Heatsink and package structure for wirebond chip rework and replacement
US5757073A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 13, 1996 |
| Grant date | May 26, 1998 |
| Priority date | — |
| Expiry date | Dec 13, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49147
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A direct chip attach to heatsink structure is shown and described which implements rework when the chip must be removed and replaced. A laminated heatsink includes a metal heatsink with a foil layer adhered to the chip attachment surface with the assembly secured to a carrier at a cutout opening therein that defines the chip attach site. The adhesive, either a dry film adhesive or a pressure sensitive adhesive, secures foil layer to heatsink and provides the interface of separation when a chip must be removed and replaced. By peeling the foil away from the heatsink, the foil, chip and non-reworkable die attach adhesive are removed as a unit, leaving no chip attach adhesive residue at the attachment site to be scraped or abraded away. The replacement chip can be installed either by directly installing with new die attach adhesive or by first restoring the foil layer prior to chip installation. The foil may be applied over the entire surface of the heatsink or may be patterned to provide the laminated foil coating only beneath the chip attach site. Further, the foil and heatsink may be of dissimilar metals to impart varying characteristics, such as a solderable surface to an aluminum…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.