Semiconductor device and fabrication method employing a palladium-plated heat spreader substrate
US5973398A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 4, 1997 |
| Grant date | Oct 26, 1999 |
| Priority date | — |
| Expiry date | Nov 4, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/15311
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A semiconductor device and fabrication method are presented which employ a thermally conductive substrate having an outer layer of palladium. The substrate may be made of, for example, a metal such as copper. The substrate does not itself include layers of signal traces or bonding pads which function as device terminals, but provides a stiff backing for support of a flexible circuit which includes signal traces and bonding pads. An adhesive layer bonds the flexible circuit to the substrate. The outer layer of palladium has a desired surface roughness and chemical properties which improve the adhesion of the adhesive layer to the substrate. The substrate has opposed, substantially planar upper and underside surfaces. In one embodiment, the underside surface of the substrate has a die cavity, and the flexible circuit includes a set of conductors bonded to one side of a sheet of dielectric material (e.g., polyimide film). The sheet of dielectric material has an opening extending therethrough for receiving an upper surface of an integrated circuit. Each conductor has a first end which extends laterally across the film and into the opening and a second end which terminates at a bonding …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.