Seam free titanium nitride gapfill
Embodiments of the disclosure relate to methods of depositing seam-free gapfill. In some embodiments, the gapfill consists of titanium nitride. The gapfill methods comprise forming a first layer and a second layer. The firs layer is formed without treatment or densification, while the second layer is formed with periodic treatment. The resulting gapfill in advantageously seam-free.
1 . A method of depositing titanium nitride gapfill, the method comprising:
exposing a semiconductor substrate surface to a titanium amide precursor to form a first TiN layer, the semiconductor substrate surface comprising a plurality of stacked nanosheets and at least one feature between adjacent nanosheets, the first TiN layer forming around the plurality of nanosheets; and
exposing the first TiN layer to a titanium precursor and a nitrogen-containing plasma to form a second TiN layer directly on the first TiN layer,
wherein the first TiN layer and the second TiN layer combine to completely fill the at least one feature with a TiN gapfill material which is substantially free of a seam.
2 . The method of claim 1 , wherein the at least one feature has a width in a range of about 4 nm to about 5 nm.
3 . The method of claim 1 , wherein the titanium amide precursor comprises tetrakis(dimethylamido)titanium (TDMAT).
4 . The method of claim 1 , wherein depositing the first TiN layer comprises a thermal decomposition process.
5 . The method of claim 1 , wherein the semiconductor substrate surface is maintained at a temperature in a range of about 250° C. to about 350° C. while forming the first TiN layer.
6 . The method of claim 1 , wherein the semiconductor surface is exposed to the titanium amide precursor at a pressure in a range of about 1 Torr to about 5 Torr.
7 . The method of claim 1 , wherein the first TiN layer is formed by a plurality of dep-purge cycles comprising at least one deposition phase and at least one purge phase.
8 . The method of claim 1 , wherein the second TiN layer is formed by a plurality of dep-treat cycles comprising at least one deposition phase and at least one treatment phase.
9 . The method of claim 8 , wherein the deposition phase comprises exposing the first TiN layer to the titanium precursor to form an untreated TiN layer.
10 . The method of claim 9 , wherein the titanium precursor comprises tetrakis(dimethylamido)titanium (TDMAT).
11 . The method of claim 9 , wherein the treatment phase comprises exposing the untreated TiN layer to the nitrogen-containing plasma to form the second TiN layer.
12 . The method of claim 1 , wherein the nitrogen-containing plasma is formed from nitrogen gas (N2).
13 . The method of claim 1 , wherein the nitrogen-containing plasma is formed away from the semiconductor substrate surface.
14 . The method of claim 1 , wherein the nitrogen-containing plasma has a power in a range of about 2000 W to about 5000 W.
15 . The method of claim 1 , wherein the semiconductor substrate surface is maintained at a temperature in a range of about 250° C. to about 350° C. while forming the second TiN layer.
16 . The method of claim 1 , wherein the first TiN layer has a density in a range of about 3.5 g/cm 3 to about 3.8 g/cm 3 and wherein the TiN gapfill material has a density in a range of about 3.0 g/cm 3 to about 5.0 g/cm 3 .
17 . The method of claim 1 , wherein the first TiN layer is amorphous when deposited.
18 . The method of claim 1 , wherein the TiN gapfill material is majority crystalline.
19 . The method of claim 1 , wherein the method completely fills the at least one feature without an etch process to remove material from the semiconductor substrate surface.
20 . A method of depositing titanium nitride gapfill, the method comprising:
depositing a first TiN layer by a thermal decomposition process comprising exposing a semiconductor substrate surface to TDMAT, the semiconductor substrate surface comprising a plurality of stacked nanosheets and at least one feature between adjacent nanosheets, the first TiN layer forming around the plurality of nanosheets and the first TiN layer being amorphous; and
exposing the first TiN layer to a plurality of cycles comprising a deposition phase and treatment phase, the deposition phase comprising TDMAT, the treatment phase comprising a nitrogen-containing plasma, to form a second TiN layer directly on the first TiN layer,
wherein the first TiN layer and the second TiN layers combine to completely fill the at least one feature with a substantially crystalline TiN gapfill material which is substantially free of a seam.