Atomic composition controlled ruthenium alloy film formed by plasma-enhanced atomic layer deposition
First Claim
1. A method of forming a metal film on a substrate, comprising:
- (i) placing a substrate in a reaction space;
(ii) conducting atomic layer deposition of Ta or Ti X times, each atomic layer deposition of Ta or Ti being accomplished by introducing a Ta or Ti source gas containing N into the reaction space and applying a reducing gas plasma to the reaction space;
(iii) after step (ii), conducting atomic layer deposition of Ru Y times, each atomic layer deposition of Ru being accomplished by introducing a Ru source gas into the reaction space and applying a reducing gas plasma in the reaction space;
(iva) repeating steps (ii) and (iii) Z1 times wherein a ratio of Y/X defined as a first ratio is 1 to 3, and Z1 is 10 to 100, thereby forming a first section of a metal film on the substrate; and
then(ivb) repeating steps (ii) and (iii) Z2 times using a second ratio of Y/X which is greater than the first ratio wherein Z2 is 10 to 100, thereby forming a second section of the metal film, wherein a proportion of a hydrogen gas plasma in the reducing gas plasma within step (iii) in step (ivb) is higher than that in step (iva), thereby reducing an atomic proportion of N in the second section of the metal film as compared with the first section of the metal film,further comprising, between steps (iva) and (ivb), (ivc) repeating steps (ii) and (iii) Z3 times using a third ratio of Y/X which is smaller than the first and second ratios wherein Z3 is 10 to 100, thereby forming an intermediate section of the metal film,wherein the reducing gas plasma in step (iii) in steps (iva) and (ivc) is generated from a reducing gas including both nitrogen and hydrogen, and the reducing gas plasma in step (iii) in step (ivb) is generated from H2 gas.
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Abstract
A metal film composed of multiple atomic layers continuously formed by atomic layer deposition of Ru and Ta or Ti includes at least a top section and a bottom section, wherein an atomic composition of Ru, Ta or Ti, and N varies in a thickness direction of the metal film. The atomic composition of Ru, Ta or Ti, and N in the top section is represented as Ru(x1)Ta/Ti(y1)N(z1) wherein an atomic ratio of Ru(x1)/(Ta/Ti(y1)) is no less than 15, and z1 is 0.05 or less. The atomic composition of Ru, Ta or Ti, and N in the bottom section is represented as Ru(x2)Ta/Ti(y2)N(z2) wherein an atomic ratio of Ru(x2)/(Ta/Ti(y2)) is more than zero but less than 15, and z2 is 0.10 or greater.
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Citations
15 Claims
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1. A method of forming a metal film on a substrate, comprising:
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(i) placing a substrate in a reaction space; (ii) conducting atomic layer deposition of Ta or Ti X times, each atomic layer deposition of Ta or Ti being accomplished by introducing a Ta or Ti source gas containing N into the reaction space and applying a reducing gas plasma to the reaction space; (iii) after step (ii), conducting atomic layer deposition of Ru Y times, each atomic layer deposition of Ru being accomplished by introducing a Ru source gas into the reaction space and applying a reducing gas plasma in the reaction space; (iva) repeating steps (ii) and (iii) Z1 times wherein a ratio of Y/X defined as a first ratio is 1 to 3, and Z1 is 10 to 100, thereby forming a first section of a metal film on the substrate; and
then(ivb) repeating steps (ii) and (iii) Z2 times using a second ratio of Y/X which is greater than the first ratio wherein Z2 is 10 to 100, thereby forming a second section of the metal film, wherein a proportion of a hydrogen gas plasma in the reducing gas plasma within step (iii) in step (ivb) is higher than that in step (iva), thereby reducing an atomic proportion of N in the second section of the metal film as compared with the first section of the metal film, further comprising, between steps (iva) and (ivb), (ivc) repeating steps (ii) and (iii) Z3 times using a third ratio of Y/X which is smaller than the first and second ratios wherein Z3 is 10 to 100, thereby forming an intermediate section of the metal film, wherein the reducing gas plasma in step (iii) in steps (iva) and (ivc) is generated from a reducing gas including both nitrogen and hydrogen, and the reducing gas plasma in step (iii) in step (ivb) is generated from H2 gas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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Specification