Silver bonding wire for semiconductor device containing indium, gallium, and/or cadmium
The present invention provides a bonding wire which can satisfy bonding reliability, spring performance, and chip damage performance required in high-density packaging. A bonding wire contains one or more of In, Ga, and Cd for a total of 0.05 to 5 at %, and a balance being made up of Ag and incidental impurities.
1. A bonding wire for a semiconductor device containing one or more of In, Ga, and Cd for a total of 0.05 to 5 at %, and a balance being made up of Ag and incidental impurities,
wherein the bonding wire contains no more than 5 at % of Au.
2. The bonding wire for a semiconductor device according to claim 1 , further containing one or more of Ni, Cu, Rh, Pd, and Pt for a total of 0.01 to 5 at %.
3. The bonding wire for a semiconductor device according to claim 2 , further containing one or more of Be, B, P, Ca, Y, La, and Ce for a total of 10 to 300 at ppm.
4. The bonding wire for a semiconductor device according to claim 2 , wherein a total atomic percentage of In, Ga, and Cd in a layer extending in a depth direction of 0 to 10 nm from a wire surface is equal to or larger than twice the same in a layer extending in the depth direction of 20 to 30 nm from the wire surface.
5. The bonding wire for a semiconductor device according to claim 2 , wherein an average grain size in a section in a direction perpendicular to a wire axis is 0.2 to 3.5 μm.
6. The bonding wire for a semiconductor device according to claim 2 , wherein in measurement results obtained by measuring crystal directions in a section of the bonding wire, the section containing a wire axis and being parallel to the wire axis, the ratio of a crystal direction <100> having an angular difference of 15 degrees or less from a longitudinal direction of the bonding wire is between 30% and 100%, both inclusive, in terms of an area percentage.
7. The bonding wire for a semiconductor device according to claim 2 , wherein an average total atomic percentage of at least one or more elements selected from the group consisting of In, Ga, and Cd relative to a total of metallic elements in a layer extending in a depth direction of 0 to 1 nm from a wire surface is equal to or larger than 1.2 times the average total atomic percentage in a layer extending in a depth direction of 1 to 10 nm from the wire surface.
8. The bonding wire for a semiconductor device according to claim 1 , further containing one or more of Be, B, P, Ca, Y, La, and Ce for a total of 10 to 300 at ppm.
9. The bonding wire for a semiconductor device according to claim 8 , wherein a total atomic percentage of In, Ga, and Cd in a layer extending in a depth direction of 0 to 10 nm from a wire surface is equal to or larger than twice the same in a layer extending in the depth direction of 20 to 30 nm from the wire surface.
10. The bonding wire for a semiconductor device according to claim 8 , wherein an average grain size in a section in a direction perpendicular to a wire axis is 0.2 to 3.5 μm.
11. The bonding wire for a semiconductor device according to claim 8 , wherein in measurement results obtained by measuring crystal directions in a section of the bonding wire, the section containing a wire axis and being parallel to the wire axis, the ratio of a crystal direction <100> having an angular difference of 15 degrees or less from a longitudinal direction of the bonding wire is between 30% and 100%, both inclusive, in terms of an area percentage.
12. The bonding wire for a semiconductor device according to claim 8 , wherein an average total atomic percentage of at least one or more elements selected from the group consisting of In, Ga, and Cd relative to a total of metallic elements in a layer extending in a depth direction of 0 to 1 nm from a wire surface is equal to or larger than 1.2 times the average total atomic percentage in a layer extending in a depth direction of 1 to 10 nm from the wire surface.
13. The bonding wire for a semiconductor device according to claim 1 , wherein a total atomic percentage of In, Ga, and Cd in a layer extending in a depth direction of 0 to 10 nm from a wire surface is equal to or larger than twice the same in a layer extending in depth direction of 20 to 30 nm from the wire surface.
14. The bonding wire for a semiconductor device according to claim 1 , wherein an average grain size in a section in a direction perpendicular to a wire axis is 0.2 to 3.5 μm.
15. The bonding wire for a semiconductor device according to claim 1 , wherein in measurement results obtained by measuring crystal directions in a section of the bonding wire, the section containing a wire axis and being parallel to the wire axis, the ratio of a crystal direction <100> having an angular difference of 15 degrees or less from a longitudinal direction of the bonding wire is between 30% and 100%, both inclusive, in terms of an area percentage.
16. The bonding wire for a semiconductor device according to claim 1 , wherein an average total atomic percentage of at least one or more elements selected from the group consisting of In, Ga, and Cd relative to a total of metallic elements in a layer extending in a depth direction of 0 to 1 nm from a wire surface is equal to or larger than 1.2 times the average total atomic percentage in a layer extending in a depth direction of 1 to 10 nm from the wire surface.
17. The bonding wire for a semiconductor device according to claim 1 , wherein the bonding wire does not contain Au.
18. A bonding wire for a semiconductor device containing one or more of In, Ga, and Cd for a total of 0.05 to 5 at %, and a balance consisting essentially of Ag and incidental impurities.