Crystal diameter control system
US6226032A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 1997 |
| Grant date | May 1, 2001 |
| Priority date | — |
| Expiry date | Jun 10, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B15/26
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A system controls the diameter of both a neck region and a full diameter region of a monocrystalline rod being pulled from molten material held in a crucible. The system uses a video camera viewing light reflected from a meniscus around the rod where the rod emerges from a melt surface of the molten material. The video camera has a zoom lens for enlarging an image of the meniscus during growth of the neck of the rod and for reducing an image of the meniscus during growth of a full diameter body of the rod. A computer controlling a pull rate for the neck growth of the rod is rapidly responsive to a count of total camera pixels illuminated by the image of the meniscus during neck growth.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.