Fluxless solder attachment of a microelectronic chip to a substrate
US6375060B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jul 19, 2000 |
| Grant date | Apr 23, 2002 |
| Priority date | — |
| Expiry date | Jul 19, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/1581
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A chip bonding location of a microelectronic chip is joined to a substrate bonding location of a substrate using a metallic solder in the absence of a flux. Surface contamination and oxide are first removed from the chip bonding location and from the substrate bonding location. The joining is accomplished by positioning the microelectronic chip and the substrate in a facing contact with the chip bonding location and the substrate bonding location in registry in a contact region. A heating element is disposed adjacent to and below the chip bonding location and the substrate bonding location to form an assembly. There is no flux present in the assembly in the contact region. The assembly is placed into an oven having a non-oxidizing environment. The chip bonding location and the substrate bonding location are joined by heating the assembly to a preheating temperature of less than a melting temperature of the solder, and thereafter reflowing the solder by locally heating the contact region to a reflow temperature of greater than the melting temperature of the solder using the heating element, permitting the solder in the contact region to melt for a reflow period of time above the mel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.