Alumina substrate and method of manufacturing same
US4045412A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1975 |
| Grant date | Aug 30, 1977 |
| Priority date | — |
| Expiry date | Jul 14, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K1/0306
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An improved alumina substrate comprising alumina and magnesium oxide has a surface finish of no more than 0.05 .mu.m CLA and a density of at least 3.90 g/cm.sup.3 in an as-fired condition and is composed of alumina grains which are sufficiently grown to have straight grain boundaries and flat surfaces to form a surface of the substrate. The improved substrate is produced by firing a green sheet having a high content of raw material powder and a density of more than 2.60 g/cm.sup.3 at a temperature of 1525.degree. to 1650.degree. C. The green sheet with high density is formed by the process of aggregating an organic agent and a high purity alumina powder by dry milling and casting the resultant slip.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.