Forming capping layer over metal wire structure using selective atomic layer deposition

• US 7,084,060 B1
• Filed: 05/04/2005
• Issued: 08/01/2006
• Est. Priority Date: 05/04/2005
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Koburger, Charles W. III, Furukawa, Toshiharu, Horak, David V., Holmes, Steven J.
• Primary Examiner(s): Smith, Matthew
• Assistant Examiner(s): Parker, John M.
• Application Number:
  US10/908,244
• Time in Patent Office: 454 Days
• Field of Search: 438/902, 438/677, 438/643, 257/677, 257/751
• US Class Current: 438/677
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H01L 21/02178 the material containing aluminium, e.g. Al2O3
• CPC Class Codes: H01L 21/02181 the material containing hafnium, e.g. HfO2
• CPC Class Codes: H01L 21/02183 the material containing tantalum, e.g. Ta2O5
• CPC Class Codes: H01L 21/02186 the material containing titanium, e.g. TiO2
• CPC Class Codes: H01L 21/02189 the material containing zirconium, e.g. ZrO2
• CPC Class Codes: H01L 21/02205 the layer being characterised by the precursor material for deposition
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/3105 After-treatment
• CPC Class Codes: H01L 21/316 composed of oxides or glassy oxides or oxide based glass
• CPC Class Codes: H01L 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76828 thermal treatment
• CPC Class Codes: H01L 21/76829 characterised by the formation of thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76855 After-treatment introducing at least one additional element into the layer
• CPC Class Codes: H01L 21/76867 characterized by methods of formation other than PVD, CVD or deposition from a liquids PVD H01L21/2855; CVD H01L21/28556; deposition from liquids H01L21/288
• CPC Class Codes: H01L 21/76876 for deposition from the gas phase, e.g. CVD
• CPC Class Codes: Y10S 438/902 Capping layer

Abstract

Methods of forming a capping layer over a metal wire structure of a semiconductor device are disclosed. In one embodiment, the method includes providing a partially fabricated semiconductor device having exposed surfaces of the metal (e.g., copper) wire structure and a dielectric around the metal wire structure. The exposed surface of the metal wire structure is then activated by forming a seed layer thereon. The capping layer is then formed over the exposed surface of the metal wire structure by performing a selective atomic layer deposition (ALD) of a capping layer material onto the metal wire structure. As an alternative, the dielectric may be masked off to further assist the selectivity of the ALD. The invention also includes a semiconductor structure including the metal wire structure having an atomic layer deposition capping layer over an upper surface thereof.

Claims

1. A method of forming a capping layer over a metal wire structure of a semiconductor device, the method comprising the steps of:

providing a partially fabricated semiconductor device having exposed surfaces of the metal wire structure and a dielectric around the metal wire structure;

activating the exposed surface of the metal wire structure by forming a seed layer thereon by reacting the metal wire structure with at least one of the following;

a) ammonia, b) an ammonia/oxygen mixture and c) at least one of the following reactive organic compounds;

an amine, a thiol, a phosphine and an acetylene;

masking the exposed surface of the dielectric by exposing the dielectric to a reagent to form a self-assembled monolayer of hydrophobic, inert masking layer over the dielectric; and

forming the capping layer over the metal wire structure by performing a selective atomic layer deposition of a capping layer material onto the metal wire structure.

2. The method of claim 1, wherein the reagent includes at least one of the following:

alkyl-trichloro-silane, alkyl-dichlorophoshine, alkyl-triethoxysilane, alkyl-phosphonate, dialkyl-chlorosilane, dialkyl-ethoxy silane, dialkyl-chlorophosphine, diakyl-phosphonate, trialkyl-chlorosilane, trialkyl-ethoxy silane, trialkyl-chlorophosphine, trialkyl-phosphonate, tert-butyl, adamantyl, n-butyl, isopropyl, neopentyl, methyl, ethyl, n-propyl, phenyl, and alkyl-phenyl.

3. The method of claim 1, further comprising the step of removing the hydrophobic, inert masking layer after the capping layer forming step.

4. The method of claim 1, wherein the metal wire structure includes copper (Cu).

5. The method of claim 4, wherein in the case that the seed layer includes an amine, the amine includes at least one of the following:

methyl amine, ethyl amine, propyl amine, tert-butyl amine, hydroxyl-amine, sulfhydrylamine (NH₂SH), amino alcohols, amino thiols, and ethylenediamine.

6. The method of claim 1, wherein the capping layer material includes at least one of tungsten nitride (WN), titanium nitride (TiN), tantalum nitride (TaN), tantalum (Ta), titanium (TI) and tungsten (W).

7. The method of claim 1, wherein the capping layer material includes at least one of zirconium nitride (ZrN), hafnium nitride (HfN) and aluminum nitride (AlN).

8. The method of claim 1, wherein the capping layer forming step includes performing alternating cycles of a metal precursor and one of:

ammonia (NH₃) to form metal nitride and hydrogen (H₂) to form metal material.

9. The method of claim 1, wherein the capping layer has a thickness of no greater than approximately 200 Å

.

10. A method of forming a capping layer over a copper structure of a semiconductor device, the method comprising the steps of:

providing a partially fabricated semiconductor device having exposed surfaces of the copper structure and a dielectric around the copper structure;

masking the dielectric by exposing the partially fabricated semiconductor device to a reagent to form a self-assembled monolayer of hydrophobic, inert masking layer over the dielectric, the reagent including at least one of the following;

alkyl-trichloro-silane, alkyl-dichlorophoshine, alkyl-triethoxysilane, alkyl-phosphonate, dialkyl-chlorosilane, dialkyl-ethoxy silane, dialkyl-chlorophosphine, diakyl-phosphonate, trialkyl-chlorosilane, trialkyl-ethoxy silane, trialkyl-chlorophosphine, trialkyl-phosphonate, tert-butyl, adamantyl, n-butyl, isopropyl, neopentyl, methyl, ethyl, n-propyl, phenyl, and alkyl-phenyl;

activating the exposed surface of the metal wire structure by reacting the metal wire structure with at least one of the following;

a) ammonia, b) an ammonia/oxygen mixture and c) at least one of the following reactive organic compounds;

an amine, a thiol, a phosphine and an acetylene, to create a seed layer; and

forming the capping layer over the copper structure by performing a selective atomic layer deposition of a capping layer material onto the copper structure.

11. The method of claim 10, further comprising the step of removing the hydrophobic, inert masking layer after the capping layer forming step.

12. The method of claim 10, wherein in the case that the seed layer includes an amine, the amine includes at least one of the following:

methyl amine, ethyl amine, propyl amine, tert-butyl amine, hydroxyl-amine, sulfhydrylamine (NH₂SH), amino alcohols, amino thiols, and ethylenediamine.

13. The method of claim 10, wherein the capping layer material includes at least one of tungsten nitride (WN), titanium nitride (TiN), tantalum nitride (TaN), tantalum (Ta), titanium (Ti) and tungsten (W).

14. The method of claim 10, wherein the capping layer material includes at least one of zirconium nitride (ZrN), hafnium nitride (HfN) and aluminum nitride (AlN).

15. The method of claim 10, wherein the capping layer forming step includes performing alternating cycles of a metal precursor and one of:

ammonia (NH₃) to form metal nitride and hydrogen (H₂) to form metal material.

16. The method of claim 10, wherein the capping layer has a thickness of no greater than approximately 200 Å

.