Method and apparatus for solder deposition
US4801069A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1987 |
| Grant date | Jan 31, 1989 |
| Priority date | — |
| Expiry date | Mar 30, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/043
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and an apparatus for depositing solder onto component lead pads of a printed wiring board. Solder preforms which are multi-layer, solder containing members are positively biased against the pwb pad which is then introduced into a vapor phase environment defining a temperature gradient between approximately ambient and the temperature of a saturated vapor of a first selected fluid which defines a primary saturated vapor phase with a boiling point which is greater than the melting point of solder. A second fluid having a boiling point which is lower than the first fluid is utilized to generate a secondary vapor blanket in order to prevent excessive loss of the fluid defining the primary vapor phase. The pwb is heated according to a controlled process in which the temperature of the pwb is continuously monitored. The apparatus is a pressure fixture usable for vapor phase solder deposition of a pwb and comprises a first and a second member which are removably fastened together in an opposed relationship with a pwb is disposed between the first and the second members.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.