Selective deposition of aluminum and nitrogen containing material
Methods are provided for selectively depositing Al and N containing material on a first conductive surface of a substrate relative to a second, dielectric surface of the same substrate. In some aspects, methods of forming an Al and N containing protective layer or etch stop layer for use in integrated circuit fabrication are provided.
1. A process for selectively depositing a material comprising aluminum and nitrogen on a first surface of a substrate relative to a second surface of the substrate comprising Si—O bonds, the process comprising two or more deposition cycles comprising:
contacting the first surface and second surface of the substrate with a first precursor in the vapor phase and comprising aluminum to form no more than about one monolayer of the first precursor on the first surface of the substrate; and
contacting the first surface and second surface of the substrate with a second vapor phase precursor comprising nitrogen to selectively form the material comprising aluminum and nitrogen on the first surface of the substrate relative to the second surface of the substrate;
wherein the material comprising aluminum and nitrogen is selectively deposited on the first surface of the substrate relative to the second surface of the substrate with a selectivity greater than about 50% in each of the two or more deposition cycles; and
the process further comprising contacting the material comprising aluminum and nitrogen with an oxygen-containing plasma after at least one deposition cycle.
2. The process of claim 1 , wherein the first surface of the substrate comprises at least one of: copper, titanium nitride, tungsten, and silicon nitride.
3. The process of claim 1 , wherein the material comprising aluminum and nitrogen is an aluminum nitride thin film.
4. The process of claim 3 , wherein the aluminum nitride thin film comprises oxygen.
5. The process of claim 1 , wherein the first precursor comprising aluminum is an organometallic aluminum compound.
6. The process of claim 1 , wherein the first precursor comprising aluminum does not comprise any metals other than aluminum.
7. The process of claim 1 , wherein the first precursor comprising aluminum has the formula R 3 Al, wherein each R can be independently selected from C 1 -C 4 alkyl groups.
8. The process of claim 1 , wherein the first precursor comprising aluminum does not comprise a halide.
9. The process of claim 1 , wherein the first precursor comprising aluminum comprises one chlorine ligand and at least two alkyl ligands.
10. The process of claim 1 , wherein the first precursor comprising aluminum comprises at least one hydrogen ligand and at least one alkyl ligand.
11. The process of claim 1 , wherein the first precursor comprising aluminum does not comprise nitrogen, silicon, or oxygen.
12. The process of claim 1 , wherein the first precursor comprising aluminum comprises tritertbutylaluminum (TTBA), trimethylaluminum (TMA) or triethylaluminum (TEA) and the second vapor phase precursor comprising nitrogen comprises NH 3 .
13. The process of claim 1 , wherein the second surface of the substrate is a dielectric.
14. The process of claim 1 , wherein the second surface of the substrate has a resistivity of more than about 1 ohm·m.
15. The process of claim 1 , wherein the process comprises a thermal atomic layer deposition (ALD) process.
16. The process of claim 1 , wherein the process does not comprise using plasma in at least 2 consecutive deposition cycles.
17. The process of claim 1 , further comprising exposing the substrate to a pretreatment reactant prior to a first deposition cycle.
18. The process of claim 17 , wherein the pretreatment reactant comprises plasma.
19. The process of claim 1 , wherein the material comprising aluminum and nitrogen has etch selectivity relative to SiO 2 in dilute HF.
20. The process of claim 1 , wherein a ratio of the material comprising aluminum and nitrogen deposited on the first surface of the substrate relative to the second surface of the substrate is greater than about 10:1, and wherein a thickness of the material comprising aluminum and nitrogen deposited on first surface of the substrate is greater than about 5 nm.
21. The process of claim 1 , wherein a ratio of the material comprising aluminum and nitrogen deposited on the first surface of the substrate relative to the second surface of the substrate is greater than about 10:1 and wherein a thickness of the material comprising aluminum and nitrogen deposited on first surface of the substrate is greater than about 1 nm.
22. The process of claim 1 , wherein a ratio of the material comprising aluminum and nitrogen deposited on the first surface of the substrate relative to the second surface of the substrate is greater than about 10:1 and wherein the process comprises between about 1 and 25 deposition cycles.
23. The process of claim 1 , wherein a ratio of the material comprising aluminum and nitrogen deposited on the first surface of the substrate relative to the second surface of the substrate is greater than about 10:1, and wherein the process comprises between about 1 and 150 deposition cycles.
24. The process of claim 1 , wherein less than about 0.1 nm of the material comprising aluminum and nitrogen is deposited on the second surface of the substrate after between about 1 and 25 deposition cycles.
25. The process of claim 1 , wherein a ratio of a wet etch rate of the material comprising aluminum and nitrogen to a wet etch rate of SiO 2 is less than about 1:5.
26. The process of claim 1 , wherein the second surface of the substrate overlies a source/drain region, and further comprising:
removing the second surface of the substrate to thereby expose the source/drain region of the substrate; and
forming a contact over the exposed source/drain region of the substrate.