Thin metal film conductors and their manufacture

• US 20080206450A1
• Filed: 02/23/2007
• Published: 08/28/2008
• Est. Priority Date: 02/23/2007
• Status: Active Grant

• Current Assignee: Penn State Research Foundation
• Original Assignee: Penn State Research Foundation, Kemet Corporation (Yageo Corporation)
• Inventors: Randall, Michael S., Randall, Clive A., McKinstry, Susan Trolier, Ko, Song Won
• Granted Patent: US 8,293,323 B2
• Time in Patent Office: Days
• US Class Current: 427/126.1
• CPC Class Codes: C23C 18/08 characterised by the deposition of metallic material

Abstract

Metal solutions such as copper and nickel suitable for chemical solution deposition (CSD) are disclosed, and their manufacture into low resistivity thin metal films is disclosed. The films may be thermal processed at relatively low temperatures and may be co-fired with ultra low fire high K ceramic dielectrics.

Claims

1. A method of manufacture of a thin metal film comprising,

forming a first solution of a metal precursor in a solvent selected from the group consisting of glycol ethers, lower alkanols, lower alkanoic acids, and mixtures thereof,

refluxing the first solution to yield a refluxed metal solution,

mixing a continuity dopant with the refluxed metal solution to yield a doped solution,

depositing the doped solution onto an insulating substrate to yield a wet film on the substrate,

pyrolyzing the wet film to yield a pyrolyzed film, and

annealing the pyrolyzed film in a reducing atmosphere, a inert atmosphere and mixtures thereof.

2. The method of claim 1 wherein the reducing atmosphere is selected from the group consisting of a mixtures of hydrogen, wet nitrogen and dry nitrogen, CO, mixtures of CO and CO₂, and mixtures thereof, and the inert atmosphere is selected from the group consisting of Ar, N, He, Kr and mixtures thereof.

3. The method of claim 1 wherein the first solution further includes a high work function dopant.

4. The method of claim 1 wherein the metal precursor is selected from the group consisting of copper precursors, nickel precursors, silver precursors, palladium precursors, nickel precursors and mixtures thereof.

5. The method of claim 1 or 4 wherein the glycol ether is selected from a group consisting of 2-ethoxyethanol, 2-propoxyethanol, 2-isopropoxyethanol, 2-butoxyethanol, 2-phenoxyethanol, 2-benzyloxyethanol diethylene glycol monoethyl ethyl and mixtures thereof.

6. The method of claim 1 or 4 wherein the lower alkanol is selected from the group consisting of methanol, ethanol, butanol, propanol and mixtures thereof.

7. The method of claim 1 or 4 wherein the lower alkanoic acid is selected from the group consisting of acetic acid, propionic acid, butyric acid, valeric acid, myristic acid, and mixtures thereof.

8. The method of claim 4 were the copper precursor is selected from the group consisting of copper acetate, copper acetylacetonate, copper hexafluoroacetylacetonate, copper nitrate hydrate, copper chloride, copper 2-ethylhexanoate and mixtures thereof.

9. The method of claim 4 wherein the nickel precursor is selected from the group consisting of nickel acetate, nickel acetylacetonate, nickel hexafluoroacetylacetonate, nickel nitrate hydrate, nickel chloride, nickel 2-ethylhexanoate, and mixtures thereof.

10. The method of claim 1 or 4 wherein the continuity dopant is selected from the group consisting of Ti, Zr, Hf, Ku, Zn, Cd, P, Ti precursors, Zr precursors, Hf precursors, Ku precursors, Zn precursors, Cd precursors, P precursors and mixtures thereof.

11. The method of claim 1 wherein depositing of the doped solution is performed by spin casting the doped solution at about 1000 RPM to 6000 RPM at a temperature of about 0°

C. to about 90°

C. for about 20 sec to about 200 sec onto an insulating substrate.

12. The method of claim 1 wherein pyrolyzing is performed at about 100°

C. to about 500°

C.

