Flip-chip assembly with improved interconnect
US7732253B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 2006 |
| Grant date | Jun 8, 2010 |
| Priority date | — |
| Expiry date | Jun 29, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/30107
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present invention provides a unique way of connecting a flip-chip die to a substrate. Initially, metallic posts are formed on the flip-chip die and solder bumps are placed on the substrate where the metallic post will ultimately connect to the substrate. The tip layer of flash gold, tin, or other wettable electroplated material is applied to the tips of the metallic posts to prevent oxidation and enhance wettability. The sides of the metallic posts are allowed to oxidize to reduce wettability. To attach the flip-chip die to the substrate, the flip-chip die is initially positioned over the substrate, such that the metallic posts align with and come into contact with the solder bumps. Once the flip-chip die is in place over the substrate, the substrate and the flip-chip are heated to cause the solder bumps to reflow and bond to the tip layers of the metallic posts.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.