Copper alloy and liquid-crystal display device

Abstract

A method of forming an oxide film on a surface of a copper alloy, including the steps of providing a copper alloy including copper and an element selected from the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd, and diffusing atoms of the element to a surface of the copper alloy so as to form an oxide film on the surface of the copper alloy, wherein a concentration of the element in the copper alloy is more than 0.1 and not more than 20 atomic percentage and within a solubility limit of the element in the copper.

What is claimed is: 
     
       1. A method of forming an oxide film on a surface of a copper alloy, comprising the steps of:
 providing a copper alloy including copper and an element selected from the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd; and 
 diffusing atoms of the element to a surface of the copper alloy so as to form an oxide film on the surface of the copper alloy, 
 wherein a concentration of the element in the copper alloy is more than 0.1 and not more than 20 atomic percentage and within a solubility limit of the element in the copper. 
 
     
     
       2. The method of forming an oxide film on a surface of a copper alloy of  claim 1 ,
 wherein a thickness of the oxide film is 1 to 10 nm. 
 
     
     
       3. The method of forming an oxide film on a surface of a copper alloy of  claim 2 ,
 wherein an electric resistivity of the copper alloy is equal to or more than 1.7 μΩcm and equal to or less than 7 μΩcm. 
 
     
     
       4. The method of forming an oxide film on a surface of a copper alloy of  claim 1 ,
 wherein the step of diffusing atoms of the element is performed by heating the copper alloy at a temperature from 200° C. to 600° C. 
 
     
     
       5. The method of forming an oxide film on a surface of a copper alloy of  claim 4 ,
 wherein the heating is performed for 5 minutes to 2 hours. 
 
     
     
       6. A method of forming an oxide film on a surface of a copper alloy, comprising the steps of:
 providing a copper alloy including copper and an element selected from the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd; 
 forming a layer of the copper alloy on a layer of an oxide; and 
 diffusing atoms of the element to an interface between the layer of the copper alloy and the layer of the oxide so as to form an oxide film at the interface, 
 wherein a concentration of the element in the copper alloy is more than 0.1 and not more than 20 atomic percentage and within a solubility limit of the element in the copper. 
 
     
     
       7. The method of forming an oxide film on a surface of a copper alloy of  claim 6 ,
 wherein a thickness of the oxide film is 1 to 10 nm. 
 
     
     
       8. The method of forming an oxide film on a surface of a copper alloy of  claim 7 ,
 wherein an electric resistivity of the copper alloy is equal to or more than 1.7 μΩcm and equal to or less than 7 μΩcm. 
 
     
     
       9. The method of forming an oxide film on a surface of a copper alloy of  claim 6 ,
 wherein the step of diffusing atoms of the element is performed by heating the copper alloy and the layer of the oxide at a temperature from 200° C. to 600° C. 
 
     
     
       10. The method of forming an oxide film on a surface of a copper alloy of  claim 9 ,
 wherein the heating is performed for 5 minutes to 2 hours. 
 
     
     
       11. A method of forming an oxide film on a surface of a copper alloy, comprising the steps of:
 providing a copper alloy consisting essentially of copper and manganese; and 
 diffusing atoms of manganese to a surface of the copper alloy so as to form an oxide film comprising manganese on the surface of the copper alloy, 
 wherein a concentration of the manganese in the copper alloy is more than 0.1 and not more than 20 atomic percentage and within a solubility limit of the manganese in the copper. 
 
     
     
       12. The method of forming an oxide film on a surface of forming an oxide film on a surface of  claim 11 ,
 wherein a thickness of the oxide film is 1 to 10 nm. 
 
     
     
       13. The method of forming an oxide film on a surface of  claim 12 ,
 wherein an electric resistivity of the copper alloy is equal to or more than 1.7 μΩcm and equal to or less than 7 μΩcm. 
 
