Method for connecting a die to electrically conductive traces on a flexible lead-frame
US5631191A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 15, 1995 |
| Grant date | May 20, 1997 |
| Priority date | — |
| Expiry date | May 15, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/15173
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A polymer lead-frame is made from a flexible substrate with flexible conductive traces. The generally square lead-frame has diagonal cutouts partially extending from the corners towards the center, as well as a central hole that lies within a footprint of the die. The die is bonded directly to the lead frame, preferably with anisotropic, electrically conductive adhesive. The die is placed with the lead frame in a fixture. A holding force is applied to secure the die and, if necessary, a curing force is applied during a cure cycle. The fixture allows transport of the assembly to a curing oven and allows application of the curing force. The die has contact pads characterized by a non-planar, non-bump-like surface with concavities having depths of at least about one-seventh the diameter of conductive particles in the anisotropic conductive adhesive.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.