Casting of high purity oxygen free copper
US6192969A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 22, 1999 |
| Grant date | Feb 27, 2001 |
| Priority date | — |
| Expiry date | Mar 22, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB22D7/10
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method and apparatus are provided for making high purity and preferably oxygen free substantially void free and inclusion free copper castings such as billets from high purity copper. The castings are particularly useful to make sputtering targets used in sputtering deposition processes in the fabrication of electronic components. The method comprises melting high purity copper in a covered crucible using a non-contaminating heating source such as a coil induction furnace. The melted copper in the crucible is solidified using a specially controlled cooling procedure wherein the bottom of the crucible is cooled so that molten copper is maintained on top of solidified and solidifying copper until the copper is solidified. In a preferred apparatus and method, the furnace and crucible, which is disposed between the coil of the furnace and contains molten copper, are positioned above a cooling jacket and the crucible passed continuously downwardly through the opening in the cooling jacket cooling the lower portion of the crucible. A reduced heat is maintained in the furnace to heat the upper portion of the crucible within the coil and maintain a layer of molten copper over the copper …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.