     
     
       14. The method of forming an oxide film on a surface of  claim 11 ,
 wherein the diffusion is performed by heating the copper alloy at a temperature from 200° C. to 600° C. 
 
     
     
       15. The method of forming an oxide film on a surface of  claim 14 ,
 wherein the heating is performed for 5 minutes to 2 hours. 
 
     
     
       16. A method of forming an oxide film on a surface of a copper alloy, comprising the steps of:
 providing a copper alloy consisting essentially of copper and manganese; 
 forming a layer of the copper alloy on a layer of a silicon oxide; and 
 diffusing atoms of manganese to an interface between the layer of the copper alloy and the layer of the silicon oxide so as to form an oxide film including manganese, copper and silicon at the interface, 
 wherein a concentration of the manganese in the copper alloy is more than 0.1 and not more than 20 atomic percentage and within a solubility limit of the manganese in the copper. 
 
     
     
       17. The method of forming an oxide film on a surface of  claim 16 ,
 wherein a thickness of the oxide film is 1 to 10 nm. 
 
     
     
       18. The method of forming an oxide film on a surface of  claim 17 ,
 wherein an electric resistivity of the copper alloy is equal to or more than 1.7 μΩcm and equal to or less than 7 μΩcm. 
 
     
     
       19. The method of forming an oxide film on a surface of  claim 16 ,
 wherein the step of diffusing atoms of manganese is performed by heating the copper alloy at a temperature from 200° C. to 600° C. 
 
     
     
       20. The method of forming an oxide film on a surface of  claim 19 ,
 wherein the heating is performed for 5 minutes to 2 hours. 
 
     
     
       21. An electrical conductor comprising:
 a copper alloy conductor layer; and   a diffusion layer on a surface of the conductor layer, the diffusion layer comprising at least one element from the copper alloy, the at least one element having a diffusion coefficient in copper that is larger than the self-diffusion coefficient of copper;   wherein a concentration of the at least one element diffused in the copper is within a range of about 0.1 atomic percentage to about 20 atomic percentage.   
     
     
       22. The electrical conductor of claim 21, wherein atoms of the at least one element are diffused into the copper to form an oxide film including the atoms in the diffusion layer. 
     
     
       23. The electrical conductor of claim 22, wherein a thickness of the oxide film is within a range of about 1 nm to about 10 nm. 
     
     
       24. The electrical conductor of claim 21, wherein an electric resistivity of the diffusion layer is within a range of about 1.7 μΩcm to about 7 μΩcm. 
     
     
       25. A method of forming an electrical connector, comprising:
 forming a copper alloy conductive layer; and   forming a protective layer by diffusing at least one element from the copper alloy onto at least one surface of the conductive layer to form a diffusion layer, the at least one element having a diffusion coefficient that is larger than the self-diffusion coefficient of copper;   wherein a concentration of the at least one element in the copper is in a range of about 0.1 atomic percentage to about 20 atomic percentage.   
     
     
       26. The method of claim 25, wherein diffusing comprises forming an oxide film in the diffusion layer, the oxide layer comprising the at least one element. 
     
     
       27. The method of claim 26, wherein a thickness of the oxide film is within a range of about 1 nm to about 10 nm. 
     
     
       28. The method of claim 25, wherein an electric resistivity of the diffusion layer is within a range of about 1.7 μΩcm to about 7 μΩcm. 
     
     
       29. The method of claim 25, wherein diffusing comprises heating the surface of the wiring layer to a temperature in a range of about 200° C. to about 600° C. 
     
     
       30. The method of claim 29, wherein the heating is performed for a time in a range of about 5 minutes to about 2 hours. 
     
     
       31. The method of claim 29, wherein the heating is performed in an Ar gas atmosphere. 
     
     
       32. The method of claim 31, wherein the Ar gas atmosphere comprises oxygen at a level of approximately 100 ppm. 
     
     
       33. A method of forming an electrical connector, comprising:
 forming a wiring layer comprising a copper alloy; and   heating the wiring layer to form a diffusion layer comprising at least one element from the copper alloy, the at least one element having a diffusion coefficient in copper that is larger than the self-diffusion coefficient of copper;   wherein a concentration of the at least one element in the copper is in a range of about 0.1 atomic percentage to about 20 atomic percentage.   
     
