Solder self-alignment methods
US5249733A · kind A · utility
35Cited by
5References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1992 |
| Grant date | Oct 5, 1993 |
| Priority date | — |
| Expiry date | Jul 16, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/14
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A solder self-alignment process for aligning a semiconductor chip (13) with, and bonding the chip to, a substrate (12) is preformed in an atmosphere rich in gaseous formic acid, at least during the melting step. It is preferred that the formic acid atmosphere be maintained during the self-alignment step and the step of cooling and hardening the solder elements (23). With this feature, one can completely avoid the use of any solid or liquid fluxes and avoid the consequences of such use. Nonetheless, the molten solder elements (23) dependably bond to the bonding surfaces and vertically align themselves.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.