greater than or about 50:1.
14. The method of claim 13 , wherein the selectivity of the etching operation (exposed titanium nitride region: exposed tungsten region) is greater than or about 100:1.
15. The method of claim 13 , wherein the patterned substrate further comprises an exposed silicon nitride region and the selectivity of the etching operation (exposed titanium nitride region: exposed silicon nitride region) is greater than or about 10:1.
16. The method of claim 13 , wherein the patterned substrate further comprises an exposed silicon oxide region and the selectivity of the etching operation (exposed titanium nitride region: exposed silicon oxide region) is greater than or about 5:1.
17. The method of claim 13 , wherein the patterned substrate further comprises an exposed tantalum nitride region and the selectivity of the etching operation (exposed titanium nitride region: exposed tantalum nitride region) is greater than or about 10:1.
18. The method of claim 12 , wherein the substrate temperature is maintained at or above about 50° C. during the etch process.
19. The method of claim 18 , wherein the substrate temperature is maintained at or above about 200° C. during the etch process.
20. The method of claim 12 , wherein the hydrogen is flowed into the substrate processing region without being first excited in a remote plasma.
21. The method of claim 12 , wherein the hydrogen comprises molecular hydrogen (H 2 ).