Method for applying flux to ball grid array package
US5482736A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 4, 1994 |
| Grant date | Jan 9, 1996 |
| Priority date | — |
| Expiry date | Aug 4, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/181
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A method and apparatus for applying flux to a series of metallization contacts or plated contact pad a substrate exposed by an apertured solder mask, employs a compressible transfer pad. A central flux pick-up area is formed on the transfer pad bottom surface. The bottom surface may be spherical and may include a cylindrical post onto which a predetermined amount of flux is transferred, such as by dipping the pick-up area into a reservoir of semi-liquid paste flux. The transfer pad is then positioned over and compressed on the solder mask such that the picked up flux on the flux pick-up area of the transfer pad is pressure forced by compression of the transfer pad through apertures in the solder mask directly and successively into all the series of depressions formed on the substrate until all the depressions are substantially filled with flux. After breaking away and removal of the transfer pad, a solder ball or bonder applied solder is deposited in each flux-containing depression to form a metallurgical bond between the ball and a plated contact pad or package metallization such as a lead frame.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.