Solder ball and method for producing same
US6517602B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2001 |
| Grant date | Feb 11, 2003 |
| Priority date | — |
| Expiry date | Mar 14, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S75/953
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A solder ball having a diameter of 1.2 mm or less, a dispersion of a diameter distribution of 5% or less and sphericity of 0.95 or more, an area ratio of the maximum dendrite being 80% or less of a cross section including a center of the solder ball, comprises a first additional element of 0.5-8 mass % of Ag and/or 0.1-3 mass % of Cu, and 0.006-10 mass %, in total, of at least one second additional element selected from the group consisting of Bi, Ge, Ni, P, Mn, Au, Pd, Pt, S, In and Sb, the balance being substantially Sn. The solder ball is produced by a uniform droplet-spraying method comprising the steps of vibrating a melt of a solder alloy in a crucible under pressure to force the melt to drop through orifices of the crucible; permitting the melt dropping through the orifices to become spherical droplets in a non-oxidizing gas atmosphere; and rapidly solidifying them.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.