13. The method of claim 1 or 2 wherein annealing is performed by heating the pyrolyzed film at about 1°

C./min to about 50°

C./min to a maximum temperature of about 400°

C. to about 700°

C., holding at that maximum temperature for about 1 min to about 120 min, and cooling at about 1°

C./min to about 50°

C./min to room temperature.

14. The method of claim 1 wherein annealing comprises a first step of heating the pyrolyzed film at about 1°

C./min to about 600°

C./min to a maximum temperature of about 300°

C. to about 800°

C., holding at the maximum temperature for about 1 min to about 120 min, cooling at about 1°

C./min to about 600°

C./min to room temperature, and holding at room temperature for 60 sec,

followed by a second step wherein the film is heated at about 1°

C./min to about 600°

C./min to a maximum temperature of about 800°

C. to about 1200°

C., holding at the maximum temperature for about 1 min to about 120 min, and cooling at about 1°

C./min to about 600°

C./min,

wherein the first step is performed in a reducing atmosphere and the second step is performed under reduced partial pressure of oxygen.

15. The method of claim 4 wherein the nickel precursor is nickel acetate, nickel acetylacetonate, nickel hexafluoroacetylacetonate, nickel nitrate hydrate, nickel chloride, nickel 2-ethylhexanoate, and mixtures thereof.

16. The method of claim 10 wherein the Zr precursor is selected from the group consisting of Zr propoxide, zirconium acetate, zirconium acetylacetonate, zirconium isopropoxide, zirconium chloride, and zirconium ethoxide, and mixtures thereof,

the Ti precursor is selected from the group consisting of Ti isopropoxide Ti chloride, Ti ethoxide, Ti methoxide, Ti propoxide, Ti butoxide, and mixtures thereof and

the Zn precursor is selected from the group consisting of zinc acetate, zinc acetylacetonate hydrate, zinc chloride and zinc acetate dihydrate, and mixtures thereof.

17. A method of manufacture of a Cu thin film having about 0.1 m/o to about 50 m/o of a Ti continuity dopant comprising,

dissolving a Cu precursor selected from the group consisting of copper acetate, copper acetylacetonate, copper hexafluoroacetylacetonate, copper nitrate hydrate, copper chloride, copper 2-ethylhexanoate and mixtures thereof in a solvent selected from the group consisting of 2-methoxyethanol, 1-methoxy-2-butanol, 1-methoxy-2-propanol, 2-methoxyethanol, methanol, ethanol, butanol, propanol, acetic acid, propionic acid, butyric acid, valeric acid, myristic acid, and mixtures thereof to produce a Cu solution,

refluxing the copper solution for about 0.1 hr to about 20 hrs at about 100°

C. to about 160°

C. to produce a first refluxed copper solution,

adding a Ti continuity dopant precursor selected from the group

consisting of Ti isopropoxide Ti chloride, Ti ethoxide, Ti methoxide, Ti propoxide, Ti butoxide, and mixtures thereof to the first refluxed copper solution,

refluxing the first refluxed copper solution to produce a second refluxed solution,

mixing the second refluxed solution with a glycol ether solvent at about 0°

C. to about 100°

C. to produce a Ti-doped copper solution,

spin coating the Ti-doped copper solution onto an insulating substrate, at a temperature of about 0°

C. to about 90°

C.

pyrolyzing the film at about 150°

C. to about 500°

C., and

annealing the film by heating at about 1°

C./min to about 50°

C./min to a maximum temperature of about 400°

C. to about 700°

C.,

holding at that maximum temperature for about 1 min to about 120 min, and cooling at about 1°

C./min to about 50°

C./min to room temperature in a reducing atmosphere formed of a mixture of hydrogen, wet nitrogen and dry nitrogen.

18. A method of manufacture of a Cu thin film having about 0.1 m/o to about 50 m/o of a Zn continuity dopant comprising,

dissolving a Cu precursor selected from the group consisting of copper acetate, copper acetylacetonate, copper hexafluoroacetylacetonate, copper nitrate hydrate, copper chloride, copper 2-ethylhexanoate and mixtures thereof in a solvent selected from the group consisting of 2-methoxyethanol, 1-methoxy-2-butanol, 1-methoxy-2-propanol, 2-methoxyethanol, methanol, ethanol, butanol, propanol, acetic acid, propionic acid, butyric acid, valeric acid, myristic acid, and mixtures thereof to produce a Cu solution,

refluxing the copper solution for about 0.1 hr to about 20 hrs at about 100°

C. to about 160°

C. to produce a first refluxed copper solution,

adding a Zn continuity dopant precursor selected from the group consisting of zinc acetate, zinc acetylacetonate hydrate, zinc chloride and zinc acetate dihydrate and mixtures thereof,

refluxing the first refluxed copper solution to produce a second refluxed solution,

mixing the second refluxed solution with a glycol ether solvent at about 0°

C. to about 100°

C. to produce a Ti-doped copper solution,

spin coating the Ti-doped copper solution onto an insulating substrate, at a temperature of about 0°

C. to about 90°

C.

pyrolyzing the film at about 150°

C. to about 500°

C., and

annealing the film by heating at about 1°

C./min to about 50°

C./min to a maximum temperature of about 400°

C. to about 700°

C.,

holding at that maximum temperature for about 1 min to about 120 min, and cooling at about 1°

C./min to about 50°

C./min to room temperature in a reducing atmosphere formed of a mixture of hydrogen, wet nitrogen and dry nitrogen.

19. A method of manufacture of a Cu thin film having about 0.1 m/o to about 50 m/o of a Zr continuity dopant comprising

dissolving a Cu precursor selected from the group consisting of copper acetate, copper acetylacetonate, copper hexafluoroacetylacetonate, copper nitrate hydrate, copper chloride, copper 2-ethylhexanoate and mixtures thereof in a solvent selected from the group consisting of 2-methoxyethanol, 1-methoxy-2-butanol, 1-methoxy-2-propanol, 2-methoxyethanol, methanol, ethanol, butanol, propanol, acetic acid, propionic acid, butyric acid, valeric acid, myristic acid, and mixtures thereof to produce a Cu solution,

refluxing the copper solution for about 0.1 hr to about 20 hrs at about 100°

C. to about 160°

C. to produce a first refluxed copper solution,

adding a Zr continuity dopant precursor selected from the group consisting of Zr propoxide, zirconium acetate, zirconium acetylacetonate, zirconium isopropoxide, zirconium chloride, and zirconium ethoxide and mixtures thereof to first refluxed copper solution,

refluxing the first refluxed copper solution to produce a second refluxed solution,

mixing the second refluxed solution with a glycol ether solvent at about 0°

C. to about 100°

C. to produce a Zr-doped copper solution,

spin coating the Zr-doped copper solution onto an insulating substrate, at a temperature of about 0°

C. to about 90°

C.

pyrolyzing the film at about 150°

C. to about 500°

C., and

annealing the film by heating at about 1°

C./min to about 50°

C./min to a maximum temperature of about 400°

C. to about 700°

C.,

holding at that maximum temperature for about 1 min to about 120 min, and cooling at about 1°

C./min to about 50°

C./min to room temperature in a reducing atmosphere formed of a mixture of hydrogen, wet nitrogen and dry nitrogen.

20. A method of making a Zr doped Ni—

Cu films of the formula Cu_1-xNi_x where 0<

x<

1 comprising,

dissolving a copper precursor and a nickel precursor in a glycol ether solvent produce a Cu—

Ni solution,

refluxing the Cu—

Ni solution to produce a first refluxed Cu—

Ni solution.

adding a Zr continuity dopant precursor to the refluxed Cu—

Ni solution to produce a second refluxed solution,

depositing the second refluxed solution onto an insulating substrate to produce a wet film,

heating the wet film to produce a pyrolyzed film, and

annealing the pyrolyzed film.