Method for pulling a single crystal
US7264674B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 2004 |
| Grant date | Sep 4, 2007 |
| Priority date | — |
| Expiry date | May 6, 2025 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T117/1072
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
An apparatus is used to pull a single crystal, wherein a flow of an inert gas to the single crystal to be grown, a pressure in an apparatus body, and a temperature environment are always kept constant by keeping a melt level at a prescribed position in spite of changes in volume of a quartz crucible between batches and thermal deformation of the quartz crucible, so that high quality single crystals can be pulled. The apparatus has a reference reflector arranged inside an apparatus body, a level position measuring unit to measure an actual level position by detecting a mirror image position of the reference reflector reflected in the melt surface using a one-dimensional CCD camera arranged outside the apparatus body, a crucible ascent speed adjustment value calculating unit to calculate an adjustment value of the crucible ascent speed based on an output from the level position measuring unit, an adjustment value adding unit to add the adjustment value to the crucible ascent speed, and a level position controlling unit to control the level position in the crucible by controlling a motor for crucible lifting based on an output from the adjustment value adding means to control the cruc…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.