Method for controlling solder bump shape and stand-off height
US5926731A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 2, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Jul 2, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P70/50
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A conductor (112) and method for attaching a surface mount device to the conductor (112), in which solder bumps (16) formed by the method are characterized as being accurately located on the conductor (112) and having a bump height and shape that provides stress relief during thermal cycles, minimizes bridging between adjacent bumps (16), allows penetration of cleaning solutions for removing undesirable residues, and enables the penetration of mechanical bonding and encapsulation materials between the chip and its substrate (10). Such benefits are achieved by forming the conductor (112) of a nonsolderable material, on which a solderable pillar (114) is formed. The pillar (114) is selectively formed to have a shape that determines the distribution and height of the solder bump (16) on the conductor (112).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.