Process for producing high-purity ruthenium
US6036741A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 16, 1998 |
| Grant date | Mar 14, 2000 |
| Priority date | — |
| Expiry date | Jul 16, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC22B61/00
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A process comprises forming ruthenium tetroxide by blowing ozone-containing gas into crude ruthenium powder while hypochlorous acid is being added to the powder, allowing a hydrochloric acid solution to absorb the ruthenium tetroxide, evaporating the solution to dryness, and roasting the RuOCl.sub.3 crystals thus obtained in a hydrogen atmosphere. Thus a high-purity ruthenium material for thin film deposition, typically sputtering targey, is obtained which contains less than 1 ppm each of alkali metal elements, less than 1 ppm each of alkaline earth metal elements, less than 1 ppm each of transition metal elements, less than 10 ppb each of radioactive elements, a total of less than 500 ppm of carbon and gaseous ingredient elements, the material having a purity of ruthenium of at least 99.995% excluding the gaseous ingredient elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.