Solder retention ring for improved solder bump formation
US6085968A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 22, 1999 |
| Grant date | Jul 11, 2000 |
| Priority date | — |
| Expiry date | Jan 22, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/14
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method of forming solder bumps on a wafer. The wafer includes at least one substrate, a plurality of solder-wettable pads and a solder wettable retention ring about the periphery of the wafer. The method of forming solder bumps includes forming a non-solder-wettable mask on the wafer which includes a plurality of apertures which align with the solder-wettable pads, and the solder wettable retention ring surrounds the mask. The mask and wafer are positioned within an aperture of a stencil so that the solder wettable retention ring aligns with a gap between the periphery edge of the mask and an inside edge of the aperture of the stencil. Solder paste is applied to the mask so that the solder paste fills the apertures of the mask and the gap. The solder paste is reflowed forming solder bumps on the pads and a solder ring on the solder wettable retention ring. The mask is removed after formation of the solder bumps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.