Bonding wire for semiconductor
It is an object of the present invention to provide a multilayer wire which can accomplish both ball bonding property and wire workability simultaneously, and which enhances a loop stability, a pull strength, and a wedge bonding property. A semiconductor bonding wire comprises a core member mainly composed of equal to or greater than one kind of following elements: Cu, Au, and Ag, and an outer layer formed on the core member and mainly composed of Pd. A total hydrogen concentration contained in a whole wire is within a range from 0.0001 to 0.008 mass %.
1. A semiconductor bonding wire comprising:
a core member mainly composed of at least any one of Cu, Au and Ag;
an outer layer formed on the core member and mainly composed of Pd,
wherein a total concentration of hydrogen contained in a whole wire is within a range from 0.0001 to 0.004 mass %.
2. The semiconductor bonding wire according to claim 1 , wherein the total concentration of hydrogen is within a range from 0.0001 to 0.0008 mass %.
3. The semiconductor bonding wire according to claim 1 , wherein the total concentration of hydrogen is a concentration of hydrogen contained in the bonding wire measured by Thermal Desorption Spectrometry (TDS).
4. The semiconductor bonding wire according to claim 1 , wherein in a Thermal Desorption Spectrometry (TDS) measurement at a temperature rising speed of 100 to 300° C./h, a ratio of a concentration of hydrogen, detected within a temperature range from 150 to 500° C. in TDS, to the total concentration of hydrogen detected within a temperature range from a room temperature to 900° C. is equal to or larger than 50%.
5. The semiconductor bonding wire according to claim 1 , wherein the outer layer has a thickness being within a range from 0.01 to 0.2 μm.
6. The semiconductor bonding wire according to claim 1 , wherein in the outer layer, a region having a concentration of Pd relative to a total concentration of metal elements being equal to or larger than 80 mol % has a thickness of 0.003 to 0.08 μm.
7. The semiconductor bonding wire according to claim 1 , further comprising a diffusion layer formed between the outer layer and the core member and having a concentration gradient,
wherein the diffusion layer has a thickness of 0.003 to 0.15 μm.
8. The semiconductor bonding wire according to claim 1 , wherein the main constituent of the core member is Cu or Au, and the core member also contains at least one of Pd, Ag and Pt as an element, and a total concentration of the elements in the core member is within a range from 0.01 to 2 mol %.
9. The semiconductor bonding wire according to claim 1 , wherein the main constituent of the core member is Cu, and the core member contains at least one of Al, Sn, Zn, B and P as an element for alloy, and a total concentration of the elements for alloy in a whole wire is within a range from 0.0001 to 0.05 mol %.
10. The semiconductor bonding wire according to claim 1 , wherein
the core member is mainly composed of Cu, and
the semiconductor bonding wire further comprises a concentrated layer formed at an outer surface side of the outer layer and containing at least either one of Ag and Au.
11. The semiconductor bonding wire according to claim 10 , wherein the concentrated layer has a concentration gradient of at least either one of Ag and Au, in a wire diameter direction.
12. The semiconductor bonding wire according to claim 10 , wherein a concentration of Pd at an outermost surface of the concentrated layer is within a range from 20 to 90 mol %.
13. The semiconductor bonding wire according to claim 10 , further comprising a Pd single-metal layer in the outer layer.
14. The semiconductor bonding wire according to claim 10 , wherein the outer layer including the concentrated layer has a thickness of 0.02 to 0.4 μm.
15. The semiconductor bonding wire according to claim 10 , wherein a total concentration of Pd, Ag and Au is within a range from 0.4 to 4 mol %.
16. The semiconductor bonding wire according to claim 10 , wherein a ratio of a total concentration of Ag and Au to a concentration of Pd is within a range from 0.001 to 0.4.
17. The semiconductor bonding wire according to claim 1 , wherein the core member is mainly composed of Cu,
the semiconductor bonding wire further comprises an intermediate layer formed between the core member and the outer layer, and wherein
at least either one of Ag and Au is concentrated in the intermediate layer.
18. The semiconductor bonding wire according to claim 17 , wherein the intermediate layer has a concentration gradient of at least either one of Ag and Au, in a wire diameter direction.
19. The semiconductor bonding wire according to claim 18 , wherein the intermediate layer includes a region where Pd, Cu, and at least either one of Ag and Au coexist, the region having a concentration gradient of at least three of the elements in a wire diameter direction.
20. The semiconductor bonding wire according to claim 17 , wherein a maximum total concentration of Ag and Au in the intermediate layer is within a range from 30 to 90 mol %.
21. The semiconductor bonding wire according to claim 17 , wherein a total thickness of the outer layer and the intermediate layer is within a range from 0.02 to 0.5 μm.