Laser furnace and method for zone refining of semiconductor wafers
US4780590A · kind A · utility
39Cited by
5References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Nov 21, 1985 |
| Grant date | Oct 25, 1988 |
| Priority date | — |
| Expiry date | Nov 21, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC30B13/28
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
A method of zone refining a crystal wafer (116 FIG. 1) comprising the steps of focusing a laser beam to a small spot (120) of selectable size on the surface of the crystal wafer (116) to melt a spot on the crystal wafer, scanning the small laser beam spot back and forth across the surface of the crystal wafer (116) at a constant velocity, and moving the scanning laser beam across a predetermined zone of the surface of the crystal wafer (116) in a direction normal to the laser beam scanning direction and at a selectible velocity to melt and refine the entire crystal wafer (116).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.