Offset bending of curvaceously planar radiating leadframe leads in semiconductor chip packaging
US4743956A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 15, 1986 |
| Grant date | May 10, 1988 |
| Priority date | — |
| Expiry date | Dec 15, 2006 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12361
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of forming leadframes for use in manufacturing semiconductor chips starts with fabricating a plurality of leadframes by metal stamping or etching leadframe patterns into a flat ribbon of conductive material. The leadframe patterns include a plurality of outwardly radiating leads, inner radiating leads, and a central perimeter for interconnecting the outwardly and inner radiating leads. The outwardly radiating leads are arranged in groups, each of which are directed along planar perpedicular coordinates. The inner radiating leads have 180 degrees turns in the plane of the leadframe. The inner radiating leads are then successively bent at an acute angle and parallel to the plane of said leadframe so that the inner radiating leads are offset from the plane of the leadframe. The bending is performed in such a manner that each of the leads are formed with a stable spring force for effective bonding to corresponding semiconductor chip pads.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.