Metal coating for indium bump bonding
US9190377B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 2011 |
| Grant date | Nov 17, 2015 |
| Priority date | — |
| Expiry date | May 4, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/811
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process of making efficient metal bump bonding with relative low temperature, preferably lower than the melting point of Indium, is described. To obtaining a lower processing temperature (preferred embodiments have a melting point of <100° C.), a metal or alloy layer is deposited on the indium bump surface. Preferably, the material is chosen such that the metal or alloy forms a passivation layer that is more resistant to oxidation than the underlying indium material. The passivation material is also preferably chosen to form a low melting temperature alloy with indium at the indium bump surface. This is typically accomplished by diffusion of the passivation material into the indium to form a diffusion layer alloy. Various metals, including Ga, Bi, Sn, Pb and Cd, that can be used to form a binary to quaternary low melting point alloy with indium. In addition, diffusion of metal such as Sn, Sn—Zn into Ga—In alloy; Sn, Cd, Pb—Sn into Bi—In alloy; Cd, Zn, Pb, Pb—Cd into Sn—In alloy can help adjust the melting point of the alloy.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.