Method for producing polycrystalline silicon rod, polycrystalline silicon rod, and polycrystalline silicon mass
US10377636B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 27, 2015 |
| Grant date | Aug 13, 2019 |
| Priority date | — |
| Expiry date | Oct 21, 2035 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B29/06
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A polycrystalline silicon rod is synthesized by the Siemens method (S101). After the polycrystalline silicon rod is covered from above with a plastic bag whose inner surface has been washed, and housed in the plastic bag in a reactor (S103), the polycrystalline silicon rod is removed out of the reactor (S104), and heat-sealed and stored in an enclosed state (S105). According to the present invention, steps conventionally considered as essential, such as washing, etching, and water washing, are not always necessary, and therefore the concentrations of fluorine ions, nitrate ions, and nitrogen dioxide ions remaining on the surface can each be less than 0.2 ppbw. In addition, by covering with the plastic bag, the metal contamination levels decrease significantly. Moreover, when the handling according to the present invention is performed, surface contamination hardly proceeds even if the polycrystalline silicon rod is stored for a long period.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.