Process for the self fractionation deposition of a metallic layer on a workpiece
US4876114A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1988 |
| Grant date | Oct 24, 1989 |
| Priority date | — |
| Expiry date | Aug 29, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B6/24
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A process for the evaporation deposition of a layer of metal on a workpiece is described in which a charge of a metal is placed in a crucible formed of a material having a vapor pressure lower than the vapor pressure of the metal at a selected temperature, a shield is placed between the workpiece and the crucible, and the crucible is then heated to a first temperature sufficient to melt said charge, but insufficient to cause substantial evaporation of said charge following which the crucible is heated to a second temperature level for a time sufficient to fractionally distill the charge and sublime or vaporize any non-metallic contaminants in said charge and finally the crucible is heated to a third temperature sufficient to evaporate the charge at a selected rate at which time the shield is removed from between the cricuble and the workpiece to permit evaporant from the charge to coat the workpiece.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.