Barrier layer formation for conductive feature
Embodiments described herein relate generally to one or more methods for forming a barrier layer for a conductive feature in semiconductor processing. In some embodiments, an opening is formed through a dielectric layer to a conductive feature. A barrier layer is formed in the opening along a sidewall of the dielectric layer and on a surface of the conductive feature. Forming the barrier layer includes depositing a layer including using a precursor gas. The precursor gas has a first incubation time for deposition on the surface of the conductive feature and has a second incubation time for deposition on the sidewall of the dielectric layer. The first incubation time is greater than the second incubation time. A conductive fill material is formed in the opening and on the barrier layer.
1. A method for semiconductor processing, the method comprising:
forming an opening through a dielectric layer to a conductive feature;
forming a barrier layer in the opening along a sidewall of the dielectric layer and on a surface of the conductive feature, forming the barrier layer comprising depositing a layer comprising using a first precursor gas, the first precursor gas having a first incubation time for deposition on the surface of the conductive feature and having a second incubation time for deposition on the sidewall of the dielectric layer, the first incubation time being greater than the second incubation time, wherein the first precursor gas has a carbon concentration of at least 25 atomic percent; and
forming a conductive fill material in the opening and on the barrier layer.
2. The method of claim 1 , wherein the barrier layer has a first thickness at the sidewall of the dielectric layer, and the barrier layer has a second thickness at the surface of the conductive feature, the first thickness being greater than the second thickness.
3. The method of claim 1 , wherein the barrier layer includes tantalum nitride.
4. The method of claim 1 , wherein forming the barrier layer further comprises:
performing a cleaning process through the opening to the surface of the conductive feature, performing the cleaning process comprising using a plasma with a reducing gas;
performing an atomic layer deposition (ALD) process to deposit the layer, the ALD process comprising at least one cycle comprising pulsing the first precursor gas and pulsing a reactant gas; and
densifying the layer to form the barrier layer, the densifying comprising exposing the layer to a plasma.
5. The method of claim 1 , wherein depositing the layer comprises performing a plurality of cycles, each of the plurality of cycles comprising:
pulsing the first precursor gas; and
pulsing a reactant gas.
6. The method of claim 5 , wherein the layer is a carbon-containing tantalum nitride layer having a concentration of carbon of at least 15 atomic percent throughout.
7. The method of claim 1 , wherein depositing the layer comprises:
performing a plurality of first cycles; and
after performing the plurality of first cycles, performing a plurality of second cycles;
wherein each of the plurality of first cycles comprises:
pulsing the first precursor gas without a second precursor gas, wherein the second precursor gas has a carbon concentration of less than 25 atomic percent; and
pulsing a reactant gas; and
wherein each of the plurality of second cycles comprises:
pulsing the second precursor gas without the first precursor gas; and
pulsing the reactant gas.
8. The method of claim 7 , wherein the layer comprises:
a first carbon-containing tantalum nitride sub-layer having a concentration of carbon of at least 15 atomic percent formed by the plurality of first cycles; and
a second carbon-containing tantalum nitride sub-layer having a concentration of carbon of less than 15 atomic percent formed by the plurality of second cycles.
9. The method of claim 1 , wherein depositing the layer comprises:
performing a first cycle;
after performing the first cycle, performing a second cycle; and
after performing the second cycle, performing a third cycle;
wherein the first cycle comprises:
pulsing the first precursor gas without a second precursor gas, wherein the second precursor gas has a carbon concentration of less than 25 atomic percent; and
pulsing a reactant gas;
wherein the second cycle comprises:
pulsing a mixture comprising the first precursor gas and the second precursor gas; and
pulsing the reactant gas; and
wherein the third cycle comprises:
pulsing the second precursor gas without the first precursor gas; and
pulsing the reactant gas.
10. The method of claim 9 , wherein the layer is a carbon-containing tantalum nitride layer having a gradient concentration of carbon.
11. The method of claim 1 , wherein the first precursor gas comprises Ta,[(3,4-eta)-alkyne] tris (N,N-alkylaminato) (Ta[N(CH 3 ) 2 ] 3 (C 6 H 10 )), or Ta[N(C 2 H 5 ) 2 ] 3 NC(CH 3 ) 3 .
12. A method for semiconductor processing, the method comprising:
forming an opening through a dielectric layer to a conductive feature;
depositing a carbon-containing layer in the opening along a sidewall of the dielectric layer and on a surface of the conductive feature, depositing the carbon-containing layer comprising using an atomic layer deposition (ALD) process, the ALD process comprising at least one first cycle comprising:
pulsing a first precursor gas having a carbon concentration of at least 25 atomic percent, the first precursor gas having a first incubation time for deposition on the surface of the conductive feature and having a second incubation time for deposition on the sidewall of the dielectric layer, the first incubation time being greater than the second incubation time; and
pulsing a reactant gas;
densifying the carbon-containing layer comprising exposing the carbon-containing layer to a plasma, wherein after the densifying, the carbon-containing layer is a barrier layer; and
forming a conductive fill material in the opening and on the barrier layer.
13. The method of claim 12 , wherein the carbon-containing layer is a carbon-containing tantalum nitride layer.
14. The method of claim 12 , wherein the ALD process further comprises at least one second cycle comprising:
pulsing a second precursor gas having a carbon concentration less than 25 atomic percent; and
pulsing the reactant gas.
15. A method for semiconductor processing, the method comprising:
forming an opening through a dielectric layer to a conductive feature;
forming a carbon-containing barrier layer in the opening along a sidewall of the dielectric layer and on a surface of the conductive feature, forming the carbon-containing barrier layer comprising performing a plurality of cycles, each of the plurality of cycles comprising:
pulsing a carbon-containing precursor gas, the carbon-containing precursor gas having a first incubation time for deposition on the surface of the conductive feature and having a second incubation time for deposition on the sidewall of the dielectric layer, the first incubation time being greater than the second incubation time; and
pulsing a reactant gas; and
forming a conductive fill material in the opening and on the carbon-containing barrier layer.
16. The method of claim 15 , wherein after the first incubation time and the second incubation time elapses, a deposition rate on the sidewall and a deposition rate on the conductive feature are substantially a same rate.
17. The method of claim 15 , wherein the carbon-containing precursor gas comprises a carbon-rich tantalum nitride precursor.
18. The method of claim 17 , wherein a first cycle of the plurality of cycles uses a carbon-rich tantalum nitride precursor as the carbon-containing precursor gas and a second cycle of the plurality of cycles uses a carbon-poor tantalum nitride precursor as the carbon-containing precursor gas.
19. The method of claim 18 , wherein the first cycle is performed prior to the second cycle.
20. The method of claim 15 further comprising exposing the carbon-containing barrier layer to a plasma.