Deposition of conformal copper seed layers by control of barrier layer morphology
First Claim
1. A method of forming a barrier layer comprising tantalum nitride by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
- sputtering a target comprising tantalum; and
introducing a nitrogen source in an amount so that the surface of the barrier layer displays a randomness of at least about 50%.
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Abstract
The present invention pertains to systems and methods for improving the deposition of conformal copper seed layers in integrated circuit metalization. The invention involves controlling the morphology of the barrier layer deposited underneath the copper seed layer. The barrier layer can be composed of TaN and Ta, or TaN alone. It can also be composed of TiN or TiNSi. The process conditions of the barrier layer deposition are carried out in a manner that results in a highly or completely amorphous crystalline structure. Such a barrier layer allows for conformal deposition of the copper seed layer on top of the barrier layer that is less susceptible to agglomeration.
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Citations
63 Claims
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1. A method of forming a barrier layer comprising tantalum nitride by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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sputtering a target comprising tantalum; and
introducing a nitrogen source in an amount so that the surface of the barrier layer displays a randomness of at least about 50%. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method of forming a barrier layer comprising tantalum and tantalum nitride, by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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sputtering a target comprising tantalum to deposit tantalum; and
sputtering a target comprising tantalum and introducing a nitrogen source to deposit tantalum nitride at the surface of the barrier layer, the nitrogen source being introduced in an amount so that the surface displays a randomness of at least about 50%. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method of forming a barrier layer comprising tantalum and tantalum nitride, by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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sputtering a target comprising tantalum and introducing a nitrogen source to deposit tantalum nitride in a bottom layer;
sputtering a target comprising tantalum to deposit tantalum in a middle layer; and
sputtering a target comprising tantalum and introducing a nitrogen source to deposit tantalum nitride in a top layer at the surface of the barrier layer, the nitrogen source being introduced in an amount so that the surface displays a randomness of at least about 50%. - View Dependent Claims (28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44)
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45. A method of forming a barrier layer comprising titanium nitride by chemical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
introducing a titanium-containing precursor and a nitrogen source into a chamber, nitrogen source being introduced in an amount so that the surface displays a randomness of at least about 50%. - View Dependent Claims (46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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61. A method of forming a barrier layer comprising tantalum nitride by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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sputtering a target comprising tantalum; and
introducing a nitrogen source in an amount so that the surface of the barrier layer displays a randomness of at least about 50%, wherein the method is carried at about 2 to 8 millitorr.
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62. A method of forming a barrier layer comprising tantalum and tantalum nitride, by physical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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sputtering a target comprising tantalum to deposit tantalum; and
sputtering a target comprising tantalum and introducing a nitrogen source to deposit tantalum nitride at the surface of the barrier layer, the nitrogen source being introduced in an amount so that the surface displays a randomness of at least about 50%, wherein the method is carried out at about 2 to 8 millitorr.
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63. A method of forming a barrier layer comprising titanium nitride by chemical vapor deposition on a semiconductor substrate, such that the barrier layer reduces agglomeration and notching of a copper seed layer formed on top of the barrier layer, the method comprising:
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introducing a titanium-containing precursor and a nitrogen source into a chamber, nitrogen source being introduced in an amount so that the surface displays a randomness of at least about 50%, wherein between about 10 to 100 Å
of barrier layer is formed at the bottom of a feature of the semiconductor substrate.
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Specification