     
       34. The method of claim 33, wherein heating the wiring layer comprises forming an oxide film in the diffusion layer, the oxide layer comprising the at least one element. 
     
     
       35. The method of claim 34, wherein a thickness of the oxide film is within a range of about 1 nm to about 10 nm. 
     
     
       36. The method of claim 33, wherein an electric resistivity of the diffusion layer is within a range of about 1.7 μΩcm to about 7 μΩcm. 
     
     
       37. The method of claim 33, wherein heating the wiring layer comprises heating the surface of the wiring layer to a temperature in a range of about 200° C. to about 600° C. 
     
     
       38. The method of claim 37, wherein the heating is performed for a time in a range of about 5 minutes to about 2 hours. 
     
     
       39. The method of claim 38, wherein the heating is performed in an Ar gas atmosphere. 
     
     
       40. The method of claim 39, wherein the Ar gas atmosphere comprises oxygen at a level of approximately 100 ppm. 
     
     
       41. The electrical conductor of claim 21, wherein the at least one element comprises one or more of the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd. 
     
     
       42. The method of claim 25, wherein the at least one element comprises one or more of the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd. 
     
     
       43. The method of claim 33, wherein the at least one element comprises one or more of the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd. 
     
     
       44. A method comprising:
 forming a copper alloy conductive layer on a silicon substrate, the copper alloy conductive layer comprising at least one element having a diffusion coefficient in copper that is larger than the self-diffusion coefficient of copper; and   heating the copper alloy conductive layer to form:
 a first oxide layer between the copper alloy conductive layer and the silicon substrate, the first oxide layer comprising the at least one element and silicon, and 
 a second oxide layer on a surface of the copper alloy conductive layer, the second oxide layer comprising the at least one element; 
   wherein a concentration of the at least one element in the copper alloy is in a range of about 0.1 atomic percentage to about 20 atomic percentage.   
     
     
       45. The method of claim 44, wherein the at least one element comprises one or more of the group consisting of Mn, Zn, Ga, Li, Ge, Sr, Ag, Ba, Pr and Nd. 
     
     
       46. The method of claim 44, wherein heating the wiring layer and the silicon oxide layer comprises heating the wiring layer and the silicon oxide layer to at least 400° C. 
     
     
       47. The method of claim 46, wherein the heating is performed for at least 30 minutes. 
     
     
       48. The method of claim 44, wherein the heating is performed in an Argon (Ar) gas atmosphere. 
     
     
       49. The method of claim 48, wherein the Ar gas atmosphere comprises oxygen at a level of approximately 100 ppm. 
     
     
       50. An electrical conductor comprising:
 a silicon substrate;   a conductor layer comprising a copper alloy formed on the silicon substrate, the copper alloy comprising at least one element having a diffusion coefficient in copper that is larger than the self-diffusion coefficient of copper;   a first oxide layer between the silicon substrate and the conductor layer, the first oxide layer comprising silicon and the at least one element diffused from the conductor layer; and   a second oxide layer on a surface of the conductor layer, the second oxide layer comprising the at least one element diffused from the conductor layer;   wherein a concentration of the at least one element in the copper alloy is in a range of about 0.1 atomic percentage to about 20 atomic percentage.   
     
     
       51. The electrical conductor of claim 50, wherein the first oxide layer has a thickness of less than or equal to about 8 nm. 
     
     
       52. The electrical conductor of claim 50, wherein the first oxide layer comprises a copper-manganese-silicon oxide. 
     
     
       53. The electrical conductor of claim 50, wherein the second oxide layer comprises a manganese oxide.