Ball bumping substrates, particuarly wafers
US6609652B2 · kind B2 · utility
13Cited by
70References
11Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 24, 2001 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | Jan 30, 2022 |
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 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 method for printing the mask with solder paste is described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.