Forming solder balls on substrates
US7604153B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 7, 2006 |
| Grant date | Oct 20, 2009 |
| Priority date | — |
| Expiry date | Jul 10, 2027 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/1581
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A mask (stencil) having cells (openings) is disposed on a surface of a heater stage, and is then filled (printed) with solder paste. Then a substrate is assembled to the opposite side of the mask. Then the solder paste is reflowed. This may be done partially inverted. Then the mask is separated from the substrate, either before or after cooling. Solder balls are thus formed on the substrate, which may be a semiconductor wafer. A biased chuck urges the substrate into intimate contact with the mask. A method for printing the mask with solder paste is described. Methods of forming high aspect ratio solder bumps (including balls and reflowable interconnect structures) are described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.