Circuit units, substrates therefor and method of making
US5276423A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1991 |
| Grant date | Jan 4, 1994 |
| Priority date | — |
| Expiry date | Nov 12, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/16195
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A layer of ceramic material such as alumina is plasma-deposited on a sheet member such as molybdenum or a composite laminate of molybdenum and graphite or other material of low thermal expansion to form a circuit unit substrate having a thick, adherent, electrically-insulating coating on a light, rigid and thermally-conducting base. Thick and thin film materials are deposited and fired on the insulating coating to provide conductors, insulators or resistors or the like in a circuit unit. The materials of the sheet member and of the insulating coating are selected to have matching thermal expansion coefficients so that the substrate remains flat and free of bowing during the firing of the thick and thin film materials. The plasma-deposited electrically-insulating layer is sealed to prevent moisture absorption during use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.