Method for circumferential dimension measuring and control in crystal rod pulling
US4350557A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 27, 1981 |
| Grant date | Sep 21, 1982 |
| Priority date | — |
| Expiry date | Apr 27, 2001 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B15/26
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The circumference of a crystal rod is monitored and controlled during the rod growing process by providing relative rotation between the growing crystal rod and a melt of the crystal material as the rod is being pulled from the melt according to the Czochralski method, and by using a radiation-sensitive control system for adjusting growth conditions of the rod in response to variations in a radiation signal which is indicative of the circumferential dimension of the rod. An electronic circuit integrates the radiation signal over each complete rotation of the rod, thereby eliminating unnecessary adjustment of the growth conditions in response to diametric variations of the rod which recur regularly in each rotation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.