Diffusion isolation layer for maskless cladding process
US4786674A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 10, 1986 |
| Grant date | Nov 22, 1988 |
| Priority date | — |
| Expiry date | Jan 10, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05K2203/0743
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a maskless metal cladding process for plating an existing metallurgical pattern, a protective layer is utilized to isolate those areas of underlying metallurgy on which additional metal plating is not desired. The layer acts as an isolation barrier to protect the underlying metallurgy from deposition and subsequent diffusion of the heavy metal overlay. The composition of the protective layer is selected as one having sufficient mechanical integrity to withstand process handling and support the gold overlay and having the thermal integrity to withstand the high temperatures reached during metal sputtering and diffusion processes. The isolation barrier layer has an organic component as a binder which thermally decomposes, either in a heating step before metal deposition or during the diffusion cycle, leaving no carbonaceous residue but leaving an inert, inorganic standoff to support the metal. After diffusion of the metal, the remaining inorganic standoff layer, overlying metal and any undiffused metal remaining on the non-patterned substrate is easily removed by a standard technique, such as ultrasonics.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.