Method of accommodating in volume expansion during solder reflow
US7086147B2 · kind B2 · utility
36Cited by
9References
1Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 29, 2004 |
| Grant date | Aug 8, 2006 |
| Priority date | — |
| Expiry date | Aug 20, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49171
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Solder balls such as, low melt C4 solder balls, undergo volume expansion during reflow, such as may occur during attachment of chip modules to a PCB. Where the solder balls are encapsulated, expansion pressure can cause damage to device integrity. A volume expansion region in the semiconductor chip substrate beneath each of the solder balls accommodated this volume expansion. Air-cushioned diaphgrams, deformable materials and non-wettable surfaces may be used to permit return of the solder during cooling to its original site. A porous medium with voids sufficient to accommodate expansion may also be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.