Silver-filled glass
US4401767A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 8, 1982 |
| Grant date | Aug 30, 1983 |
| Priority date | — |
| Expiry date | Mar 8, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24926
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A silver metallizing paste for attachment of silicon semi-conductive devices in lead-frame packages, specifically ceramic packages, which is less expensive than a gold preform but useable in hermetic packages, and provides better electrical and thermal conductivity, and higher bond strength, than silver polyimides. From 25 to 95% of silver is blended with a low-melting glass, preferably one having 95-96% PbO, and a paste or ink is formed with a suitable vehicle at 75-85% solids. Use of the paste follows conventional practice. Selection of Ag:glass ratio depends on the type of die bonding to be used. The paste is particularly useful in MOS technology, where low contact resistance is required, and also finds applications as a solder substitute and bonding chip capacitors. It is most advantageous in attachment of larger-area integrated circuits in that stress cracking associated with the gold-silicon eutectic is avoided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.