Gold wire for semiconductor element connection
View Patent ↗A gold wire for semiconductor element connection having high strength and bondability. The connection has a limited amount of at least one element selected from calcium and rare earth elements, and a limited amount of at least one element selected from a group consisting of titanium, vanadium, chromium, hafnium, niobium, tungsten, and zirconium. The incorporation of a suitable amount of palladium or beryllium is preferred. The incorporation of calcium and rare earth element can improve the strength and young's modulus of a gold wire, and the incorporation of titanium and the like can reduce a deterioration in the roundness of press-bonded shape of press-bonded balls in the first bonding caused by the incorporation of calcium and rare earth elements. The bonding wire can simultaneously realize mechanical properties and bondability capable of meeting a demand for a size reduction in semiconductor and a reduction in electrode pad pitch.
1. A gold wire for semiconductor element connection which comprises:
one or more elements selected from Ca and rare earth elements in total amounts of at least 0.001% by mass but not more than 0.02% by mass;
one or more elements selected from a group consisting of Ti, V, Cr, Hf, Nb, W and Zr in total amounts of at least 0.0005% by mass but not more than 0.01% by mass;
a Pr content of at least 0.0016% by mass but not more than 0.0079% by mass, and
a balance of gold and unavoidable impurities, wherein
crystal grains are <111>-oriented along a longitudinal direction of the wire, and
said wire is formed to a reduction in cross-sectional area of 99.8% or more as compared to an ingot thereof.
2. The gold wire for semiconductor element connection according to claim 1 , comprising at least one element selected from a group consisting of Ca, La, Ce, Pr, Nd and Sm in total amounts of more than 0.005% by mass but not more than 0.02% by mass, wherein a content of Ca is 0.0025% or less by mass.
3. The gold wire for semiconductor element connection according to claim 1 , further comprising Pd of 0.001% or more by mass but not more than 2% by mass.
4. The gold wire for semiconductor element connection according to claim 1 , further comprising Be of 0.0002% or more by mass but not more than 0.0011% by mass.
5. The gold wire for semiconductor element connection according to claim 1 , wherein said gold wire has an elastic modulus of 85 GPa or more in the longitudinal direction thereof.
6. The gold wire for semiconductor element connection according to claim 3 , further comprising Be of 0.0002% or more by mass but not more than 0.0011% by mass.
7. The gold wire for semiconductor element connection according to claim 3 , wherein said gold wire has an elastic modulus of 85 GPa or more in the longitudinal direction thereof.
8. The gold wire for semiconductor element connection according to claim 4 , wherein said gold wire has an elastic modulus of 85 GPa or more in the longitudinal direction thereof.
9. The gold wire for semiconductor element connection according to claim 6 , wherein said gold wire has an elastic modulus of 85 GPa or more in the longitudinal direction thereof.
10. The gold wire for semiconductor element connection according to claim 1 , wherein said wire is formed into a press-bonded ball with a defect rate between 2.6% and 9.7%.
11. The gold wire for semiconductor element connection according to claim 1 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
12. The gold wire for semiconductor element connection according to claim 2 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
13. The gold wire for semiconductor element connection according to claim 3 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
14. The gold wire for semiconductor element connection according to claim 4 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
15. The gold wire for semiconductor element connection according to claim 5 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
16. The gold wire for semiconductor element connection according to claim 6 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
17. The gold wire for semiconductor element connection according to claim 7 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
18. The gold wire for semiconductor element connection according to claim 8 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
19. The gold wire for semiconductor element connection according to claim 9 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.
20. The gold wire for semiconductor element connection according to claim 10 , further comprising at least one element selected from a group consisting of In, Ga and Ni in total amounts of 0.005% or less by mass.