Plated article having metal thin film formed by electroless plating, and manufacturing method thereof
View Patent ↗The present invention provides a plated article that has a thin seed layer having a uniform thickness, formed by electroless plating and allowing formation of ultrafine wiring, and that avoids the complicated formation of a bilayer of a barrier layer and a catalytic metal layer prior to forming the seed layer. The present invention also provides a method for manufacturing the plated article. The plated article has an alloy thin film formed on a substrate and containing a catalytically active metal (A) for electroless plating and a metal (B) capable of undergoing displacement plating with a metal ion contained in an electroless plating solution, and a metal thin film formed on the alloy thin film by electroless displacement and reduction plating. The alloy thin film of the catalytically active metal (A) and the metal (B) capable of displacement plating has a composition comprising 5at% to 40at% of the metal (A). The metal thin film formed by electroless displacement and reduction plating is a metal thin film having a thickness no greater than 10 nm and a resistivity no greater than 10 μΩ·cm. Preferably, the metal (B) has a barrier function with respect to a metal of the metal thin film.
1. A plated article which has an alloy thin film formed on a substrate and containing a catalytically active metal (A) for electroless plating and a metal (B) capable of undergoing displacement plating with a metal ion contained in an electroless plating solution, the alloy thin film is a single layer having both a barrier function and catalytic ability, and a metal thin film formed on the alloy thin film by electroless displacement and reduction plating,
wherein the alloy thin film containing the catalytically active metal (A) and the metal (B) capable of displacement plating has a composition comprising 5at% to 40at% of the catalytically active metal (A),
the thickness of the alloy thin film ranges from 3 to 20 nm,
the catalytically active metal (A) is at least one metal selected from among rhodium, ruthenium and iridium, and
the metal (B) capable of displacement plating is at least one metal selected from among iron, nickel, cobalt, tungsten, niobium, tin, magnesium, aluminum, zinc and lead, and
the metal thin film formed by electroless displacement and reduction plating is a metal thin film having a thickness no greater than 10 nm and a resistivity no greater than 10 μΩ·cm.
2. The plated article according to claim 1 , wherein the metal thin film formed by electroless displacement and reduction plating has a resistivity no greater than 5 μΩ·cm.
3. The plated article according to claim 1 , wherein a wiring portion is further formed on the metal thin film by plating.
4. The plated article according to claim 3 , wherein
the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a thin film comprising at least one metal selected from among gold, silver, copper, nickel, cobalt, iron and tin, and
the wiring portion is copper or an alloy having copper as a main component.
5. The plated article according to claim 4 , wherein the metal (B) capable of displacement plating has a barrier function of preventing diffusion of a metal of the metal thin film formed by electroless displacement and reduction plating.
6. The plated article according to claim 4 ,
wherein the catalytically active metal (A) is at least one metal selected from among rhodium and ruthenium,
the metal (B) capable of displacement plating is at least one metal selected from among tungsten and niobium,
the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a thin film of copper or of an alloy having copper as a main component, and
the wiring portion is copper or an alloy having copper as a main component.
7. The plated article according to claim 4 ,
wherein the catalytically active metal (A) is ruthenium,
the metal (B) capable of displacement plating is tungsten,
the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a copper thin film, and
the wiring portion is copper.
8. The plated article according to claim 1 , wherein the oxygen concentration at the interface between the alloy thin film and the metal thin film formed by electroless displacement and reduction plating is no greater than 1at% as analyzed by Auger electron spectroscopy.
9. The plated article according to claim 1 , wherein the metal thin film formed by electroless displacement and reduction plating is a seed layer for damascene copper wiring.
10. The plated article according to claim 1 , wherein the alloy thin film is formed by sputtering.
11. A sputtering target used for forming the alloy thin film of the plated article according to claim 10 .
12. A semiconductor element, comprising the plated article according to claim 1 .
13. A method for manufacturing a plated article comprising the steps of forming, on a substrate, an alloy thin film containing a catalytically active metal (A) for electroless plating and a metal (B) capable of undergoing displacement plating with a metal ion contained in an electroless plating solution, the alloy thin film is a single layer having both a barrier function and catalytic ability, and forming a metal thin film on the alloy thin film by electroless displacement and reduction plating,
wherein the alloy thin film containing the catalytically active metal (A) and the metal (B) capable of displacement plating has a composition comprising 5at% to 40at% of the catalytically active metal (A),
the thickness of the alloy thin film ranges from 3 to 20 nm,
the catalytically active metal (A) is at least one metal selected from among rhodium, ruthenium and iridium, and
the metal (B) capable of displacement plating is at least one metal selected from among iron, nickel, cobalt, tungsten, niobium, tin, magnesium, aluminum, zinc and lead, and
the metal thin film formed by electroless displacement and reduction plating is a metal thin film having a thickness no greater than 10 nm and a resistivity no greater than 10 μΩ·cm.
14. The method for manufacturing a plated article according to claim 13 , wherein the metal thin film formed by electroless displacement and reduction plating has a resistivity no greater than 5 μΩ·cm.
15. The method for manufacturing a plated article according to claim 13 , wherein a wiring portion is further formed on the metal thin film by plating.
16. The method for manufacturing a plated article according to claim 15 ,
wherein
the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a thin film comprising at least one metal selected from among gold, silver, copper, nickel, cobalt, iron and tin, and
the wiring portion is copper or an alloy having copper as a main component.
17. The method for manufacturing a plated article according to claim 16 , wherein the metal (B) capable of displacement plating has a barrier function of preventing diffusion of a metal of the metal thin film formed by electroless displacement and reduction plating.
18. The method for manufacturing a plated article according to claim 16 ,
wherein the catalytically active metal (A) is at least one metal selected from among rhodium and ruthenium,
the metal (B) capable of displacement plating is at least one metal selected from among tungsten and niobium, the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a thin film of copper or of an alloy having copper as a main component, and
the wiring portion is copper or an alloy having copper as a main component.
19. The method for manufacturing a plated article according to claim 16 ,
wherein the catalytically active metal (A) is ruthenium,
the metal (B) capable of displacement plating is tungsten,
the metal thin film formed on the alloy thin film by electroless displacement and reduction plating is a copper thin film, and
the wiring portion is copper.
20. The method for manufacturing a plated article according to claim 13 , wherein the oxygen concentration at the interface between the alloy thin film and the metal thin film formed by electroless displacement and reduction plating is no greater than 1 at% as analyzed by Auger electron spectroscopy.
21. The method for manufacturing a plated article according to claim 13 , wherein the metal thin film formed by electroless displacement and reduction plating is a seed layer for damascene copper wiring.
22. The method for manufacturing a plated article according to claim 13 , wherein the alloy thin film is formed by sputtering.