Microwave/millimeter wave circuit structure with discrete flip-chip mounted elements, and method of fabricating the same
US5629241A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1995 |
| Grant date | May 13, 1997 |
| Priority date | — |
| Expiry date | Jul 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/0315
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A microwave/millimeter wave circuit structure supports discrete circuit elements by flip-chip mounting to an interconnection network on a low cost non-ceramic and non-semiconductor dielectric substrate, preferably Duroid. The necessary precise alignment of the circuit elements with contact pads on the substrate network required for the high operating frequencies is facilitated by oxidizing the interconnection network, but providing the contact pads from a non-oxidizable material to establish a preferential solder bump wetting for the pads. Alternately, the contact bumps on the flip-chips can be precisely positioned through corresponding openings in a passivation layer over the interconnection network. For thin circuit substrates that are too soft for successful flip-chip mounting, stiffening substrates are laminated to the circuit substrates. In a self-contained antenna application in which two of the circuit substrates are laminated together, with an antenna on one side and circuitry on the other side, a metallic ground plane between the substrates also serves a stiffening